WEFTEC® 2023, the Water Environment Federation’s Annual Technical Exhibition and Conference, is the largest annual conference of its kind and offers water quality professionals from around the world with the best water quality education and training available today.

Purpose: Central San, a wastewater utility in San Francisco Bay Area, embarked on an organization-wide integrated planning initiative to support its goals for resiliency, sustainability, and climate adaptation. This initiative will have a parallel benefit of also supporting the agency in meeting California's increasingly stringent sustainability and resiliency requirements. The framework, which encompasses the entire organization, is designed to promote the design, construction and operation of infrastructure projects that support sustainability, resiliency, and equity. However, Central San is taking this framework beyond the project level, expanding it to the entire organization: possibly the first dedicated wastewater agency to do so. Benefits of introducing this framework at a public utility such as Central San include: 1.Supporting pursuit of enterprise and state strategic goals for resiliency, sustainability, and equity 2.Empowering all employees to be champions for the triple bottom line 3.Performance driven benchmarks supporting enhanced levels of sustainability and resiliency 4.Pursuing Infrastructure Planning through the lens of the Envision framework 5.Transparent and consistent approach to benchmarking and tracking infrastructure performance 6.Promoting industry-wide consistency in terminology and interpretations for sustainability and resiliency 7.Supporting social license to operate in service area Before Central San's Board of Directors and Management committed to this pivotal initiative, considerable time was invested with staff to identify if the framework, called Envision, would be a good fit to support our strategic and organizational endeavors. Central San worked with a consultant to determine if there were clear synergies, and if yes, how the framework could further support the realization of those corporate goals. Appreciating how complex a topic such as infrastructure resiliency, sustainability, and agility is; navigating the internal messaging and change-management for staff has been just as challenging. An organization is only as agile as its people. As Harper Lee wrote in the classic novel To Kill a Mockingbird, 'People generally see what they look for and hear what they listen for'. Having an awareness of this human trait helped the team succeed in gaining support for this once-in-a-generation initiative. Benefits of Presentation: Being perhaps the first dedicated wastewater agency in the world to endorse the use of the Envision framework for resiliency, sustainability, and equity at the organizational-wide level, attendees will learn the challenges that Central San surpassed to achieve widespread staff support. Attendees will learn: - How to assess the suitability of the framework for their organization - Learn a flexible process to identify and map synergies between their organization and the Envision framework - How to navigate stakeholders and address the 'what's in it for me' questions that may arise - How to remove barriers to organizational change - How to develop an Strategic Infrastructure Plan through the lens of the Envision framework Status of Completion: Central San staff began this journey in 2019 and gained the Board of Directors and General Manager's endorsement for implementing the framework in June 2022 after extensive internal outreach. Central San has subsequently had dedicated meetings with managers to further the advancement of the framework and to learn how to support each Department, Division and Workgroup in implementing the use of Envision at the programmatic/organization-wide level. In addition, Central San completed four retro-active Capital Project pre-screening assessments using Envision framework and has commenced piloting of the Envision verification process for a Capital Project, to better understand how to internally optimize the use of the framework with the organizations existing processes, and support every project and process at the organization being more sustainable, resilient and equitable. Central San has also embedded the framework in its 2022 Sewer System Infrastructure Plan scope so all infrastructure planning efforts go through the Envision sustainability and resiliency lens. Conclusion: The effects of changing climatic conditions are already affecting our organizations and our ability to recover from extremely disrupting events. In addition, the Social License to Operate for organizations has come to the fore in recent years as rate payers expect more, and as sustainable and equitable infrastructure has become the new norm. The organizational-wide use of the Envision framework helps to support these growing needs for wastewater organizations, however successful implementation is dependent on managing internal stakeholder's concerns. Central San will present how they are succeeding, and how they reframed their organization's approach to resiliency, sustainability, and equity. Note: Envision is administered by the not-for-profit Institute for Sustainable Infrastructure. The framework was developed in conjunction with academia, leading professional industry organizations, and public and private sectors. Note: Envision is administered by the not-for-profit Institute for Sustainable Infrastructure. The framework was developed in conjunction with academia, leading professional industry organizations, and public and private sectors.

