Conference Papers

Purpose of the research and key message and knowledge transfer In summary, the key message from this work is two-fold: Close collaboration with industry enabled the design of a scientifically rigorous and highly focused experimental program in live sewers. The latter provided conclusive answers within four months and identified a way forward leading to technology implementation and identification of researchable gaps needed to make the technology more widely usable. The specific knowledge that this paper will transfer is that reliable humidity sensors to measure relative humidity >98% in gravity sewers can be achieved. This is a tool that will help the water industry to improve the management of its concrete gravity sewers and other infrastructure that is in contact with high concentrations of gaseous H2S in humid air. No commercially available technology can do this. In this work, the authors have demonstrated experimentally, building upon advanced design work, that optical fibre sensor systems represent an innovative, versatile and affordable technology that can be brought to bear very effectively on key monitoring problems in the water industry's infrastructure. Through the work reported and results demonstrated in this paper, the research has very successfully created a synergy of the skills of an academic group and a major water utility to identify, tackle and solve key problems in sewers -- problems that impact directly on consumers and are seen world-wide in the industry. In doing so, in an effective way like this, the paper demonstrates the benefits to be gained from a close collaboration between the two groups. Above all new knowledge has been transferred -- in both directions -- and through that new and more effective approaches to problem solving developed. Specifically, the project is based on new technology for humidity measurement -- this is an essential parameter that needs to be monitored to minimize corrosion of concrete gravity sewers. No humidity sensors that last longer than ~1 week in the aggressive gaseous atmosphere of gravity sewers and can reliably measure humidity above 98% relative humidity are available. Thus supporting better predictive maintenance, in situ monitoring of a sewer and an anaerobic digester is undertaken using innovative optical fiber-based sensor systems: these being chosen because of their inherent safety in the potentially methane rich environment, their ability to be protected against biofouling, their light weight, low power consumption (or battery powered), 4G compatible and ease of use over the long lengths (up to kilometers) needed for some applications. The multi-parameter sensors systems designed and evaluated are also well suited to use with the high levels of hydrogen sulfide, coupled with high humidity seen in sewers and biogas rich environments -- environments where conventional electronic-based sensor systems regularly fail due to acid attack. Benefits of Presentation and why this presentation should be selected and will provide a benefit to our industry Sydney Water's current management strategy relies on reducing gas phase H2S by the addition of chemicals (ferrous chloride, magnesium hydroxide and calcium nitrate) to the waste water. This strategy, implemented in a number of waste-water systems in Sydney, is costly (about $4M p.a.) and its effectiveness in reducing corrosion is unknown, due to an inability to directly measure concrete corrosion and deterioration of rehabilitation materials. No matter how effective this program is in slowing the corrosion rate, there will always be concrete corrosion and a method for prediction and detection of imminent pipe failure is needed because of the enormous costs of such failures. In particular, it is necessary to determine how much of the ubiquitous H2S and H2O can be left in the air in order to reduce corrosion rates to less than what Sydney Water defines as a sustainable 0.5 mm/year. Gravity sewers are buried infrastructures that undergo chemical deterioration because of microbiological induced corrosion (MIC). Microbiologically induced oxidation (MIC) of gaseous H2S into sulfuric acid results in concrete sewer corrosion. MIC costs billions of dollars annually to the water industry and has been identified as a main cause of global sewer deterioration. Sydney Water spends about A$60-80M annually repairing and protecting concrete gravity sewers and has a regular sewer inspection program. Currently, sewer condition is determined by man entry which is inconvenient and hazardous, has major safety issues and is expensive and so there is a need to minimize man entry by reducing damage from MIC, which can be reduced by controlling moisture in the gravity sewers to values approximately below 85% RH. No conventional humidity sensors that can last longer than one week exist under these aggressive conditions. Tackling this, this work describes the first and successful attempt to use optical fiber-based photonics sensors to monitor humidity in the range >98%RH in the overhead space in gravity sewers. This information is fundamental to develop reliable models that can predict the end-of-service life (EOSL) of concrete sewers. With the ageing of an asset, there is a point in its life, termed the End of Service Life (EOSL) and by doing so, it will be possible to save hundreds of millions of dollars that would have to be spent if collapses occur or premature repairs carried out to prevent a potential collapse. The approach developed together thus supports Sydney Water's corrosion management strategy, which has been created as an outcome of over $3M in research projects striving to better understand the processes that lead to the formation of H2S dissolved in the waste-water. Status of Completion The work done together by the authors has enabled the project to reach a high level of completion and results of the use of the systems in sewers and biodigesters have been reported in the major international media. Thus to date, three trials of tailor-made fiber optic-based sensor systems to monitor humidity in the range >98% RH in sewer air that contains high gaseous H2S concentrations of up to around 400 ppnv have been successfully completed. Based on this Sydney Water is implementing the photonic sensors technology in small catchments. For extensive implementation, Sydney Water is supporting extra research to develop 'low cost' interrogators that would make the technology more cost effective, well suited to long term, in-the-field research. Conclusion and take-away message The key 'take-away' message is that this is a significant innovation in optical fiber and photonic sensors that they can now be used in these 'dirty' environments. This has also allowed in-situ long-term monitoring under conditions where current technology fails. The major outcomes of the series of experiments carried out over the last five years is clear; fiber optic sensors systems can operate effectively, in the long term, in remote locations under battery power, saving of millions of dollars.

