Conference Papers

Introduction
As impacts of climate change intensify, changes in land development, weather patterns, and sea levels may result in communities having a greater risk of flooding. State, local, tribal, and territorial governments continue to face pressures as they determine how to address the needs of communities to respond to flood hazards. Furthermore, resources for flood risk and stormwater management are often inequitably distributed even though socially underserved populations experience the worst repercussions. The debilitating impacts of disasters on underserved communities have shifted discussions around how to prioritize equity and social justice considerations for stormwater management. Federal agencies such as FEMA and EPA are reassessing current policies, programs, and practices in the field of stormwater management to examine approaches that alleviate inequities. Recent initiatives from state and local governments to address the needs of underserved communities have also informed the development of federal equity initiatives highlighting the importance of planning for stormwater management. Other relevant national shifts such as the White House Justice40 Initiative which requires 40 percent of the overall benefits from federal investments in climate and clean energy to flow to underserved communities and includes programs such as FEMA's Building Resilient Infrastructure and Communities (BRIC), Flood Mitigation Assistance (FMA) and Risk Mapping Assessment and Planning (Risk MAP) programs. Furthermore, Executive Orders 14008 and 13950 address the need to build resilience against the impacts of climate change with a focus on advancing racial equity and support for underserved communities through the federal government. Based on existing federal funding and requirements prioritizing the needs of underserved communities, this paper explores opportunities for stormwater practitioners to advance equity by strengthening green stormwater infrastructure and planning.

Methods
This policy paper utilized two forms of data collection for this analysis--document review and interviews (n=5) with individuals working on stormwater management at the state, local and federal levels. The document review consisted of peer reviewed and grey literature (n=40) and a survey of existing equity tools (n=15) that can inform stormwater management practices. We also collated best practices from state, local and federal case studies (n=8), and recommendations on strengthening equity considerations for stormwater management. Further analysis included examination of community and stakeholder engagement by state, local and federal governments to address environmental justice and equity.

Discussion and Recommendations
This presentation will use examples from the aftermath of Hurricane Ian (Florida, September 2022) and Hurricane Fiona (Puerto Rico, September 2022) to demonstrate the importance of applying an equity lens before, during, and after disasters to address the needs of underserved communities. It will also provide an overview of current state, national and federal initiatives, such as the White House's National Initiative to Advance Building Codes, FEMA's Building Codes Strategy, Building Codes Adoption Tracking Portal and the Climate and Economic Screening Justice Tool to examine opportunities to enhance stormwater management that incorporate considerations for equity and environmental justice. There is limited analysis comparing cases studies across the state, local and federal government that are moving the needle on equity and environmental justice for stormwater management. By examining frameworks that are prioritizing historically underserved communities in all processes of stormwater management, stormwater practitioners can use these tools to strengthen community engagement and equity in planning.

Summary The pandemic hit Englewood at a time of dynamic change. Under new leadership, the City's Utility Department was in the midst of developing innovative solutions to address the aging water and wastewater infrastructure while maintaining customer affordability. Transformational change was necessary to establish a new baseline for level of service, and nothing was left untouched from the planning philosophy, prioritization of capital projects, financing alternatives and major adjustments to utility billing. Even the communication to City Council and the Water and Sewer Board was adapted to garner support for the City's new approach from the governing bodies and ultimately from customers. A series of informational presentations were made to City Council following the development of the master plans, and coupled with the financial evaluation, the case was made towards a defendable adjustment of rates and fees with a plan to invest over $140 million in the systems over the next five years. Addressing capital needs, taking advantage for new types of funding, implementing major changes to billing structure and procedures, and evaluating the impacts on customers, all hinge on a utility's ability to analyze the past and develop meaningful projections of the future. Englewood was able to accomplish its objectives in spite of the disruption introduced by the pandemic, and the results may be instructive to utility managers coping with similar disruptions in the future. Abstract The City of Englewood, Colorado serves about 11,000 water service connections and over 40,000 sewer service connections in areas just south of Denver. The City's water and sewer utilities survived for many years with little to no rate adjustments, but with significant capital investment needs uncovered by the City's master planning process, the City engaged in a financial planning and rate study process to meet its long-term financial obligations. The master plans resulted in a Capital Improvement Plan for the water and sewer systems that programmatically addresses the City's largest vulnerabilities. Prioritization of capital investment and optimizing operational strategies of the existing systems were important steps to develop a feasible and affordable plan. The City implemented a long-term financial plan incorporating debt and cash funding opportunities supported by modest, annual rate increases to maximize the Utility's financing capacity. The financial planning and rate studies (yes, multiple rate studies) included evaluation and implementation of a new water rate structure, tapping into all available financing tools, and transitioning from quarterly billing to monthly billing for many customers. This presentation will introduce each area of innovation the City considered in its financial overhaul. The master plan 'wish list' and the process City staff used to narrow down key desirable projects, such as lead service line replacements and water taste and odor improvements, will be described. The dynamic financial planning process will demonstrate how master planning and financial planning go hand-in-hand, especially in a time of disruption in customer demands. Further, financing decisions and the detailed process of applying for a WIFIA loan, will be described with a focus on data needs and on the management implications to the utility. Key decision points and lessons learned will be discussed and offered. Technical Content Through the use of dynamic financial tools, impacts of master plans, funding decisions including use of a Water Infrastructure Finance and Innovation Act (WIFIA) loan, converting flat rate water customers to volumetric billing, implementing a new billing system, and changing base billing practices from quarterly to a monthly schedule and customer bill impacts were evaluated. The City's consultants worked closely with City staff to customize financial forecast that minimized impacts on customers' bills. The Water and Sewer Board reviewed each step of the process prior to City Council consideration and acceptance. Project Status The Master Plans were developed in 2019 for the Water Fund and Sewer Fund, as well as for South Platte Renew, the water resource recovery facility co-owned with the City of Littleton and the third largest wastewater treatment facility in Colorado. Rate studies for South Platte Renew and the City's water and sewer funds were completed in 2020. The water rate structure was materially modified with a new monthly Capital Improvement Fee and increases to the variable charges. Moving into year three of implementing this change, budgets and rate increases for 2022 will be implemented, the WIFIA loan is expected to be closed in early 2022 and major components to the capital investment will be underway at the time of this presentation. Benefits and Significance Not every utility has access or the means to completely evaluate its financial sustainability. The City of Englewood proves a small to medium-sized system can thoughtfully change its approach to planning, structuring, and recovering costs. Further, the project demonstrates the ability of a focused process to achieve substantial change in the face of operational disruptions and uncertainty regarding changes in usage patterns. Finally, it demonstrates the ability of a project team to increase financial resilience while successfully maintaining a focus on affordability implications. Additional Co-Authors: Roger Austin, Vice President, Hazen and Sawyer Carol Malesky, Principal, Stantec Consulting Services Inc. Siyuan Rao, Senior Consultant, Stantec Consulting Services Inc.