Purpose and Benefits This paper demonstrates the benefits of an adaptive management approach (AMA) for Combined Sewer Overflow (CSO) or Separated Sewer Overflow (SSO) reduction programs. The audience will hear about the AMA for a CSO Reduction Consent Decree (CD) program, learn components necessary to support an AMA , and see a case study of the Kansas City, Missouri (KCMO) Smart Sewer Program (SSP). Introduction The US Environmental Protection Agency (EPA) and/or state agencies enforce CSO elimination and reduction through a CD, an agreement that defines steps and the timeline for the utility to manage the CSOs. A CD describes how an Overflow Control Program (OCP) would be implemented. Thus, an OCP needs to be defined before a CD . However, since the OCP is the first step in a CD, it is often based on limited information. The AMA provides a framework to develop a CSO reduction program that can limit the impact of information uncertainties on the program's success. Adaptive Management Approach The AMA is a decision-making process designed to manage information uncertainty through iterative system monitoring and structured decision-making. The AMA uses information about past system performance to optimize the next phase, as shown in Figure 1. With AMA, CD compliance can be achieved on schedule with reduced cost compared to the original OCP. The steps of the iterative phase of the AMA approach applied to CSO reduction are: (1)Plan - Use the available information to plan the next-phase CSO reduction solutions, (2)Design - Select the next-phase solutions and the pre- and post-construction monitoring plan, (3)Implement - Deploy CSO reduction solutions, (4)Monitor - Monitor CSO reduction effectiveness, (5)Analyze - Use the hydraulic model to evaluate the performance of implemented solutions, and (6)Optimize - systemwide CSO reduction using the latest information from implemented projects. A CSO reduction program must satisfy a set of criteria for AMA use. First, the program implementation must be phased to allow the AMA to change proposed solutions. Second, the program needs to monitor the performance of the implemented solutions, thus, collecting information for AMA decision-making. A predictive model is needed to evaluate the performance of the proposed solutions. And finally, the CD compliance must be based on the observed or model-predicted system performance. 2021 KC Water CD Modification 3 provides the framework for the use of AMA on the SSP. The CD Modification 3 changes will enable the City to revise, remove, or replace projects currently contained in the CD if the EPA approves City's request. A revised or alternative control measure must: (1)Reflect sound engineering practices; (2)Results in an equal or greater level of CSO control than the original Control Measure(s); and (3)Include a schedule for implementation that is no later than the original Date of Achievement of Full Operation for the original Control Measure. KCMO Smart Sewer Program Kansas City, Missouri (KCMO) is the largest city in Missouri, with over 500,000 residents. KC Water's SSP is a 30-year, multibillion-dollar effort to reduce the volume of CSO. KCMO developed an OCP in 2009 to capture 97% of the typical year systemwide CSO volume. SSP implemented 33 projects worth over $750M in the first program decade. In 2017, KCMO submitted a request for a modification of the CD. This modification was approved in 2021. Today, SSP has the flexibility to reevaluate OCP control measures as they come for implementation and optimize systemwide, cost-effective CSO reduction. The 37th & Norton green infrastructure (GI) project is an example of how the SSP uses AMA to improve CSO reduction outcomes by changing OCP-proposed control measures based on the information collected on previous projects. 37th & Norton Case Study 37th & Norton green infrastructure (37NGI) project is located upstream from Diversion Structure 152 (DS152). DS152 contributes flow to the Blue River Interceptor Sewer (BRIS) and Blue River WWTP. The original project was proposed to manage CSO at DS152. The original suite of CSO control measures, including this project, was selected based on the basin-wide control plan that assumed that BRIS could receive increased flows. Since, the KCMO has significantly improved hydraulic models. The updated systemwide model has shown limited capacity in BRIS. Modeling indicates that this project would not provide the predicted CSO reduction systemwide. Instead, the SSP used an AMA to search for a cost-effective alternative. A green infrastructure solution was identified to replace the relief sewer control measure with a significantly greater CSO reduction and a lower cost. The Original CSO Reduction Project The original control measure was to install approximately 3,400 linear feet of 48-inch pipe between the DS152 and BRIS. The project was predicted to reduce the typical year CSO by 18 MG, from 28 MG to 10 MG, assuming BRIS had the available capacity. The relief sewer increases the peak flow and volume in the BRIS, increasing the CSO. Upon reevaluating the original control measure with the updated model, it was determined that overflow reductions gained at DS152 were significantly reduced to less than 1 MG due to increased overflow along the BRIS. Due to the BRIS flow increases from the proposed relief sewer, KC Water decided to pursue alternatives using the CD provision for the AMA. Updated GI Project An alternate control measure was proposed to separate approximately 195 acres and provide GI. The discharge from the GI would be downstream of DS152. Simulations show a significant increase in annual systemwide CSO reduction at DS152 and along BRIS. The proposed alternate has a preliminary estimated construction