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August 2024 I Project No. #220163-004 Preliminary Engineering Report CITY OF JEROME WASTEWATER SYSTEM MASTER PLAN PREPARED BY PREPARED FOR 100 EAST BOWER STREET SUITE 110 MERIDIAN, ID 83642 [PHONE REDACTED] CITY OF JEROME 152 EAST AVENUE A JEROME, ID 83338 [PHONE REDACTED] Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 8/27/2024 8/27/2024 ---PAGE BREAK--- THIS PAGE LEFT INTENTIONALLY BLANK Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 TOC - i TABLE OF CONTENTS TABLE OF CONTENTS TABLE OF CONTENTS TABLE OF CONTENTS CHAPTER 1 - PROJECT PLANNING 1-1 1.1. Location 1-1 1.2. Environmental Conditions 1-2 1.3. Population Trends 1-7 1.4. Wastewater Flows 1-7 1.5. Wastewater Loadings 1.6. Regulatory Requirements 1.7. Community Engagement CHAPTER 2 - COLLECTION SYSTEM CONDITIONS 2-1 2.1. Collection System 2-1 2.2. Existing System Conditions 2-2 2.3. Lift Station Conditions Assessment 2-4 CHAPTER 3 - COLLECTION SYSTEM PERFORMANCE 3-1 3.1. Model 3-1 3.2. Existing System Capacity Evaluation 3-2 3.3. 20-Year and 50-Year Model Construction 3-7 CHAPTER 4 - TREATMENT SYSTEM CONDITIONS 4-1 4.1. Treatment System Overview 4-1 4.2. WWTP Conditions 4-4 4.3. Equipment Age 4.4. Financial Status of Existing Facilities 4.5. System Classifications CHAPTER 5 - TREATMENT SYSTEM PERFORMANCE 5-1 5.1. Effluent Quality 5-1 5.2. WWTP Capacity 5-7 CHAPTER 6 - NEED FOR SYSTEM IMPROVEMENTS 6-1 6.1. Health, Sanitation, and Security 6-1 6.2. Aging Infrastructure 6-1 6.3. System Deficiencies 6-1 6.4. Reasonable Growth 6-3 CHAPTER 7 - COLLECTION SYSTEM ALTERNATIVES 7-1 7.1. Capacity Alternatives 7-1 7.2. Pipeline Upgrade Alternatives 7-6 7.3. Pipeline Replacement Alternatives 7-9 CHAPTER 8 - TREATMENT SYSTEM ALTERNATIVES 8-1 8.1. Secondary Treatment Alternatives 8-1 8.2. System Redundancy Alternatives 8-7 8.3. Impact Analysis Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 TOC - ii CHAPTER 9 - CAPITAL IMPROVEMENT 9-1 9.1. Initial Improvements 9-1 9.2. Engineer’s Opinion of Probable Cost 9-1 9.3. Permit Requirements 9-4 9.4. Sustainability Considerations 9-4 9.5. Short-Lived Assets 9-4 9.6. Other Annual Costs 9-5 9.7. Project Schedule / Implementation Plan 9-5 9.8. Funding Sources 9-6 9.9. User Rate and Connection Fee Analysis 9-7 9.10. Debt 9-9 9.11. Operating Expenses 9-9 9.12. Short-Lived Asset Replacement Budget 9.13. Capital Improvements Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 TOC - iii LIST OF FIGURES LIST OF FIGURES LIST OF FIGURES LIST OF FIGURES Figure 1-1: Service Area 1-1 Figure 1-2: Land Use in Jerome 1-3 Figure 1-3: Wetlands in Jerome 1-4 Figure 1-4: Air Quality Map 1-6 Figure 1-5: Population Projection 1-7 Figure 1-6: Historical Average Influent Flows 1-8 Figure 1-7: Precipitation vs. Influent Flows 1-9 Figure 1-8: Average Influent BOD5 Loads Figure 1-9: Average Influent TSS Figure 1-10: Average Influent Phosphorus Loads Figure 2-2: Lift Station Locations 2-1 Figure 3-1: Existing Gravity Pipeline Capacity Evaluation 3-3 Figure 3-2: North Jerome Trunkline Remaining Capacities 3-4 Figure 3-3: IMP Discharge Remaining Capacities 3-5 Figure 3-4: Darigold Discharge Remaining 3-6 Figure 3-5: 20-Year Gravity Pipeline Capacity 3-9 Figure 3-6: 50-Year Gravity Pipeline Capacity Figure 4-1: WWTP Layout 4-2 Figure 4-2: WWTP Flow Diagram 4-3 Figure 5-1: Average Effluent BOD5 and TSS Concentrations 5-1 Figure 5-2: Average Effluent BOD5 and TSS Loads 5-2 Figure 5-3: Average Weekly Effluent BOD5 and TSS 5-2 Figure 5-4: Average Weekly Effluent BOD5 and TSS 5-3 Figure 5-5: Average BOD5 and TSS Percent Removal 5-3 Figure 5-6: Average Effluent Total Phosphorus Load 5-4 Figure 5-7: Average Weekly Effluent Total Phosphorus Load 5-4 Figure 5-8: Effluent E. Coli Geometric Mean 5-5 Figure 5-9: Effluent E. Coli Instantaneous Maximum 5-6 Figure 5-10: Effluent pH 5-6 Figure 5-11: Percent BOD5 Removal Through Biotowers and Clarifier 1 5-9 Figure 7-1: North Jerome Service Alternative 7-4 Figure 7-2: North Jerome Service Alternative 2 7-4 Figure 7-3: North Jerome Service Alternative 3 7-5 Figure 7-4: IMP Discharge Improvement Corridor 7-7 Figure 7-5: Darigold Discharge Improvement Corridor 7-5 Figure 8-1: Status Quo (MBR Expansion) 8-2 Figure 8-2: Converting to an EBPR-AS Process 8-3 Figure 8-3: Converting to an EBPR-AS Process for New Flows 8-4 Figure 8-4: Separate Municipal Wastewater Flow 8-7 Figure 8-5: MBR System Emergency Bypass 8-8 Figure 8-6: Automatic High Load Diversion to Emergency Storage Ponds 8-9 Figure 8-7: Bio-Tower and Intermediate Clarifier Bypass Figure 9-1: Wastewater System Expenses vs. User Rate Income 9-9 Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 TOC - iv LIST OF TABLES LIST OF TABLES LIST OF TABLES LIST OF TABLES Table 1-1: Historical Populations 1-7 Table 1-2: Influent Flow Statistics (MGD) 1-9 Table 1-3: Industrial Influent Flow Statistics (MGD) Table 1-4: Residential/Commercial Influent Flow Statistics (MGD and Table 1-5: Projected Influent Flows (MGD) Table 1-6: Influent BOD5 Loading Summary (PPD) Table 1-7: Industrial Influent BOD5 Loading Summary (PPD) Table 1-8: Residential/Commercial Influent BOD5 (PPD and PPCD) Table 1-9: Influent TSS Loading Summary Table 1-10: Industrial Influent TSS Loading Summary (PPD) Table 1-11: Residential/Commercial Influent TSS (PPD and PPCD) Table 1-12: Influent Phosphorus