The land application of biosolids has provided nutrients and organics to agricultural land for decades. More than half of the solids generated in the United States during water reclamation are stabilized and beneficially used as soil amendment. The use of biosolids reduces dependence on inorganic fertilizer, increases the organic content of the soil, provides a low-cost and locally produced fertilizer to the agricultural community, reduces greenhouse gas emissions and sequesters carbon. Historically, biosolids application rates have been calculated almost exclusively on the nitrogen (N) content in the biosolids and the manner in which the biosolids were managed, surface applied, or incorporated into the soil. Basing application rate on nitrogen alone can result in applying phosphorus (P) beyond the crop's agronomic requirements. Like all fertilizers without an adequate buffer to surface water and depth to groundwater, a portion of the phosphorus applied may enter the ground or surface water. In an effort to limit the over-application of phosphorus, a number of states, including Florida, are requiring the development of nutrient management plans. These plans require the determination of the agronomic phosphorus application rate along with the one for nitrogen. The plan is for the application rate to be controlled by the more stringent of the two. Some states require soil monitoring and calculating the total cumulative amount of P that can be applied based on the Cationic Exchange Capacity of the soil. Recent regulations in some States have begun to use the percent Water Extractable Phosphorus (WEP) in estimating the agronomic rate for phosphorus application. Some States use the monitored data. The State of Florida uses multiple methods of calculating the agronomic P application rate depending on the percent WEP, above or below 14.5% WEP. The St. Johns River Water Management District, supported by the State of Florida Department of Environmental Protection (FDEP), has initiated a project titled 'Resource Enhancement and Recovery of Domestic Wastewater Residuals'. The objective of this project is to identify and evaluate technologies to recover the phosphorus (P) in biosolids, reducing the amount in the beneficially used material. The project includes: 1. Evaluate existing technologies and assess regional needs. 2. Review empirical data from technology vendors to quantify expected P-recovery performance. 3. Compare feasible technologies based on cost, performance, and capacity. This project was conducted in three separate tasks. This presentation describes the overall project with a focus on the modeling and technology comparison tasks, which were Tasks B and C. Task B included the identification, screening and evaluation of proven and promising P-recovery technologies that may recover P and reduce the content in biosolids. Twenty P-recovery technologies were screened using criteria established by the project team and the District. Following the screening of the preliminary technologies, a total of four were selected for further evaluation. The task also reviewed the impact the composting and thermal drying have on phosphorus availability. Task C included the modeling of four P-recovery technologies at two Water Reclamation Facilities (WRF) in the State. Both facilities use biological nutrient removal processes for their liquid stream treatment. One WRF anaerobically digests the solids generated during treatment. The second uses aerobic holding, which provides a degree of aerobic stabilization. Each of the selected P-recovery technologies was modeled under both treatment and stabilization scenarios. The model output allowed the project team to estimate the comparative phosphorus recovery rates. Another objective of Task C was to understand the opportunities and challenges associated with implementing a P-recovery technology. This included a cost estimate to implement P-recovery at a set capacity and the impact the technologies could have on the phosphorus concentration in the facilities' biosolids. The evaluation also used non-monetary criteria to identify the technologies that can support a wide range of WRRFs throughout Florida. The project included the development of an educational document to inform policymakers and regulators in the State of Florida regarding the benefits of biosolids and the technologies available to support that use, including P-recovery technologies. This presentation provides a summary of the work performed as part of the project and the recommended steps in support of beneficial use of biosolids in the State of Florida.