cost of $17M, which is about twice the cost of the relief sewer. However, from a cost-effectiveness standpoint, the alternate control measure cost is much lower based on the cost per CSO gallon removed. The alternative project also provides social justice benefits that were not accounted for in the comparison. At the time of this proposal submittal, the EPA has approved the alternative control measure and the planning work will be completed next year. Conclusions KC Water has used the AMA to cost-effectively substitute the original 2009 OCP interceptor relief control measure with a GI project. While the cost of the green infrastructure project is about twice as much as the originally proposed project, the proposed cost-effectiveness, expressed as the cost per CSO gallon removed, is an order of the magnitude higher than that for the original project, one dollar per gallon of CSO removed compared to almost $9. Additionally, the proposed project in this area would directly contribute to protecting high-risk populations' public health and environment and is consistent with EPA's ongoing commitment to environmental justice.

This presentation will tell the story of modeling completed near Granite Street in the City of Joliet in order to size needed sanitary storage. The traditional RTK Unit Hydrograph method provided unsatisfactory results in calibration, resulting in recommendations that required a lot of modeler's judgment. Many alternative models were considered to improve calibration and the Antecedent Moisture Model (AMM), while relatively untested by industry, was identified as the only model which could really fit the patterns of the flow meter data. This presentation will explain the AMM model at a high level and show how with a more accurate model the City was able to save $8 million in budgeted improvements. The City of Joliet, Illinois operates a combined sewer system. The City has received regulatory pressure to reduce the frequency of activation of its Combined Sewer Overflow (CSO) locations, which discharge untreated sewage to the Des Plaines River during rain events in which the combined sewer system does not have sufficient capacity. In 2010 the City agreed to a Long Term Control Plan with the Illinois Environmental Protection Agency (IEPA) that laid out a five phase plan with the goal of ensuring that by 2023 no CSO location would activate more than 20 times over any 5-year period (which is more or less an average of 4 CSOs per year plus a small factor of safety). In 2020 the City had completed the first three phases and performed additional modeling to check their progress and verify sizing and design details of the remaining two phases. Phase V of the Long Term Control Plan was intended to decrease the activation frequency at CSO 004 which serves the Granite St. basin and tentatively called for a 411,000 gallon storage tank plus a 7,600 gallons per minute (gpm) pump station, which was projected to cost roughly $8 million when indexed for construction costs. Prior modeling had been completed for the system using the RTK method. A majority of the flow in the Granite St. basins has been documented to come from sewer laterals and connected foundation drains, sources that are notorious for infiltration varying dramatically depending on antecedent moisture conditions. Prior modeling had calibrated the model with a focus toward events with the largest flow responses (i.e., the largest events and the ones with the highest antecedent moistures). This intentionally resulted in over-predicting flow responses for smaller events in order to be conservative. But it was not clear how much conservatism was appropriate. In desperately looking for a model method which would provide sufficient accuracy to make recommendations, the author came across the Antecedent Moisture Model (AMM). The AMM model was developed and used by Robert Czachorski for nearly two decades, but only recently were the equations released into the public domain. AMM is an empirically-calibrated method, similar to the RTK Unit Hydrograph method, but whereas RTK assumes a fixed capture coefficient (or percent capture), AMM allows parameters to model variability in the capture coefficient by antecedent moisture and by season. AMM has been particularly successful in modeling sanitary sewer infiltration, for which prior methods perform poorly. In 2021 the model was re-calibrated using the Antecedent Moisture Modeling (AMM) method. The new model allowed for a much better calibration, which adequately predicted both smaller events and larger events. The AMM model successfully represented the increasing percent capture rates for different soil conditions and resulted in a spectacularly better calibration. The AMM method also improved the model's ability to predict seasonal differences in infiltration, specifically the lower response during the dry summer months. After calibration, a long-term continuous simulation was conducted using a 13-year rainfall record at a nearby rain gauge to establish the existing level of protection. The model simulation showed the maximum number of activations of CSO 004 during any 5-year period to be 13, less than the limit of 20 CSOs/5 years. This indicated that Phase V was not necessary and that, as of completion of Phase III, This result was surprising, but additional quality control and comparisons between the two models showed it was reasonable. It appears the months for which meter data was available in 2015 and 2020 displayed larger moisture factors than supposed when compared to the long-term record. This skewed modeler judgment about the needed conservatism when calibrating using the RTK method. Indeed, CSO activation records from the first two years following