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HomeMy WebLinkAboutCouncil Packet - 6/5/2023CITY OF %�64TERLOO IOWA THE CITY COUNCIL OF WATERLOO, IOWA WORK SESSION TO BE HELD AT Harold E. Getty Council Chambers Monday, June 5, 2023 4:00 PM RULES FOR WORK SESSION PUBLIC COMMENT Iowa Code Chapter 21 gives the public the right to attend council meetings, but it does not require cities to allow public participation except during public hearings.The city council shall not receive any public comment during a work session. Roll Call. Agenda, as proposed or amended. 4:00 p.m. Update from Grow Cedar Valley. Submitted by: Noel Anderson, Director Approx. 4:30 Discussion of a Nutrient Reduction Study. p.m. Submitted by: Brian Bowman, Treatment Operations Supervisor ADJOURNMENT Kelley Felchle City Clerk Page 1 of 164 GROW CedarValley Business. Community. Waterloo City Council Work Session — June 5, 2023 Cary Darrah CEO Mike Mallaro Grow Cedar Valley Board Chair Stephanie Detweiler Workforce Solutions Coordinator Nicole Sallis Director of Communications Lisa Skubal Vice President, Economic Development Agenda 1. Opening Remarks 2. External Marketing & Business Growth 3. Talent Initiatives 4. Communications/Marketing Initiatives 5. TechWorks Campus 6. Closing Remarks M. Mallaro L. Skubal S. Detweiler N. Sallis C. Darrah C. Darrah 360 Westfield Ave, Suite 300, Waterloo, IA 50701 ♦ Ph: (319) 232-1156 ♦ Fax: (319) 233-4580 www.growcedarvalley.com Page 2 of 164 Waterloo City Council Update NOVEMBER 1, 2022 THROUGH APRIL 3 GROW CedarValley Business. Community./)arary� Grow Cedar Valley 360 Westfield Ave., Ste 300 Waterloo, IA 50701 319/232.1156 www.growcedarvalley.com Cary Darrah, President & CEO ca ry©a g rowceda rva I ley.com Page 3 of 164 Waterloo Economic Development Results A fundamental part of economic development work is to attract new businesses and support existing businesses to diversify the economy and reduce the region's vulnerability. Grow Cedar Valley (GCV) works very closely with the City's economic development staff and many other public and private partners with these collaborative efforts. Marketing Lead Generation • Domestic Lead Generation. Goal is to identify 4 qualified leads from a Winter 2022/23 initiative. Goal was met. The figures on the right breaks down the data. Targeted companies include durable and non -durable goods manufactures, logistics and distribution and chip manufacturers. The latter was included because of the recent federal priority to encourage more domestic manufacturing of computer chips but we haven't been successful in that endeavor due to the chip sector focusing more on mega sites with larger population clusters. Two of the companies identified and virtually met with were Illinois based. GCV suggested next step is an in person meeting in Illinois this summer which both companies where open to the request. GCV is currently identifying and trying to schedule meetings for the week of June 19th in Illinois with these two companies & others. • Site Selection Guild Conference - GCV staff participated in individual and group discussion with 26 site selection consultants during this 2 day conference the end of March. The Guild selects a certain number of economic developers to meet with the top 60 site selection consultants in the US for two days. Other Iowa economic development organizations also attending were representatives from the Iowa Economic Development Authority, Quad Cities First, and Des Moines Partnership. GCV's next engagement with the Site Selection Guild will be on August 29th with a 2 hour virtual meeting session with consultants at 15 minute intervals for an engagement with 7 site selection consultants. Some of those who are expected to be part of the virtual session are consultants GCV has submitted project proposals. Domestic Lead Generation (November 2022- March 2023) Compiled Companies - 330 Goal - Identify 4 qualified leads Completion - 4 qualified leads identified coupled with virtual meetings. # outreaches - 990 For more information and questions contact. lisa®a growcedarvalley.com Page 4 of 164 Waterloo Economic Development Results Cont. Opportunities/Projects New* Total Active Capital Job External Existing Investment Potential Projects Business Projects $369.9M 1,701 6 0 $844.9M 3,363 31 5 *Includes new projects occurring between the months of November 2022 through April 2023; some projects occurring during this timeline minus those that may have eliminated Waterloo during that same period. Note: Job Potential and Capital Investment won't correlate; some projects don't provide both or either figure. Information available depends on the project's stage; some projects are more advanced than others. New Projects 0 Total Active Projects Prospect Proposals/ Info sent to leads (does not represent multiple communications) Existing Business Services to Waterloo Companies 8 Business Services Information/services provided included discussion on expansion/retention and/or barriers such as workforce; connecting entreprenours and small business connections. External Prospect Engagement - Waterloo (11/22 - 4/23) 2 External Prospect Vlsits 4 Virtual Prospect Introductions Page 5 of 164 Waterloo Economic Development Results Cont. The Cedar Valley Manufacturers Association Grow Cedar Valley began partnering with industry leaders in March '22 to relaunch the Cedar Valley Manufacturing Association. GCV is part of ongoing quarterly meetings to support the below priorities manufacturers in Waterloo and surrounding areas have identified. Priority Areas Identified by Manufacturers • Support the alignment of the IGNITE program between lower and higher education. • Provide educational support for upcoming workforce starting at grade school to ensure the demographics of the manufacturing workforce match the demography of the community. The workforce shortage isn't expected to improve over the next several years and is even worse for manufacturers as it is estimated 20% of manufacturing workforce will retire over the next 5-10 years while incoming workforce is short to fill the demand unless GVMA does something about it. CVMA's leadership has developed a plan and will be executing with support from Grow Cedar Valley, Hawkeye Community College, Waterloo Career Center, University of Northern Iowa, and Iowa State University's Center for Industrial Research and Service. WATERLOO REGIONAL AIRPORT Airport Advocacy GCV's advisory committee helps guide the Airport Director, Airport Board and the city on airport service, industry trends and introductions and conversations with other carriers. Committee support includes: • Advisory committee leadership (David Deeds) and ALO's Air Service consultant attended an air service conference in October with scheduled meeting with Avelo, Allegiant, American, Southwest and Spring along with additional informal meetings with Sun Country Land Link and Skywest. These conversations and presence at the conference were continued conversation from the previous year's conference. • In June 2023, David Deeds along with ALO's Air Service consultant plan to attend the 2023 Jump Start conference in Milwaukee. Confirmed meetings already with American, Sun Country and Southwest airlines. There have been additional requests for meetings that won't be finalized till the end of May. Page 6 of 164 Workforce Solutions Telling our Story In December 2022, along with Cedar Valley Regional Partnership, Grow Cedar Valley participated in Iowa Economic Development Authority partners program by creating an ad on the State's "This is Iowa" quality of life website to promote the Cedar Valley Region as a place to live and work. According to IEDA officials the banner ad had the highest impressions for a co-op ad program at 12,203 during the month of December along with 27 click throughs. Do want to LIVE MORE and your Cost of Living? CLICK HERE Try the Cost of Living Ca h_444(&(--q4--,-,,,- Coasters In December 2022, the limited edition coasters that first appeared 5 years earlier was brought back to promote the Cedar Valley's Live the Valley website along with the then new quality of life magazine that was also published in December both in print and digital. The coasters were distributed to dining establishments, bars and hotels with one hospital using the coasters as welcome packets to medical doctors, nurses and technicians that are being recruited by the hospital. By the Numbers - Facebook Engagements Grow Cedar Valley and Live The Valley combined Facebook Stats unless noted otherwise. 67,801 reach, 34,400 engagements, 304 net new followers,12,050 - 3 second video views (GCV's FB) Followers Breakdown by Age:18-24 - 1.8%; 25-34 - 21.5%; 35-44 - 32.5%; 45-54 - 22.1% Gender: 70.8% women; 29.2% men Top Cities (GCV FB) - Waterloo - 1.1K; Cedar Falls -1K; Waverly - 140; Denver 65 GCV FB - Celebrating Grow Diversity Campaign (February/March 2023): Reach - 27,039; Impressions - 32,029. Page 7 of 164 Placemaking/Image One of the priority areas from GCV's strategic planning is enhancing the Image of the Cedar Valley, making it a place of choice for individuals/workforce and businesses. In 2022 Grow Cedar Valley partnered with INRCOG and John Deere Waterloo operations to create a scope of work to address vision of enhancing the Cedar River - connecting downtown Cedar Falls and downtown Waterloo. Vandewalle & Associates was hired to assemble Phase One Scope of Work for this visioning effort. Phase Two is underwritten by Grow Cedar Valley and approved by the GCV board of directors to be completed by December 2023. This scope includes a plan to implement a portion of the vision. As shared previously while GCV/Deere/INRCOG were going through the original visioning for Phase One, Governor Reynolds released a grant opportunity- Destination Iowa - for regional, transformational projects designed to help "move the needle" on Placemaking efforts. The Cedar Valley team worked with guidance from IEDA regarding the pieces of the proposed project that might fit in the Governor's project guidelines but was not awarded the grant. While the outcome of this grant application was disappointing, it helped clarify many pieces of the vision and provide momentum to continue with the Phase Two scope of work that is currently underway. What we know is the communities that invest in recreational and experience opportunities for the workforce and their families are going to be the communities that are successful in attracting and retaining talent. Page 8 of 164 Cedar Valley Leadership Institute The CVLI Class of 2022-2023 is made up of 42 emerging leaders who represent 33 businesses. This class has provided community service projects for several organizations throughout the Cedar Valley. • Retrieving Freedom • Cedar Falls CAPS • Woodruff Construction • Veridian Credit Union • Trinity Industries • VGM Homelink • John Deere • Unity Point Health • InVision Architecture • Farmers State Bank • Cedar Falls Schools • The VGM Group • CUNA Mutual • First Interstate Bank • Northwestern Mutual • Peters Construction Added Benefits Other Services to the City of Waterloo Times the City's directory listing was viewed on the Grow Cedar Valley website (over the last 12 months) • Community Bank & Trust • Junior Achievement • Tri-County Head Start • Dupaco Credit Union • University of Northern Iowa • Leader Valley • City of Cedar Falls • RSM US LLP • Grundy National Bank • Western Home Communities • Waterloo Public Library • Community Foundation of Northeast Iowa • Amperage Marketing & Fundraising • Waterloo Convention Center • Vine Valley Real Estate • CBE Group • ACCEL Group Ribbon Cuttings for Waterloo Businesses. Jobs posted by the City of Waterloo on the Grow Cedar Valley job board have been viewed 281 times in the past 12 months. Government Affairs & Advocacy Grow Cedar Valley staff attends Waterloo Council Meetings on a regular basis and, as needed, will speak on projects relevant to the growth and development of the City of Waterloo. Current legislative priorities approved can be found on GCV's website. GROW 1* CedarValley Government Affairs There have been five events including Friday Forums between December and April including with engagement of 187 people: Pre -session Legislative Reception, Legislative Session Preview, Annual Iowa Talent Poll w/Dustin Miller and Friday Forum presentations by Speaker Grassley, Senator Dotzler, Senator Dawson, chair of the Senate Ways and Means Committee and Assistant Senate Majority Leader Senator Koelker. Page 9 of 164 TechWorks Campus TechWorks continues to implement the mission of expanding manufacturing 4.0 priorities by supporting workforce training programs with Hawkeye Community College and the University of Northern Iowa. HCC began renovation on the 2nd floor of the Tech I building in preparation for the Robotics and Automation training center to open in 2023. This training center is for future workforce development in response to the manufacturing industry demands for upskilling the regional workforce. UNI and HCC have embraced several collaborative opportunities that train both workforce and industry to help companies be more competitive in the changing manufacturing environment. Grow Cedar Valley moved their offices to accommodate the renovation and recently met with HCC about the possibility of purchasing the 2nd floor through a federal grant that allows property acquisition. Additionally, TechWorks transferred the out lots of the campus to the City of Waterloo for future development and growth that will contribute to the improvements being made to the Cedar River Marina, Marriott Hotel and Grand Crossing. These advancements were all made possible with the good working relationship between TechWorks, John Deere, the Environmental Protection Agency, and the City of Waterloo - all contributing to reaching the redevelopment goals of the TechWorks Campus and the Cedar Valley region. tON Techl orks CAMPUS 1928 was the year the building was built 6 stories at 25,000 square feet each $8M valued industrial campus Deere and Company donated to TechWorks in 2007 1st "high rise" manufacturing facility in Waterloo Page 10 of 164 Meet Grow Cedar Valley Staff Elevate the economic vitality of our businesses and communities Cary Darrah President & CEO PH 319/888-4903 Steve Firman Director of Government Affairs PH 319!239-6067 Jim Schaefer Director of Investor Relations PH 3191838-4906 Bonita Cunningham Events Coordinator PH 319BS8-4902 Barb Leistad Office Manager PH 319/888-4901 Lisa Rivera Skubal, CEcD Vice President of Economic Development PH 319/868-4907 ext. 4907 Stephanie Detwei ler Workforce Solutions Coordinator PH 319/888-4904 Nicole 5allis Director of Communications PH 319/888-4909 Sandi Sommerfelt Vice President of Operation PH 319/888-4911 GROW.,ing the CedarValley Business. Community. /ppo-rGHr,; Page 11 of 164 City of Waterloo — Waste Management Services Wastewater Treatment Plant - Nutrient Reduction Study & Near -Term Upgrades City Council Working Session June 5, 2023 Brian Bowman, WMS Operations Director L94Lt CITY OF WATERLOO Waste Management Page 12 of 164 I Goals of this Presentation: Update and Educate Status of the DNR-required nutrient reduction plan at the WWTP Need to increase capacity at the WWTP Page 13 of 164 WWTP History 1990s: Most of the facilities were constructed Two plants were constructed side -by -side —20 year life (+/-) 2012: One plant was "mothballed" because the capacity wasn't needed and it was costly to operate. 2017/18: Major planning effort in conjunction with DNR required nutrient removal study Phased WWTP upgrades recommended Ultimately combine the two plants to provide capacity while meeting DNR requirements for Nutrient Reduction $101 million in three phases Page 14 of 164 Phased Implementation of Recommended Plan Near -Term (2018-2023) $55.3 million Nutrient Removal and Immediate Needs Mid -Term (2023-2028) $29.5 million Equipment Replacement Long -Term (2028+) $15.3 million Hydraulic Capacity $101 million of capital improvements identified (2018 dollars) 2019-2022 Biosolids Improvements ~ $18 million $83 million still remaining to be spent (2018 dollars) Page 15 of 164 2023 Nutrient Study (Required Update by DNR) Revisited the 2018 planning document Similar analysis, costs were updated Take -Home Points: WWTP capacity needs to be expanded or growth/industry/jobs will be impacted Lowest cost plan is still to combine the plants while achieving nutrient reductions per DNR requirements -$94 million total cost (2023 dollars) Next phase is to increase capacity while removing nutrients - $46 million (2023 dollars) Timing is becoming critical as the next phase will take 5 years to provide the needed capacity Page 16 of 164 Financial Impact -Part #1 Rate increases would be required to implement the projects outlined in the nutrient reduction study, in addition to the projects currently underway that are required by the consent decree. Projected rate increases to fund the additional required debt service are outlined below: Fiscal Year Additional Debt Service Required Annual Rate Increase Required FYE2024 $350,000 8% FYE2025 $900,000 9% FYE2026 $1,900,000 12% FYE2027 $4,700,000 24% FYE2028 $2,100,000 10% FYE2029 $2,400,000 10% Totals $12,350,000 73% These improvements would require rate increases totaling 73% over the 6 years of implementation. Waterloo has a very diverse population. The sewer costs for the largest minority group would exceed 1.5% of median household income beginning in 2027 and could exceed it by as much as 29% by 2029. Page 17 of 164 Financial Impact -Part #2-Worst Case Scenerio The City has large industrial users that would be negatively impacted by these rate increases If the largest user reduced their water/sewer use by 30%, the rate increases applied to all customers outlined above would need to double for the first few years with adjustments after those years. That would cause the sewer cost for all population groups to exceed 1.5% of median household income starting in 2026 and could exceed it by as much as 44% by 2029. ARENA Additional Debt Service Required Annual Rate Increase Required FYE2024 $350,000 10% FYE2025 $900,000 10% FYE2026 $1,900,000 15% FYE2027 $4,700,000 24% FYE2028 $2,100,000 10% FYE2029 $2,400,000 10% Totals $12,350,000 79% Page 18 of 164 What is our plan for the Financial impacts? ■ Harness Strand Associates to seek Grants for infrastructure projects like this ■ Seek no interest loans for Design Phase of Project ■ Work with SRF on Loan Forgiveness possibilities ■ Variables and unknowns exist today with future revenues from Renewable Gas Projects that may offset rate increases Page 19 of 164 Requested Council Action Approve the nutrient reduction plan (same plan as was approved 5 years ago but updated) for submittal to DNR Provide funds to implement interim upgrades at the Satellite Facility to avoid capacity issues and DNR compliance with Design Standards Begin the next phase of WWTP upgrades in FY25; with a goal to begin design in July 2024 Page 20 of 164 DRAFT-(05.03.23) Report for City of Waterloo, Iowa Nutrient Reduction Study Prepared by: STRAND ASSOCIATES, INC.° 910 West Wingra Drive Madison, WI 53715 www.strand.com May 2023 STRAND ASSOCIATES® Excellence in Engineering Since 1946 Page 21 of 164 DRAFT-(05.03.23) TABLE OF CONTENTS Page No. or Following NUTRIENT REDUCTION STUDY Existing Treatment Facilities 1 Influent and Effluent Data 5 Nutrient Reduction Goals 21 Evaluation of Operational Changes to Enhance Nutrient Removal 21 Wasteload and Flow Forecasts 22 Evaluation of Treatment Technologies to Meet Nutrient Reduction Goals 26 Implementation and Budgetary Considerations 32 Sewer Budget Impact 34 Financial Information 35 TABLES Table 1 Design Flows and Loadings 1 Table 2 Easton Influent Flow Summary 6 Table 3 Satellite Influent Flow Summary 7 Table 4 Combined Influent Flow Summary 8 Table 5 Influent Flow Summary 10 Table 6 Influent BOD Loading Summary 10 Table 7 Influent TSS Loading Summary 11 Table 8 Influent TKN Loading Summary 11 Table 9 Influent TN Loading Summary 12 Table 10 Influent TP Loading Summary 14 Table 11 Return Flow Sampling Summary —May and June 2017 16 Table 12 Return Flow Loading Estimates 16 Table 13 Effluent NH3-N 18 Table 14 Effluent TN 19 Table 15 Effluent TP 20 Table 16 Current and Projected Populations 22 Table 17 Projected 2045 Flows 24 Table 18 Projected Future Loads —Combined Influent 25 Table 19 Estimated Maximum Month Loads 25 Table 20 Design Flows and Loads 26 Table 21 BNR Present Worth Analysis Summary 28 Table 22 BNR Nonmonetary Considerations Study 29 Table 23 Recommended Near -Term Improvements for Nutrient Removal 33 Table 24 WWTP Budget Impact Summary for Near -Term Improvements 34 Table 25 Projected Rate Increases 35 Table 26 Projected Rate Increases with Reduced Industrial Use 35 Page 22 of 164 TABLE OF CONTENTS Continued DRAFT-(05.03.23) FIGURES Page No. or Following Figure 1 Wastewater Treatment Plant Process Flow Diagram 1 Figure 2 Influent Flow 9 Figure 3 Easton Influent Flow 23 APPENDICES APPENDIX A—NPDES PERMIT APPENDIX B-2018 NUTRIENT REDUCTION STUDY ii Page 23 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study This Nutrient Reduction Study (Study) was prepared as required to meet the June 1, 2023, compliance schedule in the City of Waterloo's (City's) Iowa Department of Natural Resources (IDNR) National Pollutant Discharge Elimination System (NPDES) Permit No. 0790001. The purpose of this study is to evaluate the feasibility and reasonableness of reducing the amounts of total nitrogen (TN) and total phosphorus (TP) discharged into the Cedar River by the City's wastewater treatment plants (WWTPs). EXISTING TREATMENT FACILITIES A. Background The City operates three WWTPs: an anaerobic lagoon that treats wastewater from a food processing plant before discharge into the City sanitary sewer system, the Satellite WWTP that was designed to treat the industrial wastewater from the northeast portion of the City (including the lagoon effluent), and the Easton Avenue (Easton) WWTP that was designed to treat the wastewater from all other sources in the City. The Satellite and Easton WWTPs are located at the same site and share several facilities as described later in this section and they both discharge to the Cedar River. A flow diagram of the Satellite and Easton WWTPs is presented in Figure 1. The design flows and loadings are presented in Table 1. The City's NPDES Permit No. 0790001 is included in Appendix A. Easton Plant Satellite Plant Wastewater Flow Design Average Flow (DAF) 20.4 MGD 6.7 MGD Design Average Wet Weather Flow (Maximum Month) 26.7 MGD 8.1 MGD Design Maximum Wet Weather Flow (Maximum Day) 36.0 MGD 11.1 MGD Design Peak Hourly Wet Weather Flow (PHF) 36.0 MGD 11.1 MGD Wastewater Loading 5-Day Biochemical Oxygen Demand (BOD5)—Average Day 24,000 lb/day 38,800 lb/day BOD5—Maximum Month 30,000 lb/day 58,000 lb/day BOD5—Maximum Day 70,000 lb/day 80,400 lb/day Total Kjeldahl Nitrogen (TKN)-Average Day 4,500 lb/day 7,025 lb/day TKN-Maximum Month 7,500 lb/day 13,550 lb/day TKN-Maximum Day 13,200 lb/day 19,300 lb/day Total Suspended Solids (TSS)—Average Day 18,000 lb/day 38,300 lb/day TSS—Maximum Month 25,000 lb/day 58,000 lb/day TSS—Maximum Day 66,000 lb/day 80,400 lb/day Notes: MGD=million gallons per day Ib/day=pounds per day Table 1 Design Flows and Loadings Prepared by Strand Associates, Inc.® 1 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 24 of 164 FLOW EQUAL! ZATION BASIN EASTON PRIMARY CLARI FI ER5 AND PRIMARY SLUDGE PUMP BUILDING. EQUAUZ 4TIOPI OVERFLOW TO CEDAR RIVER EQUALIZATION OVERFLOW TO SATELLITE ACTIVATED SATELLITE 'FINAL CLARIFIERS AND RAS BUILDING SATELLITE EFFLUENT SAMPLING AND METERING STRUCTURE EASTON EFFLUENT SAMPLING AND METERING STRUCTURE UV BUILDING EASTON ACTIVATED SLUDGE TANKS NITRIFIED MIXED LIQUOR RECYCLE THICKENING BUILDING WAS PUMP BUIL]LITG & WAS TANKS DEWATERINiG EWUFLDING SLTR]GE STORAGE TANK LEGEND E&,STON PRIMARY INFLUENT/EFFLUENT MIXED LIQUOR SECONDARY EFFLUENT EQUALIZATION FLOW SATELLITE INFLUENT RETURN ACTIVATED SLUDGE FROM SATELLITE COLLECTION SYSTEM BAR SCREEN BUILDING SATELLITE LIFT STAT!ON RAW WASTEWATER PUMP BUILDING ANAEROBIC DIGESTERS TAS BUILDING & TO.S TANKS WASTEWATER TREATMENT PLANT PROCESS FLOW DIAGRAM NUTRIENT REDUCTION STUDY CITY OF WATERLOO, IOWA STRAND ASSOCIATES® FIGURE 1 4463.001 • DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Wastewater service to the City was provided by the Easton WWTP alone until the Satellite WWTP was constructed in 1996. At that time, the Easton WWTP was a trickling filter WWTP with primary clarifiers, trickling filters, intermediate clarifiers, roughing filters, and final clarifiers. Following startup of the Satellite WWTP in 1998, a major upgrade to the Easton WWTP was undertaken, including the demolition or abandonment of much of the existing facility and the construction of new primary and final clarifiers along with the conversion to activated sludge biological treatment. While the Satellite WWTP was designed to treat the industrial wastewater from a portion of the City, it has been out of service for several years and is currently only used for storage during peak flow events. In March 2020, the City completed a project to convey equalization basin overflow to the Satellite WWTP activated sludge tanks for storage and blending with the Easton WWTP secondary effluent. While influent flow from the Satellite and Easton WWTP collection systems are measured separately, under current WWTP operation, the influent flow from the Satellite WWTP collection system is combined with the Easton WWTP influent flow upstream of the Easton WWTP anoxic selector basin and is treated using the Easton WWTP. Both the Satellite and Easton WWTPs are currently designed for TN removal using the Modified Ludzak-Ettinger (MLE) process. B. Easton WWTP Influent flow to the Easton WWTP passes through two 3/4-inch bar screens and enters an influent wet well where it is pumped with five raw wastewater pumps to the grit removal system. Flow is measured with magnetic flowmeters. The Bar Screen Building and the Raw Wastewater Pump Building were both constructed concurrently with the construction of the Satellite WWTP in 1996. Following pumping, wastewater flows through two vortex grit removal basins located in the Raw Wastewater Pump Building. A sampler located downstream of the influent pumps and upstream of grit removal is used to collect Easton WWTP influent samples. When flows to the Easton WWTP exceed the WWTP's hydraulic capacity, a portion of the flow can be diverted to two flow equalization basins located on the northern portion of the site using two downward opening weir gates in the grit chamber effluent channel. These basins were constructed in 1996 and have a total storage capacity of approximately 20 million gallons (MG). Wastewater stored in these basins can be returned to the Easton WWTP influent wet well when the WWTP has capacity to treat the flow. During extreme high -flow events, an overflow/bypass structure to the Cedar River can be used to discharge wastewater from the equalization basins. After grit removal, flow is discharged by gravity to two circular primary clarifiers. Three primary sludge pumps located in the Primary Sludge Pump Building are used to pump sludge from the primary clarifiers to the blended sludge tanks or to the primary sludge transfer tanks at Structure 170. The primary sludge pumps were replaced in approximately 2017. Additional modifications to the primary sludge handling system were implemented in 2022, including an intermediate wet well and pumping system that can be used to thicken primary sludge while reducing pumping issues in the long primary sludge force main. Scum that is removed from the primary clarifiers is stored in a mixed scum tank and pumped to the thickened waste activated sludge (TWAS) tanks. The primary clarifiers and Primary Sludge Pump Building were constructed in 1998. Prepared by Strand Associates, Inc.® 2 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 26 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study The activated sludge system uses the MLE process for biochemical oxygen demand (BOD), ammonia, and TN removal and includes an anoxic selector basin as well as four elongated rectangular aeration basins. The primary effluent flows into the anoxic selector basin and is mixed with the Satellite WWTP influent flow. The anoxic selector basin is mixed using coarse bubble air diffusers with a goal of maintaining anoxic conditions. This basin is also used to split the now combined flow between the four aeration basins. Each aeration basin consists of one anoxic zone with coarse bubble diffusers for mixing and three aerobic zones with fine bubble diffusers. Aeration is provided by three multistage centrifugal blowers. Flow from each of the basins is mixed in an outlet box which contains three mixed liquor (ML) recycle pumps to recycle nitrified ML to the front of the activated sludge system for alkalinity recovery and TN removal. The ML recycle pumps are constant -speed submersible pumps and do not allow operators to adjust the recycle flow based on flow and loading conditions, other than by turning more pumps on or off.. ML from the aeration tanks flow to four center -feed circular final clarifiers before joining the Satellite WWTP flow for disinfection in the Ultraviolet (UV) Building. Five return activated sludge (RAS) pumps located in the RAS Building return settled sludge to the primary effluent pipe upstream of the anoxic selector basin. Secondary effluent passes through a Parshall flume for flow measurement and is sampled before disinfection. Disinfection is provided by two UV disinfection systems operated in series. The UV disinfection system and building were installed in 2013. Following disinfection, effluent flows to one of two outfalls. A river diffuser is used under normal river level conditions (Outfall 801). When the Cedar River level is high (river flow greater than 8,500 cubic feet per second [cfs]), four effluent pumps located in the effluent lift station are used to pump the effluent to a shoreline discharge (Outfall 011). C. Satellite WWTP As described earlier, the Satellite WWTP was designed to treat mostly industrial wastewater flows from a dedicated collection system from the northeast side of the City. The Satellite WWTP has been out of service since approximately 2012. Flows from the Satellite WWTP collection system flow to the Satellite WWTP lift station at the Easton WWTP, which is on the north end of the Raw Wastewater Pump Building. Here the raw wastewater is sampled and pumped to the Magnesium Hydroxide Building using three submersible pumps. In the Magnesium Hydroxide Building, WWTP staff can add alkalinity to the raw wastewater by feeding magnesium hydroxide. Downstream of the Magnesium Hydroxide Building, wastewater discharges to the Easton WWTP primary effluent piping at the Satellite WWTP bypass structure. Under current WWTP operation, Satellite WWTP influent is diverted to the Easton WWTP through this bypass structure and no raw wastewater continues to the Satellite WWTP activated sludge system. Prepared by Strand Associates, Inc.® 3 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 27 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study The Satellite WWTP activated sludge system uses the MLE process and includes two trains, each made up of two elongated rectangular tanks. An anoxic zone is provided in each train using coarse bubble diffuser mixing. Aeration is provided by fine bubble diffusers and five multistage centrifugal blowers. Two ML recycle pumps are used to return nitrified ML through the internal tank wall to the anoxic zone for denitrification and alkalinity recovery. ML from the aeration tanks flows to four center -feed circular final clarifiers. Five RAS pumps located in the Satellite WWTP RAS Building return settled sludge to the raw wastewater piping upstream of the activated sludge tanks. Secondary effluent passes through a Parshall Flume for flow measurement and is sampled before being combined with the Easton WWTP secondary effluent at the UV Building upstream of UV disinfection. D. Sludge Processing Waste activated sludge (WAS) is pulled from the Easton and Satellite RAS headers for wasting using automated control valves and flow meters. The WAS is pumped to WAS storage tanks until it is pumped to three gravity belt thickeners (GBTs) for thickening. Scum from the final clarifiers is also pumped to the WAS tanks. The WAS tanks are mixed using coarse -bubble aeration supplied from two positive displacement blowers. TWAS is pumped from the GBTs to the three blended sludge storage tanks using three TWAS transfer pumps. In these tanks, the TWAS is mixed with the primary sludge from the Easton WWTP and primary scum to provide a consistent feed to the anaerobic digesters. Primary sludge is pumped to the Primary Sludge Transfer Tanks at the WAS Building or directly to the Blended Sludge Storage Tanks using three rotary lobe pumps. Sludge from the Primary Sludge Transfer Tanks is pumped to the Blended Sludge Storage tanks using two Primary Sludge Transfer Pumps. Before pumping, the primary sludge passes through two sludge grinders. Mixing is provided in the TWAS tanks with three submersible mixers. Sludge is pumped from the blended sludge storage tanks to the anaerobic digesters using three progressing cavity pumps. The anaerobic digestion system uses a temperature -phased anaerobic digestion (TPAD) process with two thermophilic digesters and four mesophilic digesters. Two of the mesophilic digesters are equipped with floating covers for digester gas storage. The digesters are heated using a hot water boiler system. The TPAD system produces Class A biosolids. Digested biosolids are pumped from the digesters to the biosolids storage tanks where it is stored until it is dewatered using two centrifuges and one belt filter press (BFP). Centrate from the dewatering process is discharged to a centrate equalization tank and pumped to the head of the plant. The dewatered biosolids are then land applied. Prepared by Strand Associates, Inc.® 4 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 28 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study INFLUENT AND EFFLUENT DATA A. Baseline Influent Data The City currently measures influent flow from the Satellite collection system separate from the Easton WWTP influent flow. As discussed earlier, these flows are combined at the Easton WWTP anoxic selector basin under current WWTP operation. Flow to the equalization basin is measured by summing the discharge flow from the Easton raw wastewater pumps and subtracting the Easton influent flow. Flow that is returned from the equalization basin enters the Easton influent wet well and is included in the Easton influent flow. Easton influent samples currently include process return flows, including dewatering centrate, GBT filtrate, and tank drains. Estimates of these return flow loads and their impact of Easton influent loadings are presented later in this section. Tables 2 through 4 present the 2017 through 2022 flow data by month for the Easton WWTP, Satellite WWTP, and combined influent. The average represents the average day flow for the entire month. "Min" and "Max" represent the lowest and highest day's total daily (24-hour average) flow during that month, respectively. The Easton influent flow presented in Table 2 (and included in the combined flow in Table 4) includes the flow diverted to the equalization basin and subtracts the return flow from the equalization basin to approximate the actual total wastewater flow that is conveyed to the Easton WWTP site each day. A chart of the Satellite and the adjusted Easton influent flow from 2017 to 2022 is presented in Figure 2. Prepared by Strand Associates, Inc.® 5 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 29 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 2 Easton Influent Flow Summary 2017 2018 2019 2020 2021 2022 Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max January 12.24 9.79 13.48 8.23 5.95 14.38 13.52 11.87 15.82 10.53 9.42 12.11 8.79 8.01 9.32 7.90 7.00 8.37 February 11.90 10.34 13.47 8.74 7.08 11.46 13.22 11.19 19.23 10.71 9.88 11.69 9.16 7.97 11.73 7.87 7.13 8.32 March 14.04 12.50 16.65 9.38 7.54 11.09 22.10 11.35 30.38 16.01 11.66 21.72 14.02 11.98 16.34 10.29 7.93 15.05 April 15.37 12.59 17.48 11.04 9.14 14.42 18.47 15.00 23.75 14.13 12.03 17.89 10.70 9.48 12.48 11.84 9.41 23.32 May 14.06 11.71 17.27 11.25 9.25 16.31 20.68 16.59 25.89 14.11 10.97 23.12 12.92 9.06 17.36 12.90 9.76 21.25 June 10.97 9.49 12.80 12.22 8.16 16.29 18.59 14.44 25.83 23.32 15.47 31.97 12.74 10.70 15.21 12.83 9.50 24.14 July 9.45 7.88 10.75 11.58 8.58 19.68 14.02 10.86 20.98 17.43 12.45 25.79 11.94 9.18 17.83 12.35 9.10 21.28 August 8.10 7.36 8.96 12.58 8.06 23.56 10.07 8.33 12.71 10.45 8.76 11.92 12.10 7.96 17.00 9.16 8.26 11.02 September 7.36 6.33 7.86 24.39 11.61 29.92 11.21 8.36 19.61 11.62 8.70 20.70 11.61 9.38 15.38 8.05 7.35 8.99 October November 8.52 5.64 11.75 25.29 15.79 30.67 22.80 17.49 13.12 28.41 10.40 8.44 22.57 11.42 9.55 14.61 7.33 6.51 9.50 7.80 6.53 8.74 16.37 13.43 12.07 11.17 13.37 10.71 9.12 16.99 11.92 10.38 15.68 8.12 7.02 12.43 December 7.14 5.87 7.87 14.03 10.03 24.65 11.59 9.39 13.46 9.41 8.06 10.50 9.10 6.62 12.60 7.63 7.19 8.98 Annual Average 10.58 - - 13.76 - - 15.25 - - 13.24 - - 11.37 - - 9.69 - - Minimum 7.14 5.64 - 8.23 5.95 - 10.07 8.33 - 9.41 8.06 - 8.79 6.62 - 7.33 6.51 - Maximum 15.37 - 17.48 25.29 - 30.67 22.10 - 30.38 23.32 - 31.97 14.02 - 17.83 12.90 - 24.14 Notes: Avg=average Min=minimum Max=maximum Prepared by Strand Associates, Inc.® 6 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 30 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 3 Satellite Influent Flow Summary 2017 2018 2019 2020 2021 2022 Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max January 3.14 1.65 3.96 2.93 1.12 3.76 3.11 2.14 3.99 2.65 1.38 3.51 2.82 2.35 3.22 2.75 1.14 3.42 February 3.29 2.08 4.00 2.90 1.53 3.87 3.09 2.23 3.70 2.74 1.85 3.30 2.84 1.37 3.58 2.78 1.14 3.20 March 3.00 1.48 3.71 2.94 1.28 3.80 3.40 2.33 3.97 3.39 2.81 1.77 3.46 2.50 0.18 3.21 April 3.30 2.02 4.50 2.96 1.87 3.67 3.18 2.10 4.04 2.06 0.15 3.37 2.77 2.27 3.17 2.71 1.89 3.80 May 3.15 1.07 4.15 2.86 1.79 3.77 3.25 1.95 4.11 2.19 0.12 3.53 0.45 - 3.09 2.90 1.31 4.11 June 3.26 1.83 4.28 3.24 2.01 4.18 3.18 1.98 3.92 3.14 1.43 5.97 - - 0.04 3.19 1.84 4.08 July 3.12 1.37 4.35 3.03 1.59 4.96 3.04 2.04 4.76 3.26 0.81 4.79 - - 0.00 3.05 1.45 3.94 August 3.11 1.10 4.11 3.52 2.13 4.27 2.93 1.69 4.06 3.30 2.30 3.82 - - 0.09 3.22 1.32 3.87 September 3.06 1.41 3.98 3.22 1.40 5.11 3.04 1.40 4.25 2.91 1.72 4.00 - - 0.00 3.06 1.71 3.90 October 3.24 1.59 4.02 3.33 1.59 6.62 2.85 1.59 4.65 2.85 2.17 3.63 - - 0.00 2.99 1.63 4.06 November 3.24 2.28 4.02 3.20 2.33 3.71 2.82 2.36 3.41 2.85 2.44 3.30 - - 0.00 3.02 1.60 3.87 December 3.00 0.84 3.85 3.23 1.61 4.28 2.85 1.51 3.40 2.65 1.04 3.26 1.97 - 3.27 3.12 2.04 3.61 Annual Average 3.16 - - 3.11 2.86 - - 3.06 - - 2.79 - - 2.28 - - 2.94 - - Minimum 3.00 0.84 - 1.12 - 2.82 1.40 - 2.06 0.12 - 0.45 1.37 - 2.50 0.18 - Maximum 3.30 - 4.50 3.52 - 6.62 3.40 - 4.76 3.30 - 5.97 2.84 - 3.58 3.22 - 4.11 Prepared by Strand Associates, Inc.® 7 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 31 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 4 Combined Influent Flow Summary 2017 2018 2019 2020 2021 2022 Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max Avg Min Max January 15.38 12.58 16.85 11.16 8.01 18.04 16.63 14.29 19.23 13.18 10.80 14.66 11.61 10.80 12.38 10.65 8.78 11.55 February 15.20 12.87 17.21 11.63 8.96 14.30 16.32 14.05 22.12 13.46 12.04 14.62 11.99 9.90 15.14 10.65 8.94 11.36 March 17.04 14.77 19.99 12.33 8.82 14.33 25.50 14.64 34.01 18.86 14.00 24.53 16.83 14.62 19.29 12.79 9.61 18.26 April 18.68 14.99 21.53 14.00 11.60 17.76 21.65 18.07 27.68 16.19 12.43 20.63 13.47 12.04 15.62 14.55 11.75 26.49 May 17.21 12.87 21.08 14.11 11.21 18.31 23.93 19.29 28.65 16.30 11.44 26.65 13.18 11.03 17.36 15.80 12.32 24.25 June 14.23 11.32 16.91 15.46 10.6421.77 16.72 29.52 26.46 18.16 35.40 12.74 10.70 15.21 16.02 12.19 27.90 July 12.57 10.52 14.71 14.61 10.92 22.0417.06 13.00 23.83 20.69 16.16 29.43 11.94 9.18 17.83 15.40 11.45 24.79 August 11.21 8.53 13.07 16.10 1 13.00 10.63 16.11 13.75 11.79 15.13 12.10 7.98 17.00 12.38 9.97 13.65 September 10.42 8.45 11.75 27.61 14.24 33.46 14.25 9.93 23.31 14.52 10.42 24.35 11.61 9.38 15.38 11.11 9.27 12.89 October 11.75 9.37 15.39 28.61 18.64 34.16 20.34 15.22 31.82 13.25 10.77 26.20 11.42 9.55 14.61 10.32 8.75 12.28 November 11.03 8.88 12.15 19.56 16.73 25.48 14.89 13.64 16.31 13.56 11.56 19.87 11.92 10.38 15.68 11.14 9.24 15.88 December 10.13 7.01 11.56 17.26 11.64 27.39 14.44 11.50 16.34 12.06 9.69 13.51 10.68 8.30 12.75 10.76 9.59 12.59 Annual Average 13.74 - - 16.87 - - 18.32 - - 16.02 - - 12.46 - - 12.63 - - Minimum 10.13 7.01 - 11.16 8.01 - ' 13.00 9.93 - 12.06 9.69 - 10.68 7.98 - 10.32 8.75 - Maximum 18.68 - 21.53 28.61 - 34.16 25.50 - 34.01 26.46 - 35.40 16.83 - 19.29 16.02 - 27.90 Prepared by Strand Associates, Inc.