ABSTRACT British Columbia (BC) is 1.4 times the size of Texas. While only 1% of its land base is native grassland, these areas have been historically prized for homesteading and early agriculture. Today they are mainly used for ranching, but over a century of use has left many BC grasslands in a degraded state. These grasslands support more threatened and endangered species of birds, animals, and vegetation than any other terrestrial biome in the province. The OK Ranch is a 15,000 acre cow-calf operation located in the interior of BC, and was emblematic of these challenges. The upland grasslands of the OK Ranch experienced a decrease in productivity over the last century due to long-term agricultural and grazing practices, now compounded due to climate change. First Nations oral histories tell of tall grasses 'belly high to a horse' flowing with the upland winds, but due to historic homesteading and more recent attempts at cereal production in this dry, high-altitude area, soils were exposed to harsh elements and the natural forage was unable to return to previous production levels. In 2013, SYLVIS partnered with the OK Ranch's landowner to emphasize grassland restoration using biosolids to achieve effective stewardship as well as productivity for the ranch operation. Since that time, SYLVIS and Metro Vancouver, together with several research partners, have sought to understand and quantify the benefits conferred to the site through the careful use of biosolids as a soil amendment tool. This presentation will share the unprecedented understanding of what can happen for a degraded ecosystem when provision of critical soil conditioning supports rehabilitation. Specifically, we will discuss how: -Soils have been protected through the growth and expansion of a thatch layer, and reduction of bare soil and crusting throughout the site. -Grasses have recovered and now grow with vigour, producing up to 400% more biomass, while also being more nutritious for cattle and ungulates. -The changes in biomass and resilience have resulted in significant carbon capture on the landscape, both in short-term annual carbon through above ground biomass, but also in long-term belowground carbon capture and storage in soils and roots. -The improved grass structure has resulted in favorable habitat development for endangered or threatened insects, which in turn support threatened bird species, which has become a major research focus at the OK Ranch through a partnership with the University of British Columbia. -Mammals, large ungulates, and predators appear to spend more time in the grasslands. -The productivity has resulted in increased employment at the OK Ranch, with more cattle and more hands hired to help manage those cattle. -A desktop analysis of climate change mitigation and ultimate benefits to the environment provides a compelling case for the economic, environmental and societal value of grasslands restoration. The OK Ranch grasslands restoration project is more than just land application of biosolids. It demonstrates the layers of co-benefits provided through the restoration of semi-arid grasslands of not just soil improvement, but of carbon capture, habitat recovery, and economic development. . The presentation will conclude with a discussion of what levels of awareness and information sharing might be required, and what innovative strategies are available to increase uptake of beneficial use messages to achieve this kind of scale for grassland restoration in North America.

This paper and presentation will survey and analyze the latest lawsuits and regulatory developments affecting the beneficial use of biosolids to provide wastewater and residuals professionals current information that will help inform their decisions on risk, liability, management, and planning. Slaughter and Silton regularly defend land application in litigation, and they are currently working on behalf of a major land application contractor-and its farm partners-to challenge a Pennsylvania locality's attempt to restrict land application. The speakers will discuss the challenges posed by local ordinances, tort litigation, and the ongoing campaign to regulate per- and polyfluoroalkyl substances (PFAS). This talk will outline potential risks, while also highlighting potential strategies for managing land application and discouraging attacks on beneficial use in the face of a changing legal environment and local communities that may be hostile to land application. Slaughter and Silton will first address the interplay between state and local regulation by exploring several case studies involving local attempts to restrict or ban land application. Their discussion will cover California, where decade-long litigation over a local biosolids ban resulted in a trial and settlement striking down the ban. City of Los Angeles v. Kern County, 2017 WL 1292822 (Tulare Co. Super. Ct. Mar. 14, 2017). Among other things, the Kern trial resulted in findings that land application poses few risks after hearing evidence concerning minimal concentrations of PFAS in soil and groundwater beneath a farm where biosolids had been land applied for decades. The speakers will also address recent developments in other states, including Pennsylvania, where the speakers are currently challenging application of a local waste ordinance to land application. Second, the speakers will survey risks to land application posed by tort law suits. Cases in which plaintiffs' lawyers have alleged nuisance conditions caused by land application will be discussed, including the important decision of the Pennsylvania Supreme Court in Gilbert v. Synagro Central, LLC, 131 A.3d 1, which ruled that farming with biosolids is a normal agricultural operation entitled to protection under Pennsylvania's Right to Farm Act. The speakers will also discuss a case brought in Maine, Stoneridge Farms v. 3M, in which a dairy farmer alleges that land application resulted PFAS contaminating his land, groundwater, and dairy cows. This case was voluntarily dismissed but portends a new generation of tort litigation seeking to challenge land application. Third, the talk will assess the regulatory landscape for land application. Legislators and regulators, at the behest of many advocacy groups, have turned their focus to trace chemicals that may be found in biosolids, including PFAS. Silton and Slaughter will highlight recently regulatory developments and their implications for POTWs, biosolids service providers, and farmers. The presentation will conclude with how stakeholders in land application-POTWs, contractors, and farmers-can collaborate to reduce their risks and navigate a challenging, dynamic legal and regulatory landscape.