Loading Summary (PPD) Table 1-13: Industrial Influent Phosphorus Loading Summary (PPD) Table 1-14: Residential/Commercial Influent Phosphorus (PPD and PPCD) Table 1-15: Influent Loading Projections Table 1-16: Existing NPDES Permit Limits Table 2-1: Gravity Pipe Length (FT) Inventory 2-2 Table 2-2: Pressure Pipe Length (FT) Inventory 2-3 Table 2-3: Gravity Pipe Age 2-2 Table 2-4: Pressure Pipe Age 2-4 Table 2-5: Lift Stations 2-5 Table 2-6: Lift Station Inventory Summary 2-7 Table 2-7: Continued: Lift Station Inventory Summary 2-8 Table 3-1: Lift Station Capacity Evaluation (Values in GPM) Table 3-2: Lift Station Forcemain Velocity Evaluation (Values in FPS) Table 4-1: Equipment Age Table 5-1: Equipment Rating Table 7-1: North Jerome Service Alternatives Pros And Cons 7-3 Table 7-2: North Jerome Alternatives Impact 7-5 Table 7-3: Pipeline Capacity Alternatives Impact Summary 7-8 Table 8-1: Treatment Alternatives Comparison 8-5 Table 8-2: Treatment Alternatives Cost Comparison 8-6 Table 8-3: System Redundancy Alternatives Comparison Table 8-4: General Impact Table 9-1: Capital Improvement Plan (Priority 9-2 Table 9-2: Capital Improvement Plan (Priorities 1 and 2) 9-3 Table 9-3: Short-Lived Assets 9-4 Table 9-4: Annual Cost Comparison 9-5 Table 9-5: Priority CIP Schedule 9-6 Table 9-6: User Rate Model Comparison Table 9-7: User Rate Parameter Inputs Table 9-8: 100% Debt Funded CIP Scenario 1 Table 9-9: 100% Cash Funded CIP Scenario Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 TOC - v LIST OF IST OF IST OF IST OF APPENDI APPENDI APPENDI APPENDICES CES CES CES Appendix A – Permits Appendix B – Full Sized Figures Appendix C – Financial Information Appendix D – Capital Improvement Plan Appendix E – User Rate and Connection Fee Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- THIS PAGE LEFT INTENTIONALLY BLANK Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 1 CHAPTER 1 - PROJECT PLANNING 1.1. LOCATION The City of Jerome, Idaho (City) is in the Magic Valley of south-central Idaho. The City is also the county seat of Jerome County. It is surrounded by farmland and dairies, and Interstate 84 runs along the southern edge of the City. The Snake River runs approximately 6 miles to the south of the City. Figure 1-1 shows the City limits and impact area for the City. The impact area constitutes the service area for this master plan. The City's wastewater treatment plant (WWTP) is on the west side of the City. The WWTP effluent is permitted to discharge into the J8 Canal (Appendix FIGURE 1-1: SERVICE AREA MAP Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 2 1.2. ENVIRONMENTAL CONDITIONS This master plan is solely a planning project, with recommended infrastructure and operational improvements that may have environmental impacts. While these impacts are briefly discussed in this report, a complete environmental analysis is not included. This section presents a summary of the environmental resources in Jerome. Potential consequences for improvements are discussed later in the report. 1.2.1. Physiography, Topography, Geology, And Soils The planning area coincides with the City's impact area. It consists of the City's current service area and county lands where growth is expected during the planning period. Jerome's topography includes gentile hills and shallow slopes. The elevation is approximately 3,700 feet above sea level. Soils in Jerome are primarily sandy and silty loams that are generally deep and well-drained. These soils are generally suitable for growing crops and other agricultural uses. Predominant soil types are the Sluka and Shano silt loams. 1.2.2. Surface And Groundwater Hydrology The Snake River runs to the south of the City of Jerome. The Snake River is a major river in the greater Pacific Northwest region of the United States. The water conveyed by the Snake River eventually reaches the Pacific Ocean as it crosses through Idaho and Washington. The City's effluent is discharged to the J8 Canal. Approximately 19 miles of the discharge location, the J8 Canal can potentially enter the Snake River. The Snake River in this area was deemed impaired due to sediment, pathogens, and high phosphorus discharges. A total maximum daily load (TMDL) limit has been set for this area's phosphorus discharges to the Snake River. Groundwater wells from the Eastern Snake River Aquifer supply potable water to the City. The potable water is high quality and compliant with current regulations. However, the Eastern Snake River is a Sole Source Aquifer (SSA), meaning that the aquifer supplies at least half of the drinking water consumed in the area, so its protection is essential. The Idaho Department of Environmental Quality (DEQ) has established nitrate priority areas for the state. Although City wells have not experienced high nitrate concentrations, nearby locations, such as wells in southwest Jerome County and Twin Falls, are in moderate-high nitrate priority areas. 