® 8 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 32 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study While the Satellite WWTP influent flow data was relatively consistent in each of the 6 years analyzed, the average annual Easton WWTP influent flow was significantly higher in 2019 than in previous years, with an increase of more than 40 percent from 2017 to 2019. It appears that this increase in flow began in late September 2018. While increased winter flows from precipitation or snow melt are not unusual, the increase that occurred around this time does not appear to subside during dry weather conditions. A portion of the increase in 2018 flow can be attributed to an extreme wet weather event in September 2018 that resulted in major flooding throughout northeastern and east central Iowa. According to National Oceanic and Atmospheric Administration data, the Cedar River at Waterloo crested at 18.96 feet on September 23, 2018, which is nearly 5 feet above flood stage. The City does not currently measure influent flow upstream of influent pumps and, therefore, the maximum influent flow measurement is limited by the pump capacity. However, WWTP staff indicate that there have been no known instances of basement backups resulting from influent sewer surcharging in the past. Minimum and maximum flows at one- and 30-day intervals from January 2017 to December 2022 are presented in Table 5. Prepared by Strand Associates, Inc.® 9 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 33 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Easton Influent' Satellite Influent Combined Treated Influent Influent Flow, MGD Average 12.6 3.0 15.0 Maximum Month (30-Day Maximum) 36.4 3.5 31.8 Minimum Month (30-Day Minimum) 7.0 1.4 9.9 Maximum Day 58.8 6.6 35.42 Minimum Day 5.6 0.0 7.0 'Easton influent flow includes measured flows diverted to the equalization basin. 2Total influent into the Easton WWTP was 58.8 MGD, and 34.4 MGD was diverted to the overflow basin. Table 5 Influent Flow Summary As described earlier, when influent flows exceed the capacity of the Easton WWTP, a portion of the flow can be diverted to the equalization basins. This occurred on 111 days between January 2017 and December 2012, with an average diversion volume of 5.73 MG. Typically, this wastewater would be stored in the equalization basins until the Easton WWTP has adequate treatment capacity, at which time it would be returned to the Easton influent for treatment. In extreme wet weather conditions, the equalization basins may fill and overflow to a ditch that discharges to the Cedar River. As previously discussed, the City currently has a planned project to convey equalization basin overflow to the Satellite activated sludge tanks, effectively increasing storage volume in the near -term. B. Influent BOD5, TSS, and TKN Loadings Tables 6 through 8 summarize the Easton WWTP, Satellite WWTP, and combined influent loadings of BOD5, TSS, and TKN, respectively, from January 2017 to December 2022. The Easton WWTP influent loadings in these tables include the portion of the Easton WWTP influent flow that was diverted to the equalization basins. The combined influent flow excludes the excess flow diverted to the equalization basins. Easton Influent Satellite Influent Combined Influent BOD Loading, lb/day Average 21,900 9,410 30,300 7-Day 50,600 17,800 47,800 30-Day Maximum 47,400 16,000 47,400 Table 6 Influent BOD Loading Summary Prepared by Strand Associates, Inc.' 10 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 34 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Easton Influent Satellite Influent Combined Influent TSS Loading, lb/day Average 23,300 10,900 33,000 7-Day 60,300 20,000 60,300 30-Day Maximum 53,900 17,700 53,900 Table 7 Influent TSS Loading Summary Easton Influent Satellite Influent Combined Influent TKN Loading, lb/day Average 4,460 4,850 8,470 7-Day 11,000 7,300 16,000 30-Day Maximum 10,000 6,500 11,100 Table 8 Influent TKN Loading Summary 1 The City began collecting regular influent TN and TP samples in April 2016. Tables 9 and 10 summarize influent TN and TP loadings. The Easton influent loadings in these tables includes the portion of the Easton influent flow that was diverted to the equalization basins. The TN loadings are very similar to historical TKN loadings, indicating low nitrate/nitrite in the influent. Prepared by Strand Associates, Inc.® 11 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 35 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 9 Influent TN Loading Summary Month Easton Influent Satellite Combined Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) January 2017 34 3,606 187 4,766 64 8,372 February 2017 35 3,521 172 4,661 65 8,182 March 2017 33 3,850 213 5,300 65 9,150 April 2017 31 3,922 206 4,943 58 8,865 May 2017 49 6,079 205 5,520 79 11,599 June 2017 49 4,306 202 5,540 86 9,846 July 2017 41 3,241 192 5,125 80 8,366 August 2017 59 4,058 195 5,268 97 9,326 September 2017 57 2,733 188 3,729 94 8,485 October 2017 47 3,360 165 4,387 78 7,747 November 2017 54 3,631 179 4,964 90 8,595 December 2017 57 3,536 209 4,723 97 8,259 January 2018 57 3,971 198 5,016 94 8,986 February 2018 77 5,687 210 5,177 109 10,864 March 2018 55 4,444 201 5,470 92 9,914 April 2018 50 4,684 208 5,241 83 9,924 May 2018 40 3,780 207 4,874 73 8,654 June 2018 30 3,118 178 4,838 59 7,956 July 2018 38 3,558 201 4,670 70 8,228 August 2018 33 3,581 172 4,594 60 8,175 September 2018 - - 176 4,674 - - October 2018 15 2,624 168 3,988 33 8,265 November 2018 30 4,101 187 4,871 55 8,972 December 2018 33 4,273 195 5,100 60 9,373 January 2019 34 3,760 181 4,511 60 8,271 February 2019 41 4,583 211 5,212 72 9,795 March 2019 36 3,783 227 4,659 50 8,442 April 2019 34 5,527 179 5,279 57 10,806 May 2019 26 4,230 176 4,979 48 9,209 June 2019 29 3,372 198 4,095 41 7,467 July 2019 31 3,095 221 4,626 51 7,722 August 2019 41 3,542 186 3,877 70 7,419 September 2019 41 2,668 210 4,151 61 6,819 October 2019 24 3,345 201 4,566 49 7,911 November 2019 31 3,194 237 5,278 68 8,472 December 2019 51 4,864 208 4,713 80 9,578 January 2020 37 3,282 216 4,405 48 7,687 February 2020 35 3,202 231 5,180 74 8,382 March 2020 31 3,957 197 4,660 56 8,616 April 2020 27 3,182 250 2,891 45 6,073 May 2020 33 3,547 215 3,372 56 6,919 June 2020 20 3,618 166 4,021 36 7,639 July 2020 24 3,281 181 5,180 51 8,461 August 2020 37 2,471 156 4,126 57 6,597 Prepared by Strand Associates, Inc.® 12 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 36 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Month Easton Influent Satellite Combined Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) September 2020 36 2,710 173 3,223 41 4,599 October 2020 47 3,764 181 4,271 77 8,035 November 2020 41 3,549 198 4,656 74 8,204 December 2020 40 2,562 204 3,735 76 7,828 January 2021 45 3,409 200 4,718 82 8,127 February 2021 49 3,718 200 4,977 86 8,695 March 2021 30 3,614 209 4,046 48 6,948 April 2021 55 4,821 207 4,719 87 9,540 May 2021 81 8,612 - - 81 8,612 June 2021 74 4,657 - - 44 4,657 July 2021 83 8,220 - - 83 8,220 August 2021 92 7,555 - - 73 7,555 September 2021 78 7,329 - - 78 7,329 October 2021 100 9,485 - - 100 9,485 November 2021 99 9,434 - - 99 9,434 December 2021 71 6,047 235 5,747 101 9,495 January 2022 54 3,636 216 5,234 97 8,871 February 2022 52 3,401 237 5,796 102 9,198 March 2022 55 4,751 223 5,354 87 9,034 April2022 41 2,544 247 3,969 62 6,514 May 2022 32 3,475 196 5,159 64 8,634 June 2022 35 3,488 166 4,471 63 7,959 July 2022 31 2,098 164 2,904 33 4,168 August 2022 42 2,525 175 4,081 50 6,388 September 2022 69 4,701 187 4,730 100 9,431 October 2022 49 2,423 184 4,506 75 6,929 November 2022 44 2,977 175 4,870 83 7,847 Average 46 4,110 197 4,662 70 8,287 Min Monthly 15 2,098 156 2,891 33 4,168 Max Monthly 100 9,485 250 5,796 109 11,599 Notes: ma/L=milliarams oer liter Conc.=concentration Prepared by Strand Associates, Inc.® 13 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 37 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 10 Influent TP Loading Summary Month Easton Influent Satellite Combined Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) January 2017 8 800 21 526 10 1,326 February 2017 10 1,015 22 581 13 1,596 March 2017 9 1,061 23 585 12 1,646 April 2017 6 747 21 510 8 1,258 May 2017 8 902 25 664 11 1,566 June 2017 11 980 23 635 14 1,615 July 2017 11 874 25 665 15 1,539 August 2017 15 1,007 25 690 18 1,698 September 2017 15 944 21 553 17 1,498 October 2017 14 982 21 557 16 1,539 November 2017 13 876 20 565 15 1,441 December 2017 16 1,026 22 479 17 1,505 January 2018 16 1,098 22 550 18 1,649 February 2018 12 908 22 533 14 1,441 March 2018 14 1,096 24 648 16 1,743 April 2018 11 1,056 22 562 13 1,618 May 2018 9 862 23 539 12 1,401 June 2018 7 775 22 595 10 1,371 July 2018 9 832 20 470 11 1,302 August 2018 10 1,145 18 489 12 1,633 September 2018 5 926 18 463 6 1,389 October 2018 3 553 17 408 5 1,200 November 2018 6 798 19 497 8 1,295 December 2018 7 880 19 486 9 1,366 January 2019 9 1,045 17 422 11 1,467 February 2019 9 1,009 19 477 11 1,485 March 2019 6 646 20 417 6 1,064 April 2019 5 858 19 570 8 1,428 May 2019 5 875 19 552 8 1,427 June 2019 6 754 21 445 7 1,199 July 2019 6 584 20 421 7 1,005 August 2019 9 727 22 436 11 1,162 September 2019 13 1,242 22 583 15 1,825 October 2019 6 851 23 509 9 1,360 November 2019 8 866 22 487 11 1,353 December 2019 9 851 25 575 12 1,427 January 2020 7 611 24 484 6 1,095 February 2020 13 1,214 23 528 15 1,742 March 2020 8 950 26 625 10 1,575 April 2020 6 669 18 364 8 1,033 May 2020 10 1,014 21 367 11 1,381 June 2020 4 749 25 611 7 1,360 July 2020 6 816 26 757 10 1,573 August 2020 9 790 34 883 14 1,674 Prepared by Strand Associates, Inc.® 14 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 38 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Month Easton Influent Satellite Combined Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) September 2020 9 656 33 617 9 954 October 2020 16 1,220 41 969 21 2,189 November 2020 8 725 33 775 14 1,500 December 2020 13 860 34 628 17 1,749 January 2021 12 894 40 930 19 1,825 February 2021 12 936 36 914 18 1,850 March 2021 9 1,085 37 717 11 1,632 April 2021 13 1,151 37 838 18 1,989 May 2021 20 2,107 - - 20 2,107 June 2021 16 985 - - 9 985 July 2021 19 1,892 - - 19 1,892 August 2021 18 1,469 - - 14 1,469 September 2021 19 1,815 - - 19 1,815 October 2021 18 1,729 - - 18 1,729 November 2021 22 2,101 - - 22 2,101 December2021 20 1,573 37 917 23 2,123 January 2022 16 1,049 29 706 19 1,756 February 2022 12 806 31 765 17 1,571 March 2022 13 1,042 32 763 16 1,653 April 2022 10 850 26 561 13 1,411 May 2022 12 1,366 25 662 15 2,028 June 2022 7 707 22 601 10 1,307 July 2022 8 507 19 331 7 838 August 2022 11 683 19 454 11 1,137 September 2022 16 1,093 21 530 17 1,623 October 2022 14 694 23 553 14 1,247 November 2022 15 995 23 651 17 1,646 Average 11 990 24 588 13 1,513 Min Monthly 3 507 17 331 5 838 Max Monthly 22 2,107 41 969 23 2,189 Prepared by Strand Associates, Inc.® 15 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 39 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study In -plant waste loads including filtrate from sludge thickening and dewatering operations, biosolids storage tank decant, tank drains, and digester overflow are combined in the WWTP sewer system. The WWTP sewer flows through a Palmer-Bowlus flume just east of the septage receiving station for flow measurement. WWTP staff indicate that this flume is often surcharged and does not provide reliable flow measurements. Septage is combined with these in -plant return flows downstream of the flume. These flows combine with the Easton influent in a manhole upstream of the Bar Screen Building. Therefore, the flows and loads associated with these in -plant returns are included in the Easton influent flow measurement and samples. City staff conducted special sampling in May and June 2017 that included grab samples of return flows from the GBTs and BFPs as presented in Table 11. GBT Filtrate BFP Filtrate Parameter, mg/L TP 10.3 73.8 PO4-P 6.3 33.3 Ammonia 8.9 685 TKN 38.9 715 Nitrate 13.7 1.1 Nitrite 0.2 <0.1 TSS 308 1,123 VSS 252 756 Alkalinity 218 2,491 Note: VSS=volatile suspended solids PO4-P=phosphate Table 11 Return Flow Sampling Summary —May and June 2017 Estimates of return flow loadings were made based on the 2014 to 2016 sludge flows, percent solids measurements, and estimates of wash water flows at approximately 120 gpm per GBT/BFP. This results in an estimated GBT filtrate and BFP filtrate flows of approximately 0.45 and 0.16 MGD, respectively. Estimated return loadings from these sources are presented in Table 12. Parameter, lb/day GBT Filtrate BFP Filtrate Filtrate Loading Percentage of Easton Influent TP 39 98 15% PO4-P 24 44 - Ammonia 33 914 - TKN 146 954 25% Nitrate 51 1.5 - Nitrite 0.8 <0.1 - TSS 1,160 1,500 10% VSS 950 1,010 - Alkalinity 820 Flow Loading Estimates 3,320 - Table 12 Return Prepared by Strand Associates, Inc.' 16 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 40 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study C. Wastewater Treatment Performance As described earlier, secondary effluents from the Satellite and Easton WWTPs are combined and disinfected before discharge to the Cedar River. The City has two permitted outfalls on the Cedar River: a diffuser located in the river that is used under normal conditions and a shoreline outfall that is used when the Cedar River level is high. The permitted effluent concentrations for all parameters except ammonia are identical for these two discharges. In the City's current NPDES permit, the shoreline outfall can be used during high river flows (above 8,500 cfs), resulting in higher ammonia limits both on a monthly average and daily maximum basis. Table 13 summarizes the City's average monthly effluent ammonia nitrogen (NH3-N). Effluent NH3-N during this period averaged 3.54 mg/L. The City was operating two to three of the Easton WWTP activated sludge trains for most of the 6-year period. The City has a TN mass limits of 9,285.5 lb/day on a monthly average basis with a daily maximum limit of 15,199 lb/day. Effluent TN sample results are presented in Table 14. There were no exceedances of the City's maximum day or monthly average TN mass limits in the period evaluated. While the City does not currently have a TP limit, they began monitoring effluent TP once per week in April 2016. Effluent TP data is presented in Table 15. The MLE process currently used at the Easton WWTP was designed for TN removal and successfully removes approximately 48 percent of the influent TN based on the data presented in Tables 9 and 14. The data in Tables 10 and 15 suggest that the WWTP currently removes approximately 37 percent of the influent TP. Because the MLE process does not contain an anaerobic zone necessary for successful biological phosphorus removal (BPR), the demonstrated TP removal is likely attributable to biological uptake for cell growth and the removal of particulate TP. Prepared by Strand Associates, Inc.® 17 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 41 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 13 Effluent NH3-N 2017 2018 2019 2020 2021 2022 Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (Ib/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) January 35.90 4,368 7.83 688 1.09 37 1.03 6 1.13 37 5.07 384 February 23.33 2,686 27.68 2,573 3.60 373 1.30 37 3.00 257 14.27 1,119 March 3.71 441 12.94 1,265 6.06 1,477 1.32 110 1.68 144 1.06 13 April 4.27 601 9.55 1,099 13.25 2,312 1.02 8 1.38 71 1.05 8 May 2.76 402 4.09 420 2.07 339 <1.00 0 1.31 56 <1.00 0 June 1.08 12 1.04 12 1.03 28 1.29 125 2.93 228 <1.00 0 July 5.35 445 <1.00 0 <1.00 0 1.00 13 1.28 52 <1.00 0 August 4.99 423 1.05 10 1.59 69 1.48 91 1.15 32 <1.00 0 September <1.00 0 <1.00 0 2.87 225 1.03 7 1.67 78 1.12 22 October 1.73 78 <1.00 0 <1.00 0 <1.00 0 <1.00 0 <1.00 0 November <1.00 0 1.01 12 <1.00 0 <1.00 0 1.03 7 1.49 61 December 1.02 5 1.13 41 1.87 111 1.35 70 1.46 65 - - Annual Average 7.18 788 5.78 510 3.04 414 1.15 39 1.59 85 2.52 136 Prepared by Strand Associates, Inc.® 18 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 42 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 14 Effluent TN 2017 2018 2019 2020 2021 2022 Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) January 44 5,244 43 3,862 33 4,420 34 2,835 49 4,607 48 4,079 February 35 4,037 32 3,103 36 4,511 41 4,313 51 4,918 42 3,293 March 32 4,272 39 3,882 40 4,952 30 4,278 35 3,782 36 3,363 April 26 3,601 34 3,918 29 5,379 33 4,405 44 4,735 36 2,523 May 30 4,300 40 4,565 31 5,657 27 3,451 53 5,462 36 4,579 June 47 5,227 28 4,091 33 4,319 23 5,253 44 2,502 33 3,896 July 43 4,518 33 2,981 39 4,416 31 5,051 45 4,112 28 2,165 August 57 5,407 53 7,456 42 4,392 42 4,931 51 3,151 45 4,351 September 52 4,750 24 5,387 32 3,679 39 3,690 49 1,839 44 3,726 October 49 4,893 24 6,090 30 4,713 51 5,224 47 4,110 46 3,888 November 48 4,318 33 5,411 41 4,848 45 4,853 46 4,036 46 4,055 December 52 4,130 31 4,920 42 4,895 56 5,535 48 4,136 - - Annual Average 43 4,558 34 4,639 36 4,682 38 4,485 47 3,949 40 3,629 Prepared by Strand Associates, Inc.® 19 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 43 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 15 Effluent TP 2017 2018 2019 2020 2021 2022 Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) Conc. (mg/L) Load (lb/day) January 7 784 13 1,191 4 559 6 543 12 1,152 23 1,977 February 11 1,305 7 714 5 616 7 731 12 1,176 12 939 March 7 914 10 947 6 714 6 928 8 882 9 824 April 5 689 9 998 8 1,380 11 1,435 12 1,234 8 816 May 7 1,017 7 758 4 757 6 723 12 1,221 8 1,005 June 10 1,099 7 1,019 5 664 5 1,167 11 605 7 809 July 10 1,089 6 681 5 594 7 1,190 11 960 7 517 August 14 1,296 7 1,119 6 668 11 1,333 11 698 9 861 September 10 881 3 750 19 2,017 10 963 9 352 9 776 October 9 923 3 718 7 1,002 12 1,272 10 843 10 656 November 10 918 5 879 6 751 10 1,128 17 1,488 10 901 December 12 973 5 824 8 913 11 1,083 13 1,111 - - Annual Average 9 991 7 883 7 886 9 1,041 11 977 10 917 Prepared by Strand Associates, Inc.® 20 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 44 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study NUTRIENT REDUCTION GOALS Using the influent TN and TP data collected between January 2017 and December 2022 and adjusting for the nutrient loads from return flows that were included in these samples, the average TN and TP for the combined WWTP influent are approximately 60.5 and 11.7 mg/L, respectively. Based on these influent concentrations, the IDNR's nutrient reduction goals are 20.2-mg/L TN (66 percent removal) and 2.9-mg/L TP (75 percent removal). The City currently has mass limits for TN of 9,285.5 lb/day on a 30-day average basis and 15,199 lb/day on a daily maximum basis. There is no TP limit in the City's current NPDES permit. Based on the effluent target values calculated above, the combined average wet weather (AWW) design flow of 34.8 MGD, the anticipated TN and TP mass limits are approximately 5,850 pounds TN per day and 845 pounds TP per day. EVALUATION OF OPERATIONAL CHANGES TO ENHANCE NUTRIENT REMOVAL As presented earlier, the MLE process currently used at the WWTP results in effluent TN loads between 3,000 and 5,000 lb/day with concentrations of approximately 30 to 40 mg/L. Based on this performance, the City is currently able to achieve the annual TN effluent mass target of 5,850 lb/day but it appears that it would be unable to achieve this target should influent flows increase to the design flows. Furthermore, the WWTP is not currently designed for phosphorus removal, which would require either anaerobic zones in the activated sludge system or significant chemical feed and storage facilities. Potential operational changes to improve BPR performance, such as eliminating the nitrified ML recycle to create an anaerobic zone, would result in loss of TN removal. Because of the high TKN loads to the WWTP, the elimination of the nitrified ML recycle and associated denitrification and alkalinity recovery is also anticipated to result in pH instability and the potential loss of nitrification. The City conducted special sampling in May and June 2017 to further investigate nutrient removal at the WWTP. This sampling indicated that while the WWTP was successfully nitrifying (average effluent ammonia concentration of 1.5 mg/L), denitrification in the anoxic zone was incomplete with an average nitrate nitrogen (NO3-N) concentration leaving the anoxic zone greater than 10 mg/L. The effluent TN during this period was approximately 36 mg/L, similar to the average presented earlier. The incomplete denitrification in the anoxic zone suggests that the anoxic zone is not large enough, there is too much dissolved oxygen in the anoxic zones, or there is insufficient influent BOD to completely denitrify. The anoxic retention time during this period was approximately 1.7 hours, which is within a typical range for anoxic zone sizing for the MLE process. The City does not currently have the ability to control the ML recycle rate and, therefore, operational changes associated with variable recycle rates are not feasible without capital improvements. Modifying the RAS rate or solid retention rate (SRT) is not anticipated to significantly improve TN or TP removal without detrimentally affecting other process performance (nitrification, TSS removal, etc.). Increasing the anoxic zone size by reducing the size of the aerated zone will negatively impact nitrification, which is already challenging during the winter months at current flows and loads. The existing anoxic zone is not large enough to allocate a portion as an anaerobic zone for BPR without further reducing the ability to denitrify. While the City has tankage in the Satellite WWTP that is not currently in use, the facilities to Prepared by Strand Associates, Inc.® 21 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 45 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study convey influent from the Easton collection system to the Satellite activated sludge system are not in place. Operating the Satellite WWTP treating only the Satellite influent will exacerbate existing carbon deficiencies for nutrient removal (within the Easton WWTP) in addition to introducing other operational challenges. Therefore, operational changes alone are not feasible to significantly reduce the TN and TP loads in the effluent without negative impacts on other treatment process performance. The modifications necessary for successful BNR, as noted above, will require significant capital improvements as discussed later in this report. WASTELOAD AND FLOW FORECASTS To evaluate processes and technologies to enhance existing nutrient reduction capabilities, wasteload and flow forecasts were completed for the City's WWTP service area. For the purposes of this study, it is anticipated that the overall area served by the City's WWTP will remain the same through the 20-year planning period. A. Population Trends According to the 2020 census, the City had 67,314 residents, 28,912 total households, and an average household size of 2.31 persons. Compared to the 2010 census City population of 68,406, this equates to a 10-year population decrease of approximately 0.15 percent. Population projections for the City obtained from the Black Hawk County Metropolitan Area Transportation Policy Board's 2045 Long Range Transportation Plan are presented in Table 16 below. Year 2020a City of Waterloo Population I 67,314 a2020 Census data Table 16 Current and Projected Populations 2025b 69,928 2035 71,178 2045 72,416 These projections estimate a 25-year growth of approximately 8 percent, or an annual average growth rate of approximately 0.3 percent over the period. Based on these projections, a 2045 City population of 72,416 is used for projecting future residential wastewater flows and loadings in this Study. B. Projected Wastewater Flows Projecting future wastewater flows requires identification of residential, commercial, and industrial wastewater flow, base flows, peaking factors, and anticipated residential, commercial, and industrial growth in areas tributary to the Easton and Satellite WWTPs. Table 17 shows the projected future design flows for the facility considering the expected growth. Current Easton dry weather flows used in these projections are based on the 2019 dry weather flow data. Future dry weather flow from the Easton collection system was determined by adding additional expected flow from growth at 100 gallons per capita per day (gpcd) to the dry weather Prepared by Strand Associates, Inc.22 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 46 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study base flow. The average and wet weather infiltration and inflow (1/1) values were then added to the base flow to determine the annual average, wet weather, and maximum day flows. For the Easton WWTP, the total design I/1 for annual average, maximum day flow, and wet weather flow was estimated using current peaking factors from the 2019 flow data. It is important to note that the maximum month wet weather flow at the Easton WWTP occurring in 2018 was 36.4 MGD. However, this value was found to be unusually high and not representative of typical wet weather values due to intense wet weather and flooding in the area. The 30-day rolling average between January 2017 and December 2022 are presented in Figure 3. The second highest value of 27.8 MGD occurred in 2019, and this value was used to estimate the wet weather flow peaking factor (PF). 40 35 1 1 30 25 2 20 0 ti is- r` r— co 0o co co rn am am o 0 0 N N N L f/i L Lct) L L Ui c Q c.o 2 ctC. f co - O ca Q r Q 0) � Q ll o O ▪ - Q NI( Figure 3 Easton Influent Flow DE November-20 —Easton Influent Maximum 0) September-21 December-21 October-22 January-23 The design I/1 flows for annual average and maximum day flows for the Satellite WWTP were estimated using current peaking factors from the 2017 flow data. The wet weather design I/1 for the Satellite WWTP used the 2018 maximum month flow because it exceeded the 2017 value. Additional I/1 from growth was estimated using wet weather peaking factors from the 2018 flow data and the projected additional dry weather flow from growth. Prepared by Strand Associates, Inc.® 23 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 47 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study The City is currently implementing collection system improvements related to wet weather flows under a 2017 Consent Decree, including flow monitoring, sewer condition and capacity assessments, a footing drain removal program, a hydraulic model, and the development of a Sanitary Sewer Master Plan. It is anticipated that these improvements will impact future wet weather flows and, therefore, it is recommended an evaluation of peak flows to the WWTP using the City's hydraulic model is conducted following the completion of these collection system improvements. The need for future peak flow improvements at the WWTP should be reevaluated at that time. Using this method, the projected design average flow for the Easton WWTP is 16.61 MGD, which is less than the current design average flow of 20.4 MGD. The projected design average flow of the Satellite WWTP is 3.49 MGD, which is less than the current design average flow of 6.7 MGD. The need for future peak flow improvements at the WWTP should be reevaluated at that time. Easton Flow (MGD) Satellite Flow (MGD) Combined Flow (MGD) Current Dry Weather Flow 9.58a 2.87b 12.45 Projected Residential Growthc 0.51 - 0.51 Planned Industrial Growthi - - - Projected Dry Weather Flow 10.09 2.87 12.96 Design 1/Ik Annual Average 6.52d 0.299 6.81 Wet Weather 19.22e 0.68h 19.90 Maximum Day 51.89f 3.75' 55.64 Peak Hourly' 58.40 3.65 62.10 Projected Flows Annual Average 16.61 3.16 19.77 Average Wet Weather 29.31 3.55 32.86 Maximum Day 61.97 6.62 68.59 Peak Hourly 68.49 6.52 75.01 a2019 Easton influent flow used as baseline b2017 Satellite influent flow used as baseline 'Additional residential flow of 5,102 persons at 100 gpcd. dPF=1.65 x Dry Weather Flow (based on 2019 Easton flow data) ePF=3.80 x Dry Weather Flow (based on 2019 Easton flow data) fPF=6.14 x Dry Weather Flow (based on 2019 Easton flow data) 9PF=1.10 x Dry Weather Flow (based on 2019 Easton flow data) hPF=1.24 x Dry Weather Flow (based on 2017 Satellite flow data) 'PF=2.31 x Dry Weather Flow (based on 2017 Satellite flow data) iThe City has not identified any specific planned industrial growth. kExisting I/1 + I/1 from growth 'Based on analysis from the 2018 Nutrient Reduction Study. Table 17 Projected 2045 Flows Prepared by Strand Associates, Inc.® 24 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 48 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study C. Projected Wasteloads Future loads to the Easton WWTP were projected by using the populations presented earlier and per capita values of 0.22 pounds per capita day (pcd) for BOD5, 0.22 pcd for TSS, 0.041 pcd for TKN, and 0.011 for TP, as well as the planned industrial growth. The current average BOD5, TSS, and TKN loadings are based on the January 2017 to December 2022 average. Table 18 presents the estimated future loads for BOD5, TSS, TKN, and TP. TP (lb/day) BOD5 (lb/day) TSS (lb/day) TKN (Ib/day) CurrentAveragea 30,100 32,900 8,390 1,510 Projected Residential Growth 1,100b 1,100b 210d 60e Planned Industrial Growthf - - - - Projected Average 31,200 34,000 8,600 1,570 a2017 to 2022 data as baseline bAdditional load at 0.22 pcd Additional load at 0.22 pcd dAdditional load at 0.041 pcd eAdditional load at 0.011 pcd fThe City has not identified any specific planned industrial growth. Table 18 Projected Future Loads —Combined Influent Projected maximum monthly influent loadings are estimated by using a peaking factor of 1.5 for BOD5, 1.6 for TSS, 1.3 for TKN, and 1.4 for TP. The peaking factors for BOD5, TSS, and TKN were determined by dividing the highest 30-day average loading by the annual average loading from January 2017 to December 2022. The maximum monthly loadings are shown in Table 19. BOD5 (lb/day) TSS (Ib/day) TKN (Ib/day) TP (lb/day) Projected Average Load 31,200 34,000 8,600 1,570 Peaking Factor 1.5 1.6 1.3 1.4 AWW Load Table 19 Estimated Maximum 46,200 54,300 11,180 2,270 Month Loads Table 20 summarizes the projected year 2045 flows and loadings and compares to the full permitted design flows and loadings. Existing capacity greater than the 2045 flow and loadings projection is held as reserve capacity for unforeseen growth. Prepared by Strand Associates, Inc.' 25 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 49 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 2040 Projection 2045 Projection Full Permitted Design Annual Average Flow 18.9 19.8 27.1 Average Wet Weather Flow (Maximum Month) 34.8 32.9 34.8 Maximum Wet Weather Flow (Maximum Day) 72.6 68.6 79.1a Peak Hourly Wet Weather Flow 76.8 75.0 79.1 a Annual Average BOD5 (Ib/day) 32,700 31,200 62,800 Maximum Month BOD5 (lb/day) 42,500 46,200 88,000 Annual Average TSS (lb/day) 38,600 34,000 56,300 Maximum Month TSS (lb/day) 57,900 54,300 83,000 Annual Average TKN (lb/day) 9,990 8,600 11,525 Maximum Month TKN (lb/day) 12,000 11,180 21,050 Annual Average TP (lb/day) 1,590 1,570 2,490b Maximum Month TP (lb/day) 1,900 2,770 2,980c aMaximum day and peak hour flow of Easton headworks facility=68 MGD. Maximum day and peak hour flow of Satellite=11.1 MGD. bAdditional TP load for 8.17 MGD reserve capacity at 100 gpcd and 0.011 pcd TP. cAnnual Average TP x 1.2 Peaking Factor 20 Design Flows and Loads EVALUATION OF TREATMENT TECHNOLOGIES TO MEET NUTRIENT REDUCTION GOALS As previously discussed, operational changes alone will not be sufficient to achieve a significant increase in nutrient reduction and a major capital upgrade will be required to achieve the target reductions in TN and TP. Modifications to the existing activated sludge systems for TN and TP removal were evaluated in the 2018 Nutrient Reduction Study, including those that treat the dewatering filtrate sidestreams separately from the main treatment process. System performance were evaluated using a BioWin model and the results of this modeling were presented for each alternative. A copy of the 2018 Nutrient Reduction Study is included in Appendix B. This study included the following alternatives: ■ Alternative Biological Nutrient Removal (BNR)1a—Anaerobic-anoxic-aerobic (A2O) with BOD diversion from lagoon ■ Alternative BNR1 b—A2O with VFA addition at WWTP ■ Alternative BNR1c—A2O with Struvite Harvesting; BOD diversion from lagoon ■ Alternative BNR1d—A2O with Struvite Harvesting; VFA addition at WWTP ■ Alternative BNR1e—A2O with Struvite Harvesting and primary sludge (PRS) fermentation; BOD diversion from lagoon ■ Alternative BNR1f—A2O with Struvite Harvesting and PRS fermentation; VFA addition at WWTP ■ Alternative BNR2—MLE with Chemical Phosphorus Removal (CPR) ■ Alternative BNR3—MLE with Sidestream Enhanced BPR The evaluation of the 2045 flows and loadings showed that the projections are consistent with the 2040 flow and load projections shown in the 2018 Nutrient Reduction Study. Therefore, this Study will rely on the results and findings of the 2018 Nutrient Reduction Study. For a detailed description Prepared by Strand Associates, Inc.' 26 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 50 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study of the alternatives and modeling summaries, refer to Appendix B. It is noted that other technologies could be considered, but the 2018 study is still representative of the state-of-the-art for BNR technologies because that report evaluated technologies that were very new and innovative at the time. A. Monetary Comparison Table 21 summarizes the 20-year present worth analysis for each of the BNR alternatives. Additional detail on the present worth analysis is provided in Appendix B. Note that costs are presented in second quarter 2023 values and were updated from the 2018 Nutrient Reduction Study by assuming a construction cost index (CCI) of 13,176 compared to a first quarter of 2018 CCI of 10,909. Due to uncertainty in modeling results, the quantity of phosphorus removal chemical (PRC) or volatile fatty acid (VFA) that would be required to meet the TP target with Alternative BNR3 if any, is unknown. Therefore, operational and maintenance (O&M) costs associated with Alternative BNR3 are estimated as ranges, with the maximum values assuming chemical addition equal to those of Alternative BNR2. For the alternatives that include the diversion of BOD from the anaerobic lagoon to the WWTP, it is assumed that at a minimum, a screening facility would be required on the Satellite influent, and, therefore, the present worth cost of Satellite screening facility is included with these alternatives. Additionally, these alternatives include the lost revenue from the biogas that would have been generated at the lagoon if this BOD was not diverted, estimated in the range of $0 to $20 per million British Thermal Units (MMBTU), depending on the end -use of the lagoon biogas. B. Nonmonetary Comparison Nonmonetary considerations for each alternative were evaluated and are summarized in Table 22. Prepared by Strand Associates, Inc.® 27 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 51 of 164 DRAFT (05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 21 BNR Present Worth Analysis Summary Alternative BNR1a A20 Process with BOD diversion from lagoon Alternative BNR1b A20 Process with VFA addition at WWTP Alternative BNR1c A20 Process with struvite harvesting; BOD diversion from lagoon Alternative BNR1d A20 Process with struvite harvesting; VFA addition at WWTP Alternative BNR1e A20 Process with struvite harvesting and PRS fermentation; BOD diversion from lagoon Alternative BNR1f A20 Process with struvite harvesting and PRS fermentation; VFA addition at WWTP Alternative BNR2 MLE Process with CPR Alternative BNR3 MLE with Sidestream Enhanced BPR Capital Costs Equipment/Structure Subtotal $9,200,000 $6,500,000 $11,600,000 $6,900,000 $13,500,000 $7,800,000 $4,200,000 $2,800,000 Mechanical $1,840,000 $1,320,000 $2,320,000 $1,390,000 $2,710,000 $1,560,000 $850,000 $990,000 Electrical $2,300,000 $1,600,000 $2,900,000 $1,700,000 $3,400,000 $1,900,000 $1,100,000 $700,000 Heating, ventilation, and air conditioning (HVAC) $920,000 $660,000 $1,160,000 $700,000 $1,350,000 $790,000 $420,000 $290,000 Sitework $920,000 $660,000 $1,160,000 $700,000 $1,350,000 $790,000 $640,000 $420,000 Contractor General Conditions $1,520,000 $1,090,000 $1,920,000 $1,150,000 $2,230,000 $1,290,000 $720,000 $530,000 Contingencies, Legal, and Engineering $8,300,000 $6,000,000 $10,500,000 $6,300,000 $12,300,000 $7,100,000 $4,000,000 $2,900,000 Total Opinion of Capital Costs $25,000,000 $17,890,000 $31,580,000 $18,870,000 $36,840,000 $21,180,000 $11,870,000 $8,610,000 Annual O&M Costs Labor $12,000 $12,000 $24,000 $24,000 $48,000 $48,000 $72,000 $12,000 to $72,000 Power $350,000 $350,000 $362,000 $362,000 $350,000 $350,000 $326,000 $326,000 to $362,000 Chemical $72,000 $2,657,000 $169,000 $906,000 $169,000 $531,000 $797,000 $72,000 to $2657,000 Additional Sludge Disposal Cost $266,000 $266,000 $48,000 $48,000 $48,000 $48,000 $205,000 $48,000 to $266,000 Maintenance and Supplies $24,000 $24,000 $36,000 $36,000 $48,000 $48,000 $24,000 $24,000 to $48,000 Total $725,000 $3,309,000 $640,000 $1,377,000 $664,000 $1,027,000 $1,425,000 $640,000 to $3,309,000 Present Worth of O&M $11,040,000 $50,390,000 $9,750,000 $20,970,000 $10,110,000 $15,630,000 $21,700,000 $9,750,000 to $50,390,000 Summary of Present Worth Costs Capital Cost $25,000,000 $17,890,000 $31,580,000 $18,870,000 $36,840,000 $21,180,000 $11,870,000 $8,610,000 Replacement $530,000 $530,000 $530,000 $530,000 $530,000 $530,000 $530,000 $410,000 O&M Cost $11,040,000 $50,390,000 $9,750,000 $20,970,000 $10,110,000 $15,630,000 $21,700,000 $9,750,000 to $50,390,000 Salvage Value ($1,140,000) ($1,740,000) ($1,280,000) ($1,330,000) ($1,390,000) ($1,110,000) ($1,070,000) ($680,000) Satellite Influent Screening $6,610,000 - $6,610,000 - $6,610,000 - - - Lost Biogas Revenue at Lagoon $0-$18,230,000 - $0-$5,210,000 - $0-$2,610,000 - - - TOTAL PRESENT WORTH $42,040,000 to $60,270,000 $67,070,000 $47,190,000 to $52,400,000 $39,040,000 $55,700,000 to $55,310,000 $36,230,000 $33,030,000 $8,870,000 to $27,180,000 Note: All costs in 2nd Quarter 2023 dollars. Prepared by Strand Associates, Inc.