BACKGROUND The William E. Dunn Water Reclamation Facility (WEDWRF) is in Pinellas County, Florida and is operated by Pinellas County Utilities to treat wastewater collected from the County's northern service area, and to generate reclaimed water supply for the County's reuse distribution system. The WEDWRF is a 9.0 MGD capacity advanced 5-Stage Bardenpho process wastewater treatment facility that currently operates at an annual average flow of approximately 6.5 MGD. The existing solids management system for the WEDWRF includes two (2) rotary drum thickeners (RDT) for thickening waste activated sludge (WAS), two open top sludge holding tanks, two (2) belt filter presses (BFP) and truck loading bay. The existing BFP are old and require replacement. A pilot scale dewatering study was conducted with the following objectives: 1.Evaluate the dewatering performance of new belt filter press and centrifuge. 2.Optimize the polymer dosage to maximize cake solids and solids capture. 3.The efficacy of generating thickened waste activated sludge (TWAS) using RDT to thicken WAS prior to dewatering or bypass the RDT to directly dewater WAS as an operational, energy and polymer cost saving measure. 4.Analyze composite samples of centrate/filtrate stream for Chemical oxygen demand (COD), Ammonia and Phosphorous to determine the quality of the reject stream back to the headworks. 5.Perform life cycle cost analysis of dewatering operation and maintenance for BFP and Centrifuge. PILOT TESTING SCHEDULE The pilot testing was conducted between April 18, 2023 - June 6, 2023. Alfa Laval's BFP was tested between April 18 - April 20 for WAS, April 25 - April 27 for TWAS. Andritz centrifuge was tested between May 9 - May 11 for WAS, May 15 - May 17 for TWAS. Alfa Laval's centrifuge was tested between May 23 - May 25 for WAS, June 5 - June 6 for TWAS. A filtrate/centrate stream composite sample was collected on each day of pilot testing for both WAS and TWAS. RESULTS 1.Waste Activated Sludge The percent cake solids (%TS) obtained for WAS in Alfa Laval BFP ranged between 16.8-18.5% for the polymer dosage ranging between 10.0-16.8 lb/Ton. The solids capture for BFP was between 95 - 99%. Similarly, the percent cake solids (%) obtained for Andritz and Alfa Laval Centrifuge ranged between 20.0-24.5% for polymer dosage ranging between 14.5-62.9 lb/Ton for Andritz centrifuge and 13.2-35.7 lb/Ton for Alfa Laval centrifuge. The solids capture for Andritz centrifuge ranged between 89-96% and Alfa Laval centrifuge ranged between 94-99%. 2.Thickened Waste Activated Sludge The percent cake solids (%TS) obtained for TWAS in Alfa Laval BFP ranged between 15.8-17.7% for the polymer dosage ranging between 7.3-11.4 lb/Ton. The solids capture for BFP was between 96-99%. Similarly, the percent cake solids (%) obtained for Andritz and Alfa Laval Centrifuge ranged between 18.7-22.7% for polymer dosage ranging between 18.7-44.8 lb/Ton for Andritz centrifuge and 27.0-32.0 lb/Ton for Alfa Laval centrifuge. The solids capture for Andritz centrifuge was between 84-99% and Alfa Laval centrifuge ranged between 94-99%. 3.Centrate/Filtrate Analysis A composite sample of centrate/filtrate was collected on each day of pilot testing for both WAS and TWAS. For WAS centrate stream, the concentrations of COD ranged between 60 - 470 ppm, ammoniacal nitrogen between 0.1 - 0.3 ppm, total phosphorus between 2 - 48 ppm. For TWAS centrate stream, the concentrations of COD ranged between 102 - 2,440 ppm, ammoniacal nitrogen between 0 -150 ppm, and total phosphorus between 133 - 490 ppm. It is noteworthy to mention that the concentration of analytes reported here as received from the contracted laboratory. The key observations in the filtrate/centrate composite sample analysis are: 1.Concentration of the analytes appear to be lower during the belt filter press dewatering operation when compared to the centrifuge dewatering operation. 2.Concentration of analytes for TWAS filtrate/centrate stream appear to be significantly higher than for WAS. This indicates that there is release of nutrients in the holding tank. 3.The P concentration in the filtrate for TWAS appears to be in high enough concentrations that it could lead to the formation of struvite in the facility. This could decrease the dewaterability of the sludge and create maintenance issues, due to buildup in pipes and valves, at the facility. KEY TAKE-AWAYS The pilot testing results indicate that both BFP and centrifuge technology could be suitable for WEDWRF dewatering improvements. The BFP consistently achieved a cake solids concentration of 17.5 (%TS) for WAS. In the case of TWAS, the average percent cake solids were about 17.0 (%TS). Similarly, both the centrifuges performed better than BFP producing cake solids at an average of 22.0-23.0 (%TS) for WAS and 20.0 (%TS) for TWAS. However, the polymer consumption in the case of centrifuge was at least twice as much as BFP polymer consumption for both WAS and TWAS to achieve a 3-5% increase in percent cake solids. The centrate/filtrate composite analysis samples showed interesting observations with high concentrations of nutrients for TWAS. This could be attributed to the release of nutrients in the sludge holding tank. A determination of the exact duration and conditions that would cause this release of nutrients and soluble COD is something the pilot did not focus on. An understanding of the impacts of sludge degradation in sludge holding tanks especially in hot summer months is important for this and many other plants that use sludge holding tanks as buffers to limit plant dewatering operations schedules to only a few days a week. This could also impact the dewaterability of TWAS which was evident as the cake solids (%) obtained in TWAS was relatively lower than WAS. Furthermore, higher nutrient and COD loading in the centrate stream recycled to the headworks of the plant could lead to increase in aeration demands to treat the increased ammonia load . Similarly, there could be an impact in disinfection chlorine demand. To conclude, both BFP and centrifuge should be evaluated for both WAS and TWAS to have a complete understanding of overall life-cycle cost implications on each of those equipment. Life cycle cost analysis will be performed and presented by the time of Residuals and Biosolids Conference in 2024. This presentation will cover the pilot testing equipment operating parameters, feed characteristics, relationship between wastewater sludge cake solids and polymer consumption of dewatering WAS and TWAS, important parameters for plant operations decision making. Furthermore, the presentation touches upon nutrient and COD impacts of dewatering recycle streams and their potential impacts on plant effluent limits. ACKNOWLEDGEMENTS The presenters thank Pinellas County Utilities, Alfa Laval, and Andritz for providing pilot testing equipment trailers and for assisting during the pilot testing phase.