1.2.3. Fauna, Flora, And Natural Communities The United States Fish and Wildlife Service (USFWS) lists eight species under review, candidate, threatened, or endangered in Jerome County. These include the Banbury Springs limpet (snail), the Snake River physa snail, the Utah valvata snail, the Bliss Rapids snail, the Monarch butterfly, The Greater sage-grouse, the Little brown bat, and the Gray wolf. The United States Department of Agriculture (USDA) does not list any plants in Jerome County that are on the threatened or endangered list. 1.2.4. Land Use The planning area for this study encompasses approximately 3,000 acres. The land is used for various purposes, including residential, industrial, mixed-use, commercial, and agricultural. Figure 1-2 illustrates the current and projected land uses. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 3 FIGURE 1-2: LAND USE IN JEROME 1.2.5. Cultural Resources The National Park Service's National Register of Historic Places lists several historic properties in the study area. These are primarily houses but also include the Allton Building, the City Pump House, the County Courthouse, the First Baptist Church, Jerome National Bank, and a few other properties of historical interest. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 4 1.2.6. Utility Use The wastewater is transmitted to the WWTP through gravity sewer pipelines, thirteen lift stations, and pressure sewer pipelines. Two of the thirteen lift stations are being removed from service soon. The wastewater is treated, disinfected, and discharged to the J8 Canal. Stormwater drains are not connected to the wastewater collection system. 1.2.7. Floodplains And Wetlands Floodplain information was gathered from the Federal Emergency Management Agency (FEMA) Map Service Center The maps show that the City of Jerome is outside of major flood zones in the planning area. The FEMA maps are included in Appendix B. The National Wetlands Inventory through the USFWS provides geographic information system (GIS) data outlining wetlands. Wetlands in the study area are shown in Figure 1-3. If any projects disturb jurisdictional wetlands stream crossings or wetland alteration), formal consultation with the U.S. Army Corps of Engineers, the Idaho Department of Water Resources, and the Idaho Department of Lands would be required to obtain Section 404 permits. FIGURE 1-3: WETLANDS IN JEROME Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 5 1.2.8. Wild And Scenic Rivers There are no Wild and Scenic Rivers located in the planning area. 1.2.9. Agricultural Land A vast amount of land in the planning area is designated as prime farmland. Such designations are given to soils that are economically capable of producing sustained high yields of food, seed, forage, fiber, and oilseed crops. Of the 3,000 acres in the planning study area, approximately 60% has been classified as "Prime farmland if irrigated" by the NRCS 1.2.10. Coastal Resources Due to the location of the planning study, the Coastal Zone Management Act is not anticipated to apply to the City of Jerome, Idaho. 1.2.11. Precipitation And Temperature Climatological data was retrieved from the Western Regional Climate Center for Jerome. The average precipitation (recorded from approximately 1915 to 2016) is 9.78 inches per year, of which about 3.54 inches (36%) falls from April through September. Snowfall averages approximately 15 inches per year. The average daily maximum temperature is hottest in July (91.7°F) and coldest in January (35.9°F). 1.2.12. Air Quality And Noise Idaho is among the states that have delegated authority from the U.S. Environmental Protection Agency (EPA) to issue air quality permits and enforce air quality regulations. DEQ's air protection efforts are intended to ensure compliance with federal and state health-based air quality regulations. The Clean Air Act of 1970 identified six common air pollutants of concern, called "criteria pollutants." These criteria pollutants are carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide. Fugitive dust is also closely regulated as it contributes to particulate matter. DEQ monitors air quality and publishes air quality information. Jerome is not in an area of concern, Class I area, or non-attainment area. Additionally, no noise issues have been identified for the area. A map of locations with sensitive air quality is shown in Figure 1-4. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 6 FIGURE 1-4: AIR QUALITY MAP 1.2.13. Energy Production And Consumption The City of Jerome does not produce any energy. Energy use by the City's wastewater system is primarily comprised of pumping from lift stations and treatment at the WWTP. 1.2.14. Socio-Economic Conditions Approximately 69% of the City’s population is in the labor force. About 17% of the population is over 65. The median household income (in 2021 dollars) was $69,021. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 7 1.3. POPULATION TRENDS Population growth in Jerome has been steady. Table 1-1 summarizes the historical United States Census (U.S. Census) Annual Population Estimates. The populations in 2010 and 2020 represent actual U.S. Census reported populations. On average, the City grew approximately 1.3% between 2010 and 2021. TABLE 1-1: HISTORICAL POPULATIONS Year Population 2010 10,890 2017 11,701 2018 11,835 2019 12,044 2020 12,349 2021 12,555 For this master plan to be more conservative, the City selected a growth rate of 1.5%. Figure 1-5 illustrates the historical and projected future populations. FIGURE 1-5: POPULATION PROJECTION The City has 4,220 residential utility customers. Additionally, several large industrial customers contribute 7,366 equivalent residential units (ERUs) of wastewater, and commercial customers contribute another 460 ERUs. The total number of ERUs in the City is 12,046. 