® R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docxx\050323 28 Page 52 of 164 DRAFT (05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 22 BNR Nonmonetary Considerations Summary Alternative BNR1a: A2O with BOD diversion from lagoon BNR1 b: A2O with VFA addition at WWTP Benefits • TP and TN removal without chemical addition at WWTP. • TP and TN removal without metal salt addition at WWTP. • Does not impact lagoon operation or lagoon biogas production. BNR1c: A2O with Struvite Harvesting; BOD diversion from lagoon • TP and TN removal without chemical addition at WWTP. ■ Reduction of nuisance struvite formation through harvesting/sequestration. Potential for marketable struvite product. BNR1d: A2O with Struvite Harvesting; VFA addition at WWTP ■ TP and TN removal without metal salt addition at WWTP. ■ Does not impact lagoon operation or lagoon biogas production. BNR1e: A2O with Struvite Harvesting and PRS fermentation; BOD diversion from lagoon Limitations • Significant reduction in lagoon biogas. • Potential negative impact on WWTP processes and equipment from undesirable materials in diverted lagoon influent. • Operation of BPR more challenging under varied influent conditions than CPR. • Additional chemical handling at WWTP; increase in truck traffic to site, new equipment to operate and maintain. • Operation of BPR more challenging under varied influent conditions than CPR. • Reduction in lagoon biogas production. • Potential negative impact on WWTP processes and equipment from undesirable materials in diverted lagoon influent. ■ Operation of BPR more challenging under varied influent conditions than CPR. • Increased complexity with additional process to operate and maintain. • TP and TN removal without chemical addition at WWTP. ■ Reduction of nuisance struvite formation through harvesting/sequestration. Potential for marketable struvite product. ■ VFA formation at WWTP stabilizes BPR performance under varied influent conditions. BN R1 f: A2O with Struvite Harvesting and PRS fermentation; VFA addition at WWTP BNR2: MLE with CPR BNR3: MLE with RAS Fermentation • TP and TN removal without metal salt addition at WWTP. • Does not impact lagoon operation or lagoon biogas production. • Modification to existing process, staff familiar with operation. ■ CPR more reliable than BPR, especially with varied influent conditions. • Additional chemical handling at WWTP; increase in truck traffic to site, new equipment to operate and maintain. ■ Operation of BPR more challenging under varied influent conditions than CPR. • Increased complexity with additional process to operate and maintain. • Reduction in lagoon biogas production. • Potential negative impact on WWTP processes and equipment from undesirable materials in diverted lagoon influent. • Operation of BPR more challenging under varied influent conditions than CPR. • PRS Fermentation can be challenging to operate; odor concerns. ■ Increased complexity with two additional processes to operate and maintain. • Additional chemical handling at WWTP; increase in truck traffic to site, new equipment to operate and maintain. ■ Operation of BPR more challenging under varied influent conditions than CPR. ■ PRS Fermentation can be challenging to operate; odor concerns. • Increased complexity with additional processes to operate and maintain. • Potential for TP and TN removal without chemical addition at WWTP. • Can be tested in existing tankage while using MLE process in remaining tanks. • Struvite harvesting and/or PRS fermentation could be added to improve TP removal if necessary. • Additional chemical handling at WWTP; increase in truck traffic to site, new equipment to operate and maintain. • Developing process that has not been widely implemented to date. • System performance cannot be predicted using current process modes. Prepared by Strand Associates, Inc.® R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docxx\050323 29 Page 53 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study C. Other Capital Improvements Required for Enhanced Nutrient Removal and WWTP Consolidation In this section, other capital improvements that are recommended if enhanced nutrient removal or increased capacity were to be required are presented. As previously described, the Satellite and Easton WWTPs are currently designed to operate as separate systems, each with their own influent pumps, activated sludge tanks, aeration systems, and final clarifiers. The City currently treats wastewater from both the Satellite and Easton collection systems using only the Easton WWTP activated sludge system because operating the two systems in parallel is inefficient and add significant operational complexity. It is also challenging to bring the Satellite WWTP online intermittently during periods of high flow/load, which would require ML to be manually transferred from the Easton tanks to the Satellite tanks, and for a second and significantly different activated sludge process to be initiated while biological treatment is under stress. For these reasons, it is recommended that the operations of the two facilities be combined into one common WWTP using infrastructure from both WWTPs. The proposed configuration would combine the Easton and Satellite flows before grit removal, and the existing activated sludge systems would be modified to operate as parallel sets of tanks using the same biological treatment process as indicated earlier. However, other capital improvements beyond those identified in the BNR alternatives would be required to consolidate the WWTP operation. This section describes these additional capital improvements that are required to implement the BNR alternatives. 1. Preliminary and Primary Treatment Improvements The Satellite WWTPs influent does not currently undergo preliminary or primary treatment and is discharged either directly to the Satellite activated sludge system or to the Easton activated sludge system (current operation). Because the Satellite activated sludge system is approximately 5 feet higher in elevation than the Easton activated sludge system, gravity flow of a combined influent to the two systems is not possible without hydraulic modifications to the existing primary clarifiers and splitter structure. Improvements to the preliminary and primary treatment facilities to consolidate the WWTPs are as follows: a. Replace Easton and Satellite WWTPs influent pumps. b. Modify Satellite influent pump discharge piping to allow discharge upstream of grit removal, to the primary clarifier splitter box, and to the primary effluent splitter structure. Provide new flow measurement and sampling for Satellite influent. c. Add larger opening with sluice gate between Easton and Satellite WWTPs influent wet wells to allow wet wells to operate as one. d. Modify grit influent channel to reduce grit settling. e. Replace grit collector mechanisms. f. Replace grit pumps and associated piping. Prepared by Strand Associates, Inc.® 30 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 54 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study g. Replace grit classifier with two grit washers. h. Install additional primary influent pipe between grit removal effluent channel and primary clarifier splitter structure to increase hydraulic capacity to 64 MGD. Modify grit effluent piping and equalization basin downward opening weir control in degritter effluent channel. j. Raise the walls and channels of the primary clarifiers and splitter structure approximately 5 feet to increase the water surface elevation in the primary clarifiers by approximately 5 feet. Replace primary clarifier mechanisms and weirs. k. Convert the existing Easton anoxic selector basin into primary effluent splitter structure to split flow between the Satellite and Easton activated sludge systems. Install new piping from splitter structure to Satellite activated sludge system. 2. Replacement of Aeration Blowers and Automation of Air Piping Cross -Connection Air for the activated sludge system is currently provided by eight 800-horsepower (hp) multi -stage centrifugal blowers with nominal capacities of 10,500 standard cubic feet per minute (scfm) each. The City currently operates only one or two of these blowers under normal conditions. During periods of low flow and load, these blowers do not provide the desired turndown, resulting in high dissolved oxygen (DO) concentrations in the ML that is recycled to the anoxic zones. Newer blower technologies, such as high-speed turbo blowers and single -stage centrifugal blowers, are more energy efficient and would provide better turndown than the existing blowers. It is recommended that four of the existing centrifugal blowers are replaced to improve energy efficiency and turndown while providing the oxygen for the simulated maximum month condition. For planning purposes, four 10,000 scfm high-speed turbo blowers are included in the recommended plan. It is also recommended the remaining four multistage centrifugal blowers are maintained to provide the additional air required for the full permitted design loading condition or should the anaerobic lagoon be offline for a period. In addition, new blower controls based on dissolved oxygen are recommended in all activated sludge basins. Automation is also included for the cross -connection between the existing Easton and Satellite aeration systems to allow the two aeration systems to operate as a combined system. 3. Final Clarifier Mechanism Replacement The recommended BNR improvements and WWTP consolidation will allow the City to better use the existing final clarifiers, which is anticipated to improve clarifier performance. However, the Satellite final clarifiers have been out of service for several years and it is anticipated that some work will be required to bring them back into service. Based on this, the recommended near -term improvements include a budgetary cost to replace the existing clarifier mechanisms. Note that City staff are planning to advertise a project to replace one of the Easton final clarifier mechanisms in summer 2023, which was a near -term project identified in the 2018 Nutrient Reduction Study. Prepared by Strand Associates, Inc.® 31 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 55 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study 4. Final Clarifier Cross -Connection and Flow Distribution Improvements As discussed earlier, the Satellite and Easton activated sludge systems are completely separated, not allowing for final clarifiers to be used without using the associated activated sludge system. To improve clarifier capacity following WWTP consolidation, a cross -connection between the two systems upstream of the final clarifiers is recommended to provide the ability to transfer ML from the Satellite WWTP to the Easton WWTP. In addition, modifications to the existing final clarifier flow splitter boxes for both WWTPs are recommended to improve flow distribution and control. These splitter boxes, including the cross -connection piping and downward opening weir gate with ultrasonic flow measurement to control the transfer of ML from the Satellite WWTP to the Easton WWTP, would be extensions of the existing splitter boxes and ML recycle wet wells. 5. New Effluent Flow Metering Structure Currently, secondary effluent from the Satellite and Easton WWTPs are measured separately using Parshall flumes at two different locations on -site. The existing Satellite secondary effluent flume is not adequately sized to measure the portion of the future combined WWTP flow that would be treated using the Satellite activated sludge tanks, requiring modifications to the existing means of effluent flow measurement. While the Easton secondary effluent flume is large enough to measure the portion of the future combined WWTP that would be treated using the Easton activated sludge system, it is not large enough to be used to measure the combined flows from the Easton and Satellite activated sludge systems. Therefore, the construction of a larger Parshall flume to measure the secondary effluent from both the Satellite and Easton activated sludge systems is proposed in the vicinity of the existing Easton effluent flume. IMPLEMENTATION AND BUDGETARY CONSIDERATIONS Because of the emergence of BNR technologies such as the sidestream enhanced biological phosphorus removal (EBPR) (Alternative BNR3) that are anticipated to result in significantly less chemical and energy use compared to CPR, a phased approach would allow further development and optimization of BNR at the WWTP at a lower operating cost than CPR. This approach would also provide flexibility to incorporate CPR in a future phase. In addition, the City has several planned projects to improve facility performance which will require the commitment of significant funds as noted below: 1. WWTP Improvements Not Attributed to Nutrient Removal ■ Mid -Term (2025 to 2030): $33.4 million 2. Collection System Condition and Capacity Related Improvements: • 2024 to 2026: $16.6 million (pending further review) • 2027 to 2029: $ 12.6 million (pending further review) • 2030 to 2032: $6.4 million (pending further review) Because of the significant capital funds already planned toward improving facility performance, a phased approach is appropriate to reduce the financial burden on the City's rate payers in the near future. Prepared by Strand Associates, Inc.® 32 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 56 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study A. Short -Term Improvements —Demonstrate and Optimize BNR Based on the capital and present worth cost evaluation presented in Table 21, Alternative BNR3 is the least costly alternative for enhanced nutrient removal. This process has shown successful BNR for wastewaters that are carbon -limited for conventional BNR processes. The opinion of probable construction costs (OPCC) for the improvements necessary to implement nutrient removal at the WWTP are presented in Table 23. Component OPCC Equipment/Structures Preliminary and Primary Treatment Improvements; Raise Primary Clarifiers $5,070,000 BNR3—MLE with Sidestream Enhanced BPR $2,800,000 Blower Replacement $3,910,000 Final Clarifier Mechanism Replacement $2,050,000 Final Clarifier Cross Connection and Flow Distribution Improvements $1,210,000 Return Flow and Secondary Effluent Metering $520,000 Replace Easton Bar Screens $1,090,000 Piping and Mechanical $5,890,000 Electrical $3,660,000 Sitework $1,050,000 HVAC $540,000 Contractors' General Conditions $2,780,000 Contingencies and Technical Services $15,280,000 TOTAL OPINION OF CAPITAL COSTS $45,850,000 Note: All costs are in second quarter 2023 dollars Table 23 Recommended Near -Term Improvements for Nutrient Removal B. Mid -Term Recommendations —Evaluate Struvite Recovery, Evaluate CPR If Necessary Following BNR optimization, it is recommended that the City evaluate the necessity and potential benefits of adding a process to recover or sequester struvite from the anaerobic digester sludge of filtrate/centrate. While the City does not currently experience nuisance struvite formation within its anaerobic digesters, struvite concerns are apparent in the piping and tanks downstream of the digesters and dewatering. In addition, successful implementation of BPR would increase the phosphorus content of the biosolids and potentially lead to significantly more struvite in the digesters, dewatering operations, and centrate management systems. Further evaluation of the combination of sidestream EBPR and struvite recovery is recommended following implementation of Alternative BNR3. It is anticipated that the construction of a struvite recovery or sequestration system would cost approximately $8 million assuming a sludge -based sequestration system and including technical services. CPR should also be evaluated at that time. Prepared by Strand Associates, Inc.® 33 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 57 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study SEWER BUDGET IMPACT The total OPCC for the near -term improvements is approximately $45.85 million (second Quarter 2023 dollar basis). Projecting this amount to an anticipated second Quarter 2026 bid date and applying a construction inflation rate of 4 percent annually, the anticipated total project costs are approximately $51.8 million. The WWTP improvements are anticipated to be financed through Iowa's State Revolving Fund (SRF) loan program. The SRF program provides 0 percent interest financing for planning and design services for up to 3 years that can be rolled into the SRF construction loan. Construction loans are offered at 1.75 percent interest, typically for 20-year terms. In addition to the 1.75 percent interest loan, an administrative fee of 0.25 percent is added each year to the outstanding principal balance for administering the loan. Also, an additional 0.5 percent of the loan amount (up to $100,000) is included as a loan initiation fee. Assuming a total loan amount of $51.8 million, plus the initiation fee of $100,000, the annual debt service payment is expected to be approximately $3.1 million. Table 24 presents a preliminary budget impact summary of the near -term improvements. A preliminary analysis was conducted to estimate the impact of the near -term improvements on the WWTP budget. Although many components of the identified improvements are more energy efficient that current WWTP operation, particularly the replacement of the activated sludge blowers which can account for more than one-half of the energy of the WWTP, this analysis was conducted assuming there would be no change in annual O&M costs. While the improvements would likely result in overall O&M savings, the assumptions used in this analysis provide a conservative estimate of the impact on the sewer budget. A more detailed analysis of plant operation following the near -term improvements as well as a user charge study would be conducted as part of a facilities planning effort should the City decide to proceed with this major project. Near -Term Improvements OPCC1 $51,810,000 Anticipated Annual Debt Service Payment2 $3,100,000 'Second Quarter 2026 Dollars 220-year loan at 1.75 percent interest, 0.25 percent administration fee, and $100,000 loan initiation fee Table 24 WWTP Budget Impact Summary for Near -Term Improvements The City conducted a preliminary analysis of the impact on sewer rates for the projects described in this report as presented in this next section. Prepared by Strand Associates, Inc.® 34 R:\MAD\Documents\Reports\Active\Waterloo, IA\Nutrient Reduction Study.4463.017.SKH.Apr\Report\Report.docx\050323 Page 58 of 164 DRAFT-(05.03.23) APPENDIX A NPDES PERMIT Page 59 of 164 DRAFT-(05.03.23) IOWA DEPARTMENT OF NATURAL RESOURCES National Pollutant Discharge Elimination System (NPDES) Permit OWNER NAME & ADDRESS CITY OF WATERLOO 715 MULBERRY STREET WATERLOO, IA 50703 IOWA NPDES PERMIT NUMBER: 0790001 DATE OF ISSUANCE: 06/01/2021 DATE OF EXPIRATION: 05/31/2026 FACILITY NAME & ADDRESS WATERLOO CITY OF STP 3505 EASTON AVENUE WATERLOO, IA 50702 Section 31, T89N, R12W Black Hawk County YOU ARE REQUIRED TO FILE FOR RENEWAL OF THIS PERMIT BY: 12/02/2025 EPA NUMBER: IA0042650 This permit is issued pursuant to the authority of section 402(b) of the Clean Water Act (33 U.S.C. 1342(b)), Iowa Code section 455B.174, and rule 567-64.3, Iowa Administrative Code. You are authorized to operate the disposal system and to discharge the pollutants specified in this permit in accordance with the effluent limitations, monitoring requirements and other terms set forth in this permit. You may appeal any condition of this permit by filing a written notice of appeal and request for administrative hearing with the director of the department within 30 days of permit issuance. Any existing, unexpired Iowa operation permit or Iowa NPDES permit previously issued by the department for the facility identified above is revoked by the issuance of this permit. This provision does not apply to any authorization to discharge under the terms and conditions of a general permit issued by the department or to any permit issued exclusively for the discharge of stormwater. FOR THE DEPARTMENT OF NATURAL RESOURCES Digitally signed by Ben By Ben Hucka- 2021.05.18 07:32:01 -05'00' Ben Hucka NPDES Section, Environmental Services Division Page 60 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Outfall No.: 001 EASTON AVENUE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. DRAFT-(05.03.23) Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 004 BYPASS AT THE HACKETT ROAD LIFT STATION. Receiving Stream: Route of Flow: UNNAMED CREEK UNNAMED CREEK TO CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Outfall No.: 008 SATELLITE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Page 2 Page 61 of 164 Facility Name: WATERLOO CITY OF STP DRAFT - (0 5.0 3.2 3 ) Permit Number: 0790001 Outfall No.: 009 BYPASS AT SHORELINE OVERFLOW WHEN STREAM FLOW IS LESS THAN 8500 CFS (USGS GAGE 05464000) Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 010 BYPASS AT EQUALIZATION BASIN OVERFLOW Receiving Stream: CEDAR RIVER Route of Flow: DRAINAGE DITCH TO CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Outfall No.: 011 TOTAL TREATMENT FACILITY SHORELINE DISCHARGE- STREAM FLOW IS GREATER THAN OR EQUAL TO 8500 CFS (USGS GAGE 05464000) Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Page 3 Page 62 of 164 Facility Name: WATERLOO CITY OF STP DRAFT - (0 5.0 3.2 3 ) Permit Number: 0790001 Outfall No.: 012 BYPASS AT SERGEANT RD AND FLETCHER AVE Receiving Stream: BLACK HAWK CREEK Route of Flow: BLACK HAWK CREEK Class A3 waters are children's recreational use waters in which recreational uses by children are common. Class A3 waters are water bodies having definite banks and bed with visible evidence of flow or occurrence of water. This type of use would primarily occur in urban or residential areas. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 801 TOTAL TREATMENT FACILITY DIFFUSER DISCHARGE. Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Bypasses from any portion of a treatment facility or from a sanitary sewer collection system designed to carry only sewage are prohibited. Page 4 Page 63 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Effluent Limitations: DRAFT-(05.03.23) You are prohibited from discharging pollutants except in compliance with the following effluent limitations: 001 EASTON AVENUE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Outfall: 001 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits CBOD5 Yearly 7 Day Average 40 MG/L Yearly 30 Day Average 25 MG/L TOTAL SUSPENDED SOLIDS Yearly 7 Day Average 45 MG/L Yearly 30 Day Average 30 MG/L 008 SATELLITE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Outfall: 008 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits CBOD5 Yearly 7 Day Average 40 MG/L Yearly 30 Day Average 25 MG/L TOTAL SUSPENDED SOLIDS Yearly 7 Day Average 45 MG/L Yearly 30 Day Average 30 MG/L Page 5 Page 64 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 011 TOTAL TREATMENT FACILITY SHORELINE DISCHARGE- STREAM FLOW IS GREATER THAN OR EQUAL TO 8500 CFS (USGS GAGE 05464000) DRAFT-(05.03.23) Outfall: 011 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits CBODS 85% Removal Required Yearly 7 Day Average 11609 LBS/DAY Yearly 30 Day Average 7256 LBS/DAY TOTAL SUSPENDED SOLIDS 85% Removal Required Yearly 7 Day Average 13060 LBS/DAY Yearly 30 Day Average 8707 LBS/DAY NITROGEN, TOTAL (AS N) Yearly 30 Day Average 9285.5 LBS/DAY Yearly Daily Maximum 15199.0 LBS/DAY PH Yearly Daily Maximum 9.0 STD UNITS Yearly Daily Minimum 6.0 STD UNITS E. COLI MAR Geometric Mean 126 #/100 ML APR Geometric Mean 126 #/100 ML MAY Geometric Mean 126 #/100 ML JUN Geometric Mean 126 #/100 ML JUL Geometric Mean 126 #/100 ML AUG Geometric Mean 126 #/100 ML SEP Geometric Mean 126 #/100 ML OCT Geometric Mean 126 #/100 ML NOV Geometric Mean 126 #/100 ML ACUTE TOXICITY, CERIODAPHNIA Yearly Daily Maximum 1 NO TOXICITY ACUTE TOXICITY, PIMEPHALES Yearly Daily Maximum 1 NO TOXICITY Page 6 Page 65 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 DRAFT-(05.03.23) Outfall: 011 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits AMMONIA NITROGEN (N) JAN 30 Day Average 69.4 MG/L 12696 LBS/DAY JAN Daily Maximum 69.4 MG/L 12696 LBS/DAY FEB 30 Day Average 78.4 MG/L 13832 LBS/DAY FEB Daily Maximum 78.4 MG/L 13832 LBS/DAY MAR 30 Day Average 68.0 MG/L 12392 LBS/DAY MAR Daily Maximum 68.0 MG/L 12392 LBS/DAY APR 30 Day Average 53.9 MG/L 10546 LBS/DAY APR Daily Maximum 53.9 MG/L 10546 LBS/DAY MAY 30 Day Average 60.5 MG/L 11394 LBS/DAY MAY Daily Maximum 60.5 MG/L 11394 LBS/DAY JUN 30 Day Average 59.5 MG/L 10079 LBS/DAY JUN Daily Maximum 59.5 MG/L 11114 LBS/DAY JUL 30 Day Average 64.1 MG/L 11575 LBS/DAY JUL Daily Maximum 64.1 MG/L 12395 LBS/DAY AUG 30 Day Average 62.0 MG/L 10982 LBS/DAY AUG Daily Maximum 62.0 MG/L 11823 LBS/DAY SEP 30 Day Average 55.2 MG/L 10890 LBS/DAY SEP Daily Maximum 55.2 MG/L 10890 LBS/DAY OCT 30 Day Average 54.0 MG/L 10558 LBS/DAY OCT Daily Maximum 54.0 MG/L 10558 LBS/DAY NOV 30 Day Average 52.5 MG/L 10145 LBS/DAY NOV Daily Maximum 52.5 MG/L 10145 LBS/DAY DEC 30 Day Average 54.3 MG/L 10655 LBS/DAY DEC Daily Maximum 54.3 MG/L 10655 LBS/DAY Page 7 Page 66 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 801 TOTAL TREATMENT FACILITY DIFFUSER DISCHARGE. DRAFT-(05.03.23) Outfall: 801 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits CBOD5 85% Removal Required Yearly 7 Day Average 11609 LBS/DAY Yearly 30 Day Average 7256 LBS/DAY TOTAL SUSPENDED SOLIDS 85% Removal Required Yearly 7 Day Average 13060 LBS/DAY Yearly 30 Day Average 8707 LBS/DAY NITROGEN, TOTAL (AS N) Yearly 30 Day Average 9285.5 LBS/DAY Yearly Daily Maximum 15199.0 LBS/DAY PH Yearly Daily Maximum 9.0 STD UNITS Yearly Daily Minimum 6.0 STD UNITS E. COLI MAR Geometric Mean 126 #/100 ML APR Geometric Mean 126 #/100 ML MAY Geometric Mean 126 #/100 ML JUN Geometric Mean 126 #/100 ML JUL Geometric Mean 126 #/100 ML AUG Geometric Mean 126 #/100 ML SEP Geometric Mean 126 #/100 ML OCT Geometric Mean 126 #/100 ML NOV Geometric Mean 126 #/100 ML ACUTE TOXICITY, CERIODAPHNIA Yearly Daily Maximum 1 NO TOXICITY ACUTE TOXICITY, PIMEPHALES Yearly Daily Maximum 1 NO TOXICITY Page 8 Page 67 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 DRAFT-(05.03.23) Outfall: 801 Effective Dates: 06/01/2021 to 05/31/2026 Parameter Season Limit Type Limits AMMONIA NITROGEN (N) JAN 30 Day Average 55.9 MG/L 9364 LBS/DAY JAN Daily Maximum 95.0 MG/L 16561 LBS/DAY FEB 30 Day Average 70.0 MG/L 11372 LBS/DAY FEB Daily Maximum 116.5 MG/L 19558 LBS/DAY MAR 30 Day Average 30.7 MG/L 4998.7 LBS/DAY MAR Daily Maximum 108.5 MG/L 21421 LBS/DAY APR 30 Day Average 21.5 MG/L 3519.0 LBS/DAY APR Daily Maximum 79.8 MG/L 14363.0 LBS/DAY MAY 30 Day Average 18.0 MG/L 2962.7 LBS/DAY MAY Daily Maximum 79.1 MG/L 14162.8 LBS/DAY JUN 30 Day Average 11.6 MG/L 1931.6 LBS/DAY JUN Daily Maximum 78.1 MG/L 13877.8 LBS/DAY JUL 30 Day Average 14.2 MG/L 2283.2 LBS/DAY JUL Daily Maximum 87.4 MG/L 25229 LBS/DAY AUG 30 Day Average 13.0 MG/L 2082.2 LBS/DAY AUG Daily Maximum 74.1 MG/L 13652.6 LBS/DAY SEP 30 Day Average 13.4 MG/L 2221.8 LBS/DAY SEP Daily Maximum 94.6 MG/L 16916 LBS/DAY OCT 30 Day Average 30.8 MG/L 5020.2 LBS/DAY OCT Daily Maximum 93.5 MG/L 16990 LBS/DAY NOV 30 Day Average 38.7 MG/L 6282.3 LBS/DAY NOV Daily Maximum 78.4 MG/L 13970.8 LBS/DAY DEC 30 Day Average 45.8 MG/L 8998 LBS/DAY DEC Daily Maximum 72.7 MG/L 13467 LBS/DAY Page 9 Page 68 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Non -Standard Effluent Limits DRAFT-(05.03.23) Outfall Limits Effective During Blending Mode of Operation 011 and 801 Parameter Season Limit Type Limits BIOCHEMICAL OXYGEN DEMAND (BOD5) Yearly 7 Day Average 45 MG/L 13060 LBS/DAY Yearly 30 Day Average 30 MG/L 8707 LBS/DAY Monitoring and Reporting Requirements (a) Samples and measurements taken shall be representative of the volume and nature of the monitored wastewater. (b) Analytical and sampling methods specified in 40 CFR Part 136 or other methods approved in writing by the department shall be utilized. All effluent samples for which a limit applies must be analyzed using sufficiently sensitive methods (i.e. testing procedures) approved under 567 IAC Chapter 63 and 40 CFR Part 136 for the analysis of pollutants or pollutant parameters or as required under 40 CFR chapter I, subchapter N or O. For the purposes of this paragraph, an approved method is sufficiently sensitive when: (1) the method minimum level (ML) is at or below the level of the effluent limit established in the permit for the measured pollutant or pollutant parameter; or (2) the method has the lowest ML of the approved analytical methods for the measured pollutant or pollutant parameter. Samples collected for operational testing need not be analyzed by approved analytical methods; however, commonly accepted test methods should be used. (c) You are required to report all data including calculated results needed to determine compliance with the limitations contained in this permit. The results of any monitoring not specified in this permit performed at the compliance monitoring point and analyzed according to 40 CFR Part 136 shall be included in the calculation and reporting of any data submitted in accordance with this permit. This includes daily maximums and minimums, 30-day averages and 7-day averages for all parameters that have concentration (mg/1) and mass (lbs/day) limits. In addition, flow data shall be reported in million gallons per day (MGD). (d) Records of monitoring activities and results shall include for all samples: the date, exact place and time of the sampling; the dates the analyses were performed; who performed the analyses; the analytical techniques or methods used; and the results of such analyses. (e) Results of all monitoring shall be recorded on forms provided by, or approved by, the department, and shall be submitted to the appropriate regional field office of the depaitiiient by the fifteenth day following the close of the reporting period. Your reporting period is on a MONTHLY basis, ending on the last day of each reporting period. (f) Operational performance monitoring for treatment unit process control shall be conducted to ensure that the facility is properly operated in accordance with its design. The results of any operational performance monitoring need not be reported to the department, but shall be maintained in accordance with rule 567 IAC 63.2 (455B). The results of any operational performance monitoring specified in this permit shall be submitted to the department in accordance with these reporting requirements. (g) Chapter 63 of the rules provides you with further explanation of your monitoring requirements. Page 10 Page 69 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Outfall Wastewater Parameter Sample Frequency The following monitoring requirements shall be in effect from 06/01/2021 to 05/31/2026 001 BIOCHEMICAL OXYGEN DEMAND 7/WEEK OR DAILY (BOD5) 001 001 NITROGEN, TOTAL (AS N) 001 NITROGEN, TOTAL KJELDAHL (AS N) FLOW 7/WEEK OR DAILY 1 TIME PER WEEK 1 TIME PER WEEK 001 PH 7/WEEK OR DAILY 001 PHOSPHORUS, TOTAL (AS P) 1 TIME PER WEEK 001 TEMPERATURE 7/WEEK OR DAILY 001 TOTAL SUSPENDED SOLIDS 7/WEEK OR DAILY 001 CBOD5 7/WEEK OR DAILY 001 TOTAL SUSPENDED SOLIDS 7/WEEK OR DAILY 008 BIOCHEMICAL OXYGEN DEMAND 7/WEEK OR DAILY (BOD5) 008 FLOW 008 NITROGEN, TOTAL (AS N) 008 NITROGEN, TOTAL KJELDAHL (AS N) 008 PH 008 PHOSPHORUS, TOTAL (AS P) 008 TEMPERATURE 008 TOTAL SUSPENDED SOLIDS 008 FLOW 008 CBOD5 008 TOTAL SUSPENDED SOLIDS 1 7/WEEK OR DAILY 1 TIME PER WEEK 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY Sample Type 124 HOUR COMPOSITE 24 HOUR TOTAL 24 HOUR COMPOSITE 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE 24 HOUR COMPOSITE 24 HOUR COMPOSITE 24 HOUR COMPOSITE DRAFT-(05.03.23) i Monitoring Location RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE EFFLUENT PRIOR TO DISINFECTION EFFLUENT PRIOR TO DISINFECTION RAW WASTE 24 HOUR TOTAL RAW WASTE 24 HOUR COMPOSITE RAW WASTE 24 HOUR COMPOSITE RAW WASTE GRAB RAW WASTE 24 HOUR COMPOSITE RAW WASTE GRAB I RAW WASTE 24 HOUR COMPOSITE RAW WASTE 24 HOUR TOTAL BLENDED FLOW 24 HOUR COMPOSITE EFFLUENT PRIOR TO DISINFECTION 24 HOUR COMPOSITE EFFLUENT PRIOR TO DISINFECTION Page 11 Page 70 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 DRAFT-(05.03.23) Outfall Wastewater Parameter Sample Frequency Sample Type Monitoring Location The following monitoring requirements shall be in effect from 06/01/2021 to 05/31/2026 011 011 011 011 ACUTE TOXICITY, CERIODAPHNIA ACUTE TOXICITY, PIMEPHALES AMMONIA NITROGEN (N) BIOCHEMICAL OXYGEN DEMAND (BOD5) 1 EVERY 12 MONTHS 1 EVERY 12 MONTHS 7/WEEK OR DAILY 7/WEEK OR DAILY 011 CBODS 7/WEEK OR DAILY 011 011 011 011 011 011 011 E. COLI FLOW NITROGEN, TOTAL (AS N) PH PHOSPHORUS, TOTAL (AS P) TEMPERATURE TOTAL SUSPENDED SOLIDS GEO. MEAN 1/3 MONTHS 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 7/WEEK OR DAILY 24 HOUR COMPOSITE 24 HOUR COMPOSITE 24 HOUR COMPOSITE 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION ,EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION GRAB 24 HOUR TOTAL 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION 'EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION Page 12 Page 71 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 DRAFT-(05.03.23) Outfall Wastewater Parameter Sample Frequency Sample Type Monitoring Location The following monitoring requirements shall be in effect from 06/01/2021 to 05/31/2026 801 801 801 801 801 801 STREAM FLOW FLOW FLOW FLOW BIOCHEMICAL OXYGEN DEMAND (BODS) FLOW 801 NITROGEN, TOTAL (AS N) 801 801 801 801 801 801 801 801 801 801 801 801 801 801 801 801 801 801 NITROGEN, TOTAL KJELDAHL (AS N) PHOSPHORUS, TOTAL (AS P) TOTAL SUSPENDED SOLIDS ACUTE TOXICITY, CERIODAPHNIA ACUTE TOXICITY, PIMEPHALES AMMONIA NITROGEN (N) BATHYMETRIC REPORT BIOCHEMICAL OXYGEN DEMAND (BODS) CBOD5 DIFFUSER VALIDATION REPORT E. COLI FLOW NITROGEN, TOTAL (AS N) PH PHOSPHORUS, TOTAL (AS P) TEMPERATURE TOTAL SUSPENDED SOLIDS VISUAL OBSERVATION 7/WEEK OR DAILY 7/WEEK OR DAILY MEASUREMENT 24 HOUR TOTAL 7/WEEK OR DAILY 24 HOUR TOTAL r - 7/WEEK OR DAILY 24 HOUR TOTAL 7/WEEK OR DAILY 7/WEEK OR DAILY 1 TIME PER WEEK 1 TIME PER WEEK 1 TIME PER WEEK 7/WEEK OR DAILY 1 EVERY 12 MONTHS 1 EVERY 12 MONTHS 7/WEEK OR DAILY 1 EVERY 12 MONTHS 7/WEEK OR DAILY 7/WEEK OR DAILY 1 EVERY 12 MONTHS GEO. MEAN 1/3 MONTHS 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 7/WEEK OR DAILY 1 EVERY MONTH CALCULATED CALCULATED CALCULATED CALCULATED CALCULATED CALCULATED 24 HOUR COMPOSITE 24 HOUR COMPOSITE 24 HOUR COMPOSITE MEASUREMENT 24 HOUR COMPOSITE 24 HOUR COMPOSITE VISUAL GRAB 24 HOUR TOTAL CEDAR RIVER AT USGS STREAM GAGE 05464000 FLOW EQUALIZATION BASIN OVERFLOW TO SATELLITE PLANT SPLIT FLOW EFFLUENT FLOW EQUALIZATION BASIN RETURN RAW WASTE TOTAL RAW WASTE FLOW RAW WASTE RAW WASTE RAW WASTE RAW WASTE EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER EFFLUENT AFTER DISINFECTION 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE VISUAL EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER Page 13 Page 72 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Special Monitoring Requirements DRAFT-(05.03.23) Outfall # Description 008 FLOW Flow shall be reported if partially treated wastewater from the satellite plant is diverted to the disinfection chamber as outlined on the blending mode of operation page of this permit. If partially treated effluent is not being diverted to the disinfection unit, the facility shall report "not required" on the discharge monitoring report for that day. 011, 801 BIOCHEMICAL OXYGEN DEMAND (BOD5) All BOD5 samples must be seeded at the laboratory prior to analysis when the disinfection equipment is in use. E. COLI The limit for E. coli of 126 org/100 ml specified on the limits pages of this permit for outfall(s) 801 and 011 is a monthly geometric mean. The disinfection season is established in the Iowa Administrative Code, Subparagraph 567 IAC 61.3(3)"a"(1), and is in effect from March 15 to November 15. Any disinfection system (chlorine, UV light, etc.) shall be operated to comply with the limit during the entire disinfection season whenever wastewater is being discharged from outfall(s) 801 and 011. The facility must collect and analyze a minimum of five samples in one calendar month during each 3-month period from March 15 to November 15. The 3-month periods are March — May, June — August, and September — November. The collection of five samples in each 3-month period will result in a minimum of 15 samples being collected during a calendar year. For example, for the first 3-month period, the operator may choose April as the calendar month to collect the 5 individual E. coli samples to determine compliance with the limits. The operator may also choose the months of March or May as well, as long as each of the 5 samples is collected during a single calendar month. The same principle applies to the other two 3-month periods during the disinfection season. The following requirements apply to the individual samples collected in one calendar month: Samples must be spaced over one calendar month. No more than one sample can be collected on any one day. There must be a minimum of two days between each sample. No more than two samples may be collected in a period of seven consecutive days. If the effluent has been disinfected using chlorine, ultraviolet light (UV), or any other process intended to disrupt the biological integrity of the E. coli, the samples shall be analyzed using the Most Probable Number method found in Standard Method 9223B (Colilert® or Colilert-18® made by IDEXX Laboratories, Inc.). If the effluent has not been disinfected the samples may be analyzed using either the MPN method above or EPA Method 1603: Escherichia coli (E. coli) in water by membrane filtration using modified membrane-thermotolerant E. coli agar (modified mTEC) or mColiBlue-24® made by the Hach Company. The geometric mean must be calculated using all valid sample results collected during a month. The geometric mean formula is as follows: Geometric Mean = (Sample one * Sample two * Sample three * Sample four *Sample five...Sample N)^(1/N), which is the Nth root of the result of the multiplication of all of the sample results where N = the number of samples. If a sample result is a less than value, the value reported by the lab without the less than sign should be used in the geometric mean calculation. The geometric mean can be calculated in one of the following ways: Use a scientific calculator that can calculate the powers of numbers. Enter the samples in Microsoft Excel and use the function "GEOMEAN" to perform the calculation. Use the geometric mean calculator on the Iowa DNR webpage at: http://www.iowadnr.gov/Environmental-Protection/Water-Quality/NPDES- Wastewater-Permitting/NPDES-Operator-Information/Bacteria-Sampling Page 14 Page 73 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Outfall # Description 011, 801 NITROGEN, TOTAL (AS N) DRAFT-(05.03.23) Total nitrogen shall be determined by testing for Total Kjeldahl Nitrogen (TKN) and nitrate + nitrite nitrogen and reporting the sum of the TKN and nitrate + nitrite results (reported as N). Nitrate + nitrite can be analyzed together or separately. 801 RAW WASTE FLOW Raw flow shall be calculated as the sum of the 24-hour totals from the Easton Ave facility and the Satellite facility (recirculation flow shall not be included). RAW WASTE: BOD5, TSS, TP, TN, TKN Samples are required at each influent line to determine the mass loadings from each line. The total influent load to the treatment facility shall then be calculated and reported under outfall 801. STREAM FLOW A daily minimum value shall be reported. Page 15 Page 74 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 OVERFLOW TO SATELLITE r - -- DRAFT-(05.03.23) OUTFALL AND SAMPLING LOCATIONS FLOW EOLIALIZATION BASIN FED FEED-F..' FEQ EMERGENCY I ERFLOW L_H OUTFALL008 EASTON 001 - FEO RETURN R DIFFUSER 801 OUTFALL001 HIGH RIVER OVERFLOW SATELLITE008 SHORELIN E 0ISCHARG E011 � - SHORELI NE DISCHARGE C09 Page 16 Page 75 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Blending Mode of Operation DRAFT-(05.03.23) The City of Waterloo may operate their wastewater treatment plant in the following mode during peak influent flow conditions only. Influent flows that exceed the hydraulic capacity of the Easton Avenue plant are diverted to two -flow equalization basins (FEQ) after passing through grit removal. Flows stored in the FEQ basins are returned to the Easton Wet Well once the Easton Avenue plant regains hydraulic capacity. In the event that the Easton Avenue plant has yet to regain hydraulic capacity, the flow from the FEQ will be diverted to the Satellite plant. The flows from the FEQ will be routed through the Satellite plant and returned to the headworks of the Easton Avenue plant via portable pumps. If the biological system at the Easton Avenue Plant could be jeopardized due to excessive flows, the partially treated wastewater from the Satellite plant will be diverted to the disinfection chamber and blended with the final effluent from the Easton plant. Once the Easton Avenue plant regains hydraulic capacity the facility is no longer authorized to blend the FEQ overflow via the Satellite plant. Effluent limits and permit conditions remain in effect during this mode of operation. Page 17 Page 76 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Outfall Number: 011, 801 DRAFT-(05.03.23) Ceriodaphnia and Pimephales Toxicity Effluent Testing 1. For facilities that have not been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within three (3) months of permit issuance. For facilities that have been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within twelve months (12) of the last toxicity test. 2. The test organisms that are to be used for acute toxicity testing shall be Ceriodaphnia dubia and Pimephales promelas. The acute toxicity testing procedures used to demonstrate compliance with permit limits shall be those listed in 40 CFR Part 136 and adopted by reference in rule 567 IAC 63.1(1). The method for measuring acute toxicity is specified in USEPA, October 2002, Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. USEPA, Office of Water, Washington, D.C., EPA 821-R-02-012. 