Conference Papers

Often the mesh resolution used in a 2D model comes down to reasonable run times, but what impact does that have on the analysis and ultimately the results? In this presentation we'll take a look at the results of a fully 2D hydraulic model with varying levels of mesh resolution and see how calibration was also impacted. In 2008, Iowa City, IA experienced a catastrophic flood event. Soon after the event, 23 high water marks were collected throughout the city for the purpose of building and calibrating a hydraulic model. Along with as-built plans for the bridges, land use, and DEM, a fully 2D hydraulic model was built and calibrated. Four copies of the model were made in order to build different models with varying levels of detail and ranged from having ~1.5 million cell elements to ~75k cell elements. Results from each model were compared to each other at each of the high water marks to highlight differences and statistical error between each one. Additionally, the four copies were then re-calibrated to try to reduce the amount of difference and error which ultimately resulted unrealistic modeling parameters. As 2D hydraulic modeling becomes more prevalent in the stormwater industry, its important to understand how some of the fundamental and initial decisions when beginning a 2D hydraulic analysis will impact the results. This presentation is designed to highlight why mesh resolution is such an important decision and should be given a higher level of attention beyond just a consideration for run times.

Introduction Water Resource Recovery Facilities (WRRFs) have increasingly been investigating and implementing co-digestion of food waste to generate revenue and maximize biogas production. In California, an additional regulatory driver is Senate Bill (SB) 1383, which requires organics diversion from landfills to mitigate short-term greenhouse gas emissions. To meet these goals, the City of Oxnard applied for and obtained an EPA grant to study food waste pre-processing and co-digestion implementation at the Oxnard Wastewater Treatment Plant (OWTP). Carollo developed a feasibility study for co-digestion implementation, and Dr. Matt Higgins (Bucknell University) conducted a bench-scale study involving co-digestion, dewatering, and odor testing of the City's sludge and source-separated food waste from the City's Del Norte Materials Recovery Facility (MRF). The results of the bench-scale study were then used to refine the design criteria and operational assumptions used in the feasibility study. This session will cover the approach and key findings of the bench-scale and feasibility studies. The City and the Carollo/Bucknell team hope that this study can serve as an example to other WRRFs interested in implementing food waste co-digestion. Bench Scale Study Three months of samples of primary and waste activated sludge from the OWTP and source separated food waste from the Del Norte MRF were sent to the Bucknell Anaerobic Digestion Laboratory (see photo in Figure 1) at Bucknell University. The food waste was diluted and blended before delivery. Four anaerobic digesters were operated, Digester 1 as a control with no food waste addition, and Digesters 2- 4 at increasing food waste loading rates. The target food waste VS loading rates to each digester expressed as the mass of VS from food waste divided by the total mass of VS in the digester feed (food waste plus feed sludges) were: Digester 2: 25%, Digester 3: 35%, Digester 4: 50%. In addition to evaluating digestion performance, this study also evaluated the impacts of food waste co-digestion on foaming potential, dewatering, and cake odor production. A summary of the findings from the bench-scale study is provided below: -Food waste characteristics: --The food waste slurry TS and VS content averaged 5.8 %TS and 81 %VS, respectively. -Digester performance: --The food waste did not impact the digesters pH, alkalinity, and nitrogen and phosphorus concentrations in any appreciable way at the loading rates in this study, except for the digester upset. --As expected, food waste co-digestion increased the volatile solids reduction (VSR), biogas yield (see Figure 2 for a graph of biogas production for the 4 Digesters), and methane content of the biogas. The overall VSR for the control digester averaged 45.9%, while the VSR for the test digesters was 52.4-59.5%. From this, the VSR for the food waste itself was estimated as 72-77%. --A digester upset in Digester 4 occurred when it was fed a food waste VS loading of 60% relative to the total VS loading. Based on this, a conservative maximum food waste loading for stable digestion of 45% was selected for the feasibility study. This limit allows for significant food waste addition while maintaining digester stability. -Foaming potential: --The viscosity and foaming potential increased as food waste loading increased. --No clear pattern was observed for volume expansion. The lower two loading rates of food waste (Digesters 2 and 3) had a greater volume expansion than the control, while at the highest food waste loading (Digester 4), the volume expansion was less than the control. -Dewaterability: oAs the food waste load increased, the polymer demand increased and the cake solids concentration decreased. The lower TS concentration could have been due to a lower concentration of divalent cations, which was observed in the higher food waste loading digesters. -Cake odor potential: oFood waste addition did not negatively impact cake odor potential. As a result of these bench scale results, the design team was able to refine site specific design and operational criteria for the full-scale co-digestion cost and energy feasibility study, including identifying the maximum design food waste VS ratios for stable digestion and quantifying anticipated changes in biogas production and revenue, polymer demand and costs, dewaterability and biosolids production post co-digestion. These criteria were adopted for the following desktop feasibility study. Feasibility Study The purpose of the feasibility study was to determine the required facilities, costs, and other impacts of food waste co-digestion and whether the benefits from increased biogas production and cogeneration power generation are sufficient to cover the implementation costs of a co-digestion program. A summary of the findings from the feasibility study is provided below: The capacity assessment determined that the OWTP has sufficient capacity in all their processes to handle the increased loads, except when one digester is out of service. In that instance, the City could divert a portion of the food waste to the Agromin composting facility rather than building an additional digester. The capacity assessment also found that, with food waste co-digestion, the OWTP would approximately double its biogas production. -The condition assessment found that the City has already made or plans to make many of the improvements identified in the condition assessment. Most notably, the City plans to refurbish a digester which is currently out of service. -This feasibility study evaluated a wide range of technologies for pre-treatment of source separated food waste to produce a bioslurry suitable for co-digestion. Three alternatives were selected for a more detailed life-cycle cost, site layout, and non-financial evaluation. A hammer-mill at the Del Norte MRF with additional polishing with a sludge screen at the OWTP was the preferred technology selected for this study (see Figure 3 for a process schematic). -The co-digestion program alternative was evaluated against a baseline alternative, whereby the City continues their current operations. The City's food waste is currently managed by a third party which composts it at the Agromin composting facility. -The hourly energy analysis allowed the City to accurately estimate energy savings from increased biogas production from food waste co-digestion by taking into account fluctuations in biogas production as well as varying electricity usage charges during the winter and summer and during on-peak and off-peak hours. -The energy analysis found that food waste co-digestion would increase cogeneration power generation by 79 percent compared to the baseline alternative. However, the net plant power usage for the co-digestion alternative is only 23 percent lower than the baseline when accounting for additional power loads for food waste processing. -The results from the energy analysis were fed into the cost/benefit analysis which consisted of a 20-year life-cycle cost analysis including capital and O&M costs to compare the baseline and co-digestion alternatives (see Figure 4 for cost results). The analyses found that based on the unit cost assumptions made, the co-digestion alternative is more costly both in capital and O&M costs compared to the baseline, even when accounting for the increased biogas production and cogeneration power generation of the co-digestion alternative. -The analysis identified that one of the major O&M costs is the cost for food waste slurry hauling from the MRF to the OWTP. A sensitivity analysis indicated that the hauling cost can greatly impact the affordability of food waste co-digestion compared to the baseline scenario. In conclusion, this bench scale study and feasibility study found that, while the City of Oxnard has sufficient capacity for food waste co-digestion, the co-digestion alternative is more costly compared to the status quo of continued composting of the City's food waste. These results are likely due to the fact that the biogas is used for cogeneration and to the high hauling costs assumed in this study. While the results are specific to the City of Oxnard, the approach taken in this project of combining feasibility studies with bench-scale studies can serve as an example for other WRRFs. This project demonstrated how WRRFs interested in implementing food waste co-digestion can use cost-effective bench scale studies to gain confidence in the techno-economic evaluation of full-scale food waste co-digestion.