Charlotte Water, located in Charlotte North Carolina, is the largest sewer utility in the Carolinas with approximately 4,500 miles of gravity sewer. Charlotte has been implementing a substantial and aggressive long-term sanitary sewer maintenance and rehabilitation program to reduce sewer system overflows (SSOs), correct historic maintenance problems, and reduce infiltration and inflow (I/I) into aging sewers. Charlotte Water was placed under an EPA Administrative Order in 2007 mandating the reduction of sanitary sewer overflows (SSOs). Charlotte developed a systematic and comprehensive sewer maintenance and rehabilitation program to address the Administrative Order. Due to the success of Charlotte's program, EPA lifted the Order in 2012, five years after it was issued. Maintenance and Rehabilitation Program Direction and Approach With the Administrative Order, Charlotte was faced with expanding their program and expediting the SSO reductions. Over the last 15 years, Charlotte Water has been rehabilitating their sewer system to address known maintenance issues and structural defects and to remove inflow and infiltration (I/I). Charlotte has developed a very specific, systematic maintenance and rehabilitation program and approach to renew and restore the sewer system. Charlotte's program approach has been focused on targeting known SSO areas and expediting the identification and prioritization of sewers to be rehabilitated and cutting out the lengthy review, analysis, evaluation, and reporting that is often done by municipalities that are implementing similar programs. Charlotte's sewer problems were obvious there was a list of known maintenance issues, there was a list of repeat backup areas and customer complaints, and there was detailed information on where sewer system overflows (SSO) were re-occurring that clearly showed high-density SSO problem areas. With all of these known and obvious problems, Charlotte had a very clear direction for their maintenance and rehabilitation program. Charlotte moved immediately to implementing a sewer rehabilitation program to repair the known and obvious problems while systematically implementing improved and targeted maintenance measures focused on fixing the problems, instead of proceeding along a 'traditional' approach of prolonged, expensive engineering evaluations, studies and reports. Program Components Charlotte has been systematically implementing their sewer maintenance and rehabilitation program over the last 15 years. The key components of their program include the following: 1.Implementation of a find-and-fix sewer rehabilitation approach to fast-track sewer rehabilitation construction every year. Charlotte's sewer rehabilitation budget is currently about $25.5 million. Charlotte performs three find-and-fix rehabilitation projects yearly totaling approximately $10 million per year to rehabilitate their 8' to 24' sewers. Separate large-diameter rehabilitation projects are also performed every year at a typical budget of $6 million per year. In addition, Charlotte's maintenance department manages a $1.5 million per year maintenance rehabilitation contract to repair issues identified by Charlotte's in-house crews. Charlotte follows the find-and-fix approach exclusively to rehabilitate their sewer system. The find-and-fix rehabilitation approach quickly and efficiently targets the sewer areas/basins with the highest density of SSOs. This targeted rehabilitation approach directly eliminates SSOs. 2.Implementation of a significant root control program, treating over one million feet of sewer every year. This root control program is believed to be one of the largest in the country. Roots have been a major reason for SSOs in Charlotte's sewer system. 3.Implementation of enhanced and increased sewer cleaning and television inspection efforts. The increased efforts included increased assistance from outside contractors as well as significantly increasing Charlotte Water's maintenance staff and equipment. Many of Charlotte's SSOs are caused by debris, roots, grease, and sags in the sewers, so the increased cleaning efforts directly eliminates SSOs. Charlotte Water also implemented a siphon cleaning contract to clean all of their existing 56 siphons every year, with the problematic siphons being cleaned twice per year. 4.Implementation of a targeted 'right-time' cleaning program to focus cleaning efforts on the sewers that actually need cleaned. The targeted cleaning approach efficiently utilizes the sewer cleaning crews' time and focuses the work where it needs to be done. 5.Implementation of a Smart Cover flow metering network to monitor sewer levels throughout the system. Smart Cover meters are level-only meters installed in manholes to measure wastewater flow levels. Charlotte currently has over 400 Smart Covers throughout their system and will be increasing their network to over 500 meters in 2024. When the Smart Cover meters transmit a high level alarm in the manhole, Charlotte Water crews mobilize to clean the sewers before an SSO occurs. 6.Implementation of a Multi-Sensor Inspection (MSI) program to evaluate Charlotte's largest sewers and most critical assets. A 5-year $5 million MSI inspection program will begin in 2024. Proven Success Charlotte has reduced SSOs by over 75% since 2007, an unprecedented reduction of SSOs in a relatively short period of time. Charlotte met the terms of their EPA Administrative Order by 2012 (within 5 years) due to the success of their find-and-fix sewer rehabilitation program and their enhanced operation and maintenance efforts. Charlotte has quickly and systematically fixed problems instead of studying problems. Charlotte has completed over $150 million of sewer rehabilitation construction work over the last 15 years following their find-and-fix approach. And on top of all of these significant successes, Charlotte has saved over $15 million in engineering and construction costs by following their find-and-fix approach. This presentation will review Charlotte Water's systematic and comprehensive sewer maintenance program and find-and-fix sewer rehabilitation approach/concept in detail. The presentation will detail how various maintenance programs were developed and are being implemented, how priorities are quickly developed without prolonged study and analysis, how the program is implemented including the find-and-fix construction projects, and the benefits of the approach. Documented successes, results, and the significant cost savings will be presented. And most importantly, the presentation will clearly detail how any utility can develop and follow a similar program and achieve similar results, including sharing years of lessons learned and tweaks made to the program to further achieve success.