3. The diluted effluent sample must contain a minimum of 11.60 % effluent and no more than 88.40 % of culture water. 4. One valid positive toxicity result will require, at a minimum, quarterly testing for effluent toxicity until three successive tests are determined not to be positive. 5. Two successive valid positive toxicity results or three positive results out of five successive valid effluent toxicity tests will require a toxicity reduction evaluation to be completed to eliminate the toxicity. 6. A non -toxic test result shall be indicated as a "1" on the monthly operation report. A toxic test result shall be indicated as a "2" on the monthly operation report. DNR Form 542-1381 shall also be submitted to the DNR field office along with the monthly operation report. Ceriodaphnia and Pimephales Toxicity Effluent Limits The maximum limit of "1" for the parameters Acute Toxicity, Ceriodaphnia and Acute Toxicity, Pimephales means no positive toxicity results. Definition: "Positive toxicity result" means a statistical difference of mortality rate between the control and the diluted effluent sample. For more information, see USEPA, October 2002, Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition, USEPA, Office of Water, Washington, D.C., EPA 821-R-02-012. A toxicity test performed at the dilution percentage specified in item 3 of this page shall satisfy the monitoring requirements for both outfall 011 and 801 as required on pages 12 and 13 of this permit. Page 18 Page 77 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Design Capacity Design: Easton Avenue WPCF The design capacity for the treatment works is specified in Construction Permit Number 98-361-S, issued August 21, 1998. The treatment plant is designed to treat: * An average dry weather (ADW) flow of 12.7 Million Gallons Per Day (MGD). * An average wet weather (AWW) flow of 26.7 Million Gallons Per Day (MGD). * A maximum wet weather (MWW) flow of 36.0 Million Gallons Per Day (MGD). * A design 5-day biochemical oxygen demand (BOD5) load of 30,000 lbs/day. * A design Total Kjeldahl Nitrogen (TKN) load of 7,500.00 lbs/day. Satellite WPCF The design capacity for the treatment works is specified in Construction Permit Number 95-317-S, issued July 7, 1995. The treatment plant is designed to treat: * An average dry weather (ADW) flow of 5.3 Million Gallons Per Day (MGD). * An average wet weather (AWW) flow of 8.1 Million Gallons Per Day (MGD). * A maximum wet weather (MWW) flow of 11.1 Million Gallons Per Day (MGD). * A design 5-day biochemical oxygen demand (BOD5) load of 58,000 lbs/day. * A design Total Kjeldahl Nitrogen (TKN) load of 13,550.00 lbs/day. Operator Certification Type/Grade: WW/IV DRAFT-(05.03.23) Wastes in such volumes or quantities as to exceed the design capacity of the treatment works or reduce the effluent quality below that specified in the operation permit of the treatment works are considered to be a waste which interferes with the operation or performance of the treatment works and are prohibited by rule IAC 567-62.1(7). Page 19 Page 78 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 SEWAGE SLUDGE HANDLING AND DISPOSAL REQUIREMENTS DRAFT-(05.03.23) "Sewage sludge" is solid, semisolid, or liquid residue generated during the treatment of domestic sewage in a treatment works. Sewage sludge does not include the grit and screenings generated during preliminary treatment. 1. The permittee shall comply with all existing Federal and State laws and regulations that apply to the use and disposal of sewage sludge and with technical standards developed pursuant to Section 405(d) of the Clean Water Act when such standards are promulgated. If an applicable numerical limit or management practice for pollutants in sewage sludge is promulgated after issuance of this permit that is more stringent than a sludge pollutant limit or management practice specified in existing Federal or State laws or regulations, this permit shall be modified, or revoked and reissued, to conform to the regulations promulgated under Section 405(d) of the Clean Water Act. The permittee shall comply with the limitation no later than the compliance deadline specified in the applicable regulations. 2. The permittee shall provide written notice to the Department of Natural Resources prior to any planned changes in sludge disposal practices. 3. Land application of sewage sludge shall be conducted in accordance with criteria established in rule IAC 567 67.1 through 67.11 (455B). Page 20 Page 79 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Diffuser Special Monitoring Requirements Monthly Visual Monitoring: DRAFT-(05.03.23) At a frequency of at least once per month, the permittee shall visually observe the diffuser and record the observations in a log book. The permittee is required to visually observe and record the following items: • Whether the diffuser and diffuser ports can be seen above or below the surface of the water; • Whether the effluent dispersion pattern of the ports can be seen, and whether the patterns are uniform; • Signs of non -uniform bubbling, uneven coloring or actual spraying of effluent above the water surface; • Debris or materials that have collected on or may be obstructing the diffuser; • General structural condition of the diffuser, diffuser ports, and protective materials; • Condition of the shoreline outfall 011; and • Actions taken, if applicable (i.e. corrective/ maintenance measures, adjustments of ports, removal of debris, etc.) The log book entries shall be made available to the Department upon request. The permittee will indicate completion of the visual monitoring by entering a "1" in the "VISUAL" column on the day that the visual monitoring was completed on the Discharge Monitoring Report (DMR) spreadsheet. Annual Diffuser Performance Analysis: Minimum Requirements: Annually, by June lst, the permittee is required to submit a Diffuser Performance Analysis report to the Department at both of the addresses shown below. The annual diffuser analysis should be performed at a stream flow as close as possible to stream critical low flow conditions. The annual diffuser performance analysis should identify if all diffuser ports, that were active when the mixing percentage used in the current NPDES permit was established, are functioning properly. The annual diffuser performance analysis should also assess if rapid and uniform mixing is occurring within 100 feet downstream of the active diffuser ports, determined in a manner consistent with the methods that established the mixing percentage in this NPDES permit, with the stream flow as close as possible to critical low flow conditions. If dye used in the Diffuser Performance Analysis shall meet the following requirements: 1) The Diffuser Performance Analysis shall use one of the following dyes: (a) Rhodamine WT dye (b) FWT red dye tablets (c) FLT Yellow/Green Liquid Concentrate dye (d) Green Sewer Tracing Dye (e) Fluorescent FLT Yellow/Green Powder (f) Bright Dye FWT Red Dye (g) FLT Yellow/Green dye tablets If a dye other than one listed above is used, you must obtain permission from the Department prior to use of the dye. Please contact Katie Greenstein at (515) 725-8400 or katie.greensteinna,dnr.iowa.gov to request approval of dyes other than those listed above. 2) The dye shall be used according to the instructions provided by the manufacturer; and 3) The introduction of the dye into the receiving stream shall be limited to as short a time period as possible and the amount of dye used shall be as little as possible. Page 21 Page 80 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Video and/or pictures of the demonstration should be sent along with the diffuser analysis performance report to both addresses shown below. The Diffuser Performance Analysis report shall describe any proposed location or discharge flow adjustments to the diffuser ports intended to comply with the designed operation of the diffuser. Any video and/or pictures of the demonstration should be included in the report. The permittee will indicate submittal of the Diffuser Performance Analysis report by entering a "1" in the "DIFFVAL" column on the Discharge Monitoring Report (DMR) spreadsheet on the day that the report is submitted. Select the No Discharge Indicator "NOT REQUIRED/MP" on the DMR spreadsheet during the months that the report is not required. DRAFT-(05.03.23) Additional Requirements: The Department will review the Diffuser Performance Analysis report. If the analysis does not show rapid and uniform mixing of the effluent within 100 feet downstream of the active diffuser ports, determined in a manner consistent with the methods that established the mixing percentage in this NPDES permit, you shall be notified of the requirement to submit a plan to correct diffuser deficiencies. The plan to correct the deficiencies shall be submitted to the Field Office address within 60 days of Department notification. A subsequent Diffuser Performance Analysis report shall be submitted to both addresses shown below no later than 60 days after implementing the plan to correct the diffuser deficiencies. If the subsequent Diffuser Performance Analysis report does not show rapid and uniform mixing of the effluent within 100 feet downstream of the active diffuser ports, determined in a manner consistent with the methods that established the mixing percentage in this NPDES permit, the permit shall be amended to include monitoring and limits necessary to be protective of the observed conditions. The DNR Field Office 1 shall be notified by calling 563-927-2640 at least 48 hours prior to the use of dye. Bathymetric Anay_sis: Minimum Requirements: The permittee is required to perform a Bathymetric Analysis which shall be submitted annually, by June 1st to the Department at both of the addresses shown below. The bathymetric features shall be determined by measuring the receiving stream depth at a minimum of twenty (20) equidistant intervals across the entire width of the receiving stream at the location of the diffuser. The Bathymetric Analysis report shall characterize the bathymetric features and include clear documentation of the receiving stream cross section, diffuser location, and stream bottom substrate. • Hydrologic Events: In addition, a Bathymetric Analysis must be performed if significant changes to the stream channel occur as a result of hydrologic events (such as flooding, stream channelization, reconstruction, etc.) A report of this analysis must be submitted to the Department at both of the addresses below within sixty (60) days of the event occurrence. If the Bathymetric Analysis shows that the changes to the receiving stream may alter the mixing achieved by the diffuser, a Diffuser Performance Analysis must also be performed to demonstrate the actual mixing achieved by the diffuser, determined in a manner consistent with the methods that established the mixing percentage in this NPDES permit. Modeling of the 100-foot diffuser mixing area may be used to perform the Diffuser Performance Analysis, with Department approval, if the receiving stream does not reach low flow conditions within four (4) months of the hydrologic event. The Diffuser Performance Analysis report must be submitted to the Department at both of the addresses below within ninety (90) days of the hydrologic event occurrence. A Diffuser Performance Analysis performed as a result of a hydrologic event will fulfill the annual report requirement for that year. The permittee will indicate completion of the Bathymetric Analysis report by entering a "1" in the "BATHY" column on the Discharge Monitoring Report (DMR) spreadsheet on the day that the report is submitted. Select the No Discharge Indicator "NOT REQUIRED/MP" on the DMR spreadsheet during the months that the report is not required. Addresses for Report Submittal: Iowa Department of Natural Resources Environmental Services Division DNR Field Office 1 909 West Main St., Suite 4 Manchester, IA 52057 Iowa Department of Natural Resources Ben Hucka npdes.mail@dnr.iowa.gov Page 22 Page 81 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 SIGNIFICANT INDUSTRIAL USER LIMITATIONS, MONITORING AND REPORTING REQUIREMENTS 1. You shall require all users of your facility to comply with Sections 204(b), 307, and 308 of the Clean Water Act. DRAFT-(05.03.23) Section 204(b) requires that all users of the treatment works constructed with funds provided under Sections 201(g) or 601 of the Act to pay their proportionate share of the costs of operation, maintenance and replacement of the treatment works. Section 307 of the Act requires users to comply with pretreatment standards promulgated by EPA for pollutants that would cause interference with the treatment process or would pass through the treatment works. Section 308 of the Act requires users to allow access at reasonable times to state and EPA inspectors for the purpose of sampling the discharge, reviewing, and copying records. 2. You shall continue to implement the pretreatment program approved March 14,1984 and any amendments thereto. 3. An annual report in the form prescribed by the Department is to be submitted by March 1St of each year describing the pretreatment program activities for the preceding calendar year. 4. The City shall evaluate the adequacy of its local limits to meet the general prohibitions against interference and pass through listed in 40 CFR 403.5(a) and the specific prohibitions listed in 40 CFR 403.5(b). At a minimum this evaluation shall consist of the following: (a) Identify each pollutant with the potential to cause process inhibition, pass through the treatment plant in concentrations that will violate NPDES permit limits of water quality standards, endanger POTW worker health and safety or degrade sludge quality. (b) For each treatment plant, determine the maximum allowable headworks loading for each pollutant identified in item #4(a). that will prevent interference or a pass through. (c) After accounting for the contribution of each pollutant from uncontrolled (i.e.: domestic/commercial) sources to each treatment plant, determine the maximum allowable industrial loading for each pollutant identified in item #4(a). (d) Complete the evaluation and submit to the Department, by June 1, 2022 a report containing the following information: 1) A list of pollutants identified in item #4(a). For each pollutant, state the reason(s) for its inclusion (e.g. potential to cause interference, potential to cause pass through, etc.). 2) The report shall contain all calculations used to determine the maximum allowable headworks loadings and shall identify the source(s) of all data used (e.g. literature value, site specific measurement, etc.). 3) The contribution of each pollutant identified in item #4(d)1 to each treatment plant from uncontrolled sources and an explanation of how each contribution was determined. 4) The allocation of the maximum allowable headworks loading for each pollutant to each treatment plant, and an explanation of how the allowable loadings will be allocated to significant industrial users regulated by the City's pretreatment program. 5. The City shall evaluate the approved pretreatment program for compliance with 40 CFR 403 and Iowa Administrative Code 567 — Chapter 62. Complete the evaluation and submit to the Department a report containing the findings of the evaluation, including a proposal for modifications to correct any deficiencies that are identified, by June 1, 2022. Pretreatment reports shall be submitted to Ben Hucka at npdes.mail@dnr.iowa.gov. Page 23 Page 82 of 164 Facility Name: WATERLOO CITY OF STP Permit Number: 0790001 Nutrient Reduction Requirements DRAFT-(05.03.23) In support of the Iowa Nutrient Reduction Strategy you shall prepare and submit a report that evaluates the feasibility and reasonableness of reducing the amounts of nitrogen and phosphorus discharged into surface water. The report shall be submitted no later than June 1, 2023 and shall address the following: • A description of the existing treatment facility with particular emphasis on its capabilities for removing nitrogen and phosphorus. The description shall include monitoring data that define the current amounts of total nitrogen (TKN+nitrate+nitrite) and total phosphorus in both the raw wastewater and the final effluent. A description and evaluation of operational changes to the existing treatment facility that could be implemented to reduce the amounts of total nitrogen and total phosphorus discharged in the final effluent and the feasibility and reasonableness of each. Your evaluation must discuss the projected degree of total nitrogen and total phosphorus reduction achievable for each operational change. When evaluating feasibility, you must consider what, if any, effect operational changes would have on the removal of other pollutants (e.g. CBOD5, TSS). When evaluating reasonableness, you shall include estimates of the additional cost, if any, to implement such changes and for a publicly -owned treatment works the impact on user rates. ▪ A description and evaluation of new or additional treatment technologies that would achieve significant reductions in the amounts of total nitrogen and total phosphorus discharged in the final effluent with a goal of achieving annual average concentrations of 10 mg/L total nitrogen and 1 mg/L total phosphorus for plants treating typical domestic strength sewage. For purposes of this evaluation typical domestic sewage is considered to contain approximately 25 — 35 mg/L total nitrogen and 4 - 8 mg/L total phosphorus. For plants treating wastewater with total nitrogen and/or total phosphorus concentrations greater than typical domestic strength sewage, the evaluation shall include the projected reductions in the total nitrogen and phosphorus effluent concentrations achievable with the application of feasible and reasonable treatment technology with a goal of achieving at least a 66 % reduction in nitrogen and 75% reduction in total phosphorus. For each treatment technology the report shall assess its feasibility, reasonableness, practicability, the availability of equipment, capital costs, annual operating costs, impact on user rates and any non -water quality environmental impacts (e.g. additional air pollution, increased sludge production, etc.). • Based on the evaluations of operational changes and new or additional treatment technologies the report must select the preferred method(s) for reducing total nitrogen and total phosphorus in the final effluent, the rationale for the selected method(s) and an estimate of the effluent quality achievable. • In addition to selecting operational changes and/or new or additional treatment technologies, the permittee may evaluate and propose to implement practices within the watershed that may achieve greater reductions in nitrogen or phosphorus than the preferred method(s) alone. Such evaluations are particularly encouraged when no feasible or reasonable operational changes or additional treatment technologies can be identified or when the schedule for installing the selected technology exceeds ten years. • The report must include a schedule for making operational changes and/or installing new or additional treatment technologies to achieve the concentration and/or percentage removal goals listed above. Additional financial justification must be included in the report if no operational changes or treatment technologies are feasible or reasonable. The schedule will be incorporated into the NPDES permit by amendment. Effluent discharge limits will be based on one full year of operating data after implementation of the operational changes or completion of plant modifications and a six-month optimization period. The report shall be sent to the following address: Ben Hucka NPDES Section npdes.mail@dnr.iowa.gov Page 24 Page 83 of 164 STANDARD CONDITIONS DRAFT-(05.03.23) 1. ADMINISTRATIVE RULES Rules of this Department that govem the operation of your facility in connection with this permit are published in Part 567 of the Iowa Administrative Code (IAC) in Chapters 60-65, 67, and 121. Reference to the term "rule" in this permit means the designated provision of Part 567 of the IAC. Reference to the term "CFR" means the Code of Federal Regulations. 2. DEFINITIONS (a) 7 day average means the sum of the total daily discharges by mass, volume, or concentration during a 7 consecutive day period, divided by the total number of days during the period that measurements were made. Four 7 consecutive day periods shall be used each month to calculate the 7-day average. The first 7-day period shall begin with the first day of the month. (b) 30 day average means the sum of the total daily discharges by mass, volume, or concentration during a calendar month, divided by the total number of days during the month that measurements were made. (c) Daily maximum means the total discharge by mass, volume, or concentration during a twenty-four hour period. 3. DUTY TO PROVIDE INFORMATION You must furnish to the Director, within a reasonable time, any information the Director may request to determine compliance with this permit or determine whether cause exists for modifying, revoking and reissuing, or terminating this permit, in accordance with 567 IAC 64.3(11)"c". You must also furnish to the Director, upon request, copies of any records required to be kept by this permit. 4. MONITORING AND RECORDS OF OPERATION (a) Maintenance of records. You shall retain for a minimum of three years all paper and electronic records of monitoring activities and results including all original strip chart recordings for continuous monitoring instrumentation and calibration and maintenance records. [See 567IAC 63.2(3)) Any person who falsifies, tampers with, or knowingly renders inaccurate any monitoring device or method required to be maintained under this permit shall, upon conviction, be punished by a fine of not more than $10,000 or by imprisonment for not more than two years, or both. [See 40 CFR 122.4107(5)) (b) 5. SIGNATORY REQUIREMENTS Applications, reports or other information submitted to the Department in connection with this permit must be signed and certified in accordance with 567 IAC 64.3(8). 6. OTHER INFORMATION Where you become aware that you failed to submit any relevant facts in a permit application, or submitted incorrect information in a permit application, you must promptly submit such facts or information. Where you become aware that you failed to submit any relevant facts in the submission of in any report to the director, including records of operation, you shall promptly submit such facts or information. {See 567IAC 60.4(2)"a" and 567IAC 63.7) 7. TRANSFER OF TITLE OR OWNER ADDRESS CHANGE If title to your facility, or any part of it, is transferred the new owner shall be subject to this permit. You are required to notify the new owner of the requirements of this permit in writing prior to any transfer of title. The Director shall be notified in writing within 30 days of the transfer. No transfer of the authorization to discharge from the facility represented by the permit shall take place prior to notifying the department of the transfer of title. Whenever the address of the owner is changed, the department shall be notified in writing within 30 days of the address change. Electronic notification is not sufficient; all title transfers or address changes must be reported to the department by mail. {See 567IAC 64.14) 8. PROPER OPERATION AND MAINTENANCE All facilities and control systems shall be operated as efficiently as possible and maintained in good working order. A sufficient number of staff, adequately trained and knowledgeable in the operation of your facility shall be retained at all times and adequate laboratory controls and appropriate quality assurance procedures shall be provided to maintain compliance with the conditions of this permit. [See 40 CFR 122.41(e) and 567IAC 64.7(7) ` f ') 9. PERMIT MODIFICATION, SUSPENSION OR REVOCATION (a) This permit may be modified, suspended, or revoked and reissued for cause including but not limited to those specified in 567 IAC 64.3(11). This permit may be modified due to conditions or information on which this permit is based, including any new standard the department may adopt that would change the required effluent limits. {See 567IAC 64.3(11)) (c) If a toxic pollutant is present in your discharge and more stringent standards for toxic pollutants are established under Section 307(a) of the Clean Water Act, this permit will be modified in accordance with the new standards. [See 40 CFR 122.62(a)(6) and 567IAC 64.7(7)"g") The filing of a request for a permit modification, revocation or suspension, or a notification of planned changes or anticipated noncompliance does not stay any permit condition. (b) 10. DUTY TO REAPPLY AND PERMIT CONTINUATION If you wish to continue to discharge after the expiration date of this permit, you must file a complete application for reissuance at least 180 days prior to the expiration date of this permit. If a timely and sufficient application is submitted, this permit will remain in effect until the Department makes a final determination on the permit application. {See 567 IAC 64.8(1) and Iowa Code 17A.18) 11. DUTY TO COMPLY You must comply with all conditions of this permit. Any permit noncompliance constitutes a violation of the Clean Water Act and is grounds for enforcement action; permit termination, revocation and reissuance, or modification; or denial of a permit renewal application. Issuance of this permit does not relieve you of the responsibility to comply with all local, state and federal laws, ordinances, regulations or other legal requirements applying to the operation of your facility. [See 40 CFR 122.41(a) and 567IAC 64.7(4)"e") Page 84 of 164 STANDARD CONDITIONS DRAFT-(05.03.23) 12. DUTY TO MITIGATE You shall take all reasonable steps to minimize or prevent any discharge in violation of this permit which has a reasonable likelihood of adversely affecting human health or the environment. {See 40 CFR 122.41(d) and 567IAC 64. 7(7) "i "] 13. TWENTY-FOUR HOUR REPORTING You shall report any noncompliance that may endanger human health or the environment, including, but not limited to, violations of maximum daily limits for any toxic pollutant (listed as toxic under 307(a)(1) of the Clean Water Act) or hazardous substance (as designated in 40 CFR Part 116 pursuant to 311 of the Clean Water Act). Information shall be provided orally within 24 hours from the time you become aware of the circumstances. A written submission that includes a description of noncompliance and its cause; the period of noncompliance including exact dates and times, whether the noncompliance has been corrected or the anticipated time it is expected to continue; and the steps taken or planned to reduce, eliminate, and prevent a reoccurrence of the noncompliance must be provided within 5 days of the occurrence. {See 567IAC 63.12) 14. OTHER NONCOMPLIANCE You shall report all instances of noncompliance not reported under Condition #13 at the time monitoring reports are submitted. You shall give advance notice to the appropriate regional field office of the department of any planned activity which may result in noncompliance with permit requirements. {See 567IAC 63.14) 15. INSPECTION OF PREMISES, RECORDS, EQUIPMENT, METHODS AND DISCHARGES You are required to permit authorized personnel to: Enter upon the premises where a regulated facility or activity is located or conducted or where records are kept under conditions of this permit; Have access to and copy, at reasonable times, any records that must be kept under the conditions of this permit; (c) Inspect, at reasonable times, any facilities, equipment, practices or operations regulated or required under this permit; and (d) Sample or monitor, at reasonable times, to assure compliance or as otherwise authorized by the Clean Water Act. (a) (b) 16. FAILURE TO SUBMIT FEES This permit may be revoked, in whole or in part, if the appropriate permit fees are not submitted within thirty (30) days of the date of notification that such fees are due. {See 567IAC 64.16(1)) 17. NEED TO HALT OR REDUCE ACTIVITY It shall not be a defense for a permittee in an enforcement action that it would have been necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit. {See 40 CFR 122.41(c) and 567IAC 64.7(7) `j ") 18. NOTICE OF CHANGED CONDITIONS You are required to notify the director of any changes in existing conditions or information on which this permit is based. This includes, but is not limited to, the following: (a) If your facility is a publicly owned treatment works (POTW) or otherwise may accept waste for treatment from an indirect discharger or industrial contributor (See 567 IAC 64.3(5) for further notice requirements). (b) If your facility is a POTW and there is any substantial change in the volume or character of pollutants being introduced to the POTW by a source introducing pollutants into the POTW at the time of issuance of the permit. {See 40 CFR 122.42(b)) (c) As soon as you know or have reason to believe that any activity has occurred or will occur which would result in the discharge of any toxic pollutant which is not limited in this permit. {See 40 CFR 122.42(a)) (d) If you have begun or will begin to use or manufacture as an intermediate or final product or byproduct any toxic pollutant which was not reported in the permit application. 19. PLANNED CHANGES The permittee shall give notice to the appropriate regional field office of the department 30 days prior to any planned physical alterations or additions to the permitted facility. Notice is required only when: (a) Notice has not been given to any other section of the department. (Note: Facility expansions, production increases, or process modifications which may result in new or increased discharges of pollutants must be reported to the Director in advance. If such discharges will exceed effluent limitations, your report must include an application for a new permit. If any modification of, addition to, or construction of a disposal system is to be made, you must first obtain a written permit from this Department. In addition, no construction activity that will result in disturbance of one acre or more shall be initiated without first obtaining coverage under NPDES General Permit No. 2 for "Storm water discharge associated with construction activity.") {See 567IAC 64.7(7) "a" and 64.2) (b) The alteration or addition to a permitted facility may meet one of the criteria for determining whether a facility is a new source as defined in 567 IAC 60.2; (c) The alteration or addition results in a significant change in the permittee's sludge use or disposal practices; or (d) The alteration or addition could significantly change the nature or increase the quantity of pollutants discharged. This notification applies to pollutants that are not subject to effluent limitations in the permit. {See 567IAC 63.13 and 63.14) 20. USE OF CERTIFIED LABORATORIES Analyses of wastewater, groundwater or sewage sludge that are required to be submitted to the department as a result of this permit must be performed by a laboratory certified by the State of Iowa. Routine, on -site monitoring for pH, temperature, dissolved oxygen, total residual chlorine and other pollutants that must be analyzed immediately upon sample collection, settleable solids, physical measurements, and operational monitoring tests specified in 567 IAC 63.3(4) are excluded from this requirement. Page 85 of 164 STANDARD CONDITIONS DRAFT-(05.03.23) 21. BYPASSES (a) Defmition. "Bypass" means the diversion of waste streams from any portion of a treatment facility or collection system. A bypass does not include internal operational waste stream diversions that are part of the design of the treatment facility, maintenance diversions where redundancy is provided, diversions of wastewater from one point in a collection system to another point in a collection system, or wastewater backups into buildings that are caused in the building lateral or private sewer line. Prohibitions. i. Bypasses from any portion of a treatment facility or from a sanitary sewer collection system designed to carry only sewage are prohibited. ii. Bypass is prohibited and the department may not assess a civil penalty against a permittee for bypass if the permittee has complied with all of the following: (1) Bypass was unavoidable to prevent loss of life, personal injury, or severe property damage; and (2) There were no feasible alternatives to the bypass such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance during normal periods of equipment downtime. This condition is not satisfied if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventive maintenance; and The permittee submitted notices as required by paragraph (d) of this section. (c) The Director may approve an anticipated bypass after considering its adverse effects if the Director determines that it will meet the three conditions listed above and a request for bypass has been submitted to the Department in accordance with 567 IAC 63.6(2). (d) Reporting bypasses. Bypasses shall be reported in accordance with 567 IAC 63.6. (b) (3) 22. UPSET PROVISION (a) Definition. "Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation. (b) Effect of an upset. An upset constitutes an affirmative defense in an action brought for noncompliance with such technology based permit effluent limitations if the requirements of paragraph "c" of this condition are met. No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review. (c) Conditions necessary for demonstration of an upset. A permittee who wishes to establish the affirmative defense of upset shall demonstrate through properly signed operating logs or other relevant evidence that; i. An upset occurred and that the permittee can identify the cause(s) of the upset; ii. The permitted facility was at the time being properly operated; iii. The permittee submitted notice of the upset to the Department in accordance with 567 IAC 63.6(3); and iv. The permittee complied with any remedial measures required in accordance with 567 IAC 63.6(6)"b". (d) Burden of Proof. In any enforcement proceeding, the permittee seeking to establish the occurrence of an upset has the burden of proof. 23. PROPERTY RIGHTS This permit does not convey any property rights of any sort or any exclusive privilege. (See 567IAC 64.4(3) "b ") 24. EFFECT OF A PERMIT Compliance with a permit during its term constitutes compliance, for purposes of enforcement, with Sections 301, 302, 306, 307, 318, 403 and 405(a)-(b) of the Clean Water Act, and equivalent limitations and standards set out in 567 IAC Chapters 61 and 62. (See 567IAC 64.4(3) "a' ) 25. SEVERABILITY The provisions of this permit are severable and if any provision or application of any provision to any circumstance is found to be invalid by this department or a court of law, the application of such provision to other circumstances, and the remainder of this permit, shall not be affected by such finding. Page 86 of 164 DRAFT-(05.03.23) APPENDIX B 2018 NUTRIENT REDUCTION STUDY Page 87 of 164 DRAFT-(05.03.23) • Nutrient Reduction Study Report City of Waterloo, IA March 2018 Page 88 of 164 DRAFT-(05.03.23) Report for City of Waterloo, Iowa Nutrient Reduction Study SEAL I hereby certify that this engineering document was prepared by me or under my direct personal supervision and that I am a duly licensed Professional Engineer under the laws of the State of Iowa. FOR STRAND ASSOCIAT Randall A. Wirtz, Ph.D., P.. March 26, 2018 License Number 1613 My license renewal date is December 31, 2019 Report sections covered by this seal: All sections unless otherwise noted , INC.® Prepared by: STRAND ASSOCIATES, INC.® 910 West Wingra Drive Madison, WI 53715 www.strand.com March 2018 heAl STRAND ASSOCIATES' Page 89 of 164 DRAFT-(05.03.23) TABLE OF CONTENTS Page No. or Following NUTRIENT REDUCTION STUDY Existing Treatment Facilities 1 Influent and Effluent Data 4 Nutrient Reduction Goals 14 Evaluation of Operational Changes to Enhance Nutrient Removal 14 Wasteload and Flow Forecasts 15 Evaluation of Treatment Technologies to Meet Nutrient Reduction Goals 20 Implementation and Budgetary Considerations 37 Sewer Budget Impact 39 Financial Information 41 TABLES Table 1 Design Flows and Loadings 1 Table 2 Easton Influent Flow Summary 5 Table 3 Satellite Influent Flow Summary 5 Table 4 Combined Influent Flow Summary 6 Table 5 Influent Flow Summary 8 Table 6 Influent BOD Loading Summary 9 Table 7 Influent TSS Loading Summary 9 Table 8 Influent TKN Summary 10 Table 9 Influent TN Loading Summary 10 Table 10 Influent TP Loading Summary 11 Table 11 Return Flow Sampling Summary —May and June 2017 11 Table 12 Return Flow Loading Estimates 12 Table 13 Effluent NH3-N 13 Table 14 Effluent TN 13 Table 15 Effluent TP 14 Table 16 Current and Projected Populations 16 Table 17 Planned Industrial Discharge Estimates 16 Table 18 Projected 2040 Flows 18 Table 19 Projected Future Loads —Combined Influent 19 Table 20 Estimated Maximum Month Loads 19 Table 21 Design Flows and Loads 20 Table 22 A20 Process Modeling Summary 22 Table 23 Special Sampling Data —May and June 2017 23 Table 24 A20 Process Modeling Summary —with VFA Addition at 16°C, 2040 Conditions 25 Table 25 A20 Process Modeling Summary —with VFA Addition at 16°C, Full Permitted Design Conditions 26 Table 26 MLE Process Modeling Summary with CPR 28 Page 90 of 164 DRAFT-(05.03.23) Table 27 MLW Process Modeling Summary with CPR —Two Satellite Trains Reserved for RAS Fermentation Zones 31 Table 28 BNR Present Worth Analysis Summary 32 Table 29 Biological Nutrient Removal Nonmonetary Considerations Summary 33 Table 30 Recommended Near -Term Improvements for Nutrient Removal 39 Table 31 WWTP Budget Impact Summary for Near -Term Improvements 40 FIGURES Figure 1 Wastewater Treatment Plant Process Flow Diagram 1 Figure 2 Influent Flow 6 Figure 3 Alternative BNR1 20 Figure 4 BioWin Model of A2O Process 22 Figure 5 Alternative BNR2 26 Figure 6 BioWin Model of MLE Process with CPR 27 Figure 7 RAS Fermentation Process Diagram 29 Figure 8 Alternative BNR3 30 Figure 9 Preliminary and Primary Treatment Improvements 34 APPENDICES APPENDIX A—NPDES PERMIT APPENDIX B—PRESENT WORTH ANALYSIS ii Page 91 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study This study was prepared as required to meet the April 1, 2018, compliance schedule in the City of Waterloo's (City's) Iowa Department of Natural Resources (IDNR) National Pollutant Discharge Elimination System (NPDES) Permit No. 0790001. The purpose of this report is to evaluate the feasibility and reasonableness of reducing the amounts of total nitrogen (TN) and total phosphorus (TP) discharged into the Cedar River by the City's wastewater treatment plants (WWTPs). EXISTING TREATMENT FACILITIES A. Background The City of Waterloo (City) operates three wastewater treatment plants (WWTPs): an anaerobic lagoon that treats wastewater from a food processing plant prior to discharge into the City sanitary sewer system, the Satellite WWTP that was designed to treat the industrial wastewater from the northeast portion of the City (including the lagoon effluent), and the Easton Avenue (Easton) WWTP that was designed to treat the wastewater from all other sources in the City. The Satellite and Easton WWTPs are located at the same site and share several facilities as described later in this section and they both discharge to the Cedar River. A flow diagram of the Satellite and Easton WWTPs is presented in Figure 1. The design flows and loadings are presented in Tablel. The City's National Pollutant Discharge Elimination System (NPDES) Permit No. 0790001 is included in Appendix A. Wastewater Flow Design Average Flow (DAF) Easton Plant Satellite Plant Design Average Wet Weather Flow (Maximum Month) Design Maximum Wet Weather Flow (Maximum Day) Design Peak Hourly Wet Weather Flow (PHF) 20.4 mgd 26.7 mgd 36.0 mgd 36.0 mgd Wastewater Loading 5-day Biochemical Oxygen Demand (BOD5)—Average 6.7 mgd 8.1 mgd 11.1 mgd —. 