1.4. WASTEWATER FLOWS The wastewater flow analysis in this section reviews historical wastewater flows, develops planning criteria based on the data, and provides the projected flows for the 20 and 50-year planning periods. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 8 1.4.1. Historical Flows Plant influent flows from January 2017 to September 2022 were evaluated for this master plan. Figure 1-6 shows the average influent flows during this period. The influent flows and industrial flows have increased during the period. Also, the figure indicates that industrial flows contribute more than half of the flow to the WWTP. The industrial flow data included available data from Agropur, Darigold, Idaho Milk Products (IMP), Magic Valley Quality Milk, Rite Stuff, and Commercial Creamery. FIGURE 1-6: HISTORICAL AVERAGE INFLUENT FLOWS 1.4.2. Infiltration And Inflow Infiltration is water entering the wastewater collection system through cracks, fractures, and holes in system components. Inflow is defined as the amount of flow into the sanitary sewer through a direct connection, such as a stormwater drain or direct flow through a manhole lid. Contributions from infiltration and inflow (I&I) during significant wet weather events may exceed wastewater systems' transmission or treatment capacity, resulting in surcharges or overflows that may have adverse environmental or public health impacts (U.S. EPA, 2020). No overflows were noted by City personnel. An I&I analysis conducted during the last Collection System Master Plan concluded that the City does not appear to experience significant I&I events (Keller Associates, Inc., 2013). Figure 1-7 illustrates the precipitation charted against the WWTP influent flows. Even with precipitation events, there did not appear to be a noticeable increase in flows to the WWTP. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 9 FIGURE 1-7: PRECIPITATION VS. INFLUENT FLOWS 1.4.3. Planning Flows This section summarizes the results of the flow analysis. The average day, maximum month, maximum day, and peak hour planning criteria flows are defined below. Average Day Flow (ADF) – the average daily flow for the calendar year. Maximum Month Flow (MMF) – represents the highest calendar average flow into the WWTP for the year. Maximum Day Flow (MDF) – is the maximum daily flow recorded during the year. Peak Hour Flow (PHF) – the peak hour flow (PHF) represents the highest hourly flow at the WWTP. A summary of the January 2017 to September 2022 data is presented in Table 1-2. The City provided Keller with daily flow totals and 1-hour interval flow data for the WWTP. The daily flow totals were used to inform each year's ADF, MMF, and MDF. A review of the hourly data revealed a discrepancy between the daily and hourly flow data, with the hourly data showing higher daily flows than the daily totalized data. As such, the hourly data of the highest day was used to develop a peaking factor, which was then applied to the maximum daily total to calculate peak hour flow for each year. TABLE 1-2: INFLUENT FLOW STATISTICS (MGD) 1 - For the PHF in 2019, data was available from July 26, 2019, until the end of the year. 2 - January through September 2022 flow data. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Jan-17 Apr-17 Jun-17 Sep-17 Dec-17 Mar-18 Jun-18 Sep-18 Dec-18 Mar-19 Jun-19 Sep-19 Dec-19 Mar-20 Jun-20 Sep-20 Dec-20 Mar-21 Jun-21 Sep-21 Dec-21 Mar-22 Jun-22 Sep-22 Precipitation (inches) Influent Flow (MGD) Precipitation Influent Flow Parameter Year 2017 2018 2019 1 2020 2021 2022 2 Population 11,701 11,835 12,044 12,349 12,555 12,743 ADF 2.94 3.30 3.45 3.52 3.42 3.47 MMF 3.14 3.47 3.59 3.61 3.52 3.82 MDF 4.03 4.08 3.95 4.04 4.01 4.57 PHF 5.59 6.97 7.08 8.07 Historical Flows (MGD) Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 10 The industrial flows for the main three industries, and the industries as a whole, were also analyzed. Hourly flow data from the industries was not provided. For simplicity in presentation, the highest values for the calendar year from January 2017 through September 2022 are shown in Table 1-3. TABLE 1-3: INDUSTRIAL INFLUENT FLOW STATISTICS (MGD) Determining how much flow can be attributed per person in the community is helpful. Flows in gallons per capita per day (gpcd) are used as the basis for selecting the planning criteria for residential and commercial flows. Historically, the industrial dischargers have constituted approximately 55-60% of the WWTP flows. The residential/commercial flows were calculated by subtracting industry flow data from the WWTP influent data. The residential/commercial portion of the influent flow is shown in Table 1-4. An average of the ADFs and the maximum values for the MMF, MDF, and PHF were selected for the planning criteria. TABLE 1-4: RESIDENTIAL/COMMERCIAL INFLUENT FLOW STATISTICS (MGD AND GPCD) 1 - January through September 2022 flow data. 1.4.4. Flow Projections Future residential and commercial flows can be estimated using the planning criteria (gpcd) in Table 1-3. This planning criteria is multiplied by the future populations in Table 1-1 to provide a flow for each of the parameters for the residential/commercial portion of the City. The average growth in