completion of Phase III show the activation of CSO 004 is in line with the predictions of the AMM-calibrated model. Using the AMM model, which adequately represents antecedent moisture and seasonal effects, allowed modelers to predict CSO activation frequency with much more confidence, which reduced the need for conservatism and showed the Phase V project was not needed at all. The City of Joliet has submitted the findings of its modeling and has received approval to remove Phase V from the Long Term Control Plan, saving the City an estimated $8 million. Figure: A comparison of the two calibrations for the GRANITE-1 meter showing the May 17, 2020 rain event (the largest rain event in the calibration period). The AMM model (red) is a very good fit to the meter data (blue) and clearly represents the increasing percent capture rates as the rain event wears on and soil moisture increases. The RTK model (green) does not adequately model this dynamic.

How do you plan today for significant development, when that development may not occur for 80 years? That was the conundrum facing the City of Kerrville, Texas, as it developed its Water and Wastewater Master Plan. If all the identified growth occurred across the City, total service connections would triple, but the projected buildout would not occur until the 2100 planning period. To address this challenge, the City developed two separate CIPs: one recommending existing system improvements and one recommending improvements intended to serve projected development through the long-term planning horizon. Attendees of this presentation will learn strategies for adapting their master planning process when faced with substantial development potential. The City of Kerrville, Texas, took the initiative to create a road map to proactively plan for the future of the city. The first step of this process was developing and approving their Kerrville 2050 Comprehensive Plan. The next step was performing a Water and Wastewater Master Plan to evaluate, identify, and recommend existing and future infrastructure improvements necessary to serve the anticipated growth. Planning for the future requires an attempt to predict “how”, “when”, and “where” development will occur. The “where” was tackled during the development of the Comprehensive Plan. "Catalyst areas” were identified to predict where development was most likely to occur within the established city limits. Additionally, parcels with known development interest were also identified by the City as potential sources of growth. The Comprehensive Plan, combined with historical water billing data, was utilized to determine the “when” and estimate an annual growth rate based on expected development capacity. Historical billing data could be used to quantify the past annual customer growth and project future growth. Analysis resulted in a projected annual growth rate of 1%, which was also supported by analyses performed during the Comprehensive Plan. However, this created an issue. If all the identified growth occurred across the City, the total service connections would roughly triple and with the estimated 1% annual growth rate, the projected buildout scenario would not occur until the 2100 planning period. The Master Planning team had to consider how to account for growth within a reasonable planning horizon, and then were struck with an idea. Why assume that growth occurs at the same time throughout the City? If one geographic area is developing, wouldn’t it become more attractive to additional development – why not concentrate on planning for growth in separate areas of the City. Thus, strategic “development scenarios” were born. Four “development scenarios” were generated to concentrate the growth geographically relative to existing pressure planes and sewer basins. The development scenarios were utilized to spatially distribute and concentrate the projected growth across the water distribution and wastewater collection system to help assess future capacity and size recommended system improvements. The team was then met with another challenge. Some of the recommended system improvements were triggered solely due to specific large-scale developments. Would it really be fair to the City if they had to budget for an improvement that was reliant on development occurring in a specific area. How could the WEF Collection Systems Conference team best differentiate between projects needed to serve the city in the short-term and projects that would only be triggered with large-scale development? The result of the City’s Water and Wastewater Master Plan became two separate CIPs: one plan detailing recommended existing system improvements to get through today and another recommending improvements intended to serve projected development through the long-term planning horizon. Analyses of the systems were performed for each of these four development scenarios, resulting in the combined growth-driven CIP that provides the City with a long-term plan for the water and wastewater systems. Utilizing separate CIPs will help the City budget, phase, and design their system improvements with both a priority for the existing customers and an eye on future growth. The City can prioritize addressing any existing system deficiencies and still have a plan in place for future growth. The existing system CIP was developed to address existing deficiencies and be implemented over the 25-year planning period. The growth-driven CIP was developed to address both the anticipated growth rate and the identified catalyst and development areas over the long-term planning horizon. The final steps of the City’s utility roadmap are updated rate and impact fee studies to identify potential funding mechanisms for the developed CIPs.