Background and Project Goals Reduced acceptance of wastewater solids at landfills, paired with increased disposal tip fees, are a problem noted by wastewater utilities across the nation and one that has worsened in the past two years throughout the Mid-Atlantic and Northeast. A biosolids landfill study was conducted for a wastewater utility that treats 220 million gallons of wastewater per day, generates 105,000 wet tons of solids per year, and covers a service area with a population of nearly 900,000 residents. Approximately 18% of production is managed through landfill disposal. Regional landfills have enacted limitations on the utility over a two-year period that range from reduced tonnage and disposal times to complete cessation of acceptance. In response, a biosolids trends analysis project was initiated with a focus on landfill challenges and subsequent disposal policies. The primary purpose of the project was to establish the sustainability of landfill as a routine outlet for the utility's solids, and if regional capacity exists for potential emergency situations. A secondary goal was to provide understanding of the causes of extreme landfill heating (subsurface internal temperatures 250 °F up to 1500 °F) and slope failures at landfills — challenges that landfills reported as the main cause of biosolids volume restrictions. The project included interviews with industry experts to investigate causes of extreme landfill heating and slope failure, and surveys of regional landfills to understand limitation policies and identify potential disposal opportunities. Project Findings The most noteworthy finding of the project is that 'existing' approved landfill capacity can change from week to week. Verbal reports regarding capacity and acceptance by landfill representatives is unreliable. Figure 1 shows the monthly solids production volume that would go to landfills if other management programs failed in comparison to the ever-changing 'available' and 'approved' capacity reported by regional landfill representatives. The graphic shows approved capacity at the start of the project in January 2020 (6,380 wet tons per month) compared to approved capacity in August 2020 (2,910 wet tons per month). Also displayed is the available capacity reported during project interviews conducted from March to June 2020 (11,815 wet tons per month) versus capacity landfills were willing to accept post-completion of the project in October 2020 (4,190 wet tons per month). Total approved monthly landfill capacity dropped by 54% over the course of eight months and actual capacity secured at regional landfills post-project was 65% lower than what was indicated by representatives during project surveys. When interviewed for the project, representatives from six landfills reported available capacity but only one provided an approval to the utility beyond one load per day. Additionally, four landfills reduced existing approvals to 'emergency use only' though this was not indicated during landfill interviews. Even more surprising was three of those same landfills had also reported an abundance of available capacity to the County the year prior in a pledged long term 10-year plan submission. The reasons cited to the utility consistently involved wet waste restrictions and alleged connection between biosolids and extreme landfill heating and/or slope instability. In fact, all sixteen landfills participating in surveys noted operational changes and disposal restrictions based on those issues — with only two experiencing either challenge at their site. Another key finding from the project, based on interviews with industry experts, is that biosolids are not a direct standalone cause of either of these landfill challenges. Industry experts reported that extreme landfill heating and slope instability challenges are both caused by a combination of operational, biological, and chemical factors. Saturated waste masses do increase the chances of both landfill challenges — a primary reason the landfill limits are targeting reduction of 'wet wastes' as a preventative measure. While biosolids do add to the wet waste ratio, experts reported that a ratio of 20% wet waste to 80% municipal solid waste (MSW) is acceptable as long as sound operational practices are in place. Despite this, Waste Management is enforcing a strict 5% wet waste limit as a company policy and others (i.e., Republic, Advanced Disposal) are set at 10 - 15% in a conservative effort to avoid either challenge. Although the exact mechanisms are still under investigation, primary contributors to extreme landfill heating include poor liquid management, inefficient landfill gas collection systems, and exothermic reactions between wastestreams. Elevated temperatures can lead to drastic operational challenges including melting of leachate and landfill gas collection system piping, rapid decomposition and settling within the waste mass, and geysers of leachate due to pressure built up (Figure 2). One of the most interesting findings about extreme landfill heating is that one cause is the reaction between ash (i.e., fly ash, MSW incinerator ash) and organic wastes. The oxides in the ash mixed with organic material (including biosolids) can cause exothermic reaction over time — and lead to pockets of subsurface trapped heat. In other cases, subsurface extreme heating is occurring at landfills that used mixtures of ash and organics as an alternative daily or intermediate landfill cover, leading to a disproportionate ratio of reactive wastestreams in the deep waste mass. Extreme landfill temperatures can lead to slope instability and/or failure but are only one of the reported causes. Figure 3 shows a portion of a 12-acre slope failure at a landfill due primarily to inadequate design and stability analysis. As in the case of elevated temperatures, limiting biosolids acceptance is not the key answer to assuring slope stability. Sound operational handling practices including mixing wet wastes with solid wastes, spreading wet wastes out, and avoiding wet waste disposal at the toe of slope or at the interface of two landfill cells — can help to ensure safe disposal of wet wastes including biosolids. Conclusion As more is discovered about the mechanisms of the reactions leading to extreme heating and root causes of massive slope failures are identified — the industry is shifting recommendations away from over-saturating landfills, encouraging more focus on segregation of wastestreams that could lead to exothermic reactions, and homing in on how important it is to properly mix and spread out wet wastestreams. As a result, landfills are taking precautions by setting even stricter than recommended wet waste ratio limits and in some cases ceasing acceptance altogether. The utility is bearing the results of this with the most recent restrictions effectively reducing the approved disposal sites from eight to three sites over a period of three months. The main takeaway is that even a large utility, one with 900,000 resident's dependent on their facility, can essentially be refused disposal of solids, and landfill approvals can change at any moment — making landfill disposal an unreliable long-term biosolids management plan.