Since January 1999, Onondaga County, New York has been complying with an Amended Consent Judgment (ACJ) which includes control of combined sewer overflows (CSOs) to the tributaries of Onondaga Lake. In November 2009, the ACJ was again amended to incorporate green infrastructure (GI) strategies to further reduce wet weather from entering the combined sewer system (CSS) along with requiring other upgrades at the Metropolitan Wastewater Treatment Plant (Metro). This was the first court order in the country to require the use of GI, and the new program was named Save the Rain. Since 2009, Save the Rain has resulted in the construction of over 230 GI projects and more than 10 large-scale gray infrastructure projects and four small-scale, yet significant system optimization projects. Overall, the County has achieved the remarkable milestone of 98.1% CSO capture and elimination to date while also significantly improving water quality in Onondaga Lake and it's CSO-receiving tributaries and increasing resiliency in the combined sewer system. This presentation will highlight how utilizing both GI and gray infrastructure has provided the County with the opportunity to not only abate CSOs, but also increase conveyance capacity and resiliency in a combined sewer system that dates to as early as the 1850s. Discussion topics will include: - The County's standards for enhanced CSO abatement design including over-designing systems to ensure that they are designed for managing the storms of today and the future. In an ever-changing world due to the effects of climate change, the County's efforts to plan ahead to design for the storms of the future are an excellent example of building resilience into conveyance systems. - Stormwater quantity monitoring results of completed GI projects indicating greater than expected performance. Volumes into and out of several GI projects were metered to demonstrate GI's performance to the regulators. Findings from the metering period versus the original design intent will be provided along with a summary of the important conclusions that were made regarding the effectiveness of GI. - How the inclusion of GI allowed the County to decrease their total financial commitment without sacrificing CSO abatement goals. GI has been found to be more cost-effective than traditional gray infrastructure in the County's CSO abatement program. By constructing more GI, the overall program expenditures have been less than originally budgeted allowing the County to do more and go further with the program. The specific cost savings of GI vs. gray infrastructure will be provided allowing the attendees to takeaway information that will be extremely valuable for their own stormwater and CSO programs. - Oversized design of the Clinton and Lower Harbor Brook CSO Storage Facilities providing a total 11.4 MG of CSO storage. By oversizing these two facilities the County has planned for the future with larger facilities capable of managing larger storms. Examples will be provided for larger storms that have occurred since the facilities were operational showing the benefits of oversizing the facilities. - The financial impacts of oversized GI and gray infrastructure designs and how the County creatively managed available funding to the greatest extent possible. - Other methods developed by the County for resourcefully increasing capacity within the combined sewer system including required stormwater offsets for private development. Within the combined sewer system, the County requires a 2:1 offset. That is, for every 1 gallon of sanitary flow added to the system, 2 gallons of flow must be removed. Developers have been creative in meeting this requirement by installing GI, lining sewers, lining manholes, gray water usage. - Projections of system performance during extreme events and future climate change utilizing the County's combined sewer system SWMM model. The SWMM model has been an incredibly useful tool for planning projects and assessing system performance. The methods in which the model has been utilized along with results will be provided.

Polk Regional Water Cooperative (PRWC), a collective of 16 member utilities operating in Polk County, FL, formed for the sole purpose of developing reliable, sustainable, and cost-effective alternative water supplies (AWS) to meet future demands in central Florida. As population grows in the region, so does the need to diversify away from the heavily relied-upon Upper Floridan Aquifer and towards AWS projects that are innovative and sustainable. With these unique AWS projects also comes additional treatment and disposal challenges - or opportunities - like what to do with the residual gypsum produced as a byproduct at PRWC's first treatment facility. Design is currently underway for PRWC's first AWS project, the Southeast Lower Floridan Aquifer (LFA) Wellfield and Water Production Facility, a 7.5 million gallon per day (Phase 1) reverse osmosis (RO) water treatment plant (WTP) in Lake Wales, FL. During early stages of the design, Carollo and its team of subconsultants identified that the RO concentrate stream will contain calcium sulfate levels four times saturation and will need to be pretreated prior to disposal via deep injection well (DIW) due to concerns of irreversibly plugging the calcium sulfate-saturated injection zone. Without pretreatment, the calcium sulfate precipitate will plug the well and irreversibly reduce its permeability and therefore injection capacity. Based on early discussions with equipment manufacturers and bench scale proof-of-concept evaluations, a process was tested to precipitate, thicken, and dewater calcium sulfate dihydrate (gypsum) into an ultra-high-purity end product, adapting treatment technologies typical in flue gas desulfurization (FGD) at power plants. The process will reduce the CaSO4 concentration in the supersaturated concentrate stream by approximately 75% (back down to, or below, normal saturation levels). Horizontal vacuum belt filters (HVBFs) were selected for dewatering due to their ability to dewater mineral slurries to achieve up to 90% solids in cases of high loading rates. HVBFs are not commonly found at municipal WTPs, yet they are an industry standard for dewatering FGD gypsum at power plants nationwide and are regularly used in the phosphate, mining/aggregate, and metals processing industries. To the engineer's knowledge, this is the first installation for this type of equipment and application at a municipal WTP in North America. It's estimated that the plant will produce approximately 23,000 dry tons of gypsum per year in Phase 1 and double that at buildout. This equates to more than 75 tons of dewatered gypsum daily. This natural gypsum has advantages over synthetic gypsum potentially containing high radionuclides and heavy metals generated from making phosphate fertilizers (phosphogypsum) and heavily contaminated FGD gypsum produced as a byproduct at coal-fired power plants. Rather, the gypsum produced at SE WPF will be an ultra-high-purity gypsum product useful in various industries. What options does the utility have to dispose of this gypsum? Avoiding landfills by giving it away would save this young cooperative $2.5 million dollars per year in Phase 1 alone in hauling costs. Better yet, can this beneficial resource be refined, marketed, and sold to other industries to offset operational costs for PRWC in a period of rising construction and operation costs worldwide? While the majority of gypsum produced in the US is used in manufacturing wallboard or plaster, it is also used in concrete mixes, as a soil conditioner, in food processing (e.g. tofu), in toothpaste, or even brewing beer and winemaking. The degree of final treatment for the WTP is dependent on the desired (and available or practical) end use. This presentation will highlight the design, operation, and disposal considerations associated with various end uses for the gypsum produced at the SE WPF, and one utility's challenge to turn an otherwise costly problem into a beneficial, recoverable product and source of meaningful revenue. This will include: - An overview of the SE WPF gypsum desaturation process (Figure 1), with focus on dewatering and solids handling. - Market analysis and survey of the end use/disposal options for other similar gypsum residuals in Florida and their individual quality requirements. - Design modifications to meet those requirements. - Comparison of life cycle costs for each treatment and end use scenario.

