Conference Papers

1. INTRODUCTION Considering continuous generation of wastewater sludge in vast amounts and beneficial constituents, many countries have been using sludge on land. Nevertheless, land application of insufficiently treated sludge raises concerns due to transferring pathogens and trace pollutants, including toxic organics and microplastics (MPs) into the environment. MPs constitute a large portion of pollutants in sludge because of inseparable and versatile use of plastics in our daily life. Due to their small sizes (<5 mm), MPs can easily transport across environmental compartments and reach WWTPs in great amounts. WWTPs with modern technologies can remove MPs from wastewater with >90% efficiency but concentrate them in sludge. Anaerobic digestion of sludge is a widely used management option that stabilizes the sludge and reduces the amount to be disposed of. Various pretreatment methods have been developed to improve the efficiency of digestion such as thermal hydrolysis process (THP), chemical, and mechanical techniques. Recent studies have revealed that MPs can affect the efficiency of anaerobic digestion process.1 Furthermore, corresponding deteriorative effects of stabilization on MPs have been superficially addressed.2 Despite their stiff nature, exposure to abiotic factors such as heat, light, water, chemicals, and mechanical impacts may initiate structural changes and induce biodeterioration. For example, polyethylene terephthalate (PET), can hydrolyze to a certain degree in the presence of alkaline solutions due to saponification process in ester linkages. In addition, they can hydrolyze in wet conditions at high temperatures as in the case of THP.3 For the first time in literature, this study investigates whether alkaline pretreatment, THP and combined alkaline and thermal hydrolysis pretreatment (ATHP) processes applied for sludge disintegration and biogas enhancement can concurrently deteriorate PET MPs and lead them biodegrade during anaerobic digestion. Moreover, the study investigates the effects of different concentrations of MPs on digestion efficiency. 2.MATERIALS AND METHODS WAS and anaerobically digested sludge (ADS) were taken from a conventional WWTP serving a population of 4 million with a capacity of 765,000 m3/day. The model PET MPs were obtained by cutting water bottles into square shapes using scissors. Then, the particles were passed through a series of sieves to obtain MPs in sizes of 250-500 µm. WAS solubilization efficiency of three different disintegration techniques (i.e., alkaline, THP, and ATHP) were tested in varying conditions by monitoring soluble COD (sCOD) of WAS, which was spiked with 3 mg PET/g TS. Alkaline pretreatment was carried out for 5 days by dosing WAS with 0.5 M alkali using KOH and NaOH at 0.10 and 0.40 M, respectively. THP was performed at 127 °C and 1.7 bar for 30, 60 and 120 min using an autoclave. In ATHP, WAS samples (three sets) which had been alkaline pretreated (0.5 M) for 2, 4 and 5 days were autoclaved at 127 °C for 120 min. PET MPs collected from pretreated WAS were analyzed using SEM and FTIR to observe the changes they experienced during pretreatment. Biochemical methane potential (BMP) reactors of pretreated and unpretreated sludges spiked with 0, 1, 3, 6 mg PET MPs/g TS were set up in triplicates at a food-to-microorganism ratio of 1, and a total solids content of 2%. Reactors were coded as R0, R1, R3 and R6, with the letter P added for disintegrated reactors. All reactors were operated for 60 days under mesophilic conditions. Reactors were monitored for gas production throughout their operation. At reactor termination, digester performance and plastic characteristics were analyzed. 3.RESULTS AND DISCUSSION As shown in Table 1, disintegration degree (DDCOD) reached up to 81% by alkaline pretreatment in 5 days. Considering the most evident increase (71%), two days alkali pretreatment was selected. As the duration of separate THP was prolonged, solubilization increased only slightly and reached to a DDCOD of 19% at a maximum, comparable to literature.4 Although there was no notable difference beyond 30 min, 120 min was selected as the main purpose was exposing MPs to stress conditions before anaerobic digestion. Figure 1 shows that solubilization achieved in two days of alkaline pretreatment was improved with the addition of THP. However, the contribution of THP became relatively small beyond two days of alkaline application. Two days of alkaline application and a subsequent 120 min THP was selected for ATHP, which altogether resulted in DDCOD of 79%. MPs extracted from pretreated sludges were analyzed for changes in physical and chemical structure by evaluating their FTIR spectra and SEM micro-photographs comparatively with control samples. PET exposed to different pretreatment processes experienced varying levels of changes in different regions of the polymer structure, which differentiates the impacts of thermal and chemical stress factors. Both alkaline pretreatment and THP