industrial flows is approximately 100,000 gallons per year for the past five years (see Figure 1-6). The industries are also considering further production expansion, which will generate additional wastewater. For this master plan, the City assumed a growth of 500,000 gallons per day this year with flow characteristics similar to an industry like IMP and 100,000 gallons per day per year with flow characteristics identical to the general industrial flows each subsequent year. Based on the flow data in Table 1-3, peaking factors were used to calculate the MMF and MDF. The flow projections used in this master plan are shown in Table 1-5. These flows will be used when evaluating the current wastewater system and any improvement alternatives. Parameter Year Agropur IMP Darigold Total Indust. ADF 1.09 0.40 0.49 2.08 MMF 1.13 0.44 0.53 2.17 MDF 1.34 0.50 0.64 2.39 Historical Flows (MGD) Parameter Planning Flow (gpcd) Year Population ADF 1.34 114 1.52 128 1.49 124 1.57 127 1.34 107 1.47 115 119 MMF 1.40 119 1.60 135 1.53 127 1.58 128 1.36 108 1.74 136 136 MDF 1.99 170 1.98 167 1.77 147 1.84 149 1.62 129 2.27 178 178 PHF 2.39 198 2.98 241 2.79 222 3.51 [PHONE REDACTED] 12,044 12,743 12,349 12,555 Historical Flows (MGD gpcd) 2022 1 2021 2017 11,701 2018 11,835 2019 Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 11 TABLE 1-5: PROJECTED INFLUENT FLOWS (MGD) 1.5. WASTEWATER LOADINGS The wastewater flow to the WWTP is a mixture of industrial, residential, and commercial dischargers contributions. Local septic haulers were once allowed to discharge at the Headworks but are no longer due to the materials in the septage. A description of influent quality and characteristics organized by constituent is provided in this section. The City of Jerome employs a pre-treatment program that subscribes to locally and federally established pre-treatment standards. The City also imposes a surcharge for some constituents to help defray the costs of treating high-strength industrial wastewater (City of Jerome, 2021). This section summarizes the results of the loading analysis for different constituents. Like the flow analysis, the average day, maximum month, and maximum day loads are helpful for this master plan and are defined below. Average Day Load (ADL) - the average daily load for the calendar year. Maximum Month Load (MML) – represents the highest calendar average load into the WWTP for the year. Maximum Day Load (MDL) - the maximum daily load recorded each year. 1.5.1. Influent BOD5 influent BOD5 data for January 2017 through September 2022 are shown in Figure 1-8 and summarized in Table 1-5. During this period, the recorded average influent BOD5 concentrations varied between 414 and 697 mg/L (loading rate between 11,750 and 20,560 lbs./day). The highest BOD5 loading occurred in December 2020. The industrial BOD5 loading accounted for approximately 80% of the total BOD5 loading at the treatment facility. 2025 (MGD) 2030 (MGD) 2035 (MGD) 2045 (MGD) 2075 (MGD) Res./Com. 1.59 1.71 1.84 2.14 3.34 Industrial 2.78 3.28 3.78 4.78 7.78 Total 4.37 4.99 5.62 6.92 11.1 Res./Com. 1.82 1.96 2.11 2.45 3.83 Industrial 2.94 3.44 3.95 4.99 8.11 Total 4.76 5.40 6.06 7.44 11.9 Res./Com. 2.38 2.56 2.76 3.20 5.01 Industrial 3.27 3.80 4.37 5.51 8.95 Total 5.65 6.36 7.13 8.71 14.0 Res./Com. 3.68 3.96 4.27 4.95 7.74 Industrial 6.43 7.59 8.75 11.1 18.0 Total 10.1 11.5 13.0 16.0 25.7 MDF MMF Parameter ADF PHF Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 12 FIGURE 1-8: AVERAGE INFLUENT BOD5 LOADS TABLE 1-6: INFLUENT BOD5 LOADING SUMMARY (PPD) The historical BOD5 loads from the industries are shown in Table 1-7. Similar to the flows, the highest values in the calendar year from January 2017 through September 2022 are shown for simplicity. It was noted that some of the peak loads (MDL) were higher than the peak loads recorded at the WWTP. This was due to the time it took for the load to arrive at the WWTP; the peak load would usually stretch for longer than one day into the WWTP. Also, the total industrial loads are the sum of the loads each day and may vary as the individual industries have different periods of larger discharge loadings. TABLE 1-7: INDUSTRIAL INFLUENT BOD5 LOADING SUMMARY (PPD) The residential/commercial loads were calculated using an average ratio of the historical industry load to the historical WWTP influent load for each calendar year. The residential/commercial load was assumed to be the difference between the historical WWTP influent load and the historical industry load. The historical residential/commercial load shown in Table 1-8 was then divided by the population to provide a value in pounds per capita per day (ppcd). The ppcd was used to select the planning criteria for residential/commercial flows. Parameter Year 2017 2018 2019 2020 2021 2022 Population 11,701 11,835 12,044 12,349 12,555 12,743 ADL 15,050 14,980 16,580 17,830 15,330 15,580 MML 17,400 17,780 19,900 20,560 17,990 17,180 MDL 32,980 30,320 31,590 44,220 35,280 32,830 Historical BOD5 Loads (PPD) Parameter Year Agropur IMP Darigold Total Indust. ADL 7,840 1,550 480 13,330 MML 10,740 2,120 540 17,060 MDL 38,810 4,860 1,890 44,830 Historical BOD5 Loads (ppd) Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 13 TABLE 1-8: RESIDENTIAL/COMMERCIAL INFLUENT BOD5 (PPD AND PPCD) 1.5.2. Influent TSS influent TSS loads for