In today's dynamic job market, organizations face challenges in retaining top talent and maintaining a strong workforce. Stay interviews offer a valuable tool for addressing these challenges by engaging and understanding the needs of existing employees. Stay interviews are an emerging mechanism adopted by organizations to improve employee retention. Unlike exit interviews that focus on gathering feedback from departing employees, stay interviews aim to engage and retain existing employees by addressing their concerns, needs, and professional development. This presentation provides an overview of stay interviews as a proactive retention strategy, outlining their purpose, benefits, and best practices. SPR will share their methodology for executing a stay interview project, providing insights into their data collection and analysis processes. They will also showcase their PowerBI dashboard, demonstrating how it visualizes differences between employee populations, including DEI subsets. This in-depth analysis enables leadership to address specific concerns within different groups, make necessary enhancements, and generate ideas for future offerings. Gallup research reports that only about 25% of organizations are currently conducting stay interviews, which can reduce organizational turnover by up to 20%. Overall, stay interviews serve as a valuable tool for enhancing employee engagement, satisfaction, and long-term commitment, contributing to overall organizational success.

Summary:
The Metropolitan St. Louis Sewer District (the District) was concerned with odors from solids dewatering, cake hauling, and landfilling activities. Odors from sludge disposal at the landfill were threatening to close this outlet for District sludges, severely limiting options for solids management. To meet this need, the District conducted a comprehensive evaluation of liquid treatment for sludges at their facilities, beginning with bench scale testing for all three plants and culminating in a full-scale evaluation of the PRI-TECH® process at the Lower Meramec WWTP. USP Technologies' PRI-TECH process (iron salt dosing followed by downstream hydrogen peroxide dosing) was selected for full-scale evaluation based on the bench scale testing. The District has used ferrous chloride dosing into the sludge thickeners for hydrogen sulfide (H2S) control, providing a significant amount of total and soluble iron prior to dewatering. The PRI-TECH process was implemented with the addition of hydrogen peroxide into the conveyance lines just before the belt filter press. Odor control performance was measured using H2S meters, gas detection tubes, and the recorded descriptions and observations of the District's solids handling staff. Process Selection: Initial chemical control methods were qualified using USP's shake test methodology on samples of thickened solids treated with ferrous. Samples were dosed with oxidants, mixed, the headspaces were purged, and then the samples were shaken to volatize measurable H2S, methyl mercaptan, and ammonia. The next step of the bench scale testing assessed the durational odor control for dewatered sludge. This bench scale evaluation involved pretreating thickened solids with oxidants, dewatering with a Crown Press Belt Press Simulator, incubating samples, and then measuring purgeable odorants from the dewatered cake. Calcium nitrate addition was also evaluated before or after dewatering. While calcium nitrate was effective, the addition of iron upstream of the dewatering operations showed that the dosing of H2O2 at dewatering was both effective and offered a lower cost. Full-Scale Evaluation: Dosing of hydrogen peroxide and data collection at both belt filter presses began on 1/15/2019. The sludge prior to dewatering and filtrate was analyzed for iron, sulfide, pH, and phosphate. H2S at the belt filter presses was monitored. Dewatered cake samples were obtained from the press and analyzed for purgeable odorants at 0, 24, and 48 hours after dewatering. Ferrous chloride dosing rates were held constant throughout the evaluation. The goal of this phase of the evaluation was to determine the minimum dosage required to eliminate odorants present at the dewatering process. Since odorants continue to be generated in the dewatered cake, the dosage that eliminates odorants at this step may be considered the lowest dosage that will offer durational control. Dosages ranging from 125 500 mg/L of H2O2 eliminate ~90% or more of H2S at the belt filter press and from within cake immediately upon dewatering.. H2S Removal Dosage Rate Finding: A sample of sludge taken at the sample port at the active sludge pump was analyzed. It contained 11 mg/L of aqueous total sulfide, 300 mg/L of total iron, and 200 mg/L of soluble iron. The pH was 6.2. At the lowest H2O2 dosage tested, 15 mg/L, H2S under the belt was lowered from 32 to 17 ppmv, a 47% reduction. At dosages of 125 mg/L and higher H2S was reduced by at least 90%. Filtrate Analysis: With increasing dosages of hydrogen peroxide the total and soluble iron levels within the filtrate were reduced. This is likely due to PRI-TECH reactions whereby ferrous (Fe2+) state iron is oxidized to the ferric (Fe3+) state. A drop in phosphate concentrations was observed, with baseline filtrate containing 40 mg/L and the peroxide treated samples containing 20 mg/L. Cake Solids Improvement: Cake solids percentages displayed an apparent linear response to hydrogen peroxide dosing, increasing approximately 6% points from baseline to the 500 mg/L dosage. One mechanism likely contributing to this improvement is sulfide oxidation with hydrogen peroxide, allowing more of the iron present to bind with phosphorus bearing compounds rather than sulfides. Durational Odor Control Results: In dewatered cake samples ammonia and amines were not detected. It is likely that the low pH (6.2) of the feed sludge inhibits volatilization of nitrogenous compounds. H2S appeared to be generated on a linear basis within the 48 hour time frame, with lower overall H2S levels seen with increasing H2O2 dosages. Mercaptans were not detected at 24 hours but at all but the 500 mg/L dosage were detected at 48 hours. District staff trained in odor monitoring techniques recorded observations on odor characteristics, intensity, and prevalence throughout the solids handling and transport process. This feedback was considered to determine the hydrogen peroxide dosing rates ultimately necessary to meet durational odor control needs.