11.1 mgd Day 5-day Biochemical Oxygen Demand (BOD5)—Maximum Month 5-day Biochemical Oxygen Demand (BOD5)--Maximum Day Total Kjeldahl Nitrogen (TKN)-Average Day Total Kjeldahl Nitrogen (TKN)-Maximum Month Total Kjeldahl Nitrogen (TKN)-Maximum Day 24,000 Ibs/day 30,000 Ibs/day 70,000 Ibs/day 38,800 Ibs/day 58,000 Ibs/day 80,400 Ibs/day 4,500 Ibs/day 7,500 Ibs/day 13,200 Ibs/day Total Suspended Solids (TSS)—Average Day Total Suspended Solids (TSS)--Maximum Month Total Suspended Solids (TSS)—Maximum Day Note: mgd=milliorl gallons per day Table 1 Design Flows and Loadings 18,000 Ibs/day 25,000 Ibs/day 66,000 Ibs/day 7,025 Ibs/day 13,550 Ibs/day 19,300 Ibs/day 38,300 Ibs/day 58,000 Ibs/day 80,400 Ibs/day Prepared by Strand Associates, Inc.® 1 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 92 of 164 DRAR--( r113 71) VMOI'OO1L131VM JO A110 AOl1S NOI10l03i11N312I1f1N INV2i9VIO MO1d SS33O21d 1NVld 1N3IN1V32112131VM3ISVM PPP o1 Z w a 7_I 1-2 Lcc o cn< w re 0 T. a i Page 93 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study Wastewater service to the City was provided by the Easton WWTP alone until the Satellite WWTP was constructed in 1996. At that time, the Easton WWTP was a trickling filter WWTP with primary clarifiers, trickling filters, intermediate clarifiers, roughing filters, and final clarifiers. Following startup of the Satellite WWTP in 1998, a major upgrade to the Easton WWTP was undertaken, including the demolition or abandonment of much of the existing facility and the construction of new primary and final clarifiers along with the conversion to activated sludge biological treatment. While the Satellite WWTP was designed to treat the industrial wastewater from a portion of the City, it has been out of service for several years and is currently only used for storage during peak flow events. The City currently has a project planned to convey Equalization Basin overflow to the Satellite activated sludge tanks for storage and blending with Easton secondary effluent. This project is anticipated to be completed in 2018. While influent flow from the Satellite and Easton collection systems are measured separately, under current WWTP operation the influent flow from the Satellite collection system is combined with the Easton influent flow upstream of the Easton Anoxic Selector Basin and is treated using the Easton WWTP. Both the Satellite and Easton WWTPs are currently designed for TN removal. B. Easton WWTP Influent flow to the Easton WWTP passes through two 3/4-inch bar screens and enters an influent wet well where it is pumped with five raw wastewater pumps and flow is measured with magnetic flowmeters. The Bar Screen Building and the Raw Wastewater Pump Building were both constructed concurrently with the construction of the Satellite WWTP in 1996. Following pumping, the wastewater flows through two vortex grit removal units located in the Raw Wastewater Pump Building. A sampler located downstream of the influent pumps and upstream of grit removal is used to collect Easton WWTP influent samples. When flows to the Easton WWTP exceed the WWTP's hydraulic capacity, a portion of the flow can be diverted to two flow equalization basins located on the northern portion of the site using two downward opening weir gates in the grit chamber effluent channel. These basins were constructed in 1996 and have a total storage capacity of approximately 20 million gallons (MG). Wastewater stored in these basins can be returned to the Easton influent wet well when the WWTP has capacity to treat the flow. During extreme high flow events, an overflow/bypass structure to the Cedar River can be used to discharge wastewater from the equalization basins. After grit removal, Easton WWTP influent flows through a magnetic flowmeter and to two circular primary clarifiers. Three primary sludge pumps located in the Primary Sludge Pump Building are used to pump sludge from the primary clarifiers to the thickened activated sludge (TAS) tanks. Scum that is removed from the primary clarifiers is stored in a mixed scum tank and pumped to the TAS tanks. The Primary Clarifiers and Primary Sludge Pump Building were constructed in 1998. The activated sludge system uses the Modified Ludzack-Ettinger process for BOD, ammonia, and total nitrogen (TN) removal and includes four elongated rectangular tanks as well as a separate anoxic selector basin. Primary effluent is mixed with RAS and with mixed liquor (ML) recycle flow, and flows from the Satellite Bypass Structure in the Easton Anoxic Selector Basin. This basin is mixed using coarse bubble air diffusers with a goal of maintaining anoxic conditions. This basin is Prepared by Strand Associates, Inc.® 2 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study docx\032616 Page 94 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study also used to split the flow between the four aeration basins. Each aeration basin consists of one anoxic zone with coarse bubble diffusers for mixing and three aerobic zones with fine bubble diffusers. Aeration is provided by three multistage centrifugal blowers. Flow from each of the basins is mixed in an outlet box which contains three ML recycle pumps to recycle nitrified ML to the front of the activated sludge system for alkalinity recovery and TN removal. The ML recycle pumps are constant -speed submersible pump and do not allow operators to adjust the recycle flow based on flow and loading conditions. ML from the aeration tanks flows to four center -feed circular final clarifiers. Five RAS pumps located in the RAS Building return settled sludge to the primary effluent pipe upstream of the anoxic selector basin. Secondary effluent passes through a Parshall Flume for flow measurement and is sampled prior to disinfection. Disinfection is provided by two ultraviolet (UV) disinfection systems operated in series. The ultraviolet disinfection system and building were installed in 2013. Following disinfection, effluent flows to one of two outfalls. A river diffuser is used under normal river level conditions (outfall 801). When the Cedar River level is high (river flow greater than 8,500 cfs), four effluent pumps located in the Effluent Lift Station are used to pump the effluent to a shoreline discharge (outfall 011). C. Satellite WWTP As described earlier, the Satellite WWTP was designed to treat mostly industrial wastewater flows from a dedicated collection system from the northeast side of the City and is not currently in use. Flows from the Satellite collection system flow to the Satellite Lift Station at the Easton WWTP, which is on the north end of the Raw Wastewater Pump Building. Here the raw wastewater is sampled and pumped to the Magnesium Hydroxide Building using three submersible pumps. In the Magnesium Hydroxide Building, WWTP staff can add alkalinity to the raw wastewater by feeding magnesium hydroxide. Downstream of the Magnesium Hydroxide Building, the raw wastewater piping to the Satellite WWTP is connected to the Easton WWTP primary effluent piping at the Satellite Bypass Structure. Under current WWTP operation, Satellite WWTP influent is diverted to the Easton WWTP through this bypass structure and no raw wastewater continues to the Satellite activated sludge system. The Satellite WWTP activated sludge system uses the Modified Ludzack-Ettinger process and includes two trains, each made up of two elongated rectangular tanks. An anoxic zone is provided in each train using coarse bubble diffuser mixing. Aeration is provided by fine bubble diffusers and five multistage centrifugal blowers. Two ML recycle pumps operating on variable frequency drives (VFDs) are used to return nitrified ML through the internal tank wall to the anoxic zone for denitrification and alkalinity recovery. ML from the aeration tanks flows to four center -feed circular final clarifiers. Five RAS pumps located in the Satellite RAS Builidng return settled sludge to the raw wastewater piping upstream of the activated sludge tanks. Prepared by Strand Associates, Inc ® 3 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032816 Page 95 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Secondary effluent passes through a Parshall Flume for flow measurement and is sampled prior to being combined with the Easton WWTP secondary effluent at the UV Building upstream of UV disinfection. D. Sludge Processing Waste Activated Sludge (WAS) is pulled from the Easton and Satellite RAS headers for wasting using automated control valves and flow meters. The WAS is pumped to three WAS tanks for storage until it is pumped to three gravity belt thickeners (GBTs). Scum from the final clarifiers are also pumped to the WAS tanks. The WAS tanks are mixed using coarse -bubble aeration and three positive displacement blowers. TAS is pumped from the GBTs to the three TAS tanks using three TAS transfer pumps. In these tanks, the TAS is mixed with the primary sludge from the Easton WWTP and primary scum to provide a consistent feed to the anaerobic digesters. Primary sludge is pumped to the TAS tanks using three rotary lobe pumps. Prior to pumping, the primary sludge passes through two sludge grinders. Mixing is provided in the TAS tanks with four vertical shaft mixers. Sludge is pumped from the TAS tanks to the anaerobic digesters using four progressing cavity pumps. The anaerobic digestion system uses a temperature -phased anaerobic digestion (TPAD) process with two thermophilic digesters and four mesophilic digesters. Two of the mesophilic digesters are equipped with floating covers for digester gas storage. The digesters are heated using a hot water boiler system. The TPAD system produces Class A biosolids. Digested sludge is pumped from the digesters to the Sludge Storage Tanks where it is stored until it is dewatered using three belt filter presses. The dewatered sludge is then land applied. INFLUENT AND EFFLUENT DATA A. Baseline Influent Data The WWTP currently measures influent flow from the Satellite collection system separate from the Easton WWTP influent flow. As discussed earlier, these flows are combined at the Easton WWTP Anoxic Selector Basin under current WWTP operation. Flow to the Equalization Basin is measured by summing the discharge flow from the Easton raw wastewater pumps and subtracting the Easton Influent Flow. Flow that is returned from the Equalization Basin enters the Easton influent wet well and is included in the Easton influent flow. Easton influent samples currently include process return flows. Estimates of these return flow loads and their impact of Easton influent loadings are presented later in this section. Tables 2 through 4 present the 2014 through 2016 flow data by month for the Easton WWTP, Satellite WWTP, and combined influent. The average represents the average day flow for the entire month. "Min" and "Max" represent the lowest and highest day's total daily (24-hour average) flow during that month, respectively. The Easton influent flow presented in Table 2 (and included in the combined flow in Table 4) includes the flow diverted to the Equalization Basin and subtracts the return flow from the Equalization Basin to approximate the actual total wastewater flow that is conveyed to the Easton WWTP site each day. A chart of the Satellite and this adjusted Easton Influent Flow from Prepared by Strand Associates, Inc ® 4 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw.feb\Report\Nutrient Reduction Study docx\032618 Page 96 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study 2014 to 2016 is presented in Figure 2. These reported flows are prior to ongoing wet weather improvements to the City's collection system and, therefore, do not reflect those ongoing efforts. Influent Flow (mgd) 2014 2015 2016 Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. January 6.72 5.72 7.61 8.01 7.00 8.60 12.83 10.10 18.00 February 7.43 6.20 10.52 7.82 6.92 8.24 11.88 8.92 18.50 March 9.68 6.90 13.61 8.56 6.92 9.68 14.73 11.98 19.31 April 13.51 5.40 33.24 10.63 7.55 16.22 13.36 10.98 17.83 May _ 13.07 9.43 18.32 10.34 8.52 15.91 11.67 9.49 17.46 June 19.27 8.00 53.42 11.93 8.95 18.29 15.53 12.56 22.95 July 19.09 10.31 49.62 10.31 8.39 16.01 14.26 11.79 18.26 August 9.12 8.07 10.61 9.77 7.82 23.46 13.71 12.11 17.70 September 8.33 7.03 10.36 9.48 7.82 11.79 19.26 9.82 59.71 October 8.51 6.79 15.31 8.08 7.21 9.51 14.45 11.39 19.71 November 7.39 5.98 7.94 9.01 7.42 12.47 10.97 9.06 12.74 December 8.05 6.68 10.05 15.52 9.17 31.23 10.89 9.15 13.65 Annual Average 10.85 - - 9.96 - - 13.63 - - Minimum 6.72 5.40 - 7.82 6.92 8.24 10.89 8.92 - Maximum 19.27 Flow - Summary 53.42 15.52 - 31.23 19.26 - 59.71 Table 2 Easton Influent Influent Flow (mgd) 2014 2015 2016 Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. January 3.68 2.01 9.02 3.00 1.66 3.82 3.62 2.04 4.65 February 2.95 1.80 3.82 2.94 1.42 3.78 3.39 2.40 4.40 March 3.26 1.81 4.39 2.76 1.18 3.86 3.57 1.97 4.59 April 3.43 1.49 5.20 2.96 1.44 3.94 3.46 1.59 4.25 May 3.31 0.68 4.44 2.90 0.51 3.96 3.16 1.59 4.67 June 3.34 1.94 4.71 3.19 1.32 4.27 3.29 1.79 4.51 July 2.92 1.14 4.40 3.06 1.16 4.89 2.89 1.05 3.76 August 2.62 0.79 3.98 3.10 0.75 4.75 3.29 1.20 3.88 September 2.90 0.98 4.05 3.11 0.61 4.31 3.45 1.67 4.83 October 3.06 1.27 4.37 3.20 1.43 4.30 3.64 2.24 4.60 November 3.03 1.27 3.87 3.15 1.74 4.23 3.54 2.72 4.42 December 3.05 1.59 3.83 3.63 1.09 4.78 3.54 1.87 4.31 Annual Average 3.13 - - 3.08 - - 3.40 - - Minimum 2.62 0.68 - 2.76 0.51 - 2.89 1.05 - Maximum 3.68 - 9.02 3.63 - 4.89 3.64 - 4.83 Table 3 Satellite Influent Flow Summary Prepared by Strand Associates, Inc.® 5 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 97 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Influent Flow (mgd) 2014 2015 2016 Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. January 10.40 8.06 15.57 11.02 9.05 12.33 16.45 13.05 21.94 February 10.38 8.15 13.79 10.76 8.57 11.89 15.28 11.51 22.61 March 12.94 8.93 17.73 11.32 9.10 13.39 18.31 14.62 23.90 April 16.94 6.89 35.52 13.59 9.19 19.75 16.82 13.79 21.73 May 16.38 10.52 22.37 13.24 10.53 19.18 14.83 11.23 20.57 June 22.61 10.46 56.84 15.12 10.25 21.01 18.82 14.55 27.46 July 22.01 12.16 53.59 13.37 9.55 19.88 17.16 13.02 21.15 August 11.74 9.42 13.61 12.87 8.57 27.55 17.00 13.84 21.58 September 11.24 8.57 13.61 12.58 8.43 15.17 22.71 11.86 64.18 October 11.57 8.06 19.55 11.28 8.66 13.22 18.08 13.98 23.68 November 10.42 8.38 11.81 12.16 9.17 15.65 14.51 11.98 16.59 December 11.10 8.54 12.95 19.15 12.66 35.31 14.43 12.69 16.69 Annual Average 13.98 - - 13.04 - - 17.03 - - Minimum 10.38 6.89 - 10.76 8.43 11.89 14.43 11.23 - Maximum 22.61 - 56.84 19.15 - 35.31 22.71 - 64.18 Table 4 Combined Influent Flow Summary 70.0 60.0 50.0 v 40.0 0 u- v 30.0 C 20.0 10.0 0.0 1/1/2014 Figure 2 Influent Flow 1/1/2015 -Easton Influent Flow 1/1/2016 Satellite Influent Flow 12/31/2016 Prepared by Strand Associates, Inc.® 6 R:\ MAD \Documents\Reports\Archive\20181Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 98 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study While the Satellite Influent Flow data was relatively consistent in each of the three years analyzed, the Easton Influent Flow was significantly higher in 2016 than in previous years, with an increase of over 30 percent from 2014 and 2015 to 2016. It appears that this increase in flow began sometime in November or December 2015. While increased winter flows from precipitation or snow melt are not unusual, the increase that occurred around this time does not appear to subside during dry weather conditions. This is evident in the Easton influent minimum day flow in 2016 of 8.92 mgd, which is greater than 10 of the 24 monthly average values for 2014 and 2015. A portion of the increase in 2016 flow can be attributed to an extreme wet weather event in September 2016 that resulted in major flooding throughout northeastern and east central Iowa. According to National Oceanic and Atmospheric Administration data, the Cedar River at Waterloo crested at 22.94 feet on September 26, 2016, which is nearly 10 feet above flood stage and the second highest crest on record. Power outages during this flooding event led to loss of flow measurement, resulting in estimates for reported flow values. The City does not currently measure influent flow upstream of influent pumps and, therefore, the maximum influent flow measurement is limited by the pump capacity. However, WWTP staff indicate that there have been no known instances of basement backups resulting from influent sewer surcharging in the past. An evaluation of the pump flow totalizer data for the two highest flow days in 2014 to 2016 was conducted to estimate the peak hourly flow to the Easton WWTP. On September 24, 2016, during a major flooding event with a reported daily influent flow of 59.7 mgd, the maximum one -hour flow measured by the Easton influent totalizers was approximately 61.2 mgd. Similarly, on June 30, 2014, the reported daily influent flow was 53.4 mgd and the maximum one -hour flow measured by the Easton influent totalizers was 61.9 mgd. Data was not available for the maximum flow days in 2015 as a result of a software malfunction. A similar analysis was conducted on the Satellite influent for several high flow days (influent flows above 4.4 mgd) which showed peak hour flow to daily average flow ratios of 1.2 to 1.3. Because the anaerobic lagoon provides some flow equalization and there is relatively little infiltration/inflow (1/1) observed in the Satellite collection system, the peaking factors for the Satellite influent are not anticipated to be nearly as high as those seen in the Easton influent. Based on this analysis, the current peak hour flow for the Satellite influent is estimated to be approximately 6 mgd (2016 maximum day flow of 4.8 mgd times 1.25). Minimum and maximum flows at one- and 30-day intervals for the periods of January 2014 to November 2015 and December 2015 to December 2016 are presented in Table 5. Prepared by Strand Associates, Inc.® 7 R:\MAD\Documents\Reports\Archive12018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 99 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Influent Flow January 2014 to November 2015 Average Easton Influent Satellite Influent Combined Influent Maximum Month (30-day maximum) Minimum Month (30-day minimum) Maximum Day 10.2 28.1 6.7 53.4 Minimum Day j 5.4 December 2015 to December 2016 Average _ 13.8 Maximum Month (30-day maximum) Minimum Month (30-day minimum) Maximum Day 59.7 Minimum Day 8.9 21.2* I 3.1 3.7 2.5 9.0 0.5 3.4 3.8 10.5 1 2.8 4.8 1.1 13.3 31.3 9.9 56.8 6.9 17.2 25.0* 14.0 64.2 11.2 *Includes estimated influent flow values resulting from power outage in September 2016 flooding event. Table 5 Influent Flow Summary As described earlier, when influent flows exceed the capacity of the Easton WWTP, a portion of the flow can be diverted to the Equalization Basins. This occurred on 153 days between 2014 and 2016, with an average diversion volume of 3.06 MG. Typically, this wastewater would be stored in the Equalization Basins until the Easton WWTP has adequate treatment capacity, at which time it would be returned to the Easton influent for treatment. In extreme wet weather conditions, the Equalization Basins may fill and overflow to a ditch that discharges to the Cedar River. As previously discussed, the City currently has a planned project to convey Equalization Basin overflow to the Satellite activated sludge tanks, effectively increasing storage volume in the near -term. B. Influent BOD5, TSS, and TKN Loadings Tables 6 through 8 summarize the Easton WWTP, Satellite WWTP, and combined influent loadings of BOD5, TSS, and TKN, respectively. Each influent loading is separated between the 23-month period from January 2014 through November 2015 and the 13-month period from December 2015 through December 2016. The Easton influent loadings in these tables include the portion of the Easton influent flow that was diverted to the Equalization Basins. Prepared by Strand Associates, Inc.® 8 R:\MAD\Documents\ReportsWrchive\2018\Waterloo, IA\Nutrient Reduction.4463.001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 100 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study Easton Influent Satellite Influent BOD Loading, lb/day January 2014 to November 2015 Average 7-day Maximum Combined Influent 18,746 7,877 27,989 14,253 26,634 37,681 30-day Maximum 25,213 December 2015 to December 2016 Average 7-day Maximum 30-day Maximum 18,828 29,695 27,989 Table 6 Influent BOD Loading Summary 11,161 9,817 16,562 14,620 34,175 28,645 44,066 37,832 TSS Loading, lb/day January 2014 to November 2015 Average 7-day Maximum 30-day Maximum Easton Influent Satellite Influent 18,867 December 2015 to December 2016 Average 7-day Maximum 30-day Maximum 43,235 28,037 24,782 8,846 22,897 12,878 10,990 Combined Influent 27,713 51,784 37,123 35,774 50,316 17,950 41,683 14,556 Table 7 Influent TSS Loading Summary 64,441 52,896 Prepared by Strand Associates, Inc.® 9 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 101 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study TKN Loading, lb/day January 2014 to November 2015 Average Maximum 30-day Maximum Easton Influent Satellite Influent Combined Influent 3,984 4,506 6,952 ' 7,115 8,489 12,204 5,665 6,992 December 2015 to December 2016 Average Maximum* 30-day Maximum "samples liken approximately once per week Table 8 Influent TKN Summary 3,863 5,535 5,239 5,478 6,688 6,231 11,750 9,341 11,210 10,932 The City began collecting regular influent TN and TP samples in April 2016. Tables 9 and 10 summarize influent TN and TP loadings. The Easton influent loadings in these tables includes the portion of the Easton influent flow that was diverted to the Equalization Basins. The TN loadings are very similar to historical TKN loadings, indicating low nitrate/nitrite in the influent. April 2016 May 2016 June 2016 July 2016 Easton Influent Conc. Load (mg/L) 38 41 35 26 August 2016 September 2016 October 2016 November 2016 December 2016 34 32 34 41 40 (Ibs/day) 4,125 4,238 4,164 3,323 3,575 3,962 3,980 3,884 3,723 Satellite Influent Combined Influent Conc. (mg/L) 172 170 Load (Ibs/day) 5, 074 4,685 202 205 203 185 192 211 199 Average 36 Minimum Month 26 Maximum Month 41 Note: mg/L=milligrams per Liter 3,886 3,323 4,238 193 170 Table 9 Influent TN Loading Summary 211 Conc. Smg/L) 67 5,620 5,449 5,988 5,208 5,644 6,085 5,990 5,527 4,685 6,085 68 66 Load Slbs/day) 9,199 8,923 9,784 8,772 9,563 9,170 9,624 9,969 9,713 56 70 59 64 80 80 68 9,413 56 8,772 80 9,969 Prepared by Strand Associates, Inc.® 10 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 102 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Easton Influent Conc. Load (mg/L) (Ibs/day) April 2016 10.2 1,087 May 2016 7.4 770 June 2016 7.3 843 Ju y 2016 6.2 786 August 2016 6.8 724 September 2016 _ 7.3 _ 930 October 2016 7.7 906 November 2016 11.5 1,095 December 2016 10.0 958 Satellite Influent i Combined Influent Conc. Load (mg/L) _(Ibs/day) 19.6 575 18.7 515 Conc. Load (mg/L) Albs/day) 12.2 _ 1,662 9.8 1,285 19.6 548 9.6 1,391 19.7 521 8.4 1,307 21.6 638 10.0 1,362 20.1 573 9.5 1,503 21.2 620 19.9 571 20.1 603 10.3 1,526 13.4 1,666 12.8 1,561 Average 8.3 900 Minimum Month 6.2 _ 724 Maximum Month 11.5 1,096 Table 10 Influent TP Loading Summary 20.0 574 18.7 515 21.6 638 10.7 8.4 13.4 1,474 1,285 1,666 In -plant waste loads including filtrate from sludge thickening and dewatering operations, sludge storage tank decant, tank drains, and digester overflow are combined in the WWTP sewer system. The WWTP sewer flows through a Palmer-Bowlus flume just east of the septage receiving station for flow measurement. WWTP staff indicate that this flume is often surcharged and does not provide reliable flow measurements. Septage is combined with these in -plant return flows downstream of the flume. These flows combine with the Easton influent in a manhole upstream of the Bar Screen Building. Therefore, the flows and loads associated with these in -plant returns are included in the Easton influent flow measurement and samples. City staff conducted special sampling in May and June of 2017 that included grab samples of return flows from the GBT and belt filter press (BFP) as presented in Table 11. Parameter, mg/L TP PO4-P Ammonia TKN Nitrate Nitrite _ TSS VSS GBT Filtrate 10.3 6.3 8.9 38.9 13.7 0.2 308 252 BFP Filtrate 73.8 33.3 685 715 1.1 <0.1 1,123 756 Alkalinity 218 Notes:VSS=volatile suspended solids. PO;-P=phosphate 2,491 Table 11 Return Flow Sampling Summary -May and June 2017 Estimates of return flow loadings were made based on the 2014 to 2016 sludge flows, percent solids measurements, and estimates of wash water flows at approximately 120 gpm per GBT/BFP. This Prepared by Strand Associates, Inc ® 11 R:\MAD\Documents\ReportsWrchive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 103 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study results in an estimated GBT filtrate and BFP filtrate flows of approximately 0.45 mgd and 0.16 mgd, respectively. Estimated return loadings from these sources are presented in Table 12. Parameter, Ibs/day TP PO4-P Ammonia TKN Nitrate Nitrite GBT Filtrate 39 24 33 146 BFP Filtrate 98 44 914 954 Filtrate Loading Percentage of Easton Influent 15% 25% 51 1.5 0.8 TSS VSS Alkalinity 1,160 950 820 <0.1 1,500 1,010 10% Table 12 Return Flow Loading Estimates 3,320 C. Wastewater Treatment Performance As described earlier, secondary effluent from the Satellite and Easton WWTPs are combined and disinfected prior to discharge to the Cedar River. The City has two permitted outfalls on the Cedar River: a diffuser located in the river that is used under normal conditions and a shoreline outfall that is used when the Cedar River level is high. The permitted effluent concentrations for all parameters except ammonia are identical for these two discharges. In the City's current NPDES permit, the shoreline outfall can be used during high river flows (above 8,500 cubic feet per second), resulting higher ammonia limits both on a monthly average and daily maximum basis. This shoreline discharge was used for 26 days in 2014, 14 days in 2015, and 44 days in 2016. Table 13 summarizes the City's average monthly effluent ammonia nitrogen (NH3-N). Effluent CBOD during this period averaged 8 mg/L. The City was operating two to three of the Easton WWTP activated sludge trains for most of the three-year period. Prepared by Strand Associates, Inc.® 12 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 104 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study 2014 2015 2016 Conc. (mg/L) Load (Ibs/day) 1,240 Conc. (mq/L) 19.4 Load (Ibs/day) 1,817 Conc. ,(mg/L) 27.7 Load (Ibs/day) 3,578 January 13.9 February 60.8 5,132 41.8 3,771 36.5 4,410 March 51.7 5,719 25.9 2,507 31.5 4,719 April 40.8 4,963 19.0 2,134 4.4 557 May 4.6 629 7.3 864 2.3 297 June 1.0 143 4.2 478 4.7 861 July 1.0 158 3.2 357 1.0 144 August 1.0 107 1.4 144 1.1 142 September 1.0 98 1.3 163 1.2 191 October 1.9 193 8.5 866 1.0 153 November 14.1 1,258 4.5 490 13.6 1,614 December 22.3 2,017 13.5 2,075 31.1 3,595 Annual Average 17.8 NH3-N 1,805 12.5 1,306 13.0 1,688 Table 13 Effluent The City has a TN mass limits of 9,285.5 Ibs/day on a monthly average basis with a daily maximum limit of 15,199 Ibs/day. Effluent TN sample results are presented in Table 14 below. There were no exceedances of the City's maximum day or monthly average TN mass limits in the period evaluated. 2014 2015 2016 Conc. (mg/L) Load (Ibs/day) Conc. (mg/L) Load (Ibs/day) Conc. (mg/L) Load (Ibs/day) January 41.0 3,442 41.9 3,941 38.4 5,007 February 76.1 6,493 55.2 4,982 41.7 5,035 March 56.5 6,302 42.6 4,120 38.5 6,011 April 42.4 5,391 42.9 30.8 3,435 May 27.6 3,548 29.6 _4,872 3,428 23.8 3,111 June 28.9 3,921 37.4 4,301 29.8 4,364 July 17.5 2,855 41.1 4,848 31.7 4,636 August 35.6 3,795 45.6 4,598 34.3 4,454 September 36.6 3,607 36.4 4,177 42.7 5,843 October 42.4 4,417 39.3 4,147 31.2 4,850 November 44.2 4,065 34.9 3,731 35.5 4,301 December 35.0 3,158 31.0 4,678 46.1 5,345 Annual Average 40.3 4,250 39.8 4,319 35.4 4,699 Table 14 Effluent TN While the City does not currently have a TP limit, they began monitoring effluent TP once per week in April 2016. Effluent TP data is presented in Table 15. Prepared by Strand Associates, Inc." 13 R:\MAD\Documents\Reports\Nrchive\2018\Waterloo, IA\Nutrient Reduction 4463 001.raw.feb\Report\Nutrient Reduction Study docx\032818 Page 105 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study TP Conc. (mg/L) 7 Load (Ibs/day) 826 April 2016 May 2016 7 879 June 2016 7 970 July 2016 5 758 August 2016 6 832 September 2016 7 952 October 2016 7 1,028 November 2016 9 1,150 December 2016 8 974 , Annual Average 7 930 Table 15 Effluent TP The Modified Ludzak-Ettinger (MLE) process currently used at the Easton WVVfP was designed for TN removal and successfully removes approximately 50 percent of the influent TN based on the data presented in Tables 9 and 14. The data in Tables 10 and 15 suggest that the VVVVfP currently removes approximately 37 percent of the influent TP. Because the MLE process does not contain an anaerobic zone necessary for successful biological phosphorus removal (BPR), the demonstrated TP removal is likely attributable to biological uptake for cell growth and the removal of particulate TP. NUTRIENT REDUCTION GOALS Using the influent TN and TP data collected between April and December 2016 and adjusting for the nutrient loads from return flows that were included in these samples, the average TN and TP for the combined WVVTP influent are approximately 59.3 mg/L and 9.6 mg/L, respectively. Based on these influent concentrations the IDNR's nutrient reduction goals are 20.2 mg/L TN (66 percent removal) and 2.4 mg/L TP (75 percent removal). The City currently has mass limits for TN of 9,285.5 Ibs/day on a 30-day average basis and 15,199 Ibs per day on a daily maximum basis. There is no TP limit in the City's current NPDES permit. Based on the effluent target values calculated above, the combined AWW design flow of 34.8 mgd, the anticipated TN and TP mass limits are approximately 5,863 Ibs TN per day and 697 Ibs TP per day. EVALUATION OF OPERATIONAL CHANGES TO ENHANCE NUTRIENT REMOVAL As presented earlier, the MLE process currently used at the WWTP results in effluent TN Toads between 3,000 and 5,000 Ibs/day with concentrations of approximately 30 to 40 mg/L. Based on this performance, the City is currently able to achieve the TN effluent mass target of 5,863 Ibs/day but it appears that it would be unable to achieve this target should influent flows increase to the design flows. Furthermore, the WWTP is not currently designed for phosphorus removal, which would require either anaerobic zones in the activated sludge system or significant chemical feed and storage facilities. Potential operational changes to improve BPR performance, such as eliminating the nitrified ML recycle Prepared by Strand Associates, Inc.® 14 R:\MAD\Documents\Reports\Archive12016\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx1032616 Page 106 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study to create an anaerobic zone, would result in Toss of TN removal. Because of the high TKN loads to the WWTP, the elimination of the nitrified ML recycle and associated denitrification and alkalinity recovery is also anticipated to result in pH instability and the potential loss of nitrification. The City conducted special sampling in May and June 2017 to further investigate nutrient removal at the WWTP. This sampling indicated that while the WWTP was successfully nitrifying (average effluent ammonia concentration of 1.5 mg/L), denitrification in the anoxic zone was incomplete with an average NO3-N concentration leaving the anoxic zone greater than 10 mg/L. The effluent TN during this period was approximately 36 mg/L, similar to the annual average presented earlier. The incomplete denitrification in the anoxic zone suggests that either the anoxic zone is not large enough, there is too much dissolved oxygen in the anoxic zones, or there is insufficient influent BOD to completely denitrify. The anoxic retention time during this period was approximately 1.7 hours, which is a typical value for the MLE process. The City does not currently have the ability to control the ML recycle rate and, therefore, operational changes associated with varied recycle rates are not feasible without capital improvements. Modifying the RAS rate or solid retention rate (SRT) is not anticipated to significantly improve TN or TP removal without detrimentally affecting other process performance (nitrification, TSS removal, etc.). Increasing the anoxic zone size by reducing the size of the aerated zone will negatively impact nitrification, which is already challenging during the winter months at current flows and loads. The existing anoxic zone is not large enough to allocate a portion as an anaerobic zone for BPR without further reducing the ability to denitrify. While the City has tankage in the Satellite WWTP that is not currently in use, the facilities to convey influent from the Easton collection system to the Satellite activated sludge system are not in place. Operating the Satellite WWTP treating only the Satellite influent will exacerbate existing carbon deficiencies for nutrient removal in addition to introducing other operational challenges. No operational changes alone are feasible to significantly reduce the TN and TP loads in the effluent without negative impacts on other treatment process performance. The modifications necessary for successful BPR or chemical phosphorus removal (CPR), such as anaerobic zones, larger anoxic zones, chemical storage and feed facilities, better operational control, and infrastructure to operate the Satellite activated sludge tankage parallel with the Easton activated sludge tankage will require significant capital improvements as discussed later in this report. WASTELOAD AND FLOW FORECASTS To evaluate processes and technologies to enhance existing nutrient reduction capabilities, wasteload and flow forecasts were completed for the City's WWTP service area. For the purposes of this study, it is anticipated that the overall area served by the City's WWTP will remain the same through the 20-year planning period. A. Population Trends According to the 2010 census, the City had 68,406 residents, 28,607 total households, and an average household size of 2.35 persons. Compared to the 2000 census City population of 68,747, this equates to a 10-year population decrease of approximately 0.5 percent. Based on the 2011 to 2015 American Community Survey 5-Year Estimates, the estimated 2015 population of the City is Prepared by Strand Associates, Inc ® 15 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 107 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study 68,432, for an estimated 5-year population growth of approximately 0.04 percent from 2010. Population projections for the City obtained from the Black Hawk County Metropolitan Area Transportation Policy Board's 2040 Long Range Transportation Plan are presented in Table 16 below. Year 2010a 2015b 2020 2030 2040 City of Waterloo Population 68,406 68,432 72,212 76,601 f 81,633 a2010 Census data b2011 to 2015 American Community Survey 5-Year Estimates Table 16 Current and Projected Populations These projections estimate a 25-year growth of approximately 19 percent, or an annual growth of approximately 0.7 percent over the period. Based on these projections, a 2040 City population of 81,633 is used for projecting future residential wastewater flows and loadings in this study. B. Projected Wastewater Flows Projecting future wastewater flows requires identification of residential/commercial and industrial wastewater flow, base flows, peaking factors, and anticipated residential/commercial and industrial growth in areas tributary to the Easton and Satellite WWTPs. Planned additional industrial discharges to the Satellite collection system, both upstream and downstream of the anaerobic lagoon, were provided by the City as presented in Table 17. Increased BOD5 and TSS loadings discharged from the lagoon were estimated based on new planned discharges to the lagoon and existing removal efficiencies. No reduction in TKN or TP were assumed for new discharges from the lagoon. Table To Satellite Interceptor Downstream of Lagoon To Anaerobic Lagoon From Anaerobic Lagoon Total Additional Planned Flow and Loading to Satellite/Easton WWTPs Flow, mgd 0.116 0.184 0.184 0.30 BOD, mg/L 620 3,000 430 - BOD, Ibs/day 600 4,700 700 1,300 TSS, mg/L 750 2,900 1,100 - TSS, Ibs/day 700 4,500 1,700 2,400 TKN, mg/L 150 700 700 - TKN, Ibs/day 150 1,060 1,060 1,210 TP, mg/L 37 44 44 TP, Ibs/day 36 68 68 100 pH, s.u. 17 Planned 6.1 Industrial Discharge 6.5 6.5 - Estimates Prepared by Strand Associates, Inc.® 16 R:\MAD\Documents\Reports\Archive\2018\Watedoo, IA\Nutrient Reduction 4463 001 raw.feb\Report\Nutrient Reduction Study docx\032818 Page 108 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Table 18 shows the projected future design flows for the facility considering the expected growth. Current Easton dry weather flows used in these projections are based on the 2016 dry weather flow because this value is significantly greater than previous years. Future dry weather flow from the Easton collection system was determined by adding additional expected flow from growth at 100 gallons per capita per day (gcd) to the dry weather base flow. The average and wet weather 1/I values were then added to the base flow to determine the annual average, wet weather, maximum day, and peak hourly flows. The total design 1/1 for annual average, wet weather, maximum day, and peak hourly flows were estimated using current peaking factors from the 2016 flow data, with the exception of the Easton Wet Weather I/1, which used the 2014 maximum month flow because it exceeded the 2016 value. To account for the increase in base flow in 2016 and to avoid double counting 1/1, the 2016 Dry Weather flow was subtracted from the 2014 Easton Wet Weather to estimate the current wet weather I/1. Additional I/1 from growth was estimated using wet weather peaking factors from the 2016 flow data and the projected additional dry weather flow from growth. The City is currently implementing collection system improvements related to wet weather flows under a 2017 Consent Decree, including flow monitoring, sewer condition and capacity assessments, a footing drain removal program, a hydraulic model, and the development of a Sanitary Sewer Master Plan. It is anticipated that these improvements will impact future wet weather flows and, therefore, it is recommended an evaluation of peak flows to the WWTP using the City's hydraulic model is conducted following the completion of these collection system improvements. The need for future peak flow improvements at the WWTP should be reevaluated at that time. Using this method, the projected design average flow for the Easton WWTP is 15.32 mgd, which is less than the current design average flow of 20.4 mgd. The projected design average flow of the Satellite WWTP is 3.61 mgd, which is less than the current design average flow of 6.7 mgd. The need for future peak flow improvements at the WWTP should be reevaluated at that time. Prepared by Strand Associates, Inc. 17 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IANutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032918 Page 109 of 164 DRAFT-(05.03.23) City of Waterloojlowe Nutrient Reduction Study 'PF 'PF Easton Flow (mgd) Satellite Flow (mgd) Combined Flow Smgd) Current Dry Weather Flowa 10.50 2.68 13.18 Projected Residential Growthb 1.32 - 1.32 Planned Industrial Growth - 0.30 0.30 Projected Dry Weather Flow 11.82 2.98 14.80 Design I/Ik Annual Average 3.5c 0.63g 4.13 Wet Weather 18.92d 1.11 h 20.03 Maximum Day 55.4e 2.39i 57.8 Peak Hourly 58.4f 3.651 62.1 Projected Flows Annual Average 15.32 3.61 18.93 Average Wet Weather 30.74 4.09 34.83 Maximum Day 67.22 5.37 72.59 Peak Hourly 70.18 6.63 76.81 e2016 Easton influent flow used as baseline bAdditional residential flow of 13,201 persons at 100 gcd. `PF = 1.3 x Dry Weather Flow (based on 2016 Easton flow data) °2014 Easton maximum month - 2016 Dry Weather Flow + I/1 from growth @ PF=2 0 ePF = 5.7 x Dry Weather Flow (based on 2016 Easton flow data) 'PF = 5.8 x Dry Weather Flow (based on 2016 Easton flow data) 9PF = 1.2 x Dry Weather Flow (based on 2016 Satellite flow data) hPF = 1.4 x Dry Weather Flow (based on 2016 Satellite flow data) = 1.7 x Dry Weather Flow (based on 2016 Satellite flow data) = 2.1 x Dry Weather Flow (based on 2016 Satellite flow data) kExisting I/1 + I/1 from growth Table 18 Projected 2040 Flows C. Projected Wasteloads Future loads to the Easton VWVTP were projected by using the populations presented earlier and per capita values of 0.22 pcd for BOD5, 0.22 pounds per capita per day (pcd) for TSS, 0.041 pcd for TKN, and 0.011 for TP, as well as the planned industrial growth. The current average BOD5, TSS, and TKN loadings are based on the December 2015 to December 2016 average less the estimated return flow loadings. The current average TP loadings are based on the 2016 weekly TP sampling that began in April 2016 less the estimated return flow loadings. Table 19 presents the estimated future loads for BOD5, TSS, TKN, and TP. Prepared by Strand Associates, Inc ® 18 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 110 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study BOD5 jlbs/day) Current Averages 28,500 Projected Residential Growth 2,900b Planned Industrial Growth 1,300 TSS TKN lbs/day) jlbs/da 33,300 8,240 2,900b 2,400 540d 1,210 100 TP Ibs/day) 1,340 Projected Average 32,700 ! 