Our linear infrastructure requires regular maintenance, refurbishment, upgrades, and sometimes. replacement, for it to continue to effectively serve our communities. In order to properly care for this aging infrastructure, sewage bypass projects are frequently a critical component of many of these linear infrastructure projects. Temporary bypass systems is the typical solution to transfer water and sewage flow and maintain uninterrupted service during the necessary bypass of the existing infrastructure. The unfortunate side effect of this type of bypass project is frequently an increased release of hydrogen sulfide and other sewer gasses. These gases can cause a nuisance for the surrounding community via increased odor release. Also important, these gases can cause corrosion to concrete, metals and electrical components not intended to be exposed to sewer gases, potentially shortening the useful life of critical infrastructure. Most critically, however, Hydrogen Sulfide and other sewer gases are frequently found at concentrations toxic to human health, frequently reaching fatal concentrations in sewer systems. Open access points in sewer network, plus additional turbulence at the downstream discharge point all contribute to increased exposure to the environment of the gases that would otherwise be contained within the sewer system. Sulfide control at bypass pumping has traditionally involved a fan and undersized activated carbon canister that requires frequent replacement. There are a range of better suited solutions that can be implemented to effectively manage the sewer gas releases challenge. This paper will discuss the challenges of designing and implementing a sewage bypass pumping service and the merits of implementing effective sulfide control measures for any bypass operation including the use of liquid phase chemical treatment and foul air scrubbing technologies. The available technologies will be reviewed, and examples of best practice application will be discussed. There is no single perfect solution for sewer bypass sulfide control, and the appropriate technology combination is often project specific. The vapor phase technologies suitable for bypass pumping most commonly include appropriately sized activated carbon systems and packaged biofiltration technologies. Other vapor phase technologies such as chemical scrubbing may not be suitable due to the complexity of operation and project site requirements but may suit some specific bypass pumping sulfide challenges. In addition, either instead of or supplemental to the vapor phase technologies, a range of liquid phase technologies can be utilized to reduce the release of the sulfides into the gas phase, thereby improving the work environment for those involved in the upgrade project and making the management of sulfide gas release less challenging. These liquid phase technologies include sulfide capture, alternative biological oxygen sources, fast acting oxidants and pH adjustment technologies. The reader will learn that a comprehensive sulfide control strategy allows for the effective mitigation of hazardous, odorous and corrosive sewer gasses, minimizing the impact to our communities during maintenance or capital improvement activities both at the project site and at downstream discharge points.

Purpose: Lift stations and force mains are essential to any wastewater collection system. Lift stations and associated force mains operate in a highly corrosive environment, typically subjected to widely fluctuating flows and pressure surges that affect force main integrity. Lift station and force main design seeks to avoid common damage modes, including H2S-induced corrosion and solids accumulation, but rarely benefits from the physical assessment of the installed and operating system to evaluate design robustness. The current study outlines the design and operational enhancements of lift stations and force mains as identified during the condition assessment of Lift Station 43 (LS 43) in the City of Phoenix (City). The City owns and operates 28 lift stations and approximately 72 miles of force mains, including approximately 62 miles of 12-inch and larger force mains. A comprehensive condition assessment of the LS 43 force main was performed as part of the city's ongoing efforts to understand and minimize the risk associated with buried infrastructure. The LS 43 force main conveys wastewater approximately 1.5 miles from LS 43 on 75th Avenue south of Southern Avenue along 75th Avenue to Broadway. The force main has three barrels constructed of 24-inch diameter ductile iron pipe referred to as Barrels 1, 2, and 3 and experienced two breaks associated with air accumulation. A comprehensive assessment was completed, including hydraulic modeling, CCTV, and electromagnetic (EM) inspection. The study's results can be adopted to improve the service life of not just LS 43 but any future lift station and force main. Benefits: The LS 43 assessment identified best practices to improve lift station and force main hydraulics and service life. By utilizing hydraulic modeling with different pump states, the assessment identified the areas of negative pressure and gas buildup. The results of hydraulic modeling were confirmed via CCTV assessment, which showed the presence of a miscellaneous waterline in the force main. This revealed that incorrect ARV placement obstructed the efficient functioning of the lift station and force main. This presentation will benefit that industry by outlining the factors contributing to air accumulation and remedial measures to address the concern. The presentation will also discuss design modifications such as the location and elevation of air release valves (ARVs) and the type of ARVs the industry should adopt to improve the life of the force mains. Additionally, EM assessment determined internal corrosion below the springline caused by solids accumulation, an infrequently considered damage mode for ductile iron pipe in force main service. Suspended solids in wastewater can settle in the force main and develop areas of microbially induced concrete corrosion (MICC). Efforts to allow for maximum future capacity in the initial design had resulted in low velocities and solids accumulation. Cleaning tools are regularly employed to dislodge accumulated solids, but the lift station and force main designs rarely allow for easy launch and retrieval of a cleaning tool. Additionally, there is no clear guideline on the cleaning frequency to improve the system's service life and reduce operational costs. The study aims to discuss the velocities needed to prevent solid accumulation, as well as the frequency and essential design modifications necessary to support regular cleaning. The recommendations presented in this study can be applied universally to any lift station and help the industry develop designs with cleaning and maintenance requirements in mind. Status of Completion: The investigation work to address ongoing air accumulation and internal corrosion issues is 100% complete. Results indicated the flow velocities and cleaning methodologies the City should utilize to prevent further internal corrosion and location for ARVs installation to prevent air accumulation. The City is in the process of procuring a consultant to design the recommended improvements. Conclusion: The City will now be able to allocate necessary funds for regular force main cleaning, identify locations of concerns, conduct regular maintenance, improve lift station efficiency, and improve service life. In conclusion, the study has identified best practices to improve lift station and force main hydraulics and service life. These best practices can be used to improve future force main designs.