caused an overall decrease in the absorption intensity of PET. Crystallinity of the polymer increased the most with THP and followed by ATHP. Alkali treatment did not cause a significant change. Therefore, heat application might be the mechanism of increasing the crystallinity of ATHP pretreated PET. This is possibly due to the formation of new crystalline zones in polymer's structure from the breakdown of branches in backbone and bending on themselves. Partial melting and the recrystallization of the amorphous region of the polymer can be the reason of increase in crystallinity. It is evident from Figure 3(a) that MPs exposed to alkaline environment experience a strong surface peeling in comparison to untreated samples. Furthermore, THP seems to cause the corners of the square-shaped MPs to expand outward compared to those of untreated MPs. When two techniques were combined, the notable peeling effect caused by alkaline pretreatment diminished to a great extent, possibly due to the heat applied afterwards. The expanded MPs lost the previous changes occurred on their surfaces and reformed, but the cross-sectional layers appeared. As shown in Figure 2, ATHP pretreated reactors produced statistically higher amounts (22.0%) of methane than unpretreated ones regardless of the MPs dose. This can be attributed to that pretreatment process overwhelmed the impact of MPs on digesters. In contrast, the dose of MPs significantly affected the methane yield of unpretreated reactors. Among unpretreated reactor sets, R3 yielded the highest methane production (p<0.05), which was followed by R6, R1 and R0, in decreasing order. Both crystallinity and carbonyl index of MPs showed smaller changes by anaerobic digestion compared to more dramatic effect of sole ATHP. Figure 3(b) shows that there was an observable predominant impact of digestion, giving the MPs a squashed surface appearance and decreased surface thickness at some points. These images supported the current claim that MPs pretreated prior to anaerobic digestion becomes more prone to microbial attack. Acknowledgement: This study was funded by TUBITAK through the project grant 121Y156.

PROBLEM: Water sector utilities need transformative leadership, at all levels, right away! This assertion may seem overly dramatic, but the signs are everywhere to the perceptive observer. WaterNow Alliance states on its website: 'Between aging infrastructure and the growing effects of climate change, our communities are in dire need of a water revolution.' (1) From the Water Utility Climate Alliance website: 'While water managers continually strive to maintain [a] supply-and-demand balance through long-term water resource planning and demand management, new challenges exist due to the impacts of climate change, putting the world's water resources at risk.' (2) In August 2021, AWWA's Transformative Issue Symposium series ' kick[ed] off with an overview and exploration of the environmental, social, and governance risk assessment methodology, before launching into a conversation addressing water affordability and access. The financial impacts of the global pandemic have highlighted challenges to water affordability and inequities in access to safe water . The evolution of a long-term solution to this challenge requires collaboration, communication, and community engagement.' (3) The water sector also urgently needs more diverse leadership, as a 2018 Brookings Institution report points out: 'As the U.S. economy continues to grow, many communities are struggling to translate this growth into more equitable and inclusive employment opportunities. Simultaneously, many of the nation's water infrastructure assets are in urgent need of repair, maintenance, and restoration. Yet the workers capable of carrying out these efforts are in short supply due to an aging workforce eligible for retirement and the lack of a pipeline for new talent. Women make up only a fraction of employment in some of the largest water occupations and there is a particularly low share of black and Asian workers employed in the water sector.' (4) A changing climate, demands for environmental justice, the necessity of equity and inclusion for all people, an aging and changing workforce, security threats, rising costs necessitating rate increases-the list of challenges is long. For the water sector, adaptation to change is critically important and urgently needed. Change requires local leadership−'transformative leadership'−to meet new demands. ANSWER: The Transformative Water Leadership Academy (TWLA) was designed for this purpose. Its mission: Develop and nurture diverse, emerging leaders to guide water utilities in support of just, resilient, and sustainable communities.' This 10-month leadership training program launches in Fall, 2022. Holistic Program: Diversity, Inclusion and Social Equity Concepts TWLA views diversity in the water sector workforce as valuable and intentionally recruits for a diversity of race and ethnicity, gender, age, geography and culture reflective