Conclusion:
The District decided to continue with the PRI-TECH application and awarded USP a five year full-service supply contract through a competitive RFP process. Through the full-scale evaluation period the H2O2 dosing rate range of 200 - 250 mg/L was selected as the most cost-effective treatment level that met odor control objectives.

While achieving water resiliency and sustainability in the semi-arid climate of Southern California is of great importance, a large portion of stormwater runoff that picks up pollutants along the way is directed and discharged into the Pacific Ocean. Capturing and treating such runoff not only can help address water quality objectives in a watershed, it also is a huge untapped potential for providing local water supply and diversifying the water supply portfolio in a region that imports over 50% of its water supply. The imported water is mainly sourced from the State Water Project, Los Angeles Aqueduct, and Colorado River (Figure 1). All these sources have been affected by recent droughts and increasing water demands. Yet, more water supply interruptions are anticipated in the future, accentuating the need for increasing the resiliency and sustainability of local water supply. On the other hand, the existing stormwater infrastructure in Southern California has been built approximately 100 years ago with the main objective of addressing concerns about flooding impacts by channelizing main rivers, creeks, and other waterways to convey stormwater runoff to the Ocean faster. However, today's water supply deficit in the presence of infrequent and intense precipitation patterns is dictating a dual mission for water resources managers/decision-makers to create flood protection, while supporting local water supply. In 2018, Los Angeles County residents voted for passage of Measure W, which is a multi-benefit measure that provides cities and watershed areas within the County with funds to capture, treat, and recycle stormwater. Funding is provided through a parcel tax of 2.5 cents per square foot of impermeable land area, which provides approximately $280 million per year for multi-benefit stormwater capture projects. These projects are planned to enhance water supply, water quality, and community investment benefits through nature-based solutions such as installation of bioswales, native vegetation, constructed wetlands, etc. Additionally, projects funded by Measure W usually support addressing a major river's Total Maximum Daily Load objectives, while providing local water supply. These projects also require development and implementation of a Community Outreach and Engagement Program for the public, community, and key stakeholders to maintain awareness of project development and to gather their input in key design elements from the beginning of the pre-design phase to the end of the construction. This presentation will highlight two projects with objectives aligned with or funded by Measure W. Westwood Neighborhood Greenway Project: This project provides for urban runoff treatment, green space, access to public transit, and educational and recreational needs. The design treats dry- and wet-weather stormwater flows from drainage areas surrounding the project site. Dry-weather flow is diverted from the stormdrain to capture runoff from 2,400 acres of drainage area. The runoff flow is then captured and lifted to the simulated stream for treatment by flowing through plant communities, soil medium, and exposure to sunlight. The flow is diverted through an existing culvert and transported via a lift station and finally back to the stormdrain system. The main challenge during the project design phase achieving consensus among several stakeholders. The project team conducted frequent workshops to involve neighborhood and tribal communities, stakeholders, and the public to help them understand the benefits of the project's implementation and the beautification of the site that over time led to a consensus. Wilmington Q Street Local Area Urban Flow Management Project: This Measure W-funded project will use BMPs to capture the 85th percentile, 24-hour storm event runoff and treat it using flowthrough infiltration systems to improve water quality, remove pollutants affecting local water bodies, and modernize stormwater infrastructure. To capture and infiltrate approximately 17.2 acre-feet (AF) of runoff per year, various new nature-based stormwater infrastructure improvement BMPs will be installed. These include installation of drywells to capture stormwater flow, catch basins with diversion structures, permeable concrete sidewalks, and infiltration planters (Figure 2). These BMPs could remove pollutants of concern while providing a beneficial water supply to the local groundwater basin. The Project also incorporates drought-tolerant landscaping into stormwater treatment processes and reduces heat island effect. One of the main challenges we have anticipated through our initial investigations to be encountered during the design phase is that the soil infiltration rate assumed in the project's feasibility study might not be confirmed through further geotechnical analysis. This could highly influence the total load of pollutants removed, volume of captured stormwater, and consequently groundwater recharge volume that augments local water supply. In this case, we will modify the number, size, and/or depth of the drywells to ensure adequate stormwater is captured. Through this presentation, we will provide further details about these projects and share challenges and opportunities our investigators faced, solutions we found, and lessons learned.