38,600 9,990 1,590 s2016 data as baseline (TP based on April 2016 to December 2016) less estimated return flow loadings. bAdditional load at 0.22 pcd bAdditional load at 0.22 pcd dAdditional load at 0.041 pcd eAdditional load at 0.011 pcd Table 19 Projected Future Loads —Combined Influent Projected maximum monthly influent loadings are estimated by using a peaking factor of 1.3 for BOD5, 1.5 for TSS, 1.2 for TKN, and 1.1 for TP. The peaking factors for BOD5, TSS, and TKN were determined by dividing the highest 30-day average loading by the annual average loading from December 2015 through December 2016. The peaking factor for TP was determined using the available influent TP data, which consisted of the nine -month period of April 2016 through December 2016, in which the 30-day maximum combined loading was 1,807 Ib TP per day and the average loading was 1,474 Ib TP per day. The maximum monthly loadings are shown in Table 20. Projected Averag Peaking Factor Maximum Month BOD5 TSS TKN Phosphorus (Ibs/day) (Ibs/day) (Ibs/day) (ibs/day) e Load 32.700 38,600 9,990 1. 591 I 1.3 1.5 1.2 1.2 Load 42.500 57.900 12,000 1,911 Table 20 Estimated Maximum Month Loads Table 21 summarizes the projected year 2040 flows and loadings and compares to the full permitted flows and loadings. Existing capacity greater than the 2040 flow and loadings projection is held as reserve capacity for unforeseen growth. Prepared by Strand Associates, Inc.® 19 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study.docx\032818 Page 111 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study 2040 Projection Annual Average Flow Average Wet Weather Flow (Maximum Month) Maximum Wet Weather Flow (Maximum Day) Peak Hourly Wet Weather Flow Annual Average BOD5 (Ibs/day) Maximum Month BOD5 (Ibs/day) Annual Average TSS (Ibs/day) Maximum Month TSS (Ibs/day) Annual Average TKN (Ibs/day) Maximum Month TKN (Ibs/day) Annual Average TP (Ibs/day) Maximum Month TP (Ibs/day) 18.9 34.8 72.6 76.8 32,700 Full Permitted Design 27.1 34.8 79.1 a 79.1a 62,800 42,500 38,600 57,900 9,990 12,000 1,590 1,900 88,000 56,300 83,000 11,525 21,050 2,490b 2,980c °Maximum day and peak hourflow of Easton headworks focilily = 68 mgd. Maximum day and peak hour flow of Satellite = 11.1 mgd. bAdditional TP load for 8 17 mgd reserve capacity at 100 gcd and 0 011 pcd TP cAnnual Average TP x 1.2 Peaking Factor Table 21 Design Flows and Loads EVALUATION OF TREATMENT TECHNOLOGIES TO MEET NUTRIENT REDUCTION GOALS As previously discussed, operational changes alone will not be sufficient to achieve a significant increase in nutrient reduction and a major capital upgrade will be required to achieve the target reductions in TN and TP. In this section, modifications to the existing activated sludge systems for TN and TP removal are evaluated, including those that treat the dewatering filtrate sidestreams separately from the main treatment process. System performance was evaluated using a BioWin model and the results of this modeling are presented for each alternative. A. Description of Alternatives 1. Altemative BNR1—A20 process In this alternative, the existing activated sludge system would be modified to implement the A20 process for biological phosphorus and nitrogen removal. These modifications include the conversion of the existing activated sludge system into eight trains using both the Satellite and Easton WVVTPs, each consisting of anaerobic, anoxic, and aerobic zones, along with new nitrified ML recycles from the aerobic zones to the anoxic zones (See Figure 3). Nitrate from the oxidation of influent ammonia is returned to the anoxic zone through the recycled ML, where it can be used by heterotrophic organisms instead of oxygen. This results in denitrification and carbon oxidation without aeration as well as alkalinity recovery. ML is typically returned at a rate of 100 to 400 percent of the influent flow and RAS is returned to the anaerobic zone where it is mixed with the primary effluent. The anaerobic zone provides an environment to select for polyphosphate -accumulating organisms (PAOs), resulting in the uptake of phosphorus in the aerobic zones and phosphorus removal through sludge wasting. Assuming adequate carbon is Prepared by Strand Associates, Inc ® 20 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 112 of 164 DRAFT-(05.03.23) er NEW PIPING EXISTING PIPING MIXED LIQUOR RECYCLE ANAEROBIC ZONE ANOXIC ZONE AERATED ZONE ALTERNATIVE BNR1 NUTRIENT REDUCTION STUDY CITY OF WATERLOO, IOWA 6:7A1 STRAND ASSOCIATES' 4 FIGURE 3 4463.001 Page 113 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study available, this process can normally attain effluent TP concentrations less than 1.0 mg/L and TN concentrations less than about 10 mg/L, depending on influent TP and TN concentrations. The conversion of the existing activated sludge system to the A20 process includes the following elements: Modify the Satellite aeration tanks to operate as four separate trains flowing north to south. 2. Modify Easton and Satellite aeration tanks with anaerobic and anoxic zones by constructing new baffle walls and installing floating or submersible mixers. 3. Install new nitrate recycle pumps, piping, and controls to recycle nitrified ML from the end of the aerated zone to anoxic zone in each train. 4. Remove existing aeration diffusers and replace diffusers in new aerated zones. 5. Install backup CPR system, consisting of two 5,000-gallon chemical storage tanks, chemical feed pumps, chemical feed piping, and Chemical Building. A calibrated BioWin model was developed for the Easton and Satellite activated sludge systems using special sampling data collected in 2017. This model was then used to predict the performance of the A20 process using the existing activated sludge tankage modified to include anaerobic, anoxic, and aerated zones (See Figure 4). Model simulations were conducted at the 2040 projected average day and maximum month flows and loadings, as well as the full permitted combined design average day and maximum month flows and loadings as presented in Table 22. Prepared by Strand Associates, Inc.® 21 R:\MAD\Documents\Reports.Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study.docx\032818 Page 114 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study E1A E1B EIC 1111 if E71 11R -1__ 1 I._1 -1 1 ( 1 17C Ian Ild 111 --i I1A E111 41C 110 F11 EY —1+ E1A E40 E<C E10 EaE EN M i76 1x 370 - 11E IN J. `I'' 13A ♦3& IIE 310 311 13a t L,1,.1-{- F --I_ NA u% SIB S11 311 lh..mophaic oyes*: ww001c n Week Wale1 Figure 4 BioWin Model of A20 Process Baosakas cake 41)1111 1 2040 Projection Full Permitted Design Average Day Maximum Month Average Day Maximum Month Influent Parameters Flow, mgd 18.9 34.8 27.1 34.8 BOD5 Load, lbs/day 32,700 42,500 62,800 88,000 TSS Load, Ibs/day 38,600 57,900 56,300 83,000 TKN Load, lbs/day 9,990 12,000 11,525 21,050 TP Load, lbs/day 1,590 1,900 2,490 2,980 Model Effluent Results cBOD5,mg/L 2.6 2.6 3.2 3.2 NH3-N, mg/L 0.4 0.4 0.3 0.3 TN, mg/L (lbs/day) 25.6 (4,102) 20.3 (5,954) 15.5 (3,546) 30.1 (8,809) TP, mg/L (lbs/day) 7.8 (1,250) 4.9 (1,424) 6.8 (1,559) 5.4 (1,581) TSS, mg/L 7.9 8.3 9.8 8.6 Table 22 A20 Process Modeling Summary The BioWin simulations for all of the scenarios presented in Table 22 predict insufficient BPR to achieve the effluent TP target of Tess than 697 Ibs TP/day. A key component of successful BPR is having adequate influent carbon in the form of volatile fatty acids (VFAs) or easily fermentable compounds to sustain the necessary PAO population. As presented in Table 23, the special Prepared by Strand Associates, Inc.® 22 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 115 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study sampling results suggest that the BOD:TP and soluble biochemical oxygen demand (sBOD):TP ratios to the activated sludge system are approximately 14:1 and 7:1, respectively. According to the Water Environment Federation Manual of Practice No. 34: Nutrient Removal, the minimum substrate to phosphorus requirements for BPR are 25:1 for carbonaceous biochemical oxygen demand (cBOD5):TP and 15:1 for sBOD):TP, which supports the theory that the influent wastewater has inadequate carbon to provide adequate PAO activity in the process simulations. BOD, Ibs/day sBOD, Ibs/day TP, Ibs/day Easton Primary Effluent 11,350 6,200 850 Satellite Influent 9,410 Table 23 Special Sampling Data —May and June 2017 3,470 630 Combined 20,760 9,670 1,480 There are several approaches that are available for facilities that do not have adequate influent carbon for successful BPR, such as increasing influent carbon to the activated sludge system through primary sludge fermentation or removing phosphorus from the dewatering return flows. Additionally, the City is in the unique position of having a significant upstream carbon source being treated at the anaerobic lagoon that could be partially diverted to the VWVfP to increase the influent BOD:TP ratio. Each of these approaches are described further below and additional process simulations are presented that evaluate their impact on overall nutrient removal at the VVVVfP. a. Sidestream Phosr horus Removal Sidestream phosphorus removal is typically based on harvesting or sequestering struvite (magnesium ammonium phosphate) to remove phosphorus from the sludge dewatering filtrate or from the digested sludge directly. This reduces the phosphorus load to the activated sludge system, effectively increasing the BOD:TP ratio. The City has noted some maintenance issues with struvite formation based on current VWVfP operations, and implementation of a BPR process is anticipated to exacerbate struvite formation as more stored phosphorus is released in the anaerobic digesters. In addition to the reduced phosphorus loading to the activated sludge system, harvesting struvite can reduce maintenance from nuisance struvite formation, especially when harvested from the digested sludge directly. There are also opportunities to produce a marketable struvite product that can partially offset the costs of removal, depending on the technology used. b. Primary Sludge Fermentation One approach to increase VFAs to the activated sludge system is through primary sludge fermentation. This is typically accomplished in a covered, mixed tank in which thickened primary sludge is held to allow the biodegradable organic components to be fermented into VFAs. The retention time in the fermenter is closely controlled to maintain an adequate population of fermenting microorganisms while preventing methanogens from becoming Prepared by Strand Associates, Inc.® 23 R:\MAD\Documents\Reports\Archive\2016\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 116 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study prevalent. While primary sludge fermenters have been successfully implemented at many WWTPs to produce VFAs, the cost, operation, maintenance, and odors associated with fermentation must be considered. Additionally, the diversion of VFAs from the biosolids stream to the liquid stream for BPR will reduce the amount of biogas generated in the anaerobic digesters. c. Anaerobic Lagoon Influent Diversion/Chemical Carbon Addition The City's anaerobic lagoon received over 35,000 Ibs BOD/day from 2014 to 2016 and discharged approximately 5,170 Ibs BOD over the same period. The City has seen an increase in BOD loading to the lagoon in 2017, with recent months averaging over 40,000 Ibs BOD/day, and also anticipates an increase in BOD loading to the lagoon with new industries. One option to increase the influent BOD:TP ratio at the WWTP is to divert a portion of the high-BOD lagoon influent to the WWTP. However, this would result in Tess biogas production at the lagoon and would likely necessitate the installation of influent screening on the Satellite influent, as described earlier in this section. It would also necessitate additional infrastructure at the WWTP to convert carbon compounds in the lagoon influent to VFAs for the PAOs. For planning purposes, it is assumed that a new storage tank and the necessary pumping equipment to store the Satellite influent and allow fermentation to occur would be constructed if lagoon influent diversion were to be implemented. Rather than divert BOD from the anaerobic lagoon influent, the City could also choose to purchase compounds that are high in biodegradable COD or VFAs and add these directly to the primary effluent to increase the BOD:TP (or VFA:TP) ratio. Alternatives with VFA addition at the WWTP include additional chemical storage and feed systems for this purpose. Additional simulations of the A2O process with struvite harvesting and primary sludge fermentation were conducted under the 2040 projected annual average conditions to evaluate the impact of each of these processes on nutrient removal. In each of these simulations, the influent VFA deficit predicted by the model was quantified by determining the VFA addition necessary to achieve the effluent TP target. The results of these simulations are presented in Table 24. Prepared by Strand Associates, Inc.® 24 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 117 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study • Average Day Projected 2040 Conditions Average Day with Struvite Harvesting Average Day with Struvite Harvesting and PRS Fermentation Influent Parameters Flow, mgd 18.9 18.9 18.9 BODE Load, Ibs/day 32,700 _ 32,700 32,700 TSS Load, Ibs/day 38,600 38,600 38,600 TKN Load, Ibs/day 9,990 9,990 9,990 TP Load, Ibs/day 1,590 1,590 1,590 Model Results —Secondary Effluent cBOD5, mg/L 3.6 3.4 3.5 NH3-N, mg/L 0.7 0.4 0.4 TN, mg/L (Ibs/day) 22.2 (3,556) 23.9 (3,841) 23.9 (3,841) TP, mg/L (Ibs/day) 4.3 (685) 4.2 (680) 4.3 (688) TSS, mg/L 8.1 7.8 8.0 VFA Addition (Ibs/day) 23,370 6,680 3,340 Table 24 A20 Process Modeling Summary —with VFA Addition at 16°C, 2040 Conditions The BioWin simulations predict that implementation of sidestream struvite harvesting and primary sludge fermentation would significantly reduce the amount of VFAs that would either have to be added at the WWTP or diverted from the anaerobic lagoon under the projected 2040 annual average conditions to achieve the effluent TP target of 697 Ibs/day (Table 24). However, the model predicts that reaching the target would still require some VFA addition or lagoon influent diversion to increase the VFA:TP ratio. Under the full permitted design flows and loadings (Table 25), the model predicts effluent TP below the target values without VFA addition if struvite harvesting and primary sludge fermentation is implemented, because this loading condition has a more favorable BOD:TP ratio than the projected 2040 condition. Based on this evaluation, the A20 process is separated into the following alternatives: • BNR1a—A20 with BOD diversion from lagoon • BNR1b—A20 with VFA addition at WWTP • BNR1c—A20 with Struvite Harvesting; BOD diversion from lagoon • BNR1d—A20 with Struvite Harvesting; VFA addition at WWTP • BNR1e—A20 with Struvite Harvesting and PRS fermentation; BOD diversion from lagoon • BNR1f—A20 with Struvite Harvesting and PRS fermentation; VFA addition at WWTP Prepared by Strand Associates, Inc.® 25 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 118 of 164 DRAFT-(05.03.23) Ciy of Waterloo, Iowa Nutrient Reduction Study Full Permitted Design Flows and Loadings Average Day Average Day with Struvite Harvesting Average Day with Struvite Harvesting and PRS Fermentation Influent Parameters Flow, mgd 27.1 27.1 _ 27.1 BOD5 Load, Ibs/day 62,800 62,800 62,800 TSS Load, Ibs/day 56,300 56,300 56,300 TKN Load, Ibs/day 11,525 11,525 11,525 TP Load, Ibs/day 2,490 2,490 2,490 Model Results —Secondary Effluent cBOD5, mg/L 3.9 3.2 3.7 NH3-N, mg/L 0.9 0.4 0.3 TN, mg/L (Ibs/day) 14.1 (3,222) 14.6 (3,348) 13.9 (3,182) TP, mg/L (Ibs/day) 3.0 (685) 3.0 (678) 2.2 (510) TSS, mg/L 9.6 8.0 12.4 VFA Addition (Ibs/day) 18,360 0 ,, 0 Table 25 A20 Process Modeling Summary —with VFA Addition at 16°C, Full Permitted Design Conditions 2. Alternative BNR2—MLE with CPR In this alternative, the City would continue to implement the MLE process for biological nitrogen removal and would address phosphorus removal through chemical addition. The existing activated sludge system would be modified to improve performance and would result in eight trains instead of the current six by converting the Satellite activated sludge tanks into four parallel trains. New nitrified ML recycles from the aerobic zones to the anoxic zones would also be included (see Figure 5). CPR involves the addition of a metal salt (commonly an iron or aluminum salt) to flocculate and precipitate soluble phosphorus in wastewater. The precipitated phosphorus is then removed during clarification and/or filtration. CPR is a relatively simple and predictable process, especially for effluent targets over 1.0 mg/L. Jar testing with multiple CPR chemicals is often performed to determine the most cost-effective chemical and to estimate the required chemical dosages. There are several possible application points for CPR. The phosphorus removal chemical could be added to the primary influent, aeration tanks, or final clarifier influent. Application upstream of the primary clarifiers can provide additional primary removal of suspended solids and organic matter in addition to phosphorus removal, which would reduce loadings to the activated sludge system, reduce power costs, and result in additional digester gas production because of higher primary clarifier TSS and BOD removal rates. However, because of the complex nature of the raw wastewater, higher chemical dosages are typically required when added to the primary clarifier Prepared by Strand Associates, Inc ® 26 R:\MAD\Documents\Reports\Archive\2016\Waterloo, IA\Nutrient Reduction 4463 001.raw feb\Report\Nutrient Reduction Study docx\032616 Page 119 of 164 DRAFT-(05.03.23) PRIMARY EFFLUENT SPUTTER STRUCTURE LEGEND NEW PIPING EXISTING PIPING MIXED LIQUOR RECYCLE ANOXIC ZONE AERATED ZONE ALTERNATIVE BNR2 NUTRIENT REDUCTION STUDY CITY OF WATERLOO, IOWA eAl STRAND ASSOCIATES' FIGURE 5 4463.001 Page 120 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study influent, and sludge production can increase by more than 20 percent in such systems. More than one application point is typically provided for optimization and flexibility. Several chemicals are available for CPR, but aluminum sulfate (alum) and ferric chloride are two of the most commonly used. Alum is typically favored in soft water applications, while ferric chloride is used more in hard water applications. Both chemicals can affect sludge thickening and dewaterability and can also lower the pH of the wastewater. Sodium aluminate is also sometimes used for CPR and can be useful when pH or alkalinity is low because it is a basic chemical. Other chemicals that may be used include ferrous chloride, ferric or ferrous sulfate, polyaluminum chloride, and rare earth metals. For this report, it was assumed that ferric chloride would be used for CPR. Jar tests and/or full scale tests should be performed if the City elects to implement CPR to meet future effluent phosphorus limits. A calibrated BioWin model was used to predict the performance of the MLE process using the existing activated sludge tankage with modified anoxic and aerated zones (See Figure 6). Model simulations were conducted at the 2040 projected average day and maximum month flows and loadings, as well as the full permitted combined design average day and maximum month flows and loadings as presented in Table 26. 'Noon ows.s. Is ..n% .L._ [A: !!e ex W nr fr j ne rx ew 14_, 41. e� un uc :.e SR ear 11z !Id HC im 11l N+ s,j J'i:—� I--u-l- �I J'—L �'- fk 1Je W. 4]p 1 MD >K » m I .... I---Lai:--I- ->" . -' Figure 6 BioWin Model of MLE Process with CPR rn..ep�rr. ognwl w.van-'K aw7 WWI WAN Prepared by Strand Associates, Inc.® 27 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 121 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Influent Parameters 2040 Projection Maximum Average Month at Day at 16°C 16°C Flow, mid BOD5 Load, lbs/day TSS Load, Ibs/day TKN Load, Ibs/day TP Load, Ibs/day 18.9 32,700 34.8 42,500 Full Permitted Design Flows and Loadings Maximum Maximum Average Day at Month at Month at 16°C 16°C 12°C 38,600 57,900 9,990 1,590 12,000 1,900 27.1 34.8 62,800 88,000 56,300 83,000 11,525 21,050 2,490 2,980 34.8 88,000 83,000 21,050 2,980 Model Effluent Results cBOD5, mg/L NH3-N, mg/L TN, mg/L (Ibs/day) TP, mg/L (Ibs/day TSS, mg/L 1.9 0.2 26.3 (4,216) Ferric Chloride Dose, gpd 4.1 (650) 8.9 1,200 2.4 2.8 3.3 3.9 0.4 0.1 0.7 0.5 16.0 (4,687) 2.4 (694) 11.5 1,700 11.7 (2,676) 19.3 (5,655) 2.9 (663) 2.3 (680) 27.1 (7,943) 2.3 (680) 12.1 2,200 12.3 2,400 Table 26 MLE Process Modeling Summary with CPR 12.5 2,400 The BioWin simulations for the average day scenarios presented in Table 26 predict effluent TN loads below the target value of 5,863 lbs/day. Chemical doses necessary to achieve the effluent TP target of 697 lbs/day with single -point addition to the final clarifiers ranged from approximately 1,200 gpd at the projected annual average loading up to approximately 2,400 gpd at the full permitted design maximum month loading. Jar testing of various phosphorus -removal chemicals to estimate dose requirements is recommended prior to final design should this alternative be pursued further. A simulation conducted at the full permitted design maximum month condition and 12°C suggests that additional tankage is not needed to nitrify under this extreme condition. In this scenario, the ratio of anoxic to aerated volume was decreased as compared to the other simulations presented. Further refinement of zone sizes should be conducted should this alternative be pursued, potentially incorporating anoxic or aerated "swing" zones to account for varied loading conditions. This alternative includes the following elements. a. Modify the Satellite aeration tanks to operate as four separate trains flowing north to south. b. Modify Easton and Satellite aeration tanks with anoxic zones by constructing new baffle walls and installing floating or submersible mixers. Prepared by Strand Associates, Inc ® 28 R:\MAD\Documents\ReportsWrchive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study.docx\032818 Page 122 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study c. Install new nitrate recycle pumps, piping, and controls to recycle nitrified ML from the end of the aerated zone to anoxic zone in each train. d. Remove existing aeration diffusers and replace diffusers in new aerated zones. e- Install CPR system, consisting of four 10,000-gallon chemical storage tanks, chemical feed pumps, chemical feed piping, and Chemical Building. 3. Alternative BNR3—MLE with Sidestream Enhanced BPR Historically, BPR systems such as the A2O process described earlier have relied on a group of PAOs known as Accumulibacter for phosphorus uptake and removal using combinations of anaerobic and aerated zones in the main liquid process train. A more recent development in phosphorus removal is sidestream enhanced BPR using RAS fermentation (Figure 7). In this process, a portion of the RAS (typically 10 to 25 percent) is diverted to a sidestream anaerobic tank with a detention time of 24 to 48 hours (or less with VFA addition) which can select for Tetrasphaera under deep anaerobic conditions [oxidation-reduction potential (ORP) Tess than -300 millivolts (mV)]. Research suggests that Tetrasphaera can ferment higher organic compounds and produce additional VFAs for Accumulibacter to work along -side them. Therefore, it may have an advantage for situations where BPR using the A2O process is carbon -limited, such as the A2O model is predicting in this case. This configuration has also been shown to safeguard against Glycol Accumulating Organisms (GAOs) that compete against PAOs under certain conditions. Other advantages to sidestream enhanced BPR include some additional protection from biomass washout and reduced detention times under peak flow conditions. However, while the mechanisms for this BPR process are currently a subject of significant research, the existing process models do not account for these two discrete PAO populations, and, therefore, process models cannot currently predict treatment performance of this configuration. RAS Fermentation Zone Anaerobic SRT 1-2d Influent 10-25% Nitrate Recycle Ax Aerobic Return Sludge Figure 7 RAS Fermentation Process Diagram Effluent Based on the industry's experience with RAS fermentation to -date, the design considerations described above (diversion of 10 to 25 percent of RAS to an anaerobic zone with SRT of 24 to 48 hours) have been suggested in the literature. For the City's design average flow of 27.1 mgd and a typical RAS rate equal to the average influent flow, the RAS fermentation zone would be approximately 5.4 MG to provide a 48 hour SRT for 10 percent of the RAS flow. This is approximately equal to one of the existing Satellite VWVfP treatment trains, which each have a volume of approximately 5.8 MG. The remaining tanks would be configured with anoxic zones and aerated zones, similar to the MLE process described earlier. RAS flow would be diverted to Prepared by Strand Associates, Inc ® 29 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IANutrient Reduction 4463.001 raw feb\Report\Nutrient Reduction Study.docx\032818 Page 123 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study the RAS fermentation zone from the RAS headers in the Easton and Satellite RAS Buildings and controlled with pumps and/or flow control valves. Effluent from the RAS Fermentation Zone would flow to the new Primary Effluent Splitter Structure where it would be combined with primary effluent and RAS. A preliminary schematic of this layout is presented in Figure 8. This alternative includes the following elements: a Modify two of the Satellite aeration tanks to operate as two separate MLE trains flowing north to south. b. Modify Easton and two Satellite aeration tanks with anoxic zones by constructing new baffle walls and installing floating or submersible mixers. c. Install new nitrate recycle pumps, piping, and controls to recycle nitrified ML from the end of the aerated zone to the anoxic zone in each train. d. Remove existing aeration diffusers and replace diffusers in new aerated zones. e. Modify two of the Satellite aeration tanks into RAS Fermentation Zones with floating or submersible mixers. Install piping from the Easton and Satellite RAS buildings with pumps and/or flow control valves to feed RAS to the RAS Fermentation Zones. f. Install CPR system, consisting of two 10,000-gallon chemical storage tank, chemical feed pumps, chemical feed piping, and Chemical Building. This will provide backup chemical addition in the event that this process does not operate efficiently. While this process cannot be accurately modeled at this time, simulations were conducted to evaluate the ability of the activated sludge system to meet ammonia and TN targets using only the Easton tanks and two of the Satellite tanks without RAS fermentation. This scenario simulates the operation of these six trains in the MLE arrangement for TN removal without (or prior to) implementation of RAS fermentation. Several loading scenarios and conditions were evaluated as presented in Table 27. At the 2040 projected maximum month condition at 12°C, considered a stressed condition for nitrification, the simulation results predict effluent ammonia below 1.0 mg/L and TN below the target value. At the full permitted average day design loading conditions, effluent ammonia below 1.0 mg/L and TN below the target value was predicted for both 12°C and 16°C simulations. At the full permitted design maximum month condition, the simulated configuration did not completely nitrify at 12°C, with an effluent ammonia concentration of 4.5 mg/L. However, this value is significantly less than the lowest winter monthly average effluent ammonia limit in the current permit of 34.5 mg/L in December. Earlier simulations of the MLE process (presented in Table 26) suggest that the existing tankage could adequately nitrify under these conditions using all of the available tanks for the MLE process. Further evaluation should be conducted following development of process models to evaluate these loading conditions should lower effluent ammonia concentration be required in the future. Prepared by Strand Associates, Inc.® 30 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 124 of 164 DRAFT-(05.03.23) Lev RAS PIPING TO FERMENTATION ZONE LEGEND NEW PIPING EXISTING PIPING MIXED LIQUOR RECYCLE ANAEROBIC ZONE ANOXIC ZONE AERATED ZONE PRIMARY EFFLUENT SPUTTER STRUCTURE RAS PIAINGTO FERMENTATION Zan ALTERNATIVE BNR3 NUTRIENT REDUCTION STUDY CITY OF WATERLOO, IOWA eAl STRAND ASSOCIATES' FIGURE 8 4463.001 Page 125 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study i 2040 Projection Full Permitted Design Loadings Average Day At 16°C Maximum Month at 12°C Maximum Month at 12°C _ Average Day , At 12°C Influent Parameters Flow, mgd 34.8 27.1 27.1 34.8 BOD5 Load, Ibs/day 42,500 62,800 62,800 88,000 TSS Load, Ibs/day 57,900 56,300 56,300 83,000 TKN Load, Ibs/day 12,000 11,525 11,525 21,050 TP Load, Ibs/day 1,900 2,490 2,490 2,980 Model Effluent Results cBOD5, mg/L 2.3 3.6 3.4 4.1 NH3-N, mg/L 0.5 0.4 0.1 4.5 TN, mg/L (Ibs/day) 19.1 (5,596) 12.6 (2,871) 12.5 (2,848) 27.0 (7,918) TP, mg/L (Ibs/day) 2.3 (669) 2.8 (650) 2.9 (654) 2.3 (678) TSS, mg/L 10.0 12.9 12.6 13.1 Ferric Chloride Dose, gpd 1,700 2,200 2.200 2,400 Activated Sludge Volumetric Loading Rate assuming 35% removal in Primary Clarifiers (lb BOD5/1,000 cf/day) 15.0 22.0 22.0 30.9 Table 27 MLE Process Modeling Summary with CPR —Two Satellite Trains Reserved for RAS Fermentation Zones B. Monetary Comparison Table 28 summarizes the 20-year present worth analysis for each of the BNR alternatives. Additional detail on the present worth analysis is provided in Appendix B. Because the phosphorus removal performance of Altemative BNR3 cannot be predicted using process modeling at this time, the quantity of phosphorus removal chemical (PRC) or VFA that would be required to meet the TP target with this alternative, if any, is unknown. Therefore, operational and maintenance (O&M) costs associated with Altemative BNR3 are estimated as ranges, with the maximum values assuming chemical addition equal to those of Alternative BNR2. For the alternatives that include the diversion of BOD from the anaerobic lagoon to the V VVTP, it is assumed that at a minimum a screening facility would be required on the Satellite influent, and, therefore, the present worth cost of Satellite Screening facility is included with these alternatives. Additionally, these alternatives include the lost revenue from the biogas that would have been generated at the lagoon if this BOD was not diverted, estimated in the range of $0 to $20 per million British Thermal Units (MMBTU), depending on the end -use of the lagoon biogas. C. Nonmonetary Considerations Nonmonetary considerations for each alternative were evaluated and are summarized in Table 29. Prepared by Strand Associates, Inc.® 31 R:\MAD\Documents\ReportsWrchive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 126 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Table 28 BNR Present Worth Analysis Summary Alternative BNR3 MLE with Sidestream Enhanced BPR 0 0 O 0 M $820.000I 0 0 O 0 Um) 0 0 00000 o 0 N fA 0 o 0 env 0 0 0 o o 0 o ( e9 N f9 0 O a 4- A eA Annual O&M Costs Labor 1 $10,000 1 $10,000 1 $20,000 1 $20.000 I $40.000 1 $40.000 1 $60.000 I $7.000 to 60.000 0 0 00 O o O 0 N f0 EA e9 O 2 0 0 09 000'0Zs 000"OL l$ 010$ 0 0 0 O m fA YO O O O '1 N $460,000 to S17,970,000 Summary of Present Worth Costs 0 0 00 0 0 o ri 0 49 r $460,000 to S17.970.000 0 m �o a s a 0 am a n en N Alternative BNR2 MLE Process with CPR O 000 coo O O) v en O o a P.- fA O 0 m CO EA O O 00000 0 U) enen 4/3 O a 0 C) 00 O O 0 a 0 o 0 CO CD N en 69 O O a en m d- VI 000' 099E 000"0LZ$ $170.000 $20.000 O 0 O O CO iA O O a a n 0) i. A M O O O O O O 0 0 P) m o " e» 0 O 0 o N. rn r fA "• ' ai a, y O a a a N en A N N Alternative BNR1f A20 Process with struvite harvesting and PRS fermentation; VFA addition at WWTP O 0 O tU w S1,290,000 I 0 0 0 o (0 69 0 0 0 0 1c0 to 0 0 0 0 COC to $1,070,000 $5,850,000 0 0 0 O enN ^ N 0 0 0 0 0 0 d o 0 !A 000"04$ 000'04$ 0 0 0 d m O 0 0 0 a O) 1V N 0 0 0 0 0 0 0 0 4 t`en 4 0 o 0 0 N N Q a 0 N be a o a of 0 a eq Alternative BNR1e A20 Process with struvite harvesting and PRS fermentation; BOD diversion from lagoon 000 000 0.00 0 N 4-ea vi o st N O 0 m 9 00000 00000 00.000 o N,, A eA d o 10 n •m e- i63 40 a 0 N e en N $290.000 $140.000 0 0 0 0 0 0 O O V' a 0 t9 0 0 0 d U) U) A 0 0 0 a n P1 NUO) 0 0 0 0 00 0 0 0 0 0 0.-.00 0 C 69 O O 0 o 0 n N V 69 f 0 O o o .90- O eA 0 0 0 00 00 Om a A mMMen V' e9 Alternative BNR1d A20 Process with struvite harvesting; VFA addition at WWTP 000 000 NO) r` (9 U .- f9 e e') V H DOM 00 m in fA COO 69 fA p0 0 G vi N f9 0 O N EC N 000.0SLS 000.00E$ 000'OE9 000'04$ 0 O Li 0 0 100 en ^ N 000 Ohh$ 000'0Z9"9l$ $17,360.000 0 O 0 N Ft N re M Alternative BNR1c A20 Process with struvite harvesting; BOD diversion from lagoon co 000 0 O 00 Oi eA 0 d 0) e9 0 0 0 0 N en O a 0 0 m o o o o m f9•0p7� c 0 O (0 C G o ore N, antll O a a a N N o 0 o a o 0 d 0 0 a 03 f9 000'OES 000'04$ 0 o 0 O 0 O a 0 0 o 0 m N o a 0 o o a O d , o f9 N f9 $8.070.000 ($1,060.000)� $5.470.000 000'0LE'H$ 0l0$ 0 0 a o a O a 0 e A e.e a V pe bi en W Alternative BNR1a Alternative BNR1b A20 Process with A20 Process with BOD diversion from VFA addition at lagoon WWTP 000 000 000 o O eA d o e9 o C) 6 0 0 0 o R S550.000 00 00 00 O pp N $14,810,000 r 000_00Z"Z$ 000'06Z$ 000 000 000 0 rse o N 0 0 0 0 a A a 00 00 00 O O 7 4 690) 0 0 0 o r. ' O d ' 0 0 0 a tn N o O o O (00 0 $1.520,000 $1,900,000 I 0 0 a o r 0 0 0 O O r eA $1,260,000 rr $6.900,000 1 0 O O a ^ N M 00000 00000 00000 o d N CO eA d N o1� N 1A e9 d f00 EA 0 0 O a - N 00 0 0 O O O O o 4 N to fA $9,140,000 ^0 0 0 o O O a s 0 Lei 0 0 O 0 0 N U9 O 0 fA $34,810,000 to $49,900,000 Capital Costs Equipment/Structure Subtotal C ea 2 Electrical Heating, ventilation, and air conditioning (HVAC) �e 3.0' 33 iq O m - 8 LE C C D U n m m J c Y 69 y l3 s 9 c a U Total Opinion of Capital Costs Power Chemical Additional Sludge Disposal Cost Maintenance and Supplies 0 Present Worth of O&M j Capital Cost Replacement O&M Cost Salvage Value Satellite Influent Screening 1 Lost Biogas Revenue at Lagoon TOTAL PRESENT WORTH Notes: All costs in 1st Quarter 2018 dollars N Page 127 of 164 DRAFT-(05.03.23) Nutne nt Reduction Study e 0 A Table 29 Biological Nutrient Removal Nonmonetary Considerations Summary 0 m O c c 01 5 0. O E a 0 0 0 U R rocesses and equipment from undesirable materials in diverted O O0 LL C rnv f BPR more challe c N C '(0 a N 0 0) a U Q EO o!a. 2O.5 5 O N 0 N > C .N Oi N 0 E E 0 v.2 a o T.0 0 c C O = E E N O C -o w 2222 E a NA m U D N U O U N J is O 2 5 c 0 m c 01 - W 0 N y 5 N a 5 N d N > O C U O m 2 To = 0 u- m SC. O) N 2! m0 mc om UF LL ON ac 2O§tcE xay ao lS E a . m .5 F 0 s 0 7 O 0 8 O ' C CO ,, N .7 LL l0 C N ¢O m a O: U a m O a 5 (0 O C A n 0 0) E 3 c ¢ E • o(0 oval without z V m 0_ • C 2 5 U ■ • a1-3 ii3 v 0 O O mQ 1mQ=g IZ iv c OM .L- W 2 i (0 L m n 0) c C 01 N N 0 3 o •- C N w E 0a ,2 U c a U0 A .0E nj 5 {h c LL- 031 a! W a! W h mZ zZce Page 128 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study C. Other Capital Improvements Required for Enhanced Nutrient Removal and VVVVfP Consolidation In this section, other capital improvements that are recommended if enhanced nutrient removal or increased capacity were to be required are presented. Improvements identified as recommendations for those purposes does imply that the City is consenting to implement these improvements at this time. As described earlier, the Satellite and Easton VVVVfPs are currently designed to operate as separate systems, each with their own influent pumps, activated sludge tanks, aeration systems, and final clarifiers. The City currently treats wastewater from both the Satellite and Easton collection systems using only the Easton VVVVTP activated sludge system because operating the two systems in parallel is inefficient and add significant operational complexity. It is also challenging to bring the Satellite VVVVTP online intermittently during periods of high flow/load, which would require ML to be manually transferred from the Easton tanks to the Satellite tanks, and for a second and significantly different activated sludge process to be initiated while biological treatment is under stress. For these reasons, it is recommended that the operations of the two facilities be combined into one common WVVTP using infrastructure from both VVVVTPs. The proposed configuration would combine the Easton and Satellite flows prior to grit removal, and the existing activated sludge systems would be modified to operate as parallel sets of tanks using the same biological treatment process as indicated earlier. However, other capital improvements beyond those identified in the BNR alternatives would be required to consolidate the VVVVTP operation. This section describes these additional capital improvements that are required to implement the BNR alternatives. 