January 2017 through September 2022 are shown in Figure 1-9 and summarized in Table 1-9. The recorded average influent TSS concentrations varied between 195 and 448 mg/L (loading rate between 5,570 and 13,340 lbs./day). Industrial contributions have accounted for approximately 35% of the total TSS loading. FIGURE 1-9: AVERAGE INFLUENT TSS LOADS TABLE 1-9: INFLUENT TSS LOADING SUMMARY (PPD) Parameter Planning Load (ppcd) Year Population ADL 2,580 0.22 3,440 0.29 3,700 0.31 4,480 0.36 2,810 0.22 4,370 0.34 0.29 MML 2,980 0.25 4,090 0.35 4,440 0.37 5,160 0.42 3,300 0.26 4,820 0.38 0.42 MDL 5,650 0.48 6,970 0.59 7,050 0.59 11,100 0.90 6,470 0.52 9,220 0.72 0.90 11,701 11,835 12,044 12,349 12,555 12,743 Historical BOD5 Loads (PPD ppcd) 2017 2018 2019 2020 2021 2022 Parameter Year 2017 2018 2019 2020 2021 2022 Population 11,701 11,835 12,044 12,349 12,555 12,743 ADL 9,790 8,100 8,110 8,910 7,770 8,340 MML 11,050 11,950 9,250 10,550 11,900 13,340 MDL 19,290 18,910 14,460 15,280 32,310 21,590 Historical TSS Loads (PPD) Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 14 The historical industrial TSS load is shown in Table 1-10. TABLE 1-10: INDUSTRIAL INFLUENT TSS LOADING SUMMARY (PPD) The residential/commercial portion of the influent TSS load was estimated, similar to the BOD5 load, and is shown in Table 1-11. TABLE 1-11: RESIDENTIAL/COMMERCIAL INFLUENT TSS (PPD AND PPCD) 1.5.3. Influent Phosphorus Figure 1-10 and Table 1-12 show influent phosphorus measurements. Regular weekly influent total phosphorus sampling began in 2020. By comparison, BOD5 and TSS are sampled approximately daily. Recorded average influent phosphorus concentrations from January 2020 to September 2022 varied between 13.9 – 40.7 mg/L (loading rate between 393 and 1,225 lbs./day). Industrial contributions have accounted for approximately 70% of the total phosphorus loading. FIGURE 1-10: AVERAGE INFLUENT PHOSPHORUS LOADS Parameter Year Agropur IMP Darigold Total Indust. ADL 2,060 400 170 3,600 MML 2,720 560 200 4,360 MDL 6,900 1,740 710 17,830 Historical TSS Loads (ppd) Parameter Planning Load (ppcd) Year Population ADL 7,180 0.61 4,920 0.42 4,510 0.37 5,280 0.43 5,250 0.42 5,970 0.47 0.45 MML 8,100 0.69 7,260 0.61 5,150 0.43 6,250 0.51 8,030 0.64 9,550 0.75 0.75 MDL 14,140 1.21 11,490 0.97 8,040 0.67 9,050 0.73 21,810 1.74 15,460 1.21 1.74 Historical TSS Loads (PPD ppcd) 2017 2018 2019 2020 2021 2022 12,743 11,701 11,835 12,044 12,349 12,555 Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 15 TABLE 1-12: INFLUENT PHOSPHORUS LOADING SUMMARY (PPD) The historical industrial total phosphorus load is shown in Table 1-13. TABLE 1-13: INDUSTRIAL INFLUENT PHOSPHORUS LOADING SUMMARY (PPD) The residential/commercial portion of the influent total phosphorus load was estimated and is shown in Table 1-14. TABLE 1-14: RESIDENTIAL/COMMERCIAL INFLUENT PHOSPHORUS (PPD AND PPCD) Parameter Historical Phosphorus Loads (PPD ppcd) Planning Load (ppcd) Year 2020 2021 2022 Population 12,349 12,555 12,743 ADL 180 0.015 170 0.014 140 0.011 0.013 MML 210 0.017 340 0.027 170 0.013 0.027 MDL 260 0.021 1,780 0.142 400 0.031 0.142 1.5.4. Influent Nitrogen The City has a limited amount of influent nitrogen data. From July 2020 to January 2021, the City analyzed 14 samples for ammonia. Recorded influent ammonia as nitrogen concentrations varied between 23 and 51 mg/L (average 36 mg/L). More recently, in February and March 2023, the City analyzed ten influent samples for total Kjeldahl nitrogen (TKN). The influent TKN ranged from 55 to 124 mg/L (average 87 mg/L). The ammonia and TKN concentrations measured in those samples are higher than typical municipal influent. The industrial wastewater was not analyzed separately for ammonia or total Kjeldahl nitrogen (TKN). Without additional data, an average influent TKN concentration of 87 mg/L and the projected average flows were utilized to calculate the ADL. Industry-standard peaking factors of 1.36 and 3.57 were assumed for the MML and MDL, respectively (WEF MOP 8, 2018). Parameter Year 2020 2021 2022 Population 12,349 12,555 12,743 ADL 620 600 470 MML 710 1,220 570 MDL 870 6,440 1,310 Historical Phosphorus Loads (PPD) Parameter Year Agropur IMP Darigold Total Indust. ADL 200 210 60 450 MML 290 270 70 530 MDL 790 540 330 1,130 Historical Total Phosphorus Loads (ppd) Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 16 1.5.5. Loading Projections Future residential and commercial loads can be estimated using the planning criteria (ppcd) in the previous sections and multiplying by the future populations in Table 1-1. For the anticipated industrial growth for this master plan, the City assumed an additional 500,000 gallons per day this year with flow characteristics similar to an industry like IMP and 100,000 gallons per day per year for the general industrial flows each subsequent year. The loading projections for this master plan are shown in Table 1-15. TABLE 1-15: INFLUENT LOADING PROJECTIONS 2025 (PPD) 2030 (PPD) 2035 (PPD) 2045 (PPD) Res./Com. 3,880 4,180 4,510 5,230 Industrial 16,530 19,740 22,940 29,350 Total 20,410 23,920 27,450 34,580 Res./Com. 5,570 6,000 6,460 7,500 Industrial 21,050 24,980 28,920 36,800 Total 26,620 30,980 35,380 44,300 Res./Com. 11,980 12,900 13,900 16,130 Industrial 53,480 62,860 72,250 91,010 Total 65,460 75,760 86,150 107,140 Res./Com. 6,040 6,500 