In 2018, the Indiana Department of Environmental Management (IDEM) in partnership with the Indiana Finance Authority (IFA) developed state requirements that required both water and wastewater utilities to implement an asset management program (AMP). IFA produced an asset management (AM) guidance manual for utilities to follow to demonstrate technical, managerial, and financial capabilities. This presentation will walk through Evansville Water and Sewer Utility (EWSU) condensed roadmap and lessons learned to implement a best-in-class AMP that aligns with IDEM and IFA developed requirements. In 2018-2021, with limited resources and funds, EWSU began to implement an AMP to meet their needs and the state requirements. In 2020 EWSU conducted a SAM-GAP assessment as well as a gap assessment based on the IFA guidance manual. These results were used to develop a roadmap of tasks they would like to have completed over the next couple years. In 2022, EWSU recognized it was a critical time to meet new AM requirements and plan appropriately for a renegotiation of an affordable Integrated Overflow Control Plan (IOCP). EWSU saw the 2023 IOCP deadline approaching quickly and had to act fast. Suddenly a 5-year roadmap turned into a 2-year condensed plan. There are three focus areas in the first phase of EWSU's roadmap: Cityworks and GIS Support Modifications and enhancements to Cityworks and GIS were necessary to support the AM data needs and decision making. AM Gap Closing Closing technical gaps was a major outcome of the gap assessment performed in 2020. During this phase of the project EWSU successfully established the following: Preliminary budgets for water and wastewater (vertical and linear) based on risk. Leveraged dashboarding to visual risk which allowed EWSU to balance cost, risk, and level of service to meet the customer's needs. Developed a prioritized water and wastewater (vertical and linear) Capital Improvement Plan (CIP). Performed a multi-year financial analysis to determine the CIP's impact on rates. The creation of documentation to meet IDEM's AMP requirements. Master Planning (MP) This phase of the roadmap consisted of the evaluation and documentation of the existing and future demands to determine any system deficiencies through the MP process. During this phase of the project EWSU successfully established the following: Water Distribution Model Calibration American Water Infrastructure Act and Safe Drinking Water Act Compliance Review WWTP Model Review and Alternatives Evaluation Wastewater Collection System Analysis Water and wastewater (vertical and linear) MP CIP EWSU's has developed a defensible and data driven 20-year CIP includes AM, MP, and consent decree needs to provide regulators with a thorough understanding of financial requirements and vulnerabilities during the renegotiation of their IOCP. While achieving their end goal they have built a best-in-class AMP.

Learning Objectives 1.Summarize the developments that have led to creation of sewer ventilation models. 2.Explain the steps required to build and calibrate a sewer ventilation model. 3.Show an application for using the ventilation model to size an odour control unit. Introduction Sizing air extraction for vapor phase odour control is a difficult task often leading to large safety factors and oversized equipment. Fan testing can be used to determine flow rates more accurately; however, it is a costly exercise that often only captures a limited range of wastewater flow conditions. Sewer ventilation modeling has evolved to accurately predict air extraction rates and optimum locations for installing odour control. This paper discusses the history of sewer ventilation modelling and presents case studies demonstrating applications of ventilation modeling for odour control in sewers. Development of Ventilation Modelling In 2007 the Water Environment Research Foundation undertook a review of all published literature on sewer odours and corrosion. Sewer ventilation was found to be the subject in most need of further research (Apgar et al, 2007). Field tests using tracer gas were used to measure air flows in large sewers leading to a proposed conservation of momentum approach to natural ventilation with the air/water interface modelled as flat plate with a drag coefficient. However, the drag coefficient value was unknown. (Witherspoon, 2009) In 2011 the Australian research Council initiated a project to determine the interface drag coefficient. This work culminated in a model for calculating air pressure and flow in a linear sewer network (Ward, 2011), subsequently, flat plate drag coefficients were measured in laboratory-scale studies at the University of Aalborg (Bentzen,2016) for use in the conservation of momentum method. In 2020 a software tool was developed capable of solving air pressure and ventilation in large, branched sewer networks, including representation of air extraction fans, and then overlay the ventilation results in sewer process models (Ward, 2022). Work is continuing to better represent how drop structures impact ventilation rates. The ability to overlay this ventilation model with the sewer process model allows for more accurate estimation of headspace H2S concentration and the required airflow rates to maintain sewer headspaces under negative pressure. Two case studies are presented where this methodology is applied. In one, the client was able to make changes to the sewer network prior to completion of design, and in the second, odour control systems were sized without the need for costly fan testing. Case Studies Region of Vaughan New Trunk Sewer Construction: The region of Vaughan, part of the Greater Toronto Metropolitan Area (GTA) is constructing a new major truck sewer, Jane St Trunk, and twinning portions of existing trunk sewers, Keele Langstaff. The trunk sewers will provide sufficient capacity to service the projected growth in Northeast Vaughan to the year 2051. Sewer process models and overlaid ventilation models were developed for 2024 (completion of the Keele-Langstaff segments) and 2028 (completion of the Jane St segments) growth scenarios. These time frames represent the lowest flow scenarios, i.e. highest sewer detention time, which are the conditions most susceptible to sulphide generation and potential odour release. Sampling took place to allow calibration of the models. A comparison measured versus modelled data will be detailed and as well as assumptions that were made during calibration. The major finding of the study was that the planned dropped structures along the Jane St Trunk caused sulphides to be stripped from the water into the gas phase, leading to elevated levels of H2S, see Figure 1. The ventilation model predicted the trunk would operate at a slight negative pressure due to the drag forces and closed nature of the sewer (minimal laterals and openings to atmosphere) with in gassing (negative pressures) at each maintenance hole/drop structure, creating a scenario in which the odours would not escape to the ambient environment. However, the region has had issues with corrosion at drop structures and the H2S levels were high enough for the region to request a redesign of the Jane St Trunk to mitigate H2S release and corrosion. The sewer design work is currently underway. Following its completion, the sewer process modelling will be