Today's water sector operates in a complex and dynamic environment. While water utilities have been successful for generations, utility leaders have begun exploring new approaches to water services that will help them navigate these challenges. In a global survey, over 90 percent of utility executives believed that innovation was critical to the future of their organization, however only half believed that they were effectively leveraging it (WRF 4642). As a result, some utilities have formalized innovation management as a business function, including the development of innovation leadership roles that are responsible for accelerating the exploration and adoption of new services, processes, and technologies available to the water sector. While the role of innovation leader is a crucial ingredient for success, utilities must also have an executive innovation champion that works in collaboration with the innovation leader. Their role is to embed innovation management as an effective business function by providing direction and ensuring innovation remains an organizational priority. When these two roles work effectively together the benefits of innovation can reach the entire organization as well as customers. Based on a series of utility executive interviews and workshops, conducted as part of The Water Research Foundation's (WRF) Project 4907 Leading Water and Wastewater Innovation, a coalition of 76 utility partners from the United States, Canada, United Kingdom, Brazil and Australia as well as AWWA, AMWA, WEF, WSAA and NACWA found five fundamental tactics that are practiced by successful executive innovation champions to frame and sustain innovation at their organizations. In addition, two specific opportunities for collaboration with their innovation leader that are pivotal to the success of the innovation program were identified. Below you will find a summary of these five critical tactics along with utility examples and a summary of the critical action areas for collaboration. These tactics include: - Defining organizational need and expectations for innovation. Clarity is critical. Less than 40% of utilities have described the urgency or vision for innovation. Additionally, only 30% have identified key challenges or opportunities that need to be explored (WRF 4642). Without alignment with organizational priorities, innovation activities are unsustainable and fail to support a culture of exploration. Leadership must frame the priorities and expectations for innovation investments. Establishing strategic alignment between innovation program priorities, organization philosophy and critical success factors can be done by explicitly addressing innovation in the Strategic Business Plan (SBP). At Louisville MSD, innovation is linked to one of the critical success factors (CSF) in their SBP ( Blueprint 2025). This CSF states, 'Realize operational efficiencies and revenue generation through strategic partnerships and innovation.' Their organizational performance measures and transformational initiatives are tied to each critical success factor. They use these measures throughout the organization to determine organizational performance incentives and support staff evaluations. - Providing resources for exploration, development, and adoption of new concepts. An innovation program without resources will fail to achieve expectations. Only 44% of utilities have established a process or dedicated resources to support innovation (WRF 4642). The top resource needs for innovation include funding for idea development, staff time to explore concepts, physical space for experimentation, and tools for evaluation and cross functional collaboration. Executive champions should focus on identifying available resources to support these processes. At Central Arkansas Water, they found their GIS department was the most requested partner to engage when exploring a new idea. Therefore, they knew it was vital to increase the resources in the GIS department to ensure they were available to others for idea development and deployment. - Establishing measures that are aligned with expectations. Measures are just part of the story. According to WRF 4642, only 35% of utilities have established innovation-related performance measures. However, there is a wide array of performance measures used to evaluate the impact of innovation programs. These measures can include program impact indicators that assess organizational efficiency, quality, resiliency as well as revenue. While the innovation leader should be responsible for maintaining leading and lagging measures that communicate the impact of the program, the executive champion should work to ensure that quantitative and qualitative measures selected align with organizational philosophy, priorities, and desired narrative. At Urban Utilities, they started without metrics and focused on improving the culture. As their program matured, they began to focus on the return on investment for their entire innovation portfolio. Currently, they are experiencing a 10% return including both capital and operating expenditures. They also measure employee engagement in the innovation program. 40 percent of their employees are engaged in the program either through idea generation or participating in idea development sessions. - Rewarding and recognizing innovation activities - successes and failures. Reinforcement builds culture and culture is the key to sustainable innovation. Only 17% of utilities reported innovation-specific reward and recognition measures. Innovation programs track progress and recognize the contributions and the employees that generated them. Recognition can range from a simple 'thank you' to innovation activities recognized in a formal appraisal process. The executive innovation champion should work to provide a diverse range of measures to reward and recognize as well as foster collaboration with the responsible parties for communications and human resources. At the Louisville Water Company (LWC), they make it a point for their staff to be aware of LWC successes so they can be advocates and share it with their family, friends, and the community. These stories can be shared not only through employees but also through annual reports, education programs, social media, and involving the community in innovation projects. - Demonstrating continued support by example and participation. An open-door policy is not enough. The Executive Champion is the chief advocate and plays a key role in nurturing and supporting organizational behavior by participating in it. There are simple steps an executive innovation champion can perform to demonstrate a commitment to innovation including submitting an idea, participating as a judge or mentor for idea submitters, or hosting innovation meetings. At the City of Atlanta's Department of Watershed Management, they hired a Chief of Innovation to ensure time was dedicated to engaging the entire organization and developing an innovation strategy that established goals and actions aligned with the overall organizational strategy. Additionally, two specific opportunities for collaboration with the innovation leader that are pivotal to the success of the innovation program include: 1: Creating a meaningful innovation strategy. To help manage the tensions created by change, an organization can create an innovation strategy. An innovation strategy is a succinct guiding document that provides direction, pathways, and progress tracking. Strategy development provides a simple and collaborative process to align program leadership, process and culture including commitments and roles for the executive champion and innovation leader. Executive champions should ensure that the strategy uses the language of the organization and aligns with utility priorities. 2: Launching and sustaining an innovation program. Once the innovation strategy is developed, executive champions should help find a sustainable pace for the program by working with the innovation leader to align launch and management activities based on available resources, organizational priorities, and cultural change-readiness. Executive champions should also commit to regular progress and redirect meetings that may be held frequently following the launch of the program until the program has become established. Water utilities are adopting innovation management as a core practice to maximize the benefit of new technologies, services and process emerging across the water industry. A key to success is the engagement of the executive champion. This session will unpack the tactics summarized above to equip executive champions to work effectively with their innovation leaders as well as effectively leverage innovation management practices to build agile and fit for future organizations.