Conceptualized in 2006 and completed in early 2021, the Lick Run Greenway in Cincinnati, OH, is a unique example of how a community and a wastewater utility can work together on a creative, green solution for sewer overflows. On the surface, the Lick Run Greenway looks like a park with a stream running through it, but this stormwater management/combined sewer overflows (CSO) reduction project eliminates 800 million gallons of CSOs annually into the Mill Creek, which in 1997 was named the most endangered urban waterway in America. In 2006, the Metropolitan Sewer District of Greater Cincinnati (MSD) began working on a Wet Weather Program with a focused solution for the Mill Creek. The original project was a purely gray concept: a CSO storage tunnel. MSD proposed a green alternative that would not only meet the same CSO reduction goals at a reduced cost but also help revitalize a disadvantaged community. MSD deliberately selected and brought the project to South Fairmount, a low-income, transient neighborhood that was once a thriving community. The basis of the project was could we fix an environmental problem while also reinvigorating a neighborhood. From the beginning, the project sought to not only to inform local residents, but to engage them in the decision-making process, including historic/cultural mitigation and a series of community design workshops that led to a Master Plan. During construction, MSD continued to engage through public meetings, tours, neighborhood briefings, social media, website, media coverage, and monthly drone flyover videos showing construction progress. MSD additionally developed a series of educational signs on the cultural history of South Fairmount and ecological benefits of the project. The signage was also converted into a virtual experience for visitors through the Lick Run Heritage Trail website. As the project neared completion, MSD turned its attention to how to make the park welcoming, clean, and safe for visitors and a resource for outdoor and environmental education. In early 2021, MSD rolled out the Lick Run Greenway Ambassador program, which includes an Adopt-A-Spot program, hiring local youths through a partnership with the Cincinnati Recreation Commission (CRC) and Groundwork Ohio River Valley to welcome visitors and help beautify the Greenway, and designing an anti-litter campaign. MSD also began working closely with the South Fairmount Community Council and Cincinnati Recreation Commission to help bring programming to the Greenway. In early summer 2021, MSD hired a college co-op to create and host weekly interactive, pop-up environmental education events geared toward children. The intern also created partnerships with the Queen City Pollinator Project and Cincinnati Red Bike. During the summer of 2021, MSD hosted a number of programs for the community at large, including an inaugural 5K run/walk, a Cincinnati Symphony Orchestra concert, a community-wide cleanup, and a Pumpkin Fest. Planning for 2022 is already underway, with the intent of bringing more programming and more environmental education to the South Fairmount community. The South Fairmount community has embraced the Lick Run Greenway, and MSD has embraced the challenge of helping revitalize this neighborhood.

Prince George's County, MD is located within the 80,000 square mile Chesapeake Bay watershed. EPA and the State of Maryland prepared the Chesapeake Bay Total Maximum Daily Load (Bay TMDL) for restoring the Chesapeake Bay's chemically, biologically and physically impaired waters. The Bay TMDL requires States, Counties and Cities within the watershed to limit the amount of Total Phosphorus, Total Nitrogen and Total Suspended Sediment that is discharged through point and non-point sources (urban stormwater runoff). Prince George's County combined meeting regulatory requirements with targeted local workforce and business development for this pioneering alternative delivery project. Prince George's County (County) and Corvias Infrastructure Solutions (CIS) developed the Clean Water Partnership (CWP) to design, build and maintain urban stormwater quality treatment best management practices (BMPs) to meet the County's Bay TMDL obligations. In addition to infrastructure improvements, the CWP balances risk, priorities, and social needs, through this Community Based Partnership (CBP). Bringing financing, engineering design firms, contractors, outreach and social/economic goals to this project, environmental compliance is being achieved with local economic growth and community involvement. This groundbreaking and innovative alternative delivery method is the first in the country and required a pioneering, dynamic and responsive team effort to meet the multiple program objectives. The two main CBP program elements include: 1) Environmental goals of design, permitting and construction of stormwater treatment devices, located throughout the 500-square mile County, to treat urban stormwater runoff. 2) Social and economic goals to meet aggressive target class utilization (40% for local, small and minority businesses) and local workforce (51% county resident utilization). Between 2016 and 2021, CWP has successfully implemented over 150 projects, certified over 300 BMP devices to help meet the County's MS4 stormwater permit requirements. In this process, CWP spent over $140 million in design and construction and reduced approximately 53,700 lb. of Total Nitrogen (TN), 7,300 lb. of Total Phosphorus (TP) and 4,405,100 lb. of Total Suspended Solids (TSS). In addition, more than 15,000 acres of drainage area is also treated to reduce pollutants to Chesapeake Bay. A key to the success of the CWP Program has been clear programmatic metrics including indicators and beneficiaries from day one. Primary program metrics focused on schedule/speed, scale economies and performance, community outreach, local disadvantaged subcontractor utilization, local subcontractor development, workforce utilization, and workforce development. Additional metrics were related to alternative compliance and partner programs, and project budget books and schedules. Moving forward, the CWP Team is focused on executing efficiencies to design and construct additional large pond retrofit projects and stream restoration projects based on their monitoring and tracking of BMP cost-effectiveness throughout earlier phases. In addition to complete data inventories on the number of BMPs built and drainage area managed, the CWP Team analyzed pollution removal and cost data of BMPs to determine Total Nitrogen, Total Phosphorus and Total Suspended Solids reduction for 10+ different types of BMPs. This performance summary information directly influenced the planning and siting of each subsequent phase of BMP design and construction. At the same time the Program Management team will continue to rely on performance data and think creatively to achieve its program goals and metrics in future phases. The CWP team has been focusing on asset management as the Program matures to its subsequent phases. This presentation will provide useful information for utility and public works department leaders, and stormwater management staff about creating or tailoring an existing program to meet large-scale targets for capital project delivery intended to meet water quality goals or other stormwater related objectives such as resiliency and flood risk reduction. Partnership goals, organizational structures and integrated delivery partners roles and responsibilities, and program metrics will be shared for discussion. Detailed information will also be presented related to specific program elements and BMP performance data that helped the CWP Team to achieve program milestones. As more communities face increasing regulation and climate-related threats to their stormwater infrastructure, bundling capital improvement projects for cost-effective and timely implementation may be necessary. The CWP Team will share lessons learned from their 6+ years of program execution, specific keys to success for other communities to consider and adaptive management strategies for future CWP success.