7,010 8,130 Industrial 4,440 5,310 6,170 7,900 Total 10,480 11,810 13,180 16,030 Res./Com. 9,990 10,760 11,590 13,450 Industrial 5,400 6,410 7,410 9,420 Total 15,390 17,170 19,000 22,870 Res./Com. 23,150 24,940 26,860 31,180 Industrial 21,080 24,810 28,540 36,000 Total 44,230 49,750 55,400 67,180 Res./Com. 170 190 200 230 Industrial 750 860 970 1,190 Total 920 1,050 1,170 1,420 Res./Com. 360 390 420 490 Industrial 890 1,010 1,130 1,380 Total 1,250 1,400 1,550 1,870 Res./Com. 1,890 2,040 2,190 2,540 Industrial 1,770 2,010 2,240 2,710 Total 3,660 4,050 4,430 5,250 ADL Total 3,170 3,620 4,080 5,020 MML Total 4,310 4,920 5,550 6,830 MDL Total 11,320 12,920 14,570 17,920 BOD5 ADL MML MDL TKN TSS ADL MML MDL TP ADL MML MDL Parameter Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 17 It should be noted that based on the available information, the Jerome WWTP has the potential to experience a nearly 60% increase in influent pollutant loading over the 20-year planning period due to the projected population increase and the expected increase in industrial contributions. These projections should be re-evaluated periodically to confirm population growth and industrial growth occur as planned. New industrial dischargers have the potential to significantly impact future loadings depending on the nature of the business they are performing. The newly developed trigger spreadsheet, discussed in Section 4.2.3, can be used to determine the potential impact of proposed developments and industrial users on the WWTP processes. 1.6. REGULATORY REQUIREMENTS 1.6.1. Surface Water Discharge The City of Jerome discharges treated effluent under the National Pollution Discharge Elimination System (NPDES) Permit No. ID-002016-8 into the J8 Canal. The City's permit went into effect on July 1, 2010, with an expiration date of June 30, 2015; however, the permit has been administratively extended. As of July 1, 2018, EPA has transferred authority to administer and enforce this permit to the Idaho Department of Environmental Quality (DEQ). DEQ will also be the issuing body for the City's upcoming discharge permit, which will replace the current permit. The new surface water discharge permit will be an Idaho Pollutant Discharge Elimination System (IPDES) permit. Existing effluent limits are summarized in Table 1-16. The complete NPDES permit and fact sheet are included in Appendix A. TABLE 1-16: EXISTING NPDES PERMIT LIMITS Parameter Average Average Weekly Maximum Daily Biochemical Oxygen Demand (BOD5) 30 mg/L 750 lbs./day ≥85% removal 45 mg/L 1,100 lbs./day Total Suspended Solids (TSS) 30 mg/L 750 lbs./day ≥85% removal 45 mg/L 1,100 lbs./day Total Phosphorus (as P) 204.5 lbs./day 377 lbs./day Total Residual Chlorine 0.5 mg/L 1.0 mg/L E. coli Bacteria 126/100 mL (geometric mean) 406/100 mL (instantaneous maximum) pH Daily minimum and maximum between 6.5 and 9.0 Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 18 At the point of discharge from the J8 Canal, the Snake River is designated for the beneficial uses of primary contact recreation, cold water aquatic life, salmonid spawning, industrial and agricultural water supply, wildlife habitats, and aesthetics. The J8 Canal is in the Upper Snake-Rock Subbasin (Hydraulic Unit Code (HUC) 17040212), and the assessment unit where it connects with the Snake River is called Snake River - Rock Creek to Box Canyon Creek (ID17040212SK007_07). As of 2022, the assessment unit was impaired for the beneficial uses of cold water aquatic life and salmonid spawning due to flow regime modification, temperature, total suspended solids, and total phosphorus. A TMDL has been created for total phosphorus and total suspended solids. A waste load allocation (WLA) was provided for Jerome with the phosphorus limit shown in the permit. The TSS level shown in the permit is based on technology-based limits since they were more stringent than the TMDL-based limit for TSS. Predicting whether substantive changes will be included within the City's upcoming IPDES Permit is difficult. Idaho DEQ has provided no formal communications regarding potential changes. The Middle Snake River Advisory Group (WAG) noted to the City that a more stringent phosphorus limit (approximately 33% lower) may be in the future; however, no timetable was provided. Also, it is unclear whether temperature will be a requirement in a future permit. For example, the City of Boise received a compliance schedule for effluent temperature at the West Boise Water Renewal Facility by 2030. However, the City of Boise is also pursuing a thermal variance and alternative thermal effluent limits through a demonstration project. Metals and other hazardous substances can also have significant effects on surface water. Although monitoring for nickel and zinc was included in the current permit, it is unclear if any changes to the permit will be made for these substances. Within the general wastewater industry, a class of 'emerging contaminants' has been discussed increasingly as regulators' attention has turned from nutrient pollutants to other constituents. It is not anticipated that limitations will be imposed for these contaminants as part of the City's next permit, as DEQ has indicated that requirements in Idaho will initially be based on EPA guidance, which is not scheduled to be released until late 2024 at the