Executive Summary: The GLWA (Detroit) and NEORSD (Cleveland) are two large regional wastewater utilities that face similar challenges (e.g. funding/rates, aging infrastructure, CSOs, employee turnover) and have recently initiated innovation programs to help address these issues. Innovation is critical to current and future operations within their organizations. Both organizations have 'formal' innovation programs, but they are different stages of maturity. This paper (and presentation) will compare the GLWA Innovation Programs and the NEORSD Innovation Program — from inception through launch through current day to day operations. The goal of this paper is to provide some key insights to other water and wastewater utilities that may be considering implementing an innovation program or those that may need to take a 'step back' and look at their current innovation program frameworks. Innovation Programs — 2 Different Utilities - 2 Different Approaches Based on recent Water Research Foundation studies, a vast majority (>90%) of utilities surveyed believe that innovation is critical to their future. Additionally, 70% of the utilities participating in the research have developed formal innovation programs within the last 10 years. The GLWA and NEORSD have formal innovation programs in their organizations — but the journey they have taken has been different and they are at differing stages of maturity and have different approaches to various innovation program components. GLWA Launch — The GLWA 'Innovation Program' launch was initiated to help motivate and retain staff engagement, track ideas related to efficiency and operational improvements, and to help provide an assessment point for reviewing and screening external technologies. The GLWA launch benefitted from already having a successful research program, due to existing relationships and collaborations, but also experienced challenges from those same relationships due to the differences between research (narrow focus on a small subject) and innovation (broad focus on many subjects). GLWA initiated it's innovation program with two primary components: a quarterly workshop which focused on assessing external technologies via a series of vender presentations and developing an internal GLWA idea management software platform. This paper focuses on the idea management aspect of the GLWA innovation program. NEORSD Launch — NEORSD launched their initial Innovation Program framework in 2018 — utilizing a fairly 'informal/voluntary' administrative approach with a 'Big Bang' communication mode (1 organization wide email announcing idea submission form is available). As time passed, it was quickly realized that this approach did not achieve the desired goal of 'develop, encourage and sustain a culture of innovation' with NEORSD. Subsequently, NEORSD changed its approach to innovation program management, dedicating resources and designing a new innovation program framework — with the original program goal continuing to be a driving principle. In February 2020, NEORSD started the evolution of their innovation program framework — with a comprehensive relaunch strategy developed. Many challenges have been encountered and many lessons have been learned on this journey. See Figure 1 for a visual summary of the NEORSD Innovation Program framework - detailing the three primary components - communication, process and administration. Idea Management - 2 Different Approaches Ideas (like water lines, pumps, sewers and manholes and other equipment we use) should be considered as assets — and managed accordingly. Not all ideas will get implemented, and not all implemented ideas will be implemented right away. Sometimes an idea must be postponed, or slowly grown, until the timing is right, and resources are allocated for implementation. A key component of an innovation program is idea management and GLWA and NEORSD have taken different approaches in managing their ideas. GLWA Approach — GLWA approaches idea management as somewhat of a 'free for all' of good ideas and community engagement. However, those ideas must be managed within a structure of submission, commentary, review, and engagement with potential implementers. Idea management must have three specific components: 1) idea tracking, 2) feedback to the ideator, and 3) database of idea submissions, as shown in Figure 2. GLWA chose to implement a third party vendor software provide this structure. NEORSD Approach — The NEORSD idea management approach is less formal and structured when compared to GLWA and it has been recognized as a key area as part the NEORSD innovation program relaunch activities. Ideas that are managed by paper lists/post-its, emails and spreadsheets are not conducive to being able to be accessed, analyzed, reported or managed. A comprehensive idea management approach is being developed at NEORSD in 2021-2022. Steps that NEORSD is taking to develop this approach will be shared in the paper/presentation. Summary — Lessons Learned The GLWA and NEORSD have taken different approaches in their development and administration of their innovation programs. Many challenges and successes have been achieved along the way for both organizations — and there are lessons learned to share with other water and wastewater utilities that may be considering developing or revamping an innovation program. Innovation at a water or wastewater utility are not typically encouraged. The water sector must produce via a series of specific tasks to meet a set of specific requirements. Novelty is not beneficial or necessarily even useful. As a result, when trying to engage and develop your workforce innovation, there are often roadblocks preventing clear discussion, and clear understanding, of what might be gained. As each of us have developed our utility's respective innovation programs, we have encountered different aspects of institutional resistance or indifference. At the same time, we have also encountered various pockets of unexpected creativity. Some of these issues are listed below. 1.Communication differences 2.Rigid thinking versus 'free form' innovation 3.Team engagement and marketing the program 4.Differences of opinions 5.Differences in expectations We summarize our presentation and paper with the discussion of these challenges and some of the remedies we have used to circumvent them.