1. Preliminary and Primary Treatment Improvements The Satellite influent does not currently undergo preliminary or primary treatment and is discharged either directly to the Satellite activated sludge system or to the Easton activated sludge system (current operation). Because the Satellite activated sludge system is approximately 5 feet higher in elevation than the Easton activated sludge system, gravity flow of a combined influent to the two systems is not possible without hydraulic modifications to the existing primary clarifiers and splitter structure. Improvements to the preliminary and primary treatment facilities to consolidate the WWTPs are as follows (see Figure 9): a Replace Easton and Satellite influent pumps. b. Modify Satellite influent pump discharge piping to allow discharge upstream of grit removal, to the Primary Clarifier Splitter Box, and to the primary effluent splitter structure. Provide new flow measurement and sampling for Satellite influent. c. Add larger opening with sluice gate between Easton and Satellite influent wet wells to allow wetwells to operate as one. d. Modify grit influent channel to reduce grit settling. e. Replace grit collector mechanisms. f. Replace grit pumps and associated piping. Prepared by Strand Associates, Inc ® 34 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463.001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 129 of 164 VMOI `OO1831VM O Al1O AOf11S N0Ilo1103e11N3II1f1N S.N3W3/NOHdWl 1N3W.V32I1 A21VWIad ONV AHIVNIWI1321d Page 130 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Replace grit classifier with two grit washers. g. h. Install additional primary influent pipe between grit removal effluent channel and primary clarifier splitter structure to increase hydraulic capacity to 64 mgd. Modify grit effluent piping and equalization basin downward opening weir control in degritter effluent channel. Raise the walls and channels of the primary clarifiers and splitter structure approximately 5 feet to increase the water surface elevation in the primary clarifiers by approximately 5 feet. Replace primary clarifier mechanisms and weirs. k. Convert existing Easton Anoxic Selector Basin into primary effluent splitter structure to split flow between the Satellite and Easton activated sludge systems. Install new piping from splitter structure to Satellite activated sludge system. 2. Replacement of Aeration Blowers and Automation of Air Piping Cross -Connection Air for the activated sludge system is currently provided by eight 800 horsepower (hp) multi -stage centrifugal blowers with nominal capacities of 10,500 standard cubic feet per minute (scfm) each. The City currently operates only one or two of these blowers under normal conditions. During periods of low flow and load these blowers do not provide the desired turndown, resulting in high dissolved oxygen concentrations in the ML that is recycled to the anoxic zones. Newer blower technologies, such as high speed turbo blowers and single -stage centrifugal blower, are more energy efficient and would provide better turndown than the existing blowers. Based on the projected 2040 maximum month loading conditions, 1.1 Ib 02/lb BOD, and 4.6 Ib 02/Ib TKN, an estimated oxygen transfer efficiency of 16 percent, and a diurnal peaking factor of 1.5, the air required for the activated sludge system is approximately 38,600 scfm. This conservative estimate does not account for the oxygen recovered from the recycled ML. Based on the process modeling presented earlier, a total airflow of approximately 14,600 scfm (22,000 scfm with a 1.5 diurnal peaking factor) is required to maintain a dissolved oxygen concentration of 2.0 mg/L in the aerated zones of the MLE process under the projected 2040 maximum month loading conditions. Under the full permitted combined design loading conditions (influent BOD of 88,000 Ibs/day and TKN of 21,050 Ibs/day), the air required for the activated sludge system based on the theoretical oxygen demand is approximately 73,000 scfm, which is similar to the total installed blower capacity. The influent BOD loading under this condition is similar to what the influent load to the VWVTPs would be if the anaerobic lagoon were offline. It is recommended that four of the existing centrifugal blowers are replaced to improve energy efficiency and turndown while providing the oxygen for the simulated maximum month condition. For planning purposes, four 10,000 scfm high speed turbo blowers are included in the recommended plan. It is also recommended the remaining four multistage centrifugal blowers are maintained to provide the additional air required for the full permitted design loading condition or should the anaerobic lagoon be offline for a period. In addition, new blower controls based on Prepared by Strand Associates, Inc.® 35 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw.feb\Report\Nutrient Reduction Study docx\032818 Page 131 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study dissolved oxygen are recommended in all activated sludge basins. Automation is also included for the cross -connection between the existing Easton and Satellite aeration systems to allow the two aeration systems to operate as a combined system. 3. Final Clarifier Mechanism Replacement The recommended BNR improvements and WWTP consolidation will allow the City to better use the existing final clarifiers, which is anticipated to improve clarifier performance. However, the Satellite final clarifiers have been out of service for several years and it is anticipated that some work will be required to bring them back into service. In addition, City staff indicates that one of the Easton final clarifier mechanisms has become out of plumb and will likely require repair or replacement in the near future. Based on this, the recommended near -term improvements include a budgetary cost to replace two clarifier mechanisms. This cost is also anticipated to cover the cost of repairs should several clarifier mechanisms require less extensive repairs rather than full mechanism replacement. 4. Final Clarifier Cross -Connection and Flow Distribution Improvements As discussed earlier, the Satellite and Easton activated sludge systems are completely separated, not allowing for final clarifiers to be used without using the associated activated sludge system. To improve clarifier capacity following WWTP consolidation, a cross -connection between the two systems upstream of the final clarifiers is recommended to provide the ability to transfer ML from the Satellite WWTP to the Easton WWTP. In addition, modifications to the existing final clarifier flow splitter boxes for both WWTPs are recommended to improve flow distribution and control. These splitter boxes, including the cross -connection piping and downward opening weir gate with ultrasonic flow measurement to control the transfer of ML from the Satellite WWTP to the Easton WWTP, would be extensions of the existing splitter boxes and ML recycle wet wells. 5. New Effluent Flow Metering Structure Currently, secondary effluent from the Satellite and Easton WWTPs are measured separately using Parshall flumes at two different locations on -site. The existing Satellite secondary effluent flume is not adequately sized to measure the portion of the future combined WWTP flow that would be treated using the Satellite activated sludge tanks, requiring modifications to the existing means of effluent flow measurement. While the Easton secondary effluent flume is large enough to measure the portion of the future combined WWTP that would be treated using the Easton activated sludge system, it is not large enough to be used to measure the combined flows from the Easton and Satellite activated sludge systems. Therefore, the construction of a larger Parshall flume to measure the secondary effluent from both the Satellite and Easton activated sludge systems is proposed in the vicinity of the existing Easton effluent flume. 6. BFP Filtrate Equalization Currently, the filtrate from the digested sludge dewatering process is discharged to a return flow pipe that discharges directly to the Easton influent pipe. As presented earlier, the return flows from the dewatering process are high in ammonia, which results in slug loads to the WWTP during Prepared by Strand Associates, Inc.® 36 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction.4463 001 raw feb\Report\Nutrient Reduction Study docx\032818 Page 132 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study dewatering operation. Furthermore, if BPR is implemented at the WWTP, the phosphorus content of the filtrate will increase significantly as more phosphorus is released in the anaerobic digesters. To reduce the impact of these slug loadings on the WWTP, a new filtrate equalization tank is recommended to store filtrate (or centrate) from the dewatering process and slowly return it to the head of the WWTP. This tank consists of a 0.25 MG below -grade concrete structure, which would provide storage for more than one day of filtrate, as well as a submersible pumping station to allow a controlled discharge of this filtrate to the head of the WWTP. For planning purposes, it is assumed that this equalization tank would be located near the Dewatering Building and the drain piping that carries the filtrate from the building would be modified to discharge to the equalization tank. 7. Expansion of WAS Storage The existing WAS storage volume of approximately 269,000 gallons provides less than a day of storage based on the current average WAS rate of over 360,000 gallons per day. This requires WWTP staff to reduce wasting rates over the weekend when the GBTs are not operating, significantly limiting operational control. It is recommended that additional WAS storage is provided, so that the total storage volume will exceed three days of storage at the anticipated wasting rate. The existing WAS storage tanks are located adjacent to an old final clarifier that has been out of service since the Easton WWTP was constructed. Converting this final clarifier tank to WAS storage would provide an additional 1.2 MG. This would bring the total WAS storage volume to approximately 1.5 MG, or over four days of storage at the current WAS rate. Conversion of this final clarifier to WAS storage includes the following elements: a Demolition of existing clarifier mechanism and effluent trough. Abandon existing ML and secondary effluent piping to and from clarifier. b. Addition of new WAS piping from WAS Building to WAS storage tanks. c. Addition of new diffusers, aeration blower, and associated air piping. d. Replacement of Thickener Feed Pumps. e. Modifications to WAS and Thickener Feed Pump piping in WAS Building to allow pumping of WAS to and from new WAS Storage Tanks. IMPLEMENTATION AND BUDGETARY CONSIDERATIONS Because of the emergence of BNR technologies such as the sidestream enhanced biological phosphorus removal (EBPR) (Altemative BNR3) that are anticipated to result in significantly less chemical and energy use compared to CPR, a phased approach would allow further development and optimization of BNR at the WWTP at a lower operating cost than CPR. This approach would also provide flexibility to incorporate CPR. In addition, the City has several planned projects to improve facility performance which will require the commitment of significant funds as noted below: Prepared by Strand Associates, Inc.® 37 R:\MAD\Documents\Reports\Archive\2016\Waterloo, IA\Nutrient Reduction 4463 001 raw.feb\Report\Nutrient Reduction Study docx\032616 Page 133 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study • WVVTP Improvements Not Attributed to Nutrient Removal o Near Term Improvements (2018 to 2023): $18.5 million o Mid Term (2023-2028): $30 million • Collection System Condition and Capacity Related Improvements: O 2018 to 2020: $15.1 million O 2021 to 2023: $22.3 million O 2024 to 2026: $16.6 million (pending further review) O 2027 to 2029: $ 12.6 million (pending further review) O 2030 to 2032: $6.4 million (pending further review) Because of the significant capital funds already planned toward improving facility performance, a phased approach is appropriate to reduce the financial burden on the City's rate payers in the near future. A. Near -Term Improvements —Demonstrate and Optimize BNR Based on the capital and present worth cost evaluation presented in Table 28, Alternative BNR3 is the least costly alternative for enhanced nutrient removal. This is an emerging process that has shown promise for successful BPR for wastewaters that are carbon -limited for conventional BPR processes, but the ability to meet the City's nutrient targets cannot be predicted with current process models. Because of this, providing several years to implement and optimize the process as industry experience grows will allow the City to determine the potential for the process to achieve its effluent nutrient targets without significant chemical addition. The opinion of probable construction costs for the improvements necessary to implement nutrient removal at the WWTP are presented in Table 30. As mentioned earlier, approximately $18.5 million in additional near -term capital improvements have been identified to address other needs at the WWTP, including improvements to biosolids handling facilities and beneficial use of digester gas. Prepared by Strand Associates, Inc.® 38 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001,raw feb\Report\Nutrient Reduction Study docx\032918 Page 134 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study Component Equipment/Structures Preliminary and Primary Treatment Improvements; Raise Primary Clarifiers BNR3—MLE with Sidestream Enhanced BPR Blower replacement Final Clarifier Mechanism Replacement Opinion of Probable Capital Cost $4,200,000 Final Clarifier cross connection and flow distribution improvements Return flow and secondary effluent metering Expansion of WAS Storage, replacement of WAS storage pumps and aeration system BFP Filtrate Equalization Piping and Mechanical Electrical Sitework HVAC Contractors' General Conditions Contingencies and Technical Services TOTAL OPINION OF CAPITAL COSTS Note: All costs are in 1st quarter 2018 dollars $2,320,000 $3,240,000 $430,000 $1,000,000 $430,000 $920,000 $500,000 $4,790,000 _ $2,850,000 $890,000 $760,000 I $2,230,000 $12,280,000 Table 30 Recommended Near -Term Improvements for Nutrient Removal $36,840,000 B. Mid -Term Recommendations —Evaluate Struvite Recovery, Evaluate CPR if necessary Following BNR optimization, it is recommended that the City evaluate the necessity and potential benefits of adding a process to recover struvite from the anaerobic digester sludge of filtrate/centrate. While the City does not currently experience nuisance struvite formation in its anaerobic digesters, successful implementation of BPR would increase the phosphorus content of the biosolids and potentially lead to the formation of struvite in the digester heating system, mixers, digester tanks, or downstream processes, including BFP filtrate equalization and pumping. As presented earlier, struvite recovery is anticipated to improve phosphorus removal and may allow the City to achieve its nutrient reduction targets if they are not achieved by BPR alone. Further evaluation of the combination of sidestream EBPR and struvite recovery is recommended following implementation of Alternative BNR3. It is anticipated that the construction of a struvite recovery system would cost approximately $6 million assuming a sludge -based sequestration system and including technical services. Additional CPR should also be evaluated at this time. SEWER BUDGET IMPACT The total opinion of capital costs for the near -term improvements is approximately $55.3 million (1st Quarter 2018 dollar basis). Projecting this amount to an anticipated 4th Quarter 2019 bid date, and Prepared by Strand Associates, Inc ® 39 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study.docx\032818 Page 135 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Nutrient Reduction Study applying a construction inflation rate of 3 percent annually, the anticipated total project costs are approximately $58.3 million. The WWTP improvements are anticipated to be financed through Iowa's State Revolving Fund (SRF) loan program. The SRF program provides 0 percent interest financing for planning and design services for up to three years that can be rolled into the SRF construction loan. Construction loans are offered at 1.75 percent interest, typically for 20-year terms. In addition to the 1.75 percent interest loan, an administrative fee of 0.25 percent is added each year to the outstanding principal balance for administering the loan. Also, an additional 0.5 percent of the loan amount (up to $100,000) is included as a loan initiation fee. Assuming a total loan amount of $58.3 million, plus the initiation fee of $100,000, the annual debt service payment is expected to be approximately $3.6 million. If the digester gas utilization improvements are not included in the near -term project, the annual debt service payment is expected to decrease to approximately $3.2 million (total loan amount of $51.3 million in 4th Quarter 2019 dollars). A preliminary analysis was conducted to estimate the impact of the near -term improvements on the WWTP budget. Although many components of the identified improvements are more energy efficient that current WWTP operation, particularly the replacement of the activated sludge blowers which can account for over half of the energy of the WWTP, this analysis was conducted assuming there would be no change in annual O&M costs. While the improvements would likely result in overall O&M savings, the assumptions used in this analysis provide a conservative estimate of the impact on the sewer budget. Table 31 presents a preliminary budget impact summary of the near -term improvements with and without the capital improvements necessary for the production of pipeline quality gas. A more detailed analysis of plant operation following the near -term improvements as well as a user charge study is recommended to further evaluate the impact on sewer user rates. Component Opinion of Probable Capital Cost1 Anticipated Annual Debt Service Payment2 Annual Revenue from Digester Gas3 Near -Term Near -Term Improvements Improvements Without With Pipeline Quality Pipeline Quality Gas Gas Improvements Improvements $58,300,000 $51,300,000 $3,600,000 $3,200,000 ($1,200,000) $0 Net Debt Service Payment _ $2,400,000 $3,200,000 14th Quarter 2019 Bid 220-year loan at 1 75 percent interest, 0.25 percent administration fee, and $100,000 loan initiation fee 3Net revenue for Alternative DG2 as presented in Wastewater Facilities Plan Table 31 WWTP Budget Impact Summary for Near -Term Improvements Prepared by Strand Associates, Inc® 40 R:\MAD\Documents\Reports\Archive\2018\Waterloo, IA\Nutrient Reduction 4463 001 raw.feb\Report\Nutrient Reduction Study docx\032916 Page 136 of 164 DRAFT-(05.03.23) City of Waterloo. Iowa Nutrient Reduction Study The City conducted a preliminary analysis of the impact on sewer rates for the projects described in this report as presented in the next section. FINANCIAL INFORMATION Substantial rate increases would be required to implement the projects outlined in the Nutrient Reduction Study, in addition to the projects currently underway that are required by the Consent Decree. Projected rate increases to fund the additional required debt service are outlined below. Additional Debt Rate Service Required Increase Fiscal Year Annually Required FYE2021 $1,200,000 13% FYE2022 $1,200,000 10% FYE2023 $1,150,000 9% FYE2024 $1,100,000 8% FYE2025 $1,100,000 7% FYE2026 $600,000 4% Totals $6,350,000 57% These improvements would require rate increases totaling 51 percent over the six years of implementation. The City has a very diverse population. The sewer costs for the largest minority group would exceed 1.5 percent of median household income beginning in 2022 and could exceed it by as much as 36 percent by 2026. The City has large industrial users that would be negatively impacted by these rate increases. If the largest user reduced their water/sewer use by 30 percent, the rate increases applied to all customers outlined above would need to double to cover the annual debt service payments. That would cause the sewer cost for all population groups to exceed 1.5 percent of median household income for all years. Additional Debt Rate Service Required Increase Fiscal Year Annually Required FYE2021 $1,200,000 26% FYE2022 $1,200,000 20% FYE2023 $1,150,000 18% FYE2024 $1,100,000 16% FYE2025 $1,100,000 14% FYE2026 $600,000 8% Totals $6,350,000 114% Prepared by Strand Associates, Inc.® 41 R:\MAD\Documents\Reports\Archive12018\Waterloo, IA\Nutrient Reduction 4463 001 raw feb\Report\Nutrient Reduction Study docx\032918 Page 137 of 164 DRAFT-(05.03.23) APPENDIX A NPDES PERMIT Page 138 of 164 DRAFT-(05.03.23) IOWA DEPARTMENT OF NATURAL RESOURCES National Pollutant Discharge Elimination System (NPDES) Permit OWNER NAME & ADDRESS FACILITY NAME & ADDRESS CITY OF WATERLOO 715 MULBERRY STREET WATERLOO, IA 50703 IOWA NPDES PERMIT NUMBER: 0790001 DATE OF ISSUANCE: 04/01/2016 DATE OF EXPIRATION: 03/31/2021 WATERLOO CITY OF STP 3505 EASTON AVENUE WATERLOO, IA 50702 Section 31, T89N, R12W Black Hawk County YOU ARE REQUIRED TO FILE FOR RENEWAL OF THIS PERMIT BY: 10/02/2020 EPA NUMBER: IA0042650 This permit is issued pursuant to the authority of section 402(b) of the Clean Water Act (33 U.S.0 1342(b)), Iowa Code section 455B.174, and rule 567-64.3, Iowa Administrative Code. You are authorized to operate the disposal system and to discharge the pollutants specified in this permit in accordance with the effluent limitations, monitoring requirements and other terms set forth in this permit. You may appeal any condition of this permit by filing a written notice of appeal and request for administrative hearing with the director of this department within 30 days of your receipt of this permit. Any existing unexpired Iowa operation permit or Iowa NPDES permit previously issued by the department for the facility identified above is revoked by the issuance of this permit. This provision does not apply to any authorization to discharge under the terms and conditions of a general permit issued by the department or to any permit issued exclusively for the discharge of stormwater. FOR THE DEPARTMENT OF NATURAL RESOURCES By Brandy Beavers NPDES Section ENVIRONMENTAL SERVICES DIVISION Outfall No.: 001 EASTON AVENUE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Receiving Stream: CEDAR RIVER hops://programs.iowadnr.gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9B24 6/22/16, 6:05 PM Page 1 of 19 Page 139 of 164 DRAFT-(05.03.23) Route of Flow: CEDAR RIVER Class A I waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 004 BYPASS LOCATED AT THE HACKETT ROAD LIFT STATION. Receiving Stream: UNNAMED CREEK Route of Flow: UNNAMED CREEK TO CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(W W I) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Outfall No.: 008 SATELLITE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 009 BYPASS AT SHORELINE OVERFLOW WHEN STREAM FLOW IS LESS THAN 8500 CFS (USGS GAGE 05464000) Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 010 BYPASS AT EQUALIZATION BASIN OVERFLOW Receiving Stream: CEDAR RIVER Route of Flow: DRAINAGE DITCH TO CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW l) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Outfall No.: 011 TOTAL TREATMENT FACILITY SHORELINE DISCHARGE- STREAM FLOW IS GREATER THAN OR EQUAL hops://programs.iowadnr.gov/wwpie/Default,aspx?cmd=SendFileCommand&DawnioadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 2 of 19 Page 140 of 164 DRAFT-(05.03.23) TO 8500 CFS (USGS GAGE 9540000) Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class HH are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Outfall No.: 801 TOTAL TREATMENT FACILITY DIFFUSER DISCHARGE. Receiving Stream: CEDAR RIVER Route of Flow: CEDAR RIVER Class Al waters are primary contact recreational use waters in which recreational or other uses may result in prolonged and direct contact with the water, involving considerable risks of ingesting water in quantities sufficient to pose a health hazard. Such activities would include, but not be limited to, swimming, diving, water skiing, and water contact recreational canoeing. Waters designated Class B(WW1) are those in which temperature, flow and other habitat characteristics are suitable to maintain warm water game fish populations along with a resident aquatic community that includes a variety of native nongame fish and invertebrates species. These waters generally include border rivers, large interior rivers, and the lower segments of medium -size tributary streams. Waters designated Class H H are those in which fish are routinely harvested for human consumption or waters both designated as a drinking water supply and in which fish are routinely harvested for human consumption. Bypasses from any portion of a treatment facility or from a sanitary sewer collection system designed to carry only sewage are prohibited. Effluent Limitations: You are prohibited from discharging pollutants except in compliance with the following effluent limitations: 001 EASTON AVENUE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Outfall: 001 Effective Dates: 04/01/2016 to 03/31/2021 Parameter' Season Uinta= Limits TOTAL SUSPENDED SOLIDS Yearly 7 Day Average 45 MG/L Yearly 30 Day Average 30 MG/L 008 SATELLITE ACTIVATED SLUDGE WASTEWATER TREATMENT FACILITY. Outfall: 008 Effective Dates: 04/01/2016 to 03/31/2021 Parameter Season Limit Type TOTAL SUSPENDED SOLIDS Limits https://programs.lowadnr.gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6 05 PM Page 3 of 19 Page 141 of 164 DRAFT-(05.03.23) Yearly 7 Day Average 45 MG/L Yearly 30 Day Average 30 MG/L 011 TOTAL TREATMENT FACILITY SHORELINE DISCHARGE- STREAM FLOW IS GREATER THAN OR EQUAL TO 8500 CFS (USGS GAGE 05464000) Outfall: 011 Effective Dates: 04/01/2016 to 03/31/2021 Parameter Season Limit Type Limits BIOCHEMICAL OXYGEN DEMAND (BOD5) 85% Removal Required Yearly 7 Day Average 45 MG/L 13060 LBS/DAY Yearly 30 Day Average 30 MG/L 8707 LBS/DAY TOTAL SUSPENDED SOLIDS 85% Removal Required Yearly 7 Day Average 13060 LBS/DAY Yearly 30 Day Average 8707 LBS/DAY NITROGEN, TOTAL (AS N) Yearly 30 Day Average 9285.5 LBS/DAY Yearly Daily Maximum 15199.0 LBS/DAY PH Yearly Daily Maximum 9.0 STD UNITS Yearly Minimum 6.0 STD UNITS E. COLI MAR Geometric Mean 126 #/100 ML APR Geometric Mean 126 #/100 ML MAY Geometric Mean 126 #/100 ML JUN Geometric Mean 126 #/100 ML JUL Geometric Mean 126 #/100 ML AUG Geometric Mean 126 #/100 ML SEP Geometric Mean .126 #/100 ML OCT Geometric Mean 126 #/100 ML NOV Geometric Mean 126 #/100 ML ACUTE TOXICITY, CERIODAPHNIA Yearly Daily Maximum 1 NO TOXICITY ACUTE TOXICITY, PIMEPHALES !Yearly 1Daily Maximum 1 NO TOXICITY Outfall: 011 Effective Dales: 04/01/2016 to 03/31/2021 Parameler Sesser{! Limit Tvp Limits AMMONIA NITROGEN (N) hops://programs.iowadnr.gov/wwpie/Default,aspx?cmd=SendFileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 4 of 19 Page 142 of 164 DRAFT-(05.03.23) JAN 30 Day Average 104.2 MG/L 17791 LBS/DAY JAN Daily Maximum 104.2 MG/L 17791 LBS/DAY FEB 30 Day Average 120.6 MG/L 20091 LBS/DAY FEB Daily Maximum 120.6 MG/L 20091 LBS/DAY MAR 30 Day Average 88.6 MG/L 15404 LBS/DAY MAR Daily Maximum 88.6 MG/L 15404 LBS/DAY APR 30 Day Average •66.5 MG/L 12343 LBS/DAY APR Daily Maximum 66.5 MG/L 12343 LBS/DAY MAY 30 Day Average 65.8 MG/L 12146 LBS/DAY MAY Daily Maximum 65.8 MG/L 12146 LBS/DAY JUN 30 Day Average 64.8 MG/L 10079 LBS/DAY JUN Daily Maximum 64.8 MG/L 11864 LBS/DAY JUL 30 Day Average 73.0 MG/L 12696 LBS/DAY JUL Daily Maximum 73.0 MG/L 13673 LBS/DAY AUG 30 Day Average 62.2 MG/L 11578 LBS/DAY AUG Daily Maximum 62.2 MG/L 11846 LBS/DAY SEP 30 Day Average 76.5 MG/L 11693 LBS/DAY SEP Daily Maximum 78.2 MG/L 14193 LBS/DAY OCT 30 Day Average 77.1 MG/L 13895 LBS/DAY OCT Daily Maximum 77.1 MG/L 13895 LBS/DAY NOV 30 Day Average 65.1 MG/L 11956 LBS/DAY NOV Daily Maximum 65.1 MG/L 11956 LBS/DAY DEC 30 Day Average 77.5 MG/L 13992 LBS/DAY DEC Daily Maximum 77.5 MG/L 13992 LBS/DAY 801 TOTAL TREATMENT FACILITY DIFFUSER DISCHARGE. Outfall: 801 Effective Dates: 04/01/2016 to 03/31/2021 Parameter Season Limit Type Limits BIOCHEMICAL OXYGEN DEMAND (BOD5) 85% Removal Required Yearly 7 Day Average '45 MG/L 13060 LBS/DAY Yearly 30 Day Average 30 MG/L 8707 LBS/DAY TOTAL SUSPENDED SOLIDS 85% Removal Required Yearly 7 Day Average 13060 LBS/DAY Yearly 30 Day Average 8707 LBS/DAY NITROGEN, TOTAL (AS N) Yearly 30 Day Average 9285.5 LBS/DAY Yearly Daily Maximum 15199.0 LBS/DAY PH Yearly Daily Maximum 9.0 STD UNITS Yearly Minimum 6.0 STD UNITS E. COLI MAR Geometric Mean 126 #/100 ML APR Geometric Mean 126 #/100 ML MAY Geometric Mean 126 #/100 ML JUN Geometric Mean 126 #/100 ML JUL Geometric Mean 126 #/100 ML AUG Geometric Mean 126 #/100 ML SEP Geometric Mean 126 #/100 ML OCT Geometric Mean 126 #/100 ML NOV Geometric Mean 126 #/100 ML ACUTE TOXICITY, CERIODAPHNIA Yearly Daily Maximum 1 NO TOXICITY ACUTE TOXICITY, PIMEPHALES https://programs.iowadnr.gov/wwpie/Default,aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 5of19 Page 143 of 164 DRAFT-(05.03.23) Yearly Daily Maximum l NO TOXICITY Outfall: 801 Effective Dales: 04/01/2016 to 03/31/2021 EarameterlSeason Limit Type Limits AMMONIA NITROGEN (N) JAN 30 Day Average 46.5 MG/L 7708 LBS/DAY JAN Daily Maximum 97.8 MG/L 16824 LBS/DAY FEB 30 Day Average 52.9 MG/L 8750 LBS/DAY FEB Daily Maximum 112.9 MG/L 18934 LBS/DAY MAR 30 Day Average 23.2 MG/L 3868 LBS/DAY MAR Daily Maximum 83.3 MG/L 14602 LBS/DAY APR 30 Day Average 16.2 MG/L 2733 LBS/DAY APR Daily Maximum 62.9 MG/L 11801 LBS/DAY MAY 30 Day Average 13.7 MG/L 2306 LBS/DAY MAY Daily Maximum 62.2 MG/L 11348 LBS/DAY JUN 30 Day Average 8.8 MG/L 1516 LBS/DAY JUN Daily Maximum 50.5 MG/L 6791 LBS/DAY JUL 30 Day Average 10.7 MG/L 1751 LBS/DAY JUL Daily Maximum 40.3 MG/L 5369 LBS/DAY AUG 30 Day Average 9.7 MG/L 1597 LBS/DAY AUG Daily Maximum 44.1 MG/L 5892 LBS/DAY SEP 30 Day Average 10.2 MG/L 1738 LBS/DAY SEP Daily Maximum 46.3 MG/L 6182 LBS/DAY OCT 30 Day Average 23.3 MG/L 3885 LBS/DAY OCT Daily Maximum 72.7 MG/L 13233 LBS/DAY NOV 30 Day Average 29.1 MG/L 4853 LBS/DAY NOV Daily Maximum 61.5 MG/L 11415 LBS/DAY DEC 30 Day Average 34.5 MG/L 5738 LBS/DAY DEC Daily Maximum 73.1 MG/L 13330 LBS/DAY Monitoring and Reporting Requirements (a) Samples and measurements taken shall be representative of the volume and nature of the monitored wastewater. (b) Analytical and sampling methods specified in 40 CFR Part 136 or other methods approved in writing by the department shall be utilized. Samples collected for operational testing need not be analyzed by approved analytical methods; however, commonly accepted test methods should be used. (c) You are required to report all data including calculated results needed to determine compliance with the limitations contained in this permit. The results of any monitoring not specified in this permit performed at the compliance monitoring point and analyzed according to 40 CFR Part 136 shall be included in the calculation and reporting of any data submitted in accordance with this permit. This includes daily https://programs,iowadnr,gov/wwpie/Detault.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 6of19 Page 144 of 164 DRAFT-(05.03.23) maximums and minimums and 30-day and 7-day averages for all parameters that have concentration (mg/1) and mass (lbs/day) limits. In addition, flow data shall be reported in million gallons per day (MGD). (d) Results of all monitoring shall be recorded on forms provided by, or approved by, the department, and shall be submitted to the appropriate regional field office of the department by the fifteenth day following the close of the reporting period. Your reporting period is on a ANNUAL basis, ending on the last day of each reporting period. (e) Any records of monitoring activities and results shall include for all samples: the date, exact place and time of the sampling; the dates the analyses were performed; who performed the analyses; the analytical techniques or methods used; and the results of such analyses. (f) Chapter 63 of the Iowa Administrative Code contains further explanation of these monitoring requirements. Outfa Wastewater Parameter 11 Sample Frequency Sample Type The following monitoring requirements shall be in effect from 04/01/2016 to 03/31/2021 001 BIOCHEMICAL OXYGEN DEMAND 7/WEEK OR DAILY (SODS) 001 FLOW 7/WEEK OR DAILY 001 NITROGEN, TOTAL (AS N) 1 TIME PER WEEK 001 NITROGEN, TOTAL KJELDAHL (AS I EVERY 2 WEEKS N) 001 PH 7/WEEK OR DAILY 001 PHOSPHORUS, TOTAL (AS P) 1 TIME PER WEEK 001 TEMPERATURE 7/WEEK OR DAILY 001 TOTAL SUSPENDED SOLIDS 7/WEEK OR DAILY 001 CBODS 7/WEEK OR DAILY Monitoring Location 24 HOUR COMPOSITE RAW WASTE 24 HOUR TOTAL RAW WASTE 24 HOUR COMPOSITE RAW WASTE 24 HOUR COMPOSITE RAW WASTE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE 24 HOUR COMPOSITE 001 TOTAL SUSPENDED SOLIDS 7/WEEK OR DAILY 24 HOUR COMPOSITE 001 SETTLEABLE SOLIDS 7/WEEK OR DAILY GRAB 001 ALKALINITY, TOTAL (AS CACO3) 2 TIMES PER WEEK GRAB 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 001 ALKALINITY, TOTAL (AS CACO3) 2 TIMES PER WEEK GRAB 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 001 ALKALINITY, TOTAL (AS CACO3) 2 TIMES PER WEEK GRAB 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 001 ALKALINITY, TOTAL (AS CACO3) 2 TIMES PER WEEK GRAB RAW WASTE RAW WASTE RAW WASTE RAW WASTE EFFLUENT PRIOR TO DISINFECTION EFFLUENT PRIOR TO DISINFECTION EFFLUENT AFTER FINAL CLARIFIER ANAEROBIC DIGESTER 6 CONTENTS ANAEROBIC DIGESTER 6 CONTENTS ANAEROBIC DIGESTER 6 CONTENTS ANAEROBIC DIGESTER 6 CONTENTS ANAEROBIC DIGESTER 5 CONTENTS ANAEROBIC DIGESTER 5 CONTENTS ANAEROBIC DIGESTER 5 CONTENTS ANAEROBIC DIGESTER 5 CONTENTS ANAEROBIC DIGESTER 4 CONTENTS ANAEROBIC DIGESTER 4 CONTENTS ANAEROBIC DIGESTER 4 CONTENTS ANAEROBIC DIGESTER 4 CONTENTS ANAEROBIC DIGESTER 3 https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 7of19 Page 145 of 164 DRAFT-(05.03.23) 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS Outfall Wastewater Parameter The foll 001 ALKALINITY, TOTAL (AS CACO3) 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS 001 ALKALINITY, TOTAL (AS CACO3) 001 PH 001 TEMPERATURE 001 VOLATILE ACIDS 001 30-MINUTE SETTLEABILITY 001 DISSOLVED OXYGEN 001 SOLIDS, MIXED LIQUOR SUSPENDED 001 TEMPERATURE 001 30-MINUTE SETTLEABILITY 001 DISSOLVED OXYGEN 001 SOLIDS, MIXED LIQUOR SUSPENDED 001 TEMPERATURE 001 30-MINUTE SETTLEABILITY 001 DISSOLVED OXYGEN 001 SOLIDS, MIXED LIQUOR SUSPENDED 001 TEMPERATURE 001 30-MINUTE SETTLEABILITY 001 DISSOLVED OXYGEN 001 SOLIDS, MIXED LIQUOR SUSPENDED 001 TEMPERATURE 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB CONTENTS ANAEROBIC DIGESTER 3 CONTENTS ANAEROBIC DIGESTER 3 CONTENTS ANAEROBIC DIGESTER 3 CONTENTS Sample Frequency Sample Type Monitoring Location owing monitoring requirements shall be in effect from 04/01/2016 to 03/31/2021 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 2 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB ANAEROBIC DIGESTER 2 CONTENTS ANAEROBIC DIGESTER 2 CONTENTS ANAEROBIC DIGESTER 2 CONTENTS ANAEROBIC DIGESTER 2 CONTENTS ANAEROBIC DIGESTER 1 CONTENTS ANAEROBIC DIGESTER 1 CONTENTS ANAEROBIC DIGESTER 1 CONTENTS ANAEROBIC DIGESTER 1 CONTENTS AERATION BASIN 4 CONTENTS AERATION BASIN 4 CONTENTS AERATION BASIN 4 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 4 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 3 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 3 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 3 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 3 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 2 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 2 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 2 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 2 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 1 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 1 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 1 CONTENTS 5 TIMES PER WEEK GRAB AERATION BASIN 1 CONTENTS Outfal Wastewater Parameter Sample Frequency Sample Type The following monitoring requirements shall be in effect from 04/01/2016 to 03/31/2021 Monitoring Location 008 BIOCHEMICAL OXYGEN DEMAND 7/WEEK OR DAILY 24 HOUR COMPOSITE RAW WASTE (BODS) 008 FLOW 008 NITROGEN, TOTAL (AS N) 008 NITROGEN, TOTAL KJELDAHL (AS N) 008 PH 008 PHOSPHORUS, TOTAL (AS P) 008 TEMPERATURE 7/WEEK OR DAILY 1 TIME PER WEEK 1 EVERY2 WEEKS 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 24 HOUR TOTAL 24 HOUR COMPOSITE 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE RAW WASTE http5;//programs.i'owadnr_gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1 &Pernlitattachmentid=9824 6/22/16, 6:05 PM Page 8 of 19 Page 146 of 164 DRAFT-(05.03.23) 008 TOTAL SUSPENDED SOLIDS 008 CBODS 008 TOTAL SUSPENDED SOLIDS 008 SETTLEABLE SOLIDS 008 30-MINUTE SETTLEABILITY 008 DISSOLVED OXYGEN 008 SOLIDS, MIXED LIQUOR SUSPENDED 008 TEMPERATURE 008 30-MINUTE SETTLEABILITY 008 DISSOLVED OXYGEN 008 SOLIDS, MIXED LIQUOR SUSPENDED 008 TEMPERATURE Outfa Wastewater Parameter II The following monitoring requirements shall be 011 ACUTE TOXICITY, CERIODAPHN1A 011 ACUTE TOXICITY, PIMEPHALES 011 AMMONIA NITROGEN (N) 011 BIOCHEMICAL OXYGEN DEMAND (BODS) 011 E. COLI 011 FLOW 011 NITROGEN, TOTAL (AS N) 011 PH 011 PHOSPHORUS, TOTAL (AS P) 011 TEMPERATURE 011 TOTAL SUSPENDED SOLIDS 7/WEEK OR DAILY 7/WEEK OR DAILY 24 HOUR 24 HOUR 7/WEEK OR DAILY 24 HOUR 7/WEEK OR DAILY GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB 5 TIMES PER WEEK GRAB Sample Frequency in effect from 04/01/2016 1 EVERY 12 MONTHS 1 EVERY 12 MONTHS 7/WEEK OR DAILY 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 7/WEEK OR DAILY COMPOSITE RAW WASTE COMPOSITE EFFLUENT PRIOR TO DISINFECTION COMPOSITE EFFLUENT PRIOR TO DISINFECTION EFFLUENT AFTER FINAL CLARIFIER AERATION BASIN 2 CONTENTS AERATION BASIN 2 CONTENTS AERATION BASIN 2 CONTENTS AERATION BASIN 2 CONTENTS AERATION BASIN 1 CONTENTS AERATION BASIN 1 CONTENTS AERATION BASIN 1 CONTENTS AERATION BASIN 1 CONTENTS Sample Type Monitoring Location to 03/31/2021 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION GRAB 24 HOUR TOTAL 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE Outfall Wastewater Parameter Sample Frequency Sample Type The following monitoring requirements shall be in effect from 04/01/2016 to 03/31/2021 801 STREAM FLOW 801 FLOW 801 FLOW 801 FLOW 801 BIOCHEMICAL OXYGEN DEMAND (BODS) 801 FLOW 801 NITROGEN, TOTAL (AS N) 801 NITROGEN, TOTAL KJELDAHL (AS N) 801 PHOSPHORUS, TOTAL (AS P) 801 TOTAL SUSPENDED SOLIDS 801 ACUTE TOXICITY, CERIODAPHNIA 801 ACUTE TOXICITY, PIMEPHALES 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 7/WEEK OR DAILY 1 TIME PER WEEK 1 EVERY 2 WEEKS 1 TIME PER WEEK 7/WEEK OR DAILY 1 EVERY 12 MONTHS 1 EVERY 12 MONTHS MEASUREMENT 24 HOUR TOTAL 24 HOUR TOTAL 24 HOUR TOTAL CALCULATED CALCULATED CALCULATED CALCULATED CALCULATED CALCULATED 24 HOUR COMPOSITE 24 HOUR COMPOSITE EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION Monitoring Location CEDAR RIVER AT USGS STREAM GAGE 05464000 FLOW EQUALIZATION BASIN RETURN FLOW EQUALIZATION BASIN OVERFLOW TO SATELLITE PLANT SPLIT FLOW EFFLUENT RAW WASTE TOTAL RAW WASTE FLOW RAW WASTE RAW WASTE RAW WASTE RAW WASTE EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION https://programs.iowadnr,gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 9of19 Page 147 of 164 DRAFT-(05.03.23) 801 AMMONIA NITROGEN (N) 801 BATHYMETRIC REPORT 801 BIOCHEMICAL OXYGEN DEMAND (BOD5) 801 DIFFUSER VALIDATION REPORT 801 E. COLI 801 FLOW 801 NITROGEN, TOTAL (AS N) 801 PH 801 PHOSPHORUS, TOTAL (AS P) 801 TEMPERATURE 801 TOTAL SUSPENDED SOLIDS 801 VISUAL OBSERVATION 7/WEEK OR DAILY ONCE PER PERMIT CYCLE 7/WEEK OR DAILY 1 EVERY 12 MONTHS I TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 1 TIME PER WEEK 7/WEEK OR DAILY 7/WEEK OR DAILY 1 EVERY MONTH 24 HOUR COMPOSITE MEASUREMENT 24 HOUR COMPOSITE VISUAL GRAB 24 HOUR TOTAL 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE GRAB 24 HOUR COMPOSITE VISUAL Special Condition EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION INSTREAM EFFLUENT DIFFUSER From April 1, 2016 until March 31, 2017, the facility may choose to collect the samples stated in the table below at a frequency of 3/week on non-consecutive days. After March 31, 2017 all effluent sampling frequencies are required at the frequencies listed on pages 11-14 of this permit. Outfall Wastewater Parameter 001 BIOCHEMICAL OXYGEN DEMAND (BOD5) 001 TOTAL SUSPENDED SOLIDS 001 BIOCHEMICAL OXYGEN DEMAND (BOD5) 001 TOTAL SUSPENDED SOLIDS 001 SETTLEABLE SOLIDS 008 BIOCHEMICAL OXYGEN DEMAND (BOD5) 008 TOTAL SUSPENDED SOLIDS 008 BIOCHEMICAL OXYGEN DEMAND (BOD5) 008 TOTAL SUSPENDED SOLIDS 008 SETTLEABLE SOLIDS 011 AMMONIA NITROGEN (N) 011 BIOCHEMICAL OXYGEN DEMAND (BOD5) 011 TOTAL SUSPENDED SOLIDS 801 BIOCHEMICAL OXYGEN DEMAND (BOD5) 801 TOTAL SUSPENDED SOLIDS 801 AMMONIA NITROGEN (N) Monitoring Location RAW WASTE RAW WASTE EFFLUENT PRIOR TO DISINFECTION EFFLUENT PRIOR TO DISINFECTION EFFLUENT AFTER FINAL CLARIFIER RAW WASTE RAW WASTE EFFLUENT PRIOR TO DISINFECTION EFFLUENT PRIOR TO DISINFECTION EFFLUENT AFTER FINAL CLARIFIER EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION EFFLUENT AFTER DISINFECTION RAW WASTE RAW WASTE EFFLUENT AFTER DISINFECTION https://programs. iowadnr.gov/wwpie/Default. aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 10 of 19 Page 148 of 164 DRAFT-(05.03.23) 801 BIOCHEMICAL OXYGEN DEMAND EFFLUENT AFTER (BOD5) DISINFECTION 801 TOTAL SUSPENDED SOLIDS Special Monitoring Requirements EFFLUENT AFTER DISINFECTION Outfall # Description 011, 801 AMMONIA NITROGEN (N) Ammonia shall be sampled and analyzed using an EPA approved method specified in 40 CFR 136 or using the Timberline Method Ammonia-001 alternative test procedure. $IOCHEMICAI, OXYGEN DEMAND (GODS) All BOD5 samples must be seeded at the laboratory prior to analysis when the disinfection equipment is in use. E. COLI The limit for E. coli of 126 org/100 ml specified on the limits pages of this permit for outfall(s) 801, 009 and 011 is a monthly geometric mean. The disinfection season is established in the Iowa Administrative Code, Subparagraph 567 IAC 61.3(3)"a"(1), and is in effect from March 15 to November 15. Any disinfection system (chlorine, UV light, etc.) shall be operated to comply with the limit during the entire disinfection season whenever wastewater is being discharged from outfall(s) 801, 009 and 011. The facility must collect and analyze a minimum of a weekly sample from March 15 to November 15. The collection of weekly samples will result in a minimum of 35 samples being collected during a calendar year. The following requirements apply to the individual samples collected in one calendar month: There must be a minimum of two days between each sample. No more than two samples may be collected in a period of seven consecutive days. If the effluent has been disinfected using chlorine, ultraviolet light (UV), or any other process intended to disrupt the biological integrity of the E. coli, the samples shall be analyzed using the Most Probable Number method found in Standard Method 9223B (Colilert® or Colilert-18® made by IDEXX Laboratories, Inc.). If the effluent has not been disinfected the samples may be analyzed using either the MPN method above or EPA Method 1603: Escherichia coli (E. coli) in water by membrane filtration using modified membrane-thermotolerant E. coli agar (modified mTEC) or mColiBlue-24® made by the Hach Company. The geometric mean must be calculated using all valid sample results collected during a month. The geometric mean formula is as follows: Geometric Mean = (Sample one * Sample two * Sample three * Sample four *Sample five... Sample N)*(1/N), which is the Nth root of the result of the multiplication of all of the sample results where N = the number of samples. If a sample result is a less than value, the value reported by the lab without the less than sign should be used in the geometric mean calculation. The geometric mean can be calculated in one of the following ways: Use a scientific calculator that can calculate the powers of numbers. Enter the samples in Microsoft Excel and use the function "GEOMEAN" to perform the calculation. Use the geometric mean calculator on the Iowa DNR webpage at: http://www. iowadnr.gov/InsideDNR/RegulatoryWater/NPDES WastewaterPermitting/NPDESOperatorinformation/Bact eriaSampling.aspx. TOTAL NITROGEN Total nitrogen shall be determined by testing for Total Kjeldahl Nitrogen (TKN) and nitrate + nitrite nitrogen and reporting the sum of the TKN and nitrate + nitrite results (reported as N). Nitrate + nitrite can be analyzed together or separately. 