of an increasingly diverse America and beyond. TWLA embeds the values of diversity, inclusion, and social equity throughout the curriculum. Finally, alliance with influential international, national, and regional organizations serve as a resource for the program to bring better understanding of biases and inequities. TWLA prepares graduates for leadership within the water sector and equips them to build sustainable communities and address the substantial change within utilities. The curriculum and 'hosted' group discussions guide participants to consider and balance social, environmental, equity, managerial, technical and financial matters, distinguishing this program from others. TWLA also recruits a diverse participant pool across geographic, racial, occupational, and economic groups to build a cohort of water leaders able to meet their communities' challenges. TWLA pursues five primary strategies: 1)Diversity: Increase the leadership skills and actions of emerging water leaders at any level of their organizations, with an emphasis on underrepresented racial and ethnic groups, and nontraditional education and experience. 2) Commitment: Through long-term interactions with these emerging leaders, cultivate a commitment to the practices of communication and collaboration supporting resilient organizations for a healthy environment and a wholesome, just community. 3)Action: Support participants in finding and defining their leadership objective and help them put it to use so that they can become community leaders with purpose. 4)Structure: Strengthen communities through direct involvement of academy participants. The participants will be in a better position following the program to advocate for improved programming and policy within their communities. This will have direct implications for communities and better enable them to contribute to the betterment of public health. 5)Network: Build connections for participants and the program through the Community Cooperative Alliance whose organizations and networks have unique abilities to interact with affected communities, react quickly to community needs and issues and engage with affected groups. Innovative Method: Experiential Learning The program incorporates experiential learning methods, connecting class work and theories to real experience so participants better grasp concepts, use their creativity, and fully engage in learning. A consensus of researchers on learning theory finds the most effective adult learning occurs on the job, and through rapid application of new knowledge or skills. (5) TWLA emphasizes the application of leadership skills and personal agency using acquired knowledge and skills on-the-job and in the community. Additionally, participants will be required to complete a 'Capstone' project chosen to address a specific problem in their utility, community, or a larger region. A project could address issues of affordability, stakeholder communication, resilience to climate change, source water protection, or other challenges utilities face. Participants share information about their projects, the results, and the lessons learned at a conference or community event. AWWA and WaterNow Alliance−A Creative Partnership The American Water Works Association (AWWA) and WaterNow Alliance (WNA), two nonprofit organizations with national and international reach form the partnership at the center of the Transformative Water Leadership Academy. These partners also enlist other organizations to extend program outreach for diversity, and for sharing results to a wider audience. WNA is a network of, and forum for local water leaders supporting environmentally sustainable, affordable, equitable and climate resilient water strategies. As partners in TWLA, these organizations complement each other's strengths and core audience. Whereas AWWA reaches about every occupation within the water utility, WNA focuses on the employee leaders of water sector organizations, as well as elected and appointed council, commission, and board members. The combination creates a target audience for the TWLA program that includes emerging leaders employed by water utilities across the nation and beyond, and also the emerging leaders in policy and decision-making bodies. A Significant Difference, Positive Outcomes Results will be shown through several means. The orientation of the Academy to develop individual agency and active leadership skills means participants will have communication assignments during the course. Upon completion, graduates will also be challenged to exercise their communication leadership in at least one of two ways: (a) make an oral presentation on how to lead within one's utility and occupational position; and (b) write an account of how the Transformative Water Leadership Academy experience affected their understanding of the impact individual and utility leadership can make for positive change. The full positive outcomes of the Academy will be revealed over time, as successive cohorts move into new and higher