Introduction The U.S. EPA estimates that water resource recovery facilities (WRRFs) emit nearly 40 million metric tons of carbon dioxide equivalent (CO2eq) greenhouse gas (GHG) each year, representing nearly 1% of all domestic emissions sources. Landfills, which are interlinked with WRRFs by residuals management especially for small to moderate WRRFs, represent an additional 1.5% of all U.S. GHG emissions. WRRFs and landfills may also represent the single largest sources of GHGs in municipalities that own and operate these systems. To mitigate concerns about the long-term economic and environmental sustainability of landfill disposal, WRRFs are investigating technologies that reduce the mass and volume of biosolids before end-use. Mass reduction, such as anaerobic digestion or thermal drying, is a strategy to lower hauling and disposal costs, which typically are the largest line items in a WRRF's biosolids management budget. Several moderately sized WRRFs (<10 million gallon per day [MGD]) are considering thermal drying systems that use heat to remove moisture from dewatered sludge and can represent a 70-80% decrease in the mass of material hauled. Though capitally intensive, the process can represent a significant reduction in operating costs due to the mass reduction and the higher quality biosolids product (Class A) produced. The process is especially economically attractive in areas where natural gas prices are low and biosolids are hauled long distances, such as Ohio. Widespread adoption of sludge drying can potentially impact the GHG footprint of WRRFs and the municipalities that own them. Increased use of natural gas will undoubtedly raise direct GHG emissions at the facilities. However, dried biosolids will require fewer trucks, reducing fossil fuel demands associated with truck traffic. Additionally, high quality biosolids have been shown to improve soil health upon land application and contribute to carbon sequestration. It is currently unclear what net impact sludge drying will have on GHG emissions. Quantification of these emissions is critical to better understand the environmental impacts of the technology. Study Objectives The goal of this study was to quantify impacts of sludge drying technology and anaerobic digestion on greenhouse gas emissions at WRRFs. The goal was met by completing the following objectives: - Develop a mass and energy balance model to quantify direct and indirect GHG emissions for sludge treatment and disposal at a moderate sized (<10MGD) WRRF. - Compare GHG emissions profiles for the following sludge treatment trains: 1.Sludge Dewatering with Landfilling of Undigested Sludge 2. Sludge Dewatering with Drying and Land Application of Class A biosolids 3. Sludge Thickening, Mesophilic Anaerobic Digestion, Digestate Dewatering, and Land Application of Class B Biosolids. Biogas combusted at combined heat and power (CHP) for renewable electricity and heat generation. 4. Sludge Thickening, Mesophilic Anaerobic Digestion, Digestate Dewatering, Drying, and Land Application of Class A Biosolids. Biogas combusted at CHP for renewable electricity and heat generation. Heat requirements not met by CHP fueled by Natural Gas. Scenario 1 was considered a baseline condition because it is a common procedure for small to moderate size biological nutrient removal (BNR) WRRFs in Western Ohio. Scenarios 2 through 4 are common treatment trains evaluated during biosolids master planning efforts at moderate size facilities. Methodology The mass and energy balance model (Microsoft Excel based) allows users to input facility sludge flow data and select common sludge handling unit operations such as sludge thickening, dewatering, digestion, drying, and others. Mass flows are resolved around the whole process and individual unit operations. Energy requirements (electricity and heat) are calculated based on typical parameters provided by equipment vendors. The baseline model was developed around a ~10 MGD BNR WRRF that does not include primary treatment and produces a waste activated sludge (WAS) flow of 100,000 gpd with 10,000 lb/d of total suspended solids (TSS). This treatment train is common to many small to moderate sized WRRFs in the state of Ohio. The boundary of the analysis only includes sludge treatment operations, residuals transportation (via diesel truck) and end-use (e.g., landfill, land application). Emissions for unit processes outside of the solids treatment and end-use boundary were not included (e.g. liquid train treatment). Direct GHG emissions were quantified by multiplying modeled utility consumption (kWh/yr; MMBTU/yr) by US EPA and USEIA emissions factors for the region of interest. Indirect GHG emissions were primarily attributed to the residuals end-use method. End use emissions were quantified using the Biosolids Emissions Assessment Model (BEAM) model version 1.1 from the Canadian Council of Ministers of the Environment (CCME). Total GHG emissions for a particular case were calculated as the sum of net direct (consumption - production) and indirect GHG emissions (residuals end use). Results and Discussion Figure 1 shows the impact of sludge treatment train and residuals end-use on GHG emissions. The results show that sludge dewatering and landfilling was associated with the most GHG emissions (>5,000 T CO2eq/yr), mostly from uncaptured methane emissions at landfills. The integration of sludge drying, and Class A land application reduced GHG emissions by nearly 80% compared to dewatering and landfilling. This is attributed primarily to limited methane release in farm fields (due to low moisture content coupled with aerobic oxidation) and somewhat to net negative emissions from Class A land application GHG emissions were lowest for Scenario 3 (anaerobic digestion, Class B land application option) because of the potential to recover renewable power and heat. In fact, more heat and power is produced than needed, resulting in negative emissions for Scenarios 3 and 4. Scenario 4 (anaerobic digestion with drying, Class A land application) was comparable to Scenario 2 (Sludge Dryer Only). Figure 1 clearly shows that technologies for mass and volume reduction are likely to reduce GHG emissions associated with sludge treatment and end-use. However, many WRRFs typically make technology decisions based on a cost-benefit analysis. Table 1 summarizes approximate capital expenditures and GHG emissions offsets compared to Scenario 1. The results show that Scenario 2 & Sludge Drying provides the greatest net reduction in GHG emissions normalized to spent capital. This indicates that sludge drying may provide a cost-effective means to improve the GHG emissions profile at small to moderately sized WRRFs. Conclusions and Future Work WRRFs require cost-effective and environmentally sustainable solutions for sludge treatment and end-use. The results from this work show that technologies for mass and volume reduction are likely to reduce GHG emissions associated with sludge handling. This modeling work showed that land application of Class A and Class B biosolids provides significant benefits including soil carbon sequestration and fertilizer offsets compared to landfilling. Sludge drying was shown to provide the most greenhouse gas emissions offsets per unit of capital expenditure, indicating the technology may be a cost-effective method to improve the environmental footprint of municipalities that own and operate small to moderate sized WRRFs. This is significant because sludge drying may become a technology to prepare for higher cost end-use outlets caused by emerging contaminant regulations (e.g. PFAS). Sludge drying is also a potential precursor process to PFAS destruction technologies such as high-temperature incineration, gasification, and pyrolysis. Future applications of this work include an evaluation of the GHG emissions profile of PFAS destruction technologies and more sustainable landfilling practices, such as enhanced methane capture for renewable natural gas (RNG).