earliest and will likely take some time after its release to implement. However, the potential for permit implications is possible. Among these emerging contaminants are pharmaceuticals and personal care products and 'forever chemicals,' such as per and poly-fluoroalkyl substances (PFAS). are becoming more common in surface waters due to societal changes and advancements in medical technologies. As the relative concentration of these compounds increases, there is concern regarding the impacts these products may have on aquatic life and communities located of where they're introduced. Municipal wastewater discharge is a known mechanism by which are introduced into the environment. Many that persist after wastewater treatment are included in a class of compounds referred to as endocrine disruptors (EDCs). EDCs are compounds that alter the normal function of organisms' endocrine (hormonal) system and can result in various adverse health impacts. Because of the nature of these compounds, negative health impacts are chronic rather than acute, and traditional toxicity tests do not adequately predict nor detect their effects. The EPA is working to update current ambient water quality protections to better accommodate these emerging pollutants. No imminent regulations regarding are anticipated. Thousands of known PFAS chemicals are currently used in everyday products such as non-stick cookware and waterproof clothing. These substances have become prevalent as emerging contaminants due to their ability to bioaccumulate and persist in the environment. The EPA specifically calls out point source dischargers and municipally generated biosolids as sources of PFAS contamination; however, the principal parties responsible for these compounds are those industries involved in their manufacture and use. The EPA has identified a strategic roadmap that will lead to future regulatory guidance regarding PFAS within the next several years. The greatest impact to municipal wastewater treatment plants will likely be regarding biosolids handling. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN CITY OF JEROME I KA 220163-004 1 - 19 1.6.2. Recycled Water The City has not indicated any plans to pursue a reuse permit to grant the ability to land apply treated wastewater. DEQ has permit authority for reuse permits for treated wastewater discharge; associated rules are documented in IDAPA 58.01.17. Due to the amount of effluent flow from the WWTP, it is not likely that wastewater reuse would substantially benefit IPDES permit compliance. Still, it could be investigated as an alternative water source for industries or the community in the future. 1.6.3. Biosolids The City is permitted to dispose of biosolids in the Milner Butte Landfill under its current Biosolids Management Plan. The City may consider pursuing a Class A or Class B biosolids designation, allowing the biosolids to be beneficially used. It is worth noting that future EPA guidance on PFAS compounds could have implications for biosolids handling and disposal, which could require modification of the Biosolids Management Plan. No known modifications due to PFAS are known at this time and will be based on EPA Guidance scheduled to be released after 2024. 1.6.4. Air Quality The City is not considered to be within an air quality non-attainment or maintenance area, and air quality is also not listed as an area of concern. The City has an air quality permit to construct associated with the anaerobic digesters, digester boilers and flare, generators, and heaters. The permit to construct is included in Appendix A. 1.7. COMMUNITY ENGAGEMENT The City plans to make this Facility Plan Report available at City Hall as part of the community engagement requirement of the project following the approval of the Facility Plan Report. If there is significant interest, a town hall meeting could be held. It would be made open to the public to help the community develop an understanding of the need for the project, the utility operational service levels required, and the funding and revenue strategies used to complete the project. No special efforts are anticipated to be needed for poor, minority, or limited English proficiency community residents. Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- THIS PAGE LEFT INTENTIONALLY BLANK Docusign Envelope ID: F0DF4C1C-D572-471D-87C8-A7E8D2A601E0 ---PAGE BREAK--- AUGUST 2024 I WASTEWATER SYSTEM MASTER PLAN ► CHAPTER 2 - COLLECTION SYSTEM CONDITIONS 2.1. COLLECTION SYSTEM OVERVIEW The City of Jerome owns and operates a sanitary sewer collection system and wastewater treatment plant, which serves approximately 3,700 acres within city limits. The collection system consists of approximately 60 miles of gravity sewer pipe, 1,082 manholes, and 12 miles of pressure sewer pipe. Refer to Section 2.2 for detailed information on pipelines. There are 13 lift stations (LS, also referred to as pump stations), two of which are slated to be decommissioned in the near future. Refer to Section 2.3 for detailed information on lift stations. Figure 2-1: Existing Collection System illustrates the existing collection system. FIGURE 2-7: EXISTING COLLECTION SYSTEM \ lt.Vl(of' m O)UT.t1 '1 w,,tr'o.n. NK- t.,ltt; th;:in ■.kwffil"«I _ -Charity 111'1) -!U!II) - -au) -ro,2 10 0.5 CITY OF JEROME I KA 220163-004 1 Milcsl , I • . . • h