801 RAW WASTE FLOW Raw flow shall be calculated as the sum of the 24 hour totals from the Easton Ave facility and the Satellite facility. JIAW WASTE: BODS, TSS, TP, TN, TKN Samples are required at each influent line to determine the mass loadings from each line. The total influent load to the treatment facility shall then be calculated and reported under outfall 801. STREAM FLOW A daily minimum value shall be reported. https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 11 of 19 Page 149 of 164 DRAFT-(05.03.23) OUTFALL AND SAMPLING LOCATIONS .i17Se•I2.131i Yap W .'e'f�i R�11' Y1 •.1 M...1 • 1.....n 1. 1.0a Blending Mode of Operation This alternative mode of operation will be authorized on a temporary basis for the one permit cycle and is not subject to extension past March 31, 2021. The City of Waterloo may operate their wastewater treatment plant in the following mode during peak influent flow conditions only. Influent flows that exceed the hydraulic capacity of the Easton Avenue plant are diverted to two - flow equalization basins (FEQ) after passing through grit removal. Flows stored in the FEQ basins are returned to the Easton Wet Well once the Easton Avenue plant regains hydraulic capacity. In the event that the Easton Avenue plant has yet to regain hydraulic capacity, the flow from the FEQ will be diverted to the Satellite plant. The flows from the FEQ will be routed through the Satellite plant and returned to the headworks of the Easton Avenue plant via portable pumps. If the biological system at the Easton Avenue Plant could be jeopardized due to excessive flows, the partially treated wastewater from the Satellite plant will be diverted to the disinfection chamber and blended with the final effluent from the Easton plant. Once the Easton Avenue plant regains hydraulic capacity the facility is no longer authorized to blend the FEQ overflow via the Satellite plant. https://programs.iowadnr.govlwwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachreentid=9824 6/22/16, 6:05 PM Page 12 of 19 Page 150 of 164 DRAFT-(05.03.23) Effluent limits and permit conditions remain in effect during this mode of operation. Outfall Number: 011, 801 Ceriodaphnia and Pimephales Toxicity Effluent Testing 1. For facilities that have not been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within three (3) months of permit issuance. For facilities that have been required to conduct toxicity testing by a previous NPDES permit, the initial annual toxicity test shall be conducted within twelve months (12) of the last toxicity test. 2. The test organisms that are to be used for acute toxicity testing shall be Ceriodaphnia dubia and Pimephales promelas. The acute toxicity testing procedures used to demonstrate compliance with permit limits shall be those listed in 40 CFR Part l36 and adopted by reference in rule 567--63.1(1). The method for measuring acute toxicity is specified in USEPA, October 2002, Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition. U.S. Environmental Protection Agency, Office of Water, Washington, D.C., EPA 821-R-02-012. 3. The diluted effluent sample must contain a minimum of 12.40 % effluent and no more than 87.60 % of culture water. 4. One valid positive toxicity result will require, at a minimum, quarterly testing for effluent toxicity until three successive tests are determined not to be positive. 5. Two successive valid positive toxicity results or three positive results out of five successive valid effluent toxicity tests will require a toxicity reduction evaluation to be completed to eliminate the toxicity. 6. A non -toxic test result shall be indicated as a "1" on the monthly operation report. A toxic test result shall be indicated as a "2" on the monthly operation report. DNR Form 542-138j, shall also be submitted to the DNR field office along with the monthly operation report. Ceriodaphnia and Pimephales Toxicity Effluent Limits The maximum limit of "1" for the parameters Acute Toxicity, Ceriodaphnia and Acute Toxicity, Pimephales means no positive toxicity results. Definition: "Positive toxicity result" means a statistical difference of mortality rate between the control and the diluted effluent sample. For more information see USEPA, October 2002, Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fifth Edition, U.S. Environmental Protection Agency, Office of Water, Washington, D.C., EPA 821-R-02-012. Design Capacity Design: Easton Avenue WPCF https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=SendFileCommand&Downloadrype=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 13 of 19 Page 151 of 164 DRAFT-(05.03.23) The design capacity for the treatment works is specified in Construction Permit Number 98-361-S, issued August 21, 1998. The treatment plant is designed to treat: * An average dry weather (ADW) flow of 12.7 Million Gallons Per Day (MGD). * An average wet weather (AWW) flow of 26.7 Million Gallons Per Day (MGD). * A maximum wet weather (MWW) flow of 36.0 Million Gallons Per Day (MGD). * A design 5-day biochemical oxygen demand (BOD5) load of 30,000 lbs/day. * A design Total Kjeldahl Nitrogen (TKN) load of 7,500.00 lbs/day. Satellite WPCF The design capacity for the treatment works is specified in Construction Permit Number 95-317-S, issued July 7, 1995. The treatment plant is designed to treat: * An average dry weather (ADW) flow of 5.3 Million Gallons Per Day (MGD). * An average wet weather (AWW) flow of 8.1 Million Gallons Per Day (MGD). * A maximum wet weather (MWW) flow of 11.1 Million Gallons Per Day (MGD). * A design 5-day biochemical oxygen demand (BOD5) load of 58,000 lbs/day. * A design Total Kjeldahl Nitrogen (TKN) load of 13,550.00 lbs/day. Operator Certification Type/Grade: WW/IV Wastes in such volumes or quantities as to exceed the design capacity of the treatment works or reduce the effluent quality below that specified in the operation permit of the treatment works are considered to be a waste which interferes with the operation or performance of the treatment works and are prohibited by rule IAC 567-62.1(7). SEWAGE SLUDGE HANDLING AND DISPOSAL REQUIREMENTS "Sewage sludge" is solid, semisolid, or liquid residue generated during the treatment of domestic sewage in a treatment works. Sewage sludge does not include the grit and screenings generated during preliminary treatment. 1. The permittee shall comply with all existing Federal and State laws and regulations that apply to the use and disposal of sewage sludge and with technical standards developed pursuant to Section 405(d) of the Clean Water Act when such standards are promulgated. If an applicable numerical limit or management practice for pollutants in sewage sludge is promulgated after issuance of this permit that is more stringent than a sludge pollutant limit or management practice specified in existing Federal or State laws or regulations, this permit shall be modified, or revoked and reissued, to conform to the regulations promulgated under Section 405(d) of the Clean Water Act. The permittee shall comply with the limitation no later than the compliance deadline specified in the applicable regulations. 2. The permittee shall provide written notice to the Department of Natural Resources prior to any planned changes in sludge disposal practices. 3. Land application of sewage sludge shall be conducted in accordance with criteria established in rule IAC 567--67.1 through 67.11 (455B). JDiffuser Special Monitoring Requirement Monthly Visual Monitoring: At a frequency of at least once per month, the permittee shall visually observe the diffuser and record the observations in a log book. The permittee is required to visually observe and record the following items: https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6 05 PM Page 14 of 19 Page 152 of 164 DRAFT-(05.03.23) • Whether the diffuser and diffuser ports can been seen above or below the surface of the water; • Whether the effluent dispersion pattern of the ports can be seen, and whether the patterns are uniform; • Signs of non -uniform bubbling, uneven coloring or actual spraying of effluent above the water surface; • Debris or materials that have collected on or may be obstructing the diffuser; • General structural condition of the diffuser, diffuser ports, and protective materials; • Condition of the shoreline outfall OOX; and • Actions taken, if applicable (i.e. corrective/ maintenance measures, adjustments of ports, removal of debris, etc.) The log book entries shall be made available to the Department upon request. The permittee will indicate completion of the visual monitoring by entering a "1" in the Visual Observation column on the day that the visual monitoring was completed on the Discharge Monitoring Report (DMR) spreadsheet. Annual Diffuser Performtance:An.ysis: Minimum Requirements. Annually, by April 1, the permittee is required to submit a Diffuser Performance Analysis report to the Department at both of the addresses shown below. The annual diffuser analysis should be performed at a stream flow as close as possible to stream critical low flow conditions. The annual diffuser performance analysis should identify if all diffuser ports, that were active when thc mixing zone percentage used in the current NPDES permit was established, arc functioning properly. The annual diffuser performance analysis should also assess if rapid mixing is occurring within 100 feet downstream of the active diffuser ports with the stream flow as close as possible to critical low flow conditions. The dye used in the Diffuser Performance Analysis shall meet the following requirements. 1) The Diffuser Performance Analysis shall use one of the following dyes: (a) Rhodamine WT dye (b) FWT red dye tablets (C) FLT Yellow/Green Liquid Concentrate dye (d) Green Sewer Tracing Dye (e) Fluorescent FLT Yellow/Green Powder (f) Bright Dye FWT Red Dye (g) FLT Yellow/Green dye tablets If a dye other than one listed above is used, you must obtain permission from the Department prior to use of the dye. Please contact Connie Dou at (515] 725-g400 or eastnieclou e@dnr lowq,gov to request approval of dyes other than those listed above. 2) The dye shall be used according to the instructions provided by the manufacturer; and 3) The introduction of the dye into the receiving stream shall be limited to as short a time period as possible and the amount of dye used shall be as little as possible. Video and/or pictures of the demonstration should be sent along with the diffuser analysis performance report to both addresses shown below. The Diffuser Performance Analysis report shall describe any proposed location or discharge flow adjustments to the diffuser ports intended to comply with the designed operation of the diffuser. Any video and/or pictures of the demonstration should be included in the report. The permittee will indicate submittal of the Diffuser Performance Analysis report by entering a "1" in the Diffuser Performance Analysis column on the Discharge Monitoring Report (DMR) spreadsheet on the day that the report is submitted. Select the No Discharge Indicator "NOT REQUIRED/MP" on the DMR spreadsheet during the months that the report is not required. Additional Requirements: The Department will review Itc Diffuser Performance Analysis report. If the analysis does not show raoSl and complete mixing of the effluent, you shall be notified of the requirement to submit a plan to correct diffuser deficiencies. The plan to correct the deficiencies shall be submitted to the Field Office address within 60 days of Department notification. If, after the submittal of a plan to correct deficiencies, the subsequent Diffuser Performance Analysis report does not show rapid and complete mixing of the effluent, the facility shall comply with the limits for Outfall {insert bank discharge ourfall number}. Bathymetric Analysis: Minimum Rcquiremattls: By April 1, 2020, the permittee is required to perform a Bathymetric Analysis and submit a Bathymetric Analysis report to the Department at both of the addresses below. The bathymetric features shall be determined by measuring the receiving stream depth at a minimum of twenty (20) equidistant intervals across the entire width of the receiving stream at the location of the diffuser. The Bathymetric Analysis report shall characterize the bathymetric features and include clear documentation of the receiving stream cross section, diffuser location, and stream bottom substrate. The permittec will indicate submittal of the Bathymetric Analysis Report by entering a "1" in thc Bathymetric Report column of the DMR spreadsheet on the day that the report was submitted. Select the No Discharge Indicator "NOT REQUIRED/MP" on the DMR spreadsheet during the months that the report is not required. • Hydrologic Events: In addition, a Bathymetric Analysis must be performed if significant changes to the stream channel occur as a result of hydrologic events (such as flooding, stream channelization, reconstruction, etc.) A report of this analysis must be submitted to the Department at both of the hops://programs.iowadnr.goy/wwpie/Default.aspx?crud=SendFileCommand&Download Type=1&Permitattachmentid=9824 .6/22/16, 6:05 PM Page 15 of 19 Page 153 of 164 DRAFT-(05.03.23) addresses below within sixty (60) days of the event occurrence. If the Bathymetric Analysis shows that the changes to the receiving stream may alter the mixing achieved by the diffuser, a Diffuser Performance Analysis must also be performed to demonstrate the actual mixing achieved by the diffuser. Modeling of the mixing zone may be used to perform the Diffuser Performance Analysis, with Department approval, if the receiving stream does not reach low flow conditions within four (4) months of the hydrologic event. The Diffuser Performance Analysis report must be submitted to the Department at both of the addresses below within ninety (90) days of the hydrologic event occurrence. A Diffuser Performance Analysis performed as a result of a hydrologic event will fulfill the annual report requirement for that year. Diffuser Mixing Tone Study Requiremc_u1 The effluent limits in this permit arc based on the percent mixing capability of your diffuser. The current assumed percent mixing for your facility's diffuser is 73%. A mixing zone study shall be submitted with the permit renewal application to confirm the assumed percent mixing. If no such study is completed, effluent limits in the renewal permit will be bascd on default mixing. The permittee is authorized to conduct a mixing zone study under the following conditions: 1) The mixing zone study shall use one of the following dyes: a) Rhodaminc WT dye b) FWT red dye tablets C) FLT Yellow/Green Liquid Concentrate dye d) Green Sewer Tracing Dyc e) Fluorescent FLT Yellow/Green Powder f) Bright Dyc FWT Red Dyc g) FLT Yellow/Green dye tablets If a dye other than one listed above is used, you must obtain permission from the Department prior to use of the dye. Please contact Connie Dou at (515) 2S i-335Q or Foanic.dott(g]dm:iown goy for approval of dyes other than those listed above. 2) The dye shall be used according to the instructions provided by the manufacturer. 3) The introduction of the dye into the receiving stream shall be limited to as short a time period as possible and the amount of dye used shall be as little as possible. 4) The mixing zone study shall be conducted during low river flow conditions and it shall follow the DNR Mixing Zone Study Guidelines. 5) The mixing zone study report shall include clear documentation of the mixing characteristics and the percentages of the total river flows in the mixing zone. 6) The following restrictions to the maximum allowed mixing zone shall be recorded in the mixing zonc study documentation: a) The distance to the juncture of two perennial streams. b) The distance to a public water supply intake. c) The distance to the upstream limits of an established recreational area, such as public beaches, and state, county and local parks. d) The distance to the middle of a crossover point in a stream where the main current flows from one bank across to the opposite bank. 7) The distance to another mixing zone. The mixing zone does not exceed a distance of 100 feet. The DNR Field Office at least 48 hours prior to the use of dye. Add roses for Retort Submittal: Iowa Department of Natural Resources Environmental Services Division DNR Field Office Iowa Department of Natural Resources 502 E. 9th Street Des Moincs, IA 50319 SIGNIFICANT INDUSTRIAL USER LIMITATIONS, MONITORING AND REPORTING REQUIREMENTS 1. You shall require all users of your facility to comply with Sections 204(b), 307, and 308 of the Clean Water Act. Section 204(b) requires that all users of the treatment works constructed with funds provided under Sections 201(g) or 601 of the Act to pay their proportionate share of the costs of operation, maintenance and replacement of the treatment works. https://programs.iowadnr.gov/wwpie/Default.aspx?crud=SendFileCommand&Download Type=1&Permitattachmentid=9f324 6/22/16, 6 05 PM Page 16 of 19 Page 154 of 164 DRAFT-(05.03.23) Section 307 of the Act requires users to comply with pretreatment standards promulgated by EPA for pollutants that would cause interference with the treatment process or would pass through the treatment works. Section 308 of the Act requires users to allow access at reasonable times to state and EPA inspectors for the purpose of sampling the discharge, reviewing, and copying records. 2. You shall continue to implement the pretreatment program approved March 14, 1984 and any amendments thereto. 3. An annual report in the form prescribed by the Department is to be submitted by March 1=` of each year describing the pretreatment program activities for the preceding calendar year. 4. The City shall evaluate the adequacy of its local limits to meet the general prohibitions against interference and pass through listed in 40 CFR 403.5(a) and the specific prohibitions listed in 40 CFR 403.5(b). At a minimum this evaluation shall consist of the following: (a) Identify each pollutant with the potential to cause process inhibition, pass through the treatment plant in concentrations that will violate NPDES permit limits of water quality standards, endanger POTW worker health and safety or degrade sludge quality. (b) For each treatment plant, determine the maximum allowable headworks loading for each pollutant identified in item #4(a). that will prevent interference or a pass through. (c) After accounting for the contribution of each pollutant from uncontrolled (i.e.: domestic/commercial) sources to each treatment plant, determine the maximum allowable industrial loading for each pollutant identified in item #4(a). (d) Complete the evaluation and submit to the Department, by April 1, 2017 a report containing the following information: 1) A list of pollutants identified in item #4(a). For each pollutant, state the reason(s) for its inclusion (e.g. potential to cause interference, potential to cause pass through, etc.). 2) The report shall contain all calculations used to determine the maximum allowable headworks loadings and shall identify the source(s) of all data used (e.g. literature value, site specific measurement, etc.). 3) The contribution of each pollutant identified in item #4(d)1 to each treatment plant from uncontrolled sources and an explanation of how each contribution was determined. 4) The allocation of the maximum allowable headworks loading for each pollutant to each treatment plant, and an explanation of how the https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 17 of 19 Page 155 of 164 DRAFT-(05.03.23) allowable loadings will be allocated to significant industrial users regulated by the City's pretreatment program. 5. The City shall evaluate the approved pretreatment program for compliance with 40 CFR 403 and Iowa Administrative Code 567 — Chapter 62, specifically with regards to the pretreatment streamlining rule published in the Federal Register on October 14, 2005. Complete the evaluation and submit to the Department a report containing the findings of the evaluation, including a proposal for modifications to correct any deficiencies that are identified, by April 1, 2017.0 2-4-14 cw/ ccsw Nutrient Reduction Requirements In support of the Iowa Nutrient Reduction Strategy you shall prepare and submit a report that evaluates the feasibility and reasonableness of reducing the amounts of nitrogen and phosphorus discharged into surface water. The report shall be submitted no later than April 1, 2018 and shall address the following: A description of the existing treatment facility with particular emphasis on its capabilities for removing nitrogen and phosphorus. The description shall include monitoring data that define the current amounts of total nitrogen (TKN+nitrate+nitrite) and total phosphorus in both the raw wastewater and the final effluent. A description and evaluation of operational changes to the existing treatment facility that could be implemented to reduce the amounts of total nitrogen and total phosphorus discharged in the final effluent and the feasibility and reasonableness of each. Your evaluation must discuss the projected degree of total nitrogen and total phosphorus reduction achievable for each operational change. When evaluating feasibility you must consider what, if any, effect operational changes would have on the removal of other pollutants (e.g. CBODS, TSS). When evaluating reasonableness you shall include estimates of the additional cost, if any, to implement such changes and for a publicly -owned treatment works the impact on user rates. A description and evaluation of new or additional treatment technologies that would achieve significant reductions in the amounts of total nitrogen and total phosphorus discharged in the final effluent with a goal of achieving annual average mass limits based on AWW design flow equivalent to concentrations of 10 mg/L total nitrogen and 1 mg/L total phosphorus for plants treating typical domestic strength sewage. For purposes of this evaluation typical domestic sewage is considered to contain approximately 25 — 35 mg/L total nitrogen and 4 - 8 mg/L total phosphorus. For plants treating wastewater with total nitrogen and/or total phosphorus concentrations greater than typical domestic strength sewage, the evaluation shall include the projected reductions in the total nitrogen and phosphorus effluent concentrations achievable with the application of feasible and reasonable treatment technology with a goal of achieving at least a 66 % reduction in nitrogen and 75% reduction in total phosphorus. For each treatment technology the report shall assess its feasibility, reasonableness, practicability, the availability of equipment, capital costs, annual operating costs, impact on user rates and any https://programs.iowadnr,gov/wwpie/Default.aspx?cmd=SendFileCommand&Download Type=1&Permitattachmentid=9824 6/22/16, 6 05 PM Page 18 of 19 Page 156 of 164 DRAFT-(05.03.23) non -water quality environmental impacts (e.g. additional air pollution, increased sludge production, etc.). Based on the evaluations of operational changes and new or additional treatment technologies the report must select the preferred method(s) for reducing total nitrogen and total phosphorus in the final effluent, the rationale for the selected method(s) and an estimate of the effluent quality achievable. The report must include a schedule for making operational changes and/or installing new or additional treatment technologies to achieve the concentration and/or percentage removal goals listed above. Additional financial justification must be included in the report if no operational changes or treatment technologies are feasible or reasonable. The schedule will be incorporated into the NPDES permit by amendment. Effluent discharge limits will be based on one full year of operating data after implementation of the operational changes or completion of plant modifications and a six month optimization period. The report shall be sent to the following address: Brandy Beavers NPDES Section Iowa Department of Natural Resources 502 East 9th Street Des Moines, IA 50319 Page 27 https://programs.iowadnr.gov/wwpie/Default.aspx?cmd=Send FileCommand&DownloadType=1&Permitattachmentid=9824 6/22/16, 6:05 PM Page 19 of 19 Page 157 of 164 DRAFT-(05.03.23) APPENDIX B PRESENT WORTH ANALYSIS Page 158 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Wastewater Nutrient Reduction Study Opinion of Present Worth Cost Alternative BNR1a - A2O Process with BOD diversion from lagoon Discount Rate 2,750% Future Capital Replacement Replacement 20-Year Salvage Value ITEM Initial Capital Cost Cost Year Cost (P.W.) Salvage Value (P.W.) Satellite Aeration Tank Structural Modifications $ 250,000 $ • 40 S - $ 130.000 5 80,000 Baffle Walls - Anaerobic Zones $ 230,000 $ 40 $ $ 120 000 5 70,000 Baffe Walls -Anoxic Zones $ 230,000 $ 40 5 $ 120.000 S 70,000 Ana.=briMokr[ Mixers $ 480,000 $ - 20 5 $ S Fine Bubble Diffusers $ 600,000 $ 600,000 15 S 4Q6.0'..`3 $ 400 000 5 230,000 Nitrate Recycle Pumps $ 320,000 $ 20 5 $ - 5 Lagoon Influent Structure Modifications $ 100,000 $ - 40 5 $ 50 000 5 30,000 Lagoon Influent Fermentation Tank and Appurtenances $ 5,000,000 20 $ - 5 Chemical Storage Tank - CPR Backup $ 80,000 $ - 20 $ $ 5 - Chemical Feed Systems $ 60,000 $ 60,000 15 5 40,000 $ 40.000 5 20,000 Chemical 0u long 250.000 5 40 5 - 5 1a0,000 5 60,000 Subtotal 5 7.600,090 5 880,000 Piping and Mechanical (20%) S 1,520,000 $ 40 $ • 5 760.000 $ 440,000 HVAC (10%) $ 760,000 $ 20 $ - 5 • $ - Electrical (25%) 5 1,900,000 5 - 20 $ • 5 - $ Sitework (10%) 5 780,000 Subtotal 5 '2.540.000 Contractor GCs (10%) 5 1,260,000 Total Construction Costs $ 13,800,000 Contingencies and Engineering Services (50%) 5 6.90O.0 0 Total Capital Costs $ 20.700.000 $ 440,000 5 1,620,000 5 940,000 Present Worth of Capital Costa $ 20,700,000 Relative Labor ($40/hr) $ 10,000 Maintenance (-2% of equipment) $ 20,000 Power ($0. 04/kWh) $ 290,000 Solids Disposal $ 220,000 c memos! Uso 5 60.000 Total O&M Costs 5 800,000 Present Worth of O&M S 9,140,000 Summary of Present Worth Costs Capital Cost 5 20,700,000 Replacement 5 440,000 O&M Cost 5 9,140,000 Salvage Value $ (940,000) Total Present Worth $ 29,340,000 Alternative S3 - Satellite Bar Screen Building Annual Lost Biogas Value Present Worth of Lost Biogas Revenue Altemative BNR1a + 53 $ 5,470,000 50-5990,000 50-515,090,000 5 34,610,000 With Sieges Value 534,810,000 - $49,900,000 $ 440,000 5 940,000 Page 159 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Wastewater Nutrient Reduction Study Opinion of Present Worth Cost Discount Rate 2.750% Alternative BNR1b - A2O Process with VFA addition at WWTP Initial Capital Future Capital Replacement Replacement 20-Year Salvage Value ITEM Cost Cost Year Cost (P.W.) Salvage Value (P.W.) Salellde Aeration Tank Structural Modifications $ 250,000 $ 40 5 5 130,000 5 80,000 Baffle Walls - Anaerobic Zones $ 230,000 5 40 S $ 120,000 5 70,000 Bathe Walls - Anoxic Zones $ 230,000 5 40 5 5 120,000 S 70,000 Anaerobic/Anoxic Mixers $ 480,000 S 20 5 - 5 S . Fine Bubble Diffusers $ 600,000 5 600,000 15 5 400,000 S 400,000 $ 230,000 Nitrate Recycle Pumps $ 320,000 5 - 20 5 - $ - 5 Chemical Storage Tanks - CPR Backup and VFA $ 750,000 5 20 5 - S • $ Chemical Feed Systems $ 60,000 5 60,000 15 5 40,000 5 40,000 $ 20,000 Chemical Building $ 2.500 .0'.3 S 40 5 - $ 1.250.000 $ 730,000 Subtotal $ 5,420,000 $ 660,000 Piping and Mechanical (20%) $ 1,090,000 $ 40 $ - S 550,000 5 320,000 HVAC (10%) $ 550,000 $ 20 $ 5 • $ Electrical (25%) $ 1,360,000 $ 20 $ - S 5 - Sitework (10%) $ 550,000 Subtotal $ 8,970,000 Contractor GCs (10 % ) Total Construction Costs Contingencies and Engineering Services (50%) Total Capital Costs $ 900,000 $ 9,870,000 $ 4,940,000 $ 14,810,000 $ 440,000 $ 2,480,000 $ 1,440,000 Present Worth of Capital Costs $ 14,810,000 Relative Labor ($40Ihr) $ 10,000 Maintenance (-2% of equipment) $ 20,000 Power ($0 04/kWh) $ 290,000 Sotids Disposal $ 220,000 Chemical Use $ 2,200,000 Total O&M Costs $ 2,740,000 Present Worth of O&M $ 41,720,000 Summary of Present Worth Costs Capital Cost $ 14,810,000 Replacement $ 440,000 O&M Cost $ 41,720,000 Salvage Value S (1,440.000i iolal Present Wonh $ 55,530,000 $ 440,000 $ 1,440,000 Page 160 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Wastewater Nutrient Reduction Study Opinion of Present Worth Cost Alternative BNR1c - A2O Process with struvite harvesting; BOD diversion from lagoon Discount Rate 2,750 % Initial Capital Future Capital Replacement Replacement 20-Year Salvage Value ITEM Cost Cost Year Cost (P.W.) Salvage Value (P.W.) Satellite Aeration Tank Structural Modifications $ 250,000 5 - 40 5 • 5 130,000 5 80,000 Baffle Walls - Anaerobic Zones $ 230,000 5 40 5 5 120,000 $ 70,000 Baffe Walls - Anoxic Zones $ 230,000 $ 40 5 5 120,000 5 70,000 Anaerobic/Anoxic Mixers $ 480,000 $ 20 5 S - 5 - Fine Bubble Diffusers $ 600,000 $ 600,000 15 S 400,000 $ 400,000 S 230,000 Nitrate Recycle Pumps $ 320,000 $ 20 S 5 - 5 - Lagoon Influent Structure Modifications $ 100,000 5 40 5 - 5 50,000 5 30,000 Lagoon Influent Fermentation Tank and Appurtenances $ 5,000,000 20 5 - 5 Chemical Storage Tank - CPR backup $ 80,000 S - 20 $ - 5 • 5 - Chemical Feed System $ 60,000 5 60,000 15 $ 40,000 5 40,000 5 20,000 Chemical Building $ 250,000 $ 40 $ - 5 130,000 5 80,000 Struvite Harvesting/Sequestration 5 2,000,000 5 - 20 5 $ - 5 Subtotal $ 9,600,000 $ 660,000 Piping and Mechanical (20%) 5 1,920,000 S - 40 $ - 5 960,000 $ 560,000 HVAC (10%) 5 960,000 5 - 20 $ - $ - $ Electrical (25%) 5 2,400,000 5 - 20 $ - 5 - $ Sitework (10%) $ 960,000 Subtotal $ 15,840,000 Contractor GCs (10%) 5 1,590,000 Total Construction Costs 5 17,430,000 Contingencies and Engineering Services (50%) 5 5,720,000 Total Capital Costs $ 26,150,000 $ 440,000 $ 1,820,000 $ 1,060,000 Present Worth of Capital Costs $ 26,150,000 Relative Labor ($40/hr) $ 20,000 Maintenance (-2% of equipment) $ 30,000 Power ($004/kWh) $ 300,000 Solids Disposal $ 40,000 Chemical Use $ 140,000 Total O&M Costs $ 530,000 Present Worth of O&M $ 11,070,000 Summary of Present Worth Costs Capital Cost 5 26,150,000 Replacement i 440,000 O&M Cost S• 8,070,000 Salvage Value S (1,060,000) Total Present 'North $ 33,600,000 Altemative S3 - Satellite Bar Screen Building $ 5,470,000 Annual Lost Biogas Value $04283,000 Present Worth of Lost Biogas Revenue 50 $4,310,000 Alternative BNR1a + S3 $ 39,070,000 With Biogas Value $39,070,000-$43,380,000 5 440,000 $ 1,060,000 Page 161 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Wastewater Nutrient Reduction Study Opinion of Present Worth Cost Discount Rate 2.750% Altemative BNR1d - A2O Process with atruvite harvesting; VFA addition at WWTP Initial Capital Future Capital Replacement Replacement 20-Year Salvage Value ITEM Cost Cost Year Cost (P.W.) Salvage Value (P.W.) Satellite Aeration Tank Structural Modifications 5 250,000 5 40 5 5 130,000 S 80,000 Baffle Walls - Anaerobic Zones 5 230,000 5 40 5 S 120,000 5 70,000 Baffe Walls - Anoxic Zones 5 230,000 5 40 5 S 120,000 S 70,000 Anaerobic/Anoxic Mixers 5 480,000 5 20 5 _ 5 - Fine Bubble Diffusers 5 600,000 S 600,000 15 5 400,000 5 400,000 5 230,000 Nitrate Recycle Pumps 5 320,000 5 20 5 a - 5 - Chemical Storage Tanks - CPR backup and VFA 5 300,000 5 20 5 5 3 • Chemical Feed System 5 60,000 5 60,000 15 5 40,000 5 40,000 5 20,000 Chemical Building 5 1,250,000 5 40 5 3 630,000 $ 370,000 Struviteharva5t,ngf5eque51ration 5 2.000.000 5 - 20 5 5 - Subtotal $ 5,720,000 $ 660,000 Piping and Mechanical (20%) 5 1,150,000 $ 40 $ 5 580,000 $ 340,000 HVAC (10%) 5 580,000 $ 20 $ 3 - $ Electrical (25%) 5. 1,430,000 $ 20 $ - 5 $ Sitework (10%) 5 580.000 Subtotal $ 9,460,000 Contractor GCs (10%) Total Construction Costs Contingencies and Engineering Services (50%) Total Capital Costs $ 950,000 $ 10,410,000 $ 5,210,000 $ 15,620,000 $ 440,000 $ 1,890,000 $ 1,100,000 Present Worth of Capital Costs $ 15,620,000 Relative Labor ($40lhr) $ 20,000 Maintenance (-2 % of equipment) $ 30,000 Power ($0 04/kWh) $ 300,000 Solids Disposal $ 40,000 Chemical Use $ 750 000 Total O&M Costs $ 1,140,000 Present Worth of O&M $ 17,360,000 Summary of Present Worth Costs Capital Cost $ 15,620,000 Replacement $ 440,000 O&M Cost $ 17,360,000 Salvage Value $ (1,100.200) rota! Prunent Worth $ 32,320,000 $ 440,000 $ 1,100,000 Page 162 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa W.a5tewator Nvonent Renuction Shady Opinion of Present Worth Cost Discount Rate 2.750% Alternative BNR1e - A2O Process with struvite harvesting and PRS fermentation; BOD diversion from lagoon Initial Capital Futuna Capital Replacement Replacement 20-Year Salvage Value ITEM Coat Cost Year Cost (P W) Salvage Value (P.W.) Satellite Aeration Tank Structural Modifications $ 250,000 $ - 40 5 8 130,000 5 80,000 Baffle Walls- Anaerobic Zones $ 230,000 $ 40 5 8 120,000 $ 70,000 Baffe Walls - Anoxic Zones $ 230,000 $ 40 8 $ 120,000 5 70,000 Anaerobic/Anoxic Mixers $ 480,000 $ 20 $ - $ 5 - Fine Bubble Diffusers $ 600,000 $ 600,000 15 5 400,000 5 400,000 $ 230,000 Nitrate Recycle Pumps $ 320,000 $ 20 $ - $ - 5 Lagoon Influent Structure Modifications $ 100,000 $ 40 8 - 8 50,000 $ 30,000 Lagoon Influent Fermentation Tank and Appurtenances $ 5,000,000 20 $ - $ Chemical Storage Tank- CPR backup $ 80,000 $ - 20 $ - 8 - 5 Chemical Feed System $ 60,000 $ 60,000 15 $ 40,000 $ 40,000 $ 20,000 Chemical Building $ 250,000 $ 40 $ $ 130,000 $ 80,000 Primary Sludge Fermenter $ 1,600,000 20 $ - $ - $ - StruviteHarveslinglSequasnahon 5 2-000.000 $ 20 $ - $ • $ - Subtotal $ 11,200,000 $ 660,000 Piping and Mechanical (20%) 5 2,240,000 $ 40 $ • $ 1,120,000 5 650,000 HVAC (10%) S 1,120,000 $ 20 $ - $ • 5 Electrical (25%) 3 2,800,000 $ 20 $ $ - 8 Sitework (10%) $ 1,120,000 Subtotal $ 18,480,000 Contractor GCs (10%) Total Construction Costs Contingencies and Engineering Services (50%) Total Capital Costs $ 1,850,000 $ 20,330,000 $ 10.170.000 $ 30,500,000 440,000 $ 1,980,000 $ 1,150,000 Present Worth of Capital Costs $ 30,500,000 Relative Labor ($40Ihr) $ 40,000 Maintenance (-2% of equipment) 5 40,000 Power ($0 04/kWh) S 290,000 Solids Disposal 3 40,000 Chemical Use $ 140,000 Total O&M Costs $ 550,000 Present Worth of O&M $ 6,370,000 Summary of Present Worth Costs Capital Cost $ 30,500,000 Replacement $ 440,000 O&M Cost $ 8,370,000 Salvage Value 5 (1 1W.600) Tetai Present Worth $ 38,160,000 Altemative S3 - Satellite Bar Screen Building $ 5,470,000 Annual Lost Singes Value $0-$142,000 Present Worth of Lost Biogas Revenue $0-$2,160,000 Altemative BNR1a + S3 $ 43,630,000 With Biogas Value $43,630,000 - 545,790,000 $ 440,000 $ 1,150,000 Page 163 of 164 DRAFT-(05.03.23) City of Waterloo, Iowa Wastewater Nutrient Reduction Study Opinion of Present Worth Cost Discount Rate 2.750 % Altemative BNR1f - A2O Process with struvlte harvesting and PRS fermentation; VFA addition at WWTP Initial Capital Future Capital Replacement Replacement 20-Year Salvage Value ITEM Cost Cost Year Cost (P.W.) Salvage Value (P.W.) Satellite Aeration Tank Structural Mod,f,cni,:,r,+ $ 250,000 $ 40 $ S. 130,000 5 80,000 Baffle Walls - Anaerobic Zones $ 230,000 $ - 40 $ S 120,000 5 70,000 Baffe Walls - Anoxic Zones $ 230,000 $ 40 $ 5 120,000 5 70,000 Anaerobic/Anoxic Mixers $ 480,000 $ - 20 $ - 5 5 Fine Bubble Diffusers $ 600,000 $ 600,000 15 $ 400,000 5 400,000 c 230,000 Nitrate Recycle Pumps $ 320,000 $ 20 $ • 5 - $ Chemical Storage Tanks - CPR backup end VFA $ 150,000 $ - 20 $ • 5 5 - Chemical Feed System $ 60,000 $ 60,000 15 $ 40,000 5 40,000 5 20,000 Chemical Building $ 500,000 $ - 40 $ • 5 250,000 5 150,000 Primary Sludge Fermenter $ 1,800,000 20 $ • 5 - 5 Struvite Harvesting/Sequestration $ 2,000,000 $ 20 $ • 5 - 5 Subtotal $ 6,420,000 $ 660,000 Piping and Mechanical (20%) $ 1,290,000 $ 40 $ 5 650,000 $ 380,000 HVAC (10%) $ 650,000 $ 20 $ 5 - $ Electrical (25%) $ 1,610,000 $ 20 $ S $ - Sitework (10%) $ 850 000 Subtotal $ 10,620,000 Contractor GCs (10%) $ 1,070,000 Total Construction Costs $ 11,690,000 Contingencies and Engineering Services (50%) $ 5.650.000 Total Capital Costs $ 17,540,000 5 440,000 $ 1,580,000 $ 920,000 Present Worth of Capital Costa $ 17,540,000 5 440,000 $ 920,000 Relative Labor ($40Ihr) 5 40,000 Maintenance (-2% of equipment) $ 40,000 Power ($0-04IkWh) 5 290,000 Solids Disposal 5 40,000 Chemical Use 5 440.000 Total O&M Costs $ 850,000 Present Worth of O&M $ 12,940,000 Summary of Present Worth Coats Capital Cost $ 17,540,000 Replacement $ 440,000 O&M Cost $ 12,940,000 Salvage Value S (920,000). Total Present Worth $ 30.000,000 Page 164 of 164