Overview: Formed in 1954, East Valley Water District (EVWD) provides water and wastewater services for a population of more than 100,000 across 18,000 acres in the City of Highland and portions of the City and County of San Bernardino County, CA. EVWD initiated greenfield development of the Sterling Natural Resource Center (SNRC) to provide water recycling for groundwater recharge and enhance their core mission of water production. SNRC enables EVWD to provide in-house wastewater services to ratepayers, rather than relying on neighboring agencies. SNRC was envisioned with the ultimate goal to provide community resilience through utility reliability, resource recovery, economic development, and educational partnerships. SNRC takes a holistic approach to waste recovery, providing water recycling to replenish the Bunker Hill groundwater basin, leveraging biogas from anaerobic digestion to support plant energy needs, and converting solids to Class A soil amendment. The 2.2-acre eastern portion of SNRC houses state-of-the-art process equipment, and the western lot was developed to feature a new District headquarters, community center, and public green space. EVWD partners with community organizations to host events and activities, including educational and vocational initiatives. Following October 2018 groundbreaking, construction was completed in early 2022, and commissioning is ongoing. Operations are to begin in early 2023. EVWD worked closely with stakeholders to maintain construction progress through the pandemic. Approach to Resource Recovery: The greenfield 8 MGD wastewater resource recovery facility (WRRF) is designed to provide complete resource recovery, beyond the scope of traditional wastewater treatment. Ultimately, all wastewater entering the plant is turned into beneficial products supporting facility operations and the broader community. -Wastewater: SNRC treats up to 8 MGD wastewater, using a Fibracast membrane bioreactor (MBR) with FibrePlate membranes. Recycled water is injected underground to replenish the Bunker Hill Groundwater Basin, which serves as water supply for EVWD and neighboring communities, and improve drought-resistance. -Biosolids: Solids remaining after anaerobic digestion (AD) via Anaergia's OmnivoreTM high-solids digestion technology are transported to the nearby Anaergia Rialto Bioenergy Facility (RBF) (approximately 10 miles away) for thermal processing via pyrolysis to carbon- and nutrient-rich Class A soil amendment for agricultural use in Southern California. Nutrients: Sidestream treatment is provided by Anaergia's AMR system to recover nitrogen for use in commercial fertilizer (as discussed further below) and recycle nutrients back to regional agriculture. - Energy: Biogas produced from anaerobic digestion fuels 3MW of combined heat and power (CHP) systems to create renewable energy to meet plant power and thermal demands. In addition to self-sufficiency, this improves reliability of operations and reduces operating costs and therefore burden on ratepayers. -High-strength waste (HSW): SNRC receives up to 130,000 gallons per day of landfill-diverted HSW for co-digestion with wastewater biosolids. This supports methane emissions reductions from landfill, compliance with state organics recycling mandates, and enhances biogas production to support SNRC energy-neutrality. Tip fees collected offset operating costs at SNRC and support rate stabilization. Key Technologies: SNRC employs leading edge technologies from Anaergia and Fibracast to achieve resilient, self-sufficient operations with minimal residuals. -Fibracast MBR: Water is recycled using a MBR with FibrePlate membranes so that it may be used for groundwater recharge. These proprietary membranes combine the best advantages of hollow-fiber and flat sheet MBR systems, using aeration and mixed liquor cross filtration to continuously clean the membranes during operation. The membrane's high packing density, low trans-membrane pressure, and advanced automation leads to easy and reliable plant operations. -Anaergia Omnivore high-solids digestion: Omnivore was employed to cost-effectively provide the digester capacity required to process wastewater biosolids and HSW and generate biogas for energy neutrality. Omnivore uses Anaergia proprietary OmniMix high-solids mixing system together with robust thickening technology to increase the solids ratio in digesters, allowing for triple the feed capacity of a traditional digester, reduced footprint, and reduced and capital expense. This was particularly important at SNRC given space constraints. Anaergia screw presses are employed to pre-thicken digester feeds, which also reduces heat demand associated with heating excess liquid within the digester. Anaergia OmniMix mixers ensure the thickened digestate, including high-solids HSW, is adequately mixed to support tank turnover, digester health, and VSR. OmniMix mixers provide improved energy efficiency versus traditional mixing systems. Overall, Omnivore provides SNRC with reduced energy demand while supporting increased biogas production, advancing achievement of energy-neutrality. -Anaergia AMR sidestream treatment: After digestion, digestate is dewatered via Anaergia screw presses to 25% TS. The filtrate is processes via Anaergia AMR to recover up to 90% of nitrogen as ammonia, creating ammonium sulfate (AMS) fertilizer. AMR operations use heat generated via biogas CHP. Following sidestream treatment, filtrate is also treated via MBR for groundwater recharge. Strategic Partnerships: SNRC was conceived of primarily as a community resource beyond essential water and wastewater services. SNRC supports community and economic development by providing valuable resources for residents and strategic partnerships. -Workforce Development: SNRC resulted in creation of numerous permanent, full-time Greentech jobs within the District service area. Leveraging the new public spaces built as part of the project, EVWD intends to host community events, including educational events focused on SNRC capabilities to enhance engagement and sense of ownership. As SNRC is located across the street from Indian Springs High School, EVWD has launched a Water and Resource Recovery Career Pathway in partnership with San Bernardino City Unified School District. This program offers courses that highlight opportunities in the resource recovery sector and facilitate industry leaders sharing technical and personal stories to community members at no cost. A similar program has been established with San Bernardino Valley College. SNRC also house the Water Education Learning Lab (WELL) Program to provide readily-accessible hands-on experiences and training. Rialto Bioenergy Facility: Dewatered biosolids generated at SNRC will be transported approximately 10 miles to Anaergia's RBF, where they will be dried and pyrolyzed. The resulting Class A product is carbon- and nutrient-rich, and free of PFAS and other contaminants of emerging concern (CECs) such as microplastics and pharmaceuticals. This process allows both nutrients and energy from biosolids to be recovered and beneficially reused. Further, this partnership provides EVWD with a reliable and environmentally friendly guaranteed biosolids management outlet, compliant with California SB1383 regulations, which limit landfill disposal of organics such as biosolids. By establishing agreements within the region, vehicle miles and emissions associated with biosolids hauling are also significantly reduced. Anaergia Nutrients: EVWD and Anaergia once again teamed to develop the Anaergia Nutrients facility at an underutilized District property, approximately two miles from SNRC. The facility will blend Class A soil amendment produced at RBF with AMS recovered at SNRC to create a marketable carbon-negative commercial fertilizer. The user-friendly material can be readily substituted for more costly conventional fertilizers. As a result, two resources often treated as residuals are instead converted to a valuable product helping to close the loop on nutrient recovery and create ancillary benefits and improve profitability for California farmers. EVWD and its ratepayers directly benefit from enhanced property use, lease payments, and host fees. Waste Generators & Haulers: SNRC provides a reliable alternative HSOW disposal option that meets state organics diversion requirements that is also good for business. Rather than travel to landfill, waste haulers reduce vehicle miles and emissions by disposing of waste at SNRC and reduced trip time translates to more business. The mutual benefits mean robust and consistent feedstock source to SNRC for onsite renewable energy generation. SNRC is the result of a visionary mission for EVWD. It provides the new model for stewardship of scarce public resources while enhancing quality of life and economic growth.