recompleted. Adelaide Trunk System Odour Investigations: 18 of the 21 odour control facilities in the Adelaide Trunk system have been turned off to avoid odour complaints, resulting in a lack of ventilation along the system. The lack of ventilation has been identified as a major risk to a significant asset with severe corrosion consequences. Sampling took place to calibrate sewer process models and an overlaid ventilation model. The calibration of the ventilation model provided numerous challenges due to the large headspace in the main trunks resulting in slight pressures during sampling, uncertainty of the state of repair of large curtains pervious installed in the network to assist with zoned ventilation control and a siphon located close to the edge of the modelled domain. The zone of influence from the current fans was found to be minimal and reinstatement of decommissioned fans was not considered a suitable solution to the systemic odour and corrosion issues in the Adelaide Trunk system. Recommendations from the modelling will be discussed including recommended chemical dosing, lining sections of the trunk sewer and installing a large odour control unit in the vicinity of a new development, see Figure 2. Conclusions The development of a ventilation model which can be overlaid on a sewer process model is a value tool for accessing the generation and release of odours from the collection system and sizing odour control fans.

INTRODUCTION: This case study offers valuable insights into innovative sewer control techniques, emphasizing the management of a high-flow 48-inch diameter public interceptor sewer. It illustrates how combining bypass operations, including flow-through plugs and multiple pumping systems, can address complex challenges effectively to avoid a 'sewage river' on the Las Vegas Strip. The study serves as a testament to the adaptability and efficiency required to ensure smooth sewage control and construction in a demanding urban environment with high visibility. Furthermore, it highlights the importance of meticulous project planning and the ability to navigate multifaceted obstacles. It demonstrates the critical role of problem-solving and showcases how the careful coordination of diverse operations can lead to the successful execution of development projects. BENEFITS: WHAT YOU WILL LEARN: 1.Innovative Sewer Control Techniques: This case study offers a comprehensive understanding of sewer control methods used in managing a high-flow public interceptor sewer system. It explores forward-thinking strategies, including the combined use of sewer bypass methods such as flow-through plugs and multiple pumping systems. 2.Project Planning and Problem Solving: This case study sheds light on how complex challenges can be addressed through meticulous project planning to overcome construction obstacles including highly congested roadways, limited space, complex geotechnical conditions, and critical timelines. It illustrates how careful coordination of various operations can lead to successful development projects. 3.Effective Public Infrastructure Management: The study highlights the adaptability and efficiency required for public infrastructure management, especially in densely populated and high visibility areas like the Las Vegas Strip. STATUS OF COMPLETION: This case study delves into the implementation of an innovative and strategic approach to ensure efficient sewage control in a high-flow public interceptor sewer located on the iconic Las Vegas Strip. The Developer was presented with the formidable task of accommodating the construction timeline of a new Las Vegas Strip resort, compounded by the concurrent aggressive Formula 1 track paving schedule. The challenge to overcome was timing so a solution was devised to relocate the point of connection for the new resort to core into an existing manhole instead of a cast in place manhole that would have avoided the complex bypass pumping system that now became a reality. The solution not only saved invaluable time but also circumvented the complexities of groundwater removal and permit requirements, thereby preventing potential construction delays and ensuring the critical Formula 1 track paving deadline was met. As the case study unfolds, it becomes evident that the existing sewage flows within the interceptor sewer exceeded the capabilities of a simple flow-through plug. This realization necessitated the adoption of innovative sewer bypass methods to ensure sewage control, even in the face of extreme volumes. The pivotal solution encompassed a comprehensive sewer construction process that began with the installation of onsite sewer components, followed by offsite sewer components, and culminated with coring into the existing manhole. To complete essential corrosion-protection work on the existing manhole, a sophisticated bypass system was set up, composed of a flow-through plug operation and two additional bypass pumping operations. These operations worked simultaneously to ensure efficient sewage control during the construction process. While this solution achieved its objectives effectively, it was not without its challenges. The project grappled with space limitations due to its location on the bustling Las Vegas Strip, keeping in place access to resorts and businesses on the Strip with the abundance of temporary piping, a point of connection that was over 26 feet deep, challenging geotechnical conditions related to groundwater at the manhole's depth, a strict timeline dictated by the Formula 1 track paving, and limited space for traffic control. CONCLUSION: In conclusion, the combination of these sewer bypass methods allowed the construction of the resort to proceed seamlessly, without interruption to the surrounding hotels, casinos, and businesses on the Las Vegas Strip. Furthermore, this case study emphasizes the potential for implementing combined bypass methods, such as flow-through plugs and pumping systems, to effectively manage complex sewage control in high visibility and densely populated settings. These innovative approaches offer versatile and dynamic solutions that can be widely applied in the field of public infrastructure management. This case study serves as a practical example, providing valuable tools for developers, engineers, and public agencies facing similar challenges. It also highlights the challenges that were unexpected and could have resulted in a major sanitary sewer overflow near the Las Vegas Strip. The successful completion highlights the adaptability and forward-thinking strategies necessary to address the unique challenges of high-flow sewage systems in urban environments. SUMMARY: Innovative sewer control techniques proved highly effective in the development and management of a high-capacity sewer system. This strategic combination of bypass operations, featuring flow-through plugs and multiple pumping systems, served as a solution to overcome a spectrum of project limitations and challenges. This case study showcases the successful implementation of advanced construction techniques and places strong emphasis on the roles of adaptability and project management. The valuable insights derived from this study provide possible solutions to professionals engaged in public infrastructure projects who face similar challenges within the field of sewer collection system management.