Green infrastructure and source control technologies are increasingly accepted as a best practice for reducing stormwater impacts on water quality and aquatic habitat in urban areas. However, impacts continue to grow in many watersheds within the United States even as progress is being made on other sources of water pollution (NRC, 2009). Stormwater management practices have been improved at the site level, but they are not being implemented on a large enough scale to offset water quality degradation caused by urban and suburban land use trends (WEF Stormwater Institute, 2015). Philadelphia is one city implementing green infrastructure on a large scale as a key component of its approach to manage urban stormwater and combined sewer overflows. The Philadelphia Water Department will complete its tenth year of program implementation in 2021. This paper will cover the status of the program, provide statistics on the types and locations of green infrastructure that have been implemented, and summarize performance monitoring data collected from systems operating in the field. PWD submitted its Combined Sewer Overflow Long Term Control Plan Update in 2009, as required by its National Pollutant Discharge Elimination System permits. In 2011, a modified version of that plan was approved for implementation through a Consent Order and Agreement (COA) with the Pennsylvania Department of Environmental Protection. The COA specifies combined sewer overflow reductions, pollutant load reductions, and implementation of green stormwater infrastructure targets intended to improve water quality in local watersheds and the Delaware tidal estuary. As the program approaches the ten-year milestone, it has implemented stormwater management features managing surface runoff generated by approximately 1,100 acres of impervious urban surfaces (Figure 1). Stormwater management features have been implemented through a variety of programs and on a variety of land uses (Figure 2). These include projects on private property initiated by code requirements governing redevelopment. Projects have been implemented on public property, including streets, sidewalks, and public facilities. Finally, projects have been implemented through incentives for private property. Post-construction monitoring data from selected sites indicate that systems are generally meeting or exceeding design performance expectations (Figure 3).

PURPOSE New England communities will soon need to fund nutrient reduction projects to meet stricter regulatory requirements. Since 2011, jurisdictions within Falls Lake watershed in North Carolina have been regulated under a similarly stringent Nutrient Management Strategy for nitrogen/phosphorus. Jurisdictions found meeting these requirements difficult or infeasible. We discuss how a coalition of rural towns, larger cities, and counties collaborated to fund water quality improvements and coordinated with State regulators toward solutions that work for all. DESCRIPTION MS4 communities, such as those within the Charles River, Mystic River, and Great Bay Estuary watersheds, must significantly reduce phosphorous and nitrogen loads to meet Total Maximum Daily Load (TMDL) requirements of the Clean Water Act. Funding these costly nutrient reduction efforts, against competing priorities of replacing aging drainage infrastructure and building climate resiliency, will benefit from a collaborative and innovative approach. Since 2011, jurisdictions within the Falls Lake watershed in North Carolina have been regulated under the Falls Lake Nutrient Management Strategy ('Falls Rules'). Through phased implementation, the Falls Rules aim to reduce nutrient inputs to the lake from wastewater discharges, agriculture, state and federal facilities, and stormwater runoff from new and existing development. For the first stage of the Existing Development Rules, each jurisdiction was required to eliminate their nutrient load from development that occurred between 2007 and 2012 - a significant challenge given that site conditions and development plans were not closely tracked during this period. Achieving 'fair' nutrient load reduction estimates became difficult or infeasible for some communities, and the Rules were delayed. As a venue to discuss solutions to Falls Rules implementation challenges (among other benefits), most regulated entities within the affected watershed participate in the Upper Neuse River Basin Association (UNRBA), a regional non-profit organization focused on promoting water quality and facilitating constructive conversation among stakeholders. To support reasonable adjustments to the Falls Rules and promote the long-term health of the lake, UNRBA has conducted its own watershed and water quality monitoring and modeled various regulatory and management pathways to water quality improvement. Among these pathways, UNRBA, together with local regulatory and academic input, conducted a series of studies to expand the approved set of nutrient removal credit practices for both municipalities and private property owners. However, it was not feasible to meet nutrient reduction targets with credits alone. So, the group also designed the Interim Alternative Implementation Approach (IAIA), which focuses on a collaborative, voluntary, investment-driven participation to meet individual compliance while achieving water quality improvement. Through UNRBA's transparent process, the design of the IAIA earned support from numerous stakeholders, including regulators, and is in the process of being administratively included as an approach to achieving compliance with Stage 1 of the Rules. As the Falls Rules were going into effect in 2011, a group of five jurisdictions in the region recognized the need for increased, sustainable funding and embarked on a joint effort to create stormwater utilities to begin collecting stormwater user fee revenues. These fees fund current and future program requirements, especially those related to Rules compliance. The collaborative approach leverages efficiencies in utility administration and representation in interactions with regulators and ensures a consistent approach to applying the Rules' requirements. All five jurisdictions are currently active members of the UNRBA, contributing toward funding UNRBA's work and participating in the technical and administrative decision-making processes. BENEFITS OF PRESENTATION This case study presents many transferrable approaches and lessons learned to benefit other municipalities and non-profit organizations facing stringent TMDL requirements in New England and beyond. CONCLUSION Policy and funding collaboration among five jurisdictions and a non-profit organization resulted in an alternative compliance mechanism with TMDL rules set out by the State of North Carolina.