From June to August 2021, the U.S. Department of Health and Human Services, in collaboration with the Centers for Disease Control and Prevention, conducted the second phase of a national Covid-19 wastewater monitoring program. Through this program, >6,000 wastewater samples were collected from over 362 municipal wastewater treatment facilities across all 50 states, the District of Columbia, and 2 US territories, covering 98 million people, or 30% of all Americans. Concerns for equity guided onboarding goals, and participating plants included rural and urban communities as well as 9 tribal Indian territories. Collected samples were processed by a commercial vendor. Measured SARS-CoV-2 concentrations were uploaded into the HHS Protect and CDC NWSS databases. A subset of samples were sequenced, and viral RNA sequences were uploaded to NCBI. In multiple cases, wastewater facilities split samples, sending one aliquot to the national program vendor and another to a local university or research group, allowing for multiple real-world methodology comparison studies. Over the course of the program, key lessons about program logistics, data sharing, data quality, and data interpretation were learned. These findings and lessons should inform the design and implementation of future large-scale wastewater monitoring programs.

Odor Control Technology isn't Enough Without Effective Capture Effective odor control is not just about the technology, it is also about the capture and containment of the odor. Choosing and sizing a wet scrubber or any odor control technology is critical, however the best technologies are insignificant if nuisance odors continue to escape before they can be treated. Such issues with capture and containment of odor were present at Orange County Sanitation District (OC San) Plant No. 2 biosolids Truck Loading facility. OC San Plant No. 2 is located in Huntington Beach, California, along the Santa Ana River (which has a raised walking/bike path) and is located near residences, Huntington State Beach, a few parks, and some commercial properties. The Plant is currently treating an average wastewater flow of approximately 60 million gallons per day (MGD). The function of the Truck Loading facility is to store the dewatered biosolids and to load to the hauling trucks for offsite beneficial reuse. Newly installed centrifuges, which improved biosolids dewatering, increased odor generation at the storage and Truck Loading facilities and triggered complaints by plant personnel and community members. To address these nuisance odors, a scientific approach was implemented that consisted of four main parts: gathering data, targeted sampling, air movement monitoring, and designing a custom air capture system based on the information collected in the previous steps. This paper will provide an overview of the approach utilized and highlight key elements that aided in understanding and solving the problem. Gathering Data: A series of questions were asked to find where and when the problem was occurring. To understand and solve the problem, collaboration with the OC San Maintenance, Operations, and engineering staff was crucial. Through this collaboration, it was determined that the odor in the Truck Loading bays was caused by the centrifuge-dewatered biosolids in the truck loading operation. Odors were released when the biosolids dropped through the storage silo knife gate valves and filled the truck trailers. Odors continued to be released from the accumulation of biosolids on surfaces of the truck and Truck Loading bays from the loading process. Minor system contributors included fugitive odors where biosolids accumulate but were difficult to clean, including the floor grates associated with the truck scales, which trap biosolids from washdowns. This information determined that the central issue surrounding the Truck Loading facility was the lack of containment infrastructure. Continuous dataloggers were installed to identify the pattern of hydrogen sulfide and ammonia occurrence throughout normal operations for several weeks. Trucks generally drove into the loading bay from the north, where a door closed behind it, to prevent the wind from blowing the odor out through the facility. The original design of the building assumed that winds would dominate from the south side, and that thus air would be sufficiently contained by the door on the north while ventilation drew out the foul air. The presence of odors indicated that this design was less effective than anticipated in capturing the stronger lingering odor, and further analysis was needed to determine the best containment and ventilation approach. Targeted Sampling: Next targeted sampling was conducted to quantify the odor by pinpointing the constituents of the odor, and their concentrations so that effective capture and containment can be customized. This sampling and analysis measured a complete set of odor-causing constituents such as hydrogen sulfide and ammonia on a continuous basis as well as grab samples for other speciated reduced sulfur compounds/VOCs during the most concentrated periods of Truck Loading, at the higher areas of the loading bay, as well lower regions of the bays (Understanding that the mix of compounds present consisted of both heavier and lighter than air compounds). Air Movement Monitoring: Air movement in the Truck Loading bays was simulated using a series of smoke tests for both existing and considered future conditions. The smoke tests were conducted with smoke candles that released a large amount of smoke (up to 40,000 cubic feet) within a small period of time, to simulate the sudden release of odor while the trucks were being loaded. Each test simulated either existing or potential ventilation conditions. Potential conditions included simulating the presence of a door on the south side of the building, differing ventilation rates, and differing quantities of supply air provided. By observing the movement of the smoke during this array of conditions, conclusions were drawn about the movement of odor throughout the truck bay, including the locations of dead zones, the effectiveness of an additional door on the south side for containment, and the effectiveness of the existing ventilation system at clearing air through each region of the truck bay. The smoke tests made it clear that a second door was necessary to contain the smoke within each bay. Tests which simulated a door made clear other weaknesses with the existing ventilation system's layout, including dead zones near the ceiling. Design of a custom system: The above tests and observations indicated the specific problems that were causing issues with odor control at this particular facility. Alternatives evaluation and conceptual design of improvements to the system were entirely customized to the height and length of the building. First, a door was recommended on the south side of the Truck Loading facility, to contain the odors within the building. Positive air supply was recommended at low and high heights to move foul air with odorants heavier than air observed in step 2, and sweep dead zones found near the ceiling in step 3. A U-shaped exhaust duct layout at ceiling level was recommended to capture the most concentrated foul air on both sides, where the smoke tests indicated most of the smoke was accumulating. The above method of identification of the distinct contributors to the odor control issue at this facility was instrumental in creating a custom design to address the concerns thoroughly and efficiently. Without the observations and collaboration in the earlier steps, the conclusions that allowed for a custom solution would not have been possible.