Prevalent biosolids management practices treat wastewater treatment facilities as cost sinks, leaving them to pay ever increasing disposal costs for biosolids. Utilizing hydrothermal carbonization (HTC) to convert wastewater solids and organic wastes into valuable products turns wastewater treatment plants into sustainable, revenue producing assets. Hydrothermal Carbonization, or HTC for short, is the cornerstone technology in SoMax BioEnergy's suite of solutions for organic wastes. SoMax BioEnergy's HTC process is a continuous thermochemical process that utilizes moderate temperatures and pressures of ~350F & 430F (180C & 220C) and less than 580 psi (40 bar). The HTC reaction has variable retention times based on the feedstock from as short as thirty (30) minutes and up to four (4) hours. When considering biosolids processing, HTC's greatest advantage is that the reaction takes place in an aqueous environment, eliminating the expensive process of drying biosolids prior to processing. The HTC process + drying of the BioCoal product, uses less energy than drying the equivalent biosolids alone. In fact, HTC uses the water present in the biosolids as the primary reactant to perform chemical reactions. The key reactions that occur during the HTC process are dehydration, hydrolysis, decarboxylation, and condensation, all of which result in a product with higher C:O ratio than original feedstock. Hydrothermal carbonization of biomass generates a biochar-like solid product, known as hydrochar, and a nutrient rich process water. Comparing hydrochar to the original feedstock, it is more easily dewatered, has greater fuel characteristics, sorption capacity, and has added benefits when used as a soil amendment, such as increased fixed carbon and carbon sequestration potential. Research institutes across the globe are creating value added bioproducts from hydrochar ranging from concrete additives, to battery electrodes and activated carbon. Considering alternative methods of biosolids processing (land application, compost, and anaerobic digestion), HTC is the most carbon efficient, creates the lowest greenhouse gas emissions, and utilizes a much smaller footprint. The hydrothermal carbonization thermochemical process is also more robust as it is not subject to the same sensitivity issues biological processes encounter. The Borough of Phoenixville Wastewater Treatment Plant, in Pennsylvania, has partnered with SoMax BioEnergy to build the first commercial scale hydrothermal carbonization facility in North America. While European and Asian countries already utilize HTC to treat organic wastes including woody biomass, sewage sludge, digestate, food waste, and even municipal solid waste, North America has yet to implement this technology. This changes with the Borough of Phoenixville project, which at the time of writing this abstract, has over $1,000,000 in project funding has come from county and state grants and is under construction with commissioning set for Q1 of 2022. At capacity the Phoenixville HTC project will process ~15,000 tons of prepared 15-20% solids feedstock, generating over 1,500 tons (d.b.) of BioCoal (hydrochar). SoMax BioEnergy and the Borough of Phoenixville are implementing a two-stage approach to maximize the benefits of the HTC facility to align with the Borough's sustainability goals. The first stage of the project is utilizing HTC for treatment of sewage sludge within the plant and surrounding wastewater treatment plants to process biosolids. The second stage will expand the HTC feedstock to include food waste from the Borough and surrounding businesses. Stage two includes introducing gasification technology that utilizes the hydrochar as a solid fuel to power the wastewater treatment plant and put electricity back on the grid. The Borough Council and Management team sees electricity generation from waste they would have paid to dispose of as a win-win situation and steps in the right direction to accomplishing their 2035 goal of 100% clean and renewable energy. The Borough of Phoenixville HTC project, when fully realized will generate over 150% of the electrical demand of the WWTP, covering all electrical and thermal demands of the HTC process, while utilizing the excess electricity for other borough owned properties. Over the 20-year project lifespan, it is expected to generate over $35,000,000 in savings with a capital equipment payback period of around 7 years. In Spring of 2020, SoMax BioEnergy's hydrothermal carbonization solution received recognition from the U.S. Department of Energy as a Phase One winner in the Water Resource Recovery Prize and this fall was 1 of 6 Phase Two submissions. Unfortunately, the Phase two winners are to be announced the second week of November, just missing the deadline of the abstract submittal. In this presentation, SoMax BioEnergy will: 1) Introduce the Hydrothermal Carbonization (HTC) technology 2) Compare HTC to the status quo WWTP technologies 3) Share research developments and HTC product applications 4) Use plant data to discuss the impacts of HTC on effluents and overall mass and energy balances of the plant 5) Talk about DEP permitting and pathways forward for beneficial use 6)Discuss the experience that is commissioning a new technology