Johnson County Wastewater (JCW) owns and operates a collection system consisting of approximately 2,300 miles of gravity pipe, 40 miles of forcemains, and 60,000 manholes. As the Johnson County Wastewater (JCW) collection system and workforce continue to age, investments in maintenance, repair, rehabilitation, and knowledge transfer to sustain desired service levels and risk tolerances will continue to grow. Increasing investment needs, coupled with limited resources, has driven JCW to continuously improve the efficiency and effectiveness of service delivery while continuing to execute day-to-day work functions. To meet this challenge, JCW and HDR staff collaborated in the development and execution of JCW's Collection System Asset Management Program (CAMP) Implementation Plan which establishes a clear, practical, and strategic path forward. JCW has executed its asset management program through this approach which identifies, prioritizes, coordinates, and schedules continuous improvement initiatives at a manageable pace that strives to balance staff availability and continuous improvement objectives. The Implementation Plan Road Map, reflecting progress from 2013 - 2022 is attached to this abstract. JCW's CAMP is a comprehensive, mature asset management program that encompasses all collection system assets. The program has been in place for nearly a decade, and offers many lessons to share with utilities developing their own programs. The efforts completed through this program have enabled JCW to forecast maintenance, condition assessment, and renewal investment needs with a high level of confidence, justify appropriate investment levels, focus limited resources, increase operational efficiency, and facilitate knowledge transfer. The asset management principles this program is built upon, and the lessons learned during the execution of this program are applicable to utilities of all sizes. This presentation will present the challenges, accomplishments, and lessons learned over the past decade throughout the development and implementation of this ongoing program. The presentation will discuss the development of the program, the utilities activities executed the program, key program initiatives, challenges, and key accomplishments. Program areas include the following: - Pipe inspection and renewal program - Pipe maintenance (cleaning) program - Manhole inspection, renewal, and I/I reduction program - Forcemain program - Low pressure sewer program - Fats, oil, and grease (FOG) inspection program - Stream crossing program The key program accomplishments to date include: - Assessment and documentation of current collection system inspection, maintenance, and renewal practices and development of opportunities for continued improvement. The end result was a multi-year implementation for the Collection System Asset Management Program. This plan is updated on an annual basis. - Development of risk-based condition assessment scores for every asset within the system for which inspection data was available. These were used to develop data driven 10-year CIP projections for system maintenance and renewal along with supporting justifications allowing JCW to increase their collection system funding allotment and redirect funds to higher return-on-investment expenditures. - Development and implementation of automated prioritization tools that apply JCW's business decision making logic to live inspection, maintenance, and asset data stored with JCW's Computerized Maintenance Management System (CMMS) to make decisions and prioritize rehab/repair, inspection, and maintenance investments. These tools were initially developed for pipe renewal and maintenance. Similar automated tools have been developed to execute the structural rehabilitation and I/I reduction program for manholes. - A data driven update to JCW's preventive maintenance cleaning strategy focusing cleaning resources on cleaning pipes at the right time, allowing JCW to clean 'dirty' pipes more often, extend the life of pipes by cleaning 'clean' pipe less often. This allows JCW to clean less mileage each year, while focusing resources on areas where cleaning is needed most frequently. - Integration of JCW's wet weather management, basin planning, and I/I reduction strategies with the asset management program, for both pipes and manholes. - Renewal and operational needs forecasted through the program were incorporated into JCW's 25-year Integrated Plan for capital improvements. Implementation of the Collection System renewal and public sector I/I reduction strategies included in the plan are executed through the CAMP program, and completed in conjunction with wet weather program strategies. - Development of a Manhole Inspection and Renewal Program focused on both I/I reduction and structural renewal. - Implementation of a Forcemain Asset Management Program that addresses the challenges of managing forcemains that vary widely in age, material, and size - Implementation of a Key Performance Indicator (KPI) Plan to measure and document collection system program results, and automated generation of KPIs to regularly track collection system performance. - Implementation of a FOG program to utilize asset management principles to improve FOG management practices. - Development of a customer focused program to utilize technology to notify residents when excessive root growth is witnessed in privately owned service laterals. - Completion of a deterioration rate study of over 600 older VCP and concrete pipes within JCW's system. This study allowed JCW to better understand how quickly pipes within the system are deteriorating and refine long term investments projections in inspection and renewal of aging sewers.

Wastewater AND stormwater infrastructure nationwide are experiencing the effects of age, population growth, funding constraints, and severe weather. Municipal Sewer and Water reports that, 'According to an EPA survey, about 30 percent of [sanitary sewer] pipes are 40 to 80 years old, and roughly 10 percent of pipes are more than 80 years old.' These old pipes are leaking, often undersized and they are prone to clogging. Clean Water Act (CWA) obligations are increasingly requiring municipalities to develop and implement new compliance programs and are compelling changes to interdepartmental/interagency coordination and workflow. Entities involved in sewer and drainage system evaluation and management will find that leveraging seemingly disparate NPDES obligations will result in enhanced capital planning that address both wastewater and stormwater compliance obligations. Siloed NPDES regulatory programs and municipal management entities can drive disparate investigation and investment to meet compliance obligations and asset management needs. NPDES obligations for wastewater entities rely on Sewer System Evaluation Surveys (SSES) to identify problem infrastructure while stormwater entities rely on Illicit Discharge Detection and Elimination (IDDE) among others. Management entities often conduct these programs separately with minimal overlap in data integration and analysis, and they may never integrate their capital investments in renewal and rehabilitation into a cost-effective capital plan that address both exfiltration (IDDE) and infiltration (SSES). There is a better path forward. This session will discuss overlapping Clean Water Act-driven compliance program needs that can improve both stormwater and sewer system master planning. By developing an integrated strategy that incorporates an inclusive understanding of both sewer and stormwater system investigation and maintenance needs, municipalities or management entities can maximize compliance and cost-savings and utilize a 'one-water' approach to help obtain the political support necessary to move improvement programs forward. The presentation will feature a discussion of comprehensive SSES and IDDE programs in detail and utilize several cases studies where integrated wastewater and stormwater program results are allowing a more comprehensive consequence of failure analysis, better prioritization of capital investments, and targeted implementation of rehabilitation dollars. The result is a more sustainable effort that meets multiple regulatory obligations and saves money.

Our presentation will summarize the development and implementation of the forecasting tool for Fort Wayne City Utilities' collection system model. The tool uses an embedded Python script in PCSWMM to obtain the NOAA rainfall forecast and NWS river stage forecast to simulate 48 hours into the future for operational insight. In addition to the forecasting tool, a cloud-based Azure Function was developed to run the model in the cloud and reduce wear and tear on City computers. Fort Wayne City Utilities provides water, wastewater and stormwater to the second largest city in Indiana with approximately 72,200 customers serviced by 1,500 miles of sewers over a 68 square mile service area. City Utilities is presently implementing a combined sewer overflow (CSO) consent decree that will complete in 2025 that includes the Three Rivers Protection & Overflow Reduction Tunnel (3RPORT). As the tunnel and other consent decree projects are brought online, City Utilities needs to leverage its long term investment in hydraulic modeling by incorporating near-term forecasting. Figure 1 presents the forecasting process. The forecasting tool uses an embedded Python script in PCSWMM to obtain the following public domain, free forecasts: 1.NOAA High Resolution Rapid Refresh (HRRR). The 2.5-km, 1-hour resolution forecast provides the next 18 hours of rainfall for the wastewater service area. 2.NOAA Global Forecasting System (GFS). The 20-km, 3-hour resolution forecast provides the next 72 hours of temperature. 3.NWS Advanced Hydrologic Prediction Service (AHPS). The 6-hour resolution forecast provides the next 4-5 days of river stage from multiple gauging stations. Located at the confluence of the St. Marys, St. Joseph, and Maumee Rivers, the collection system is influenced by high river stages. The NWS river forecast is obtained by a simple web scraping technique while the NOAA forecasts are obtained using the MetPy library (Unidata, 2021). The three forecasts are then formatted to PCSWMM's structure, automatically added to the model as rainfall, climate, and river stage time series files, with the model simulation time set to the reflect the forecast period. Figure 2 presents City Utilities' model and the embedded script, which can be used to automatically run the model after obtaining the forecast. The forecasting script was completed in October 2022 and has been utilized by City Utilities staff ahead of storm events. For the October 31, 2022 event, the HRRR forecast ranged from approximately a quarter of an inch to two-thirds of an inch. Table 1 presents a comparison of the modeled forecast to actual metered CSO data. As shown in the table, the actual rainfall was consistent with the NOAA forecast, and forecast model is conservative consistent with City Utilities' periodic comparisons of historical model simulations and outfall metering data. Similar to many combined sewer communities with a Consent Decree, City Utilities frequently simulates a typical 5-year period as part of assessing CSO controls. The 5-year duration has provided challenges to staff running the long-term simulation on their laptops. To ease the burden on City Utilities' staff laptops, an Azure Function was developed to run the model in the Microsoft Azure cloud environment as a lower-cost alternative to a virtual machine (VM). The Azure function loads the model input file from an Azure storage container, runs the model using the PySWMM library (McDonnell et. al., 2020), compresses the model output, and saves it to the Azure container for City Utilities staff to download. The Azure function was completed in October 2022 and is presented in Figure 3. We believe our presentation will benefit any wastewater or stormwater utility with a hydraulic model and interest in forecast modeling or running the model in the cloud, applied hands-on by utility staff. We will present our lessons learned in deploying the forecasting tool and the cloud application and benefits to City Utilities.

PURPOSE This presentation will increase awareness of emerging dual-use auxiliary treatment strategies and benefits (both economic and non-economic) during dry and wet weather along with considerations compared to other wet-weather management strategies. BENEFITS OF PRESENTATION Attendees will learn about pile cloth filters, an innovative enhanced high-rate treatment (EHRT) technology. This technology has proven to be more cost-effective and simpler to construct, operate and maintain than previous generation EHRT technologies, particularly for satellite facilities located in collection systems. STATUS OF COMPLETION Case studies feature completed projects that Johnson County Wastewater (JCW) and Little Rock Water Reclamation Authority (LRWRA) began operating in 2021. BACKGROUND Black & Veatch helped JCW and LRWRA complete major improvements in 2021 to mitigate wet-weather flows and improve treatment capacity and resiliency. Both utilities added dual-purpose auxiliary treatment systems featuring largest-scale units of latest generation pile cloth filters that cost-effectively treat at high flow peaking factors and polish normal dry-weather effluent, providing year-round water quality benefits instead of just during peak wet-weather events. No chemicals or biology required. JCW upgraded its Tomahawk Creek Wastewater Treatment Facility (WWTF) to meet new nutrient limits and expand design capacity to 19 mgd average and 172 mgd peak. New pile cloth disk filters polish effluent up to 57 mgd and provide auxiliary treatment of wet weather flows up to 115 mgd, making it the world's largest capacity dual-purpose pile cloth disk filter installation to date. The improvements are a major milestone in JCW's Integrated Plan to identify, assess, and prioritize infrastructure initiatives and investments. The Kansas Department of Health and Environment authorized the improvements through major modifications to its National Pollutant Discharge Elimination System (NPDES) permit with no objections from the United States Environmental Protection Agency (USEPA). LRWRA added a similar 58-mgd system to its Adams Field Water Reclamation Facility for auxiliary treatment in parallel with 36 mgd of nitrifying activated sludge treatment to bring peak flow capacity up to 94 mgd. When not used for auxiliary parallel treatment, the new filters can polish secondary effluent to increase the performance and reliability of the effluent UV disinfection system. The Arkansas Department of Energy and Environment's Division of Environmental Quality authorized the improvements through NPDES permit renewal with major modifications and no objections from USEPA. A key regulatory consideration was the 2013 decision by the Eighth Circuit of the U.S. Court of Appeals in Iowa League of Cities v. EPA that upheld the practice of parallel treatment and blending. OBJECTIVES To maximize stakeholder benefits, both utilities sought auxiliary facilities that increase wet-weather treatment capacity most cost-effectively and can also polish effluent during normal flow conditions to decrease effluent total phosphorus (JCW objective) or improve operation and maintenance of UV disinfection and support reuse opportunities (LRWRA objective). METHODS AND RESULTS The JCW team conducted applied research and assessments of technologies prior to design and delivery under a construction-manager-at-risk framework. Activities and milestones include: - 2005/7/8 - Jar testing of chemically enhanced settling and ballasted flocculation at the Douglas L. Smith WWTF. Full-scale trials of chemically enhanced settling at the 75th and Nall Peak Excess Flow Treatment Facility. Side-by-side pilot testing of three different high-rate filter technology alternatives at the Nelson Complex (Fitzpatrick et al, 2010). - 2016 -- Conceptual design studies to refine recommended alternatives, project costs and schedule; conceptual level site plan to support public outreach and site permitting; negotiate and finalize discharge permit for new facilities. Results summarized in a Preliminary Design Report. Auxiliary treatment strategy estimated to save over $200M compared to storage and equalization alternatives. - 2018 -- Detailed facility design complete. Pile cloth disk filters selected after evaluation of 60% designs with both pile cloth and compressible media alternatives. Value engineering alternatives save the project over $40M. - 2021 -- Startup and testing of dual-purpose filters demonstrates achievement of specified performance criteria and effluent limitations (see Figure 1). The LRWRA team conducted similar applied research and assessments to support design-bid-build project delivery, which included: - 2001 -- Onsite pilot studies demonstrated performance of chemically enhanced high-rate settling (CEHRS) technologies. - 2016 -- Onsite side-by-side piloting of pile cloth and compressible media technologies demonstrated similar removals as CEHRS alternatives but did not require chemicals, were found to be simpler to operate and control, and improved downstream UV disinfection performance. Conceptual facility designs for five different technology alternatives were evaluated based on economic and non-economic factors. The team conducted further investigations of the top two candidates (ballasted flocculation and pile cloth filtration) including site visits to reference facilities and recommended pile cloth filter technology. The new filter system eliminated 34 million gallons of collection system storage and equalization expansion, immediately saving $10M in construction costs, and was found to be more feasible because it: (1) provides better resiliency by optimizing both storage and treatment capacities, (2) does not limit peak flow management to a finite volume, (3) requires a much smaller site, (4) does not require additional odor control, and (5) has lower life-cycle costs (Fitzpatrick et al, 2018). - 2018 - Detailed designs issued for construction including nitrification and clarification upgrades to existing activated sludge treatment process, new dual-purpose filters, expanded UV disinfection and effluent pump station. - 2021 -- Substantial completion and startup of the improvements (see Figure 2). CONCLUSIONS AND RELEVANCE Results from JCW and LRWRA agree favorably with those found from other auxiliary EHRT applications. Wet weather capacity with EHRT technologies is in many cases more affordable than other storage or treatment alternatives, and their small footprint makes EHRT facilities more feasible for constrained sites in urban and suburban settings, whether located at existing treatment sites or remotely at key points in the collection system. The simple physical process of filter technologies offers operational advantages over chemical and biological alternatives, particularly for remote facilities or intermittent operations. For all practical purposes, EHRT effluent quality is equivalent to that from conventional secondary treatment technologies when treating peak wet-weather flows. EHRT alternatives should not be pigeon-holed into the same regulatory category as traditional 'blending' technologies that achieve primary treatment equivalency. Existing NPDES regulations appear to have the flexibility to further legitimize EHRT technologies as 'auxiliary treatment' facilities within the codified definition of 'secondary treatment' (40 CFR 122 and 133). The U.S. Eighth Circuit Court refers to EHRT as 'non-biological secondary treatment' in Iowa League of Cities v. EPA This regulatory flexibility is critical as integrated wastewater and stormwater utility plans gain momentum and are implemented. Some utilities challenged with water scarcity are considering these same EHRT technologies for stormwater reuse. Over 100 POTWs worldwide operate auxiliary EHRT facilities with the earliest adopters having over 25 years of experience.