Drinking water, wastewater, and stormwater (water sector) utilities are experiencing more costly operational and financial impacts from the increased frequency and severity of climate change-related disasters. As a result, the financial and insurance industries are increasing their focus on climate change risk in their assessments of water sector utilities. Thus, it is important that water sector utilities properly identify, manage, and disclose climate change risk and resiliency efforts not only to ensure that they can continue to reliably and effectively provide essential water services, but also because doing so can influence the utilities' credit ratings, investor relations, and ability to attract investors and access insurance coverage at an affordable price. In 2022, the U.S. Environmental Protection Agency's Creating Resilient Water Utilities (CRWU) initiative convened a Financial Working Group comprised of subject matter experts from the financial and insurance industries, academia, and water sector utility managers to address this topic. The Workgroup participated in a series of virtual and in-person meetings from June 2022 through January 2023. The Workgroup recognized that water sector utilities that effectively identify, manage, and disclose climate change risk and resiliency efforts in a responsible manner are more highly rated, broaden the investor base, improve insurance access and pricing, and gain more support from ratepayers. The Workgroup further discussed three main topics: 1) data to identify climate change threats at water sector utilities; 2) methods and practices to identify and assess climate change risks; and 3) effective outreach and disclosure practices to manage these risks. This session will include a presentation of the working group's process, findings, and continued work along with an interactive panel discussion including key working group members. The panel will highlight the varying sector perspectives and discuss commonalities and areas for the sectors to better collaborate. An audience-driven question and answer session will follow the presentation and panel discussion.

Industrial activities have created many brownfields throughout the Chicago metropolitan area. Brownfields are generally associated with poor soil health, inferior nutrient cycling, and attenuated soil ecosystem services, as demonstrated in low primary production and carbon (C) sequestration, low diversity of soil biota and plants, and high runoff with impaired water quality. Thus, restoration of brownfield sites not only increases the economic value of the sites, but also increases the ecosystem services the land provides. A research and demonstration site for brownfield restoration was established on Metropolitan Water Reclamation District of Greater Chicago (MWRD) land along the Chicago Sanitary and Ship Canal, which has been classified as a brownfield site due to prior use of the site for storage of petroleum and chemicals and destruction of soil horizons. Due to their physical, chemical, and biological properties, biosolids, which contain high amounts of organic matter, are an ideal soil amendment for degraded and contaminated soils. In addition to C and nutrients, biosolids contribute to an active microbial community, which is a critical component of soil ecosystem function, including nutrient cycling, C sequestration, plant symbiosis, and contaminant degradation. Research plots were established in October-November 2021 using Split Plot design with four replications. The main treatments were 1) control (no amendments to the existing soil), 2) air-dried biosolids at one-half rate (air-dried biosolids applied at 2.5 cm depth or 130 Mg ha-1), 3) air-dried biosolids (air-dried biosolids applied at 5 cm or 260 Mg ha-1), 4) composted biosolids (woodchips composted with biosolids-3:1 at 5 cm depth or 185 Mg ha-1), and 5) a blend of biochar and air-dried biosolids (pyrolyzed biosolids at 1.25 cm depth and air-dried biosolids at 3.75 cm depth or 105 Mg ha-1 pyrolyzed biosolids mixed with 195 Mg ha-1 air-dried biosolids). For the same thickness (5 cm) of soil amendment applied, the loading rate in weight basis was lower in composted than air-dried biosolids due to the lower bulk density for composted biosolids. Since composted biosolids contained more organic C (25.8%) than air-dried biosolids (19.8%) by mass, the C input from the two amendments applied in 5-cm treatments were comparable. The biochar/air-dried biosolids blend also leads to a similar C input to the 5 cm air-dried biosolids treatment, as biochar contained 21.5% of organic C, just slightly higher than that for air-dried biosolids. Subtreatments are two prairie plant communities with C4 grasses for subtreatment 1 and C3 grasses and forbs for subtreatment 2. The subplot size was 4.5 m x 5 m. The plots were hydro-seeded with native plants in November 2021. Additional seeding by drilling is still needed due to the poor germination during the first year, which is common for establishing native plants. This report will focus on assessing the impacts of biosolids on soil health in degraded urban soil, which supports plant establishment. We sampled soil in April 2022 at 010 cm depth and analyzed the key parameters for soil health, including soil organic C (SOC), nitrogen (N) mineralization potential (NMP), microbial basal respiration, microbial biomass C (MBC), and water-holding capacity (WHC). Due to the high gravel content of the brownfield soil, all results except for soil WHC are presented as 'stock' in 010 cm soil depth by using bulk density of soil materials (< 2mm). Results for two subtreatments within a main plot are pooled for this report of the soil measurement. All soil amendments drastically increased soil WHC from 53% to 100121% (dry soil weight basis), which is associated with the increase in SOC (Table 1). Soil organic C in the control plots had a mean of 17.4 kg ha-1 in the top 10 cm (Table 1) with a range of 10.026.0 kg ha-1). The C-rich soil amendments considerably increased SOC, leading to higher than 30 kg ha-1 in soil for all four amendments. Microbial biomass C measurement indicated that microbial populations were more abundant in plots with the soil amendments than the control: however, it varied depending on the amendment type (Table 1). Microbial biomass C was highest under the air-dried biosolids, followed by air-dried biosolids at one-half rate, composted biosolids, and the biochar-biosolids blend, and lowest in the unamended control soil. Microbial respiration, the CO2 output of the microbial community, reflects microbial quantity and activities and the utilization of substrates by microbes. We found that the soil microbial basal respiration in the control plots was low relative to the treatment plots (Table 1). The high biosolids rate had a higher basal respiration rate than the other treatments. The microbial metabolic quotient (qCO2), the respiration rate per day per unit microbial biomass, helps us understand the environmental stress level for microbes in the soil. High qCO2 indicates greater environmental stress for soil microbial communities. The full rate of air-dried biosolids reduced the qCO2 compared to the control, though the other soil amendment treatments had a similar qCO2 to the control (Fig. 1), indicating that air-dried biosolids can provide a less stressful habitat for microbial communities. Nitrogen mineralizing potential is important for evaluating N accessibility to soil microorganisms and plants. For the sampling period, approximately six months after plot establishment, control plots reflecting the degraded conditions of the site had a very low NMP of only 0.01 kg ha-1, compared to a range of 2.584.2 kg ha-1 in the treatment plots (Table 1). All three treatments that received air-dried biosolids had a higher NMP than composted biosolids. The results presented here showed that the use of biosolids as a soil amendment gave rise to significant improvement in the health of degraded urban soil, which will facilitate plant establishment and possibly drive interactions among microorganisms, plants, and soil components for restoring ecosystem services of the brownfield.

Is it possible to keep an entire mile of 27-36' diameter interceptor sewer and 30 manholes under negative pressure (vacuum) conditions at all times to prevent the escape of odorous air? What ventilation rate is appropriate? The results of sewer system hydraulic modeling, sewer system ventilation modeling, CFD modeling and full-scale testing demonstrate that it is possible to centrally ventilate and treat odors from collection systems up to one mile in length provided that sufficient free area exists in the collection system for unrestricted air flow above the water surface. Multiple air inlets along the collection system are favored over fewer inlets so that inlet air is introduced in a step-feed fashion and overall pressure drop can be minimized. The results show that with sufficient ventilation, negative pressure (vacuum) conditions can be consistently maintained throughout a regional collection system to prevent the release of odorous air. A ventilation rate of 5,000 CFM corresponding to 12.0 air changes per hour was associated with stable vacuum conditions for nearly all manholes. A higher ventilation rate of 7,000 CFM corresponding to 16.8 air changes per hour was adopted for design to maintain vacuum conditions of at least 0.20' of water column and to allow more uniform flow regulation among inlet manholes. In some ways, the steeply sloped and ventilated collection system operates as a giant linear stripping column. The collected odorous air may then be treated using conventional vapor-phase treatment technologies. Design of the facilities is underway and features 13 air-inlet assemblies, jumper ventilation lines, a central vapor-phase carbon adsorption system with dispersion stack.

Introduction Sludge generated from wastewater treatment typically goes through a series of handling processes such as thickening, stabilization and dewatering, before its final use or disposal. Anaerobic digestion is widely applied in medium to large water resource recovery facilities (WRRFs) for sludge stabilization. In anaerobic sludge treatment, fugitive methane emissions can occur from digesters (due to aging infrastructure), downstream storage, from associated pressure relief valves and pipework, and also due to methane slip through combined heat and power (CHP) engines and biogas upgrading. For example, work in Denmark over the past few years has quantified methane emissions at 69 biogas facilities and shows methane emissions account for up to 7.5 percent of the gas production at WRRFs (Fredenslund, A.M et al., 2021; Scheutz & Fredebslund, 2019). Large leakage of methane may negate the positive climate impact from biogas energy recovery and contribute significantly to the facility's operational carbon footprint. A portion of the methane generated is dissolved in the digestate, which can also be released during the downstream dewatering or sidestream treatment processes. In addition, long-term sludge drying (e.g., in lagoons) is commonly applied in many countries, such as Australia, due to its ease of operation and low operational costs. Methane generated from sludge drying lagoons is typically not captured and can be a significant greenhouse gas (GHG) emission source. In the US, a country-wide standard methodology for quantifying GHG emissions from the wastewater sector does not exist. Among the available reporting protocols, methodologies for quantifying fugitive methane emissions from sludge treatment and biogas handling are limited to combustion of biomass and biogas, which essentially assumes zero methane emissions from anaerobic digestion and biosolids dewatering processes. The latest Biosolids Emissions Assessment Model (BEAM 2022) has recommended a minimum of 1 percent of methane in biogas as fugitive emission and allows a user-input value if site-specific data are available. The lack of consistent methodology and lack of facility level measurement result in significant risk to facilities in the estimation of their fugitive methane emissions through the sludge treatment and biogas handling processes. This paper presents an overview of challenges and issues in quantifying fugitive methane emissions from sludge treatment and biogas handling, impacts on GHG inventory and practical tips for reducing methane emissions based on global experience to date across a growing number of case studies. Benchmarking Fugitive Methane Emissions Methodologies and Key Considerations In the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, a three-tier method is described for quantification of methane emissions from WRRFs. Tier 1 provides global activity and emission factors; Tier 2 provides for local in-country activity factors and/or emission factors and Tier 3 methods require facility level monitoring. Accurately quantifying fugitive methane emissions requires Tier 3 facility level measurement using methods such as differential absorption lidar (DIAL), tracer gas dispersion (TDM) and inverse dispersion modelling (IDM), which may be combined with point source leak detection or other process unit methods to determine location of leaks. This practice remains emerging with significant work ongoing in Europe to provide facility level quantification and mitigation at WRRFs. Elsewhere, Tier 2 methods are common. The UK Carbon Accounting Workbook is used by Utilities to report on operational emissions and includes country-specific (Tier 2) theoretical emission factors associated with the most common sludge and biosolids processes in the UK, with emissions based on mass of methane per unit of tonnes dry solids of raw sewage sludge (UKWIR, 2020). In the Australian National Greenhouse and Energy Reporting (NGER) framework, methane process emissions are indirectly estimated using sampled influent and/or effluent streams and application of assumed biogas generation and percentage biogas utilization to calculate the net tonnes of CO2 equivalent released to the atmosphere. This approach considers facility level data but does not require direct measurement of the GHG, hence still considered Tier 2. Emissions from biogas flaring is based on best practice flow rate measurements of the flared biogas and its methane concentration. Different facilities may have a range of approaches to sampling process streams for operational, planning or reporting requirements. Sampling locations, frequencies and methodologies can result in inaccuracies in estimating the fugitive methane emissions. The recently published IWA book 'Quantification and Modelling of Fugitive Greenhouse Gas Emissions from Urban Water Systems' includes additional information on fugitive methane emissions from a range of wastewater treatment, sludge and biogas handling processes, estimated through facility level monitoring (IWA, 2022). Table 1 provides a summary of key methane emissions from global case studies including both those which directly monitor methane emissions and those which use various alternative GHG accounting methodologies, generally aligned with Tier 2 level approaches. A more complete table will be provided in the full paper. In the absence of global full scale monitoring data to estimate fugitive methane emissions, existing methodology estimates may be beneficial for benchmarking emissions from sludge treatment and biogas handling processes however, Tier 3 level facility monitoring is required to accurately estimate methane emissions and to validate any mitigation efforts. Monitoring and Reducing Fugitive Methane Emissions Whilst published literature studies of methane mitigation are limited, practical examples of programs for monitoring and mitigation across European countries show the criticality of direct methane emissions monitoring, and operational approaches to mitigate methane emissions through regular survey, proactive leak detection and repair and independent certification. Table 2 summarizes some of the key sources and (limited) mitigation approaches from work to date; further details to be provided in the full paper. In future planning, it is critical that decisions regarding anaerobic versus aerobic sludge digestion consider fugitive emissions from existing and proposed assets. Conclusions Fugitive methane emissions from sludge treatment and biogas handling processes are a significant source of GHG emissions which must be monitored and mitigated by utilities taking action to reduce their carbon footprint. These emissions are particularly critical for WRRFs with anaerobic digestion and open anaerobic systems such as sludge drying ponds. There is lack of consistent methodology for quantifying and monitoring these emissions in North America, which could lead to over- or (more likely) underestimation of their contributions to the overall GHG footprint for the WRRFs. As shown by ongoing work in Europe, facility level measurement is critical in quantifying the fugitive methane emissions. This paper will provide practical recommendations to WRRF operators to guide best practices for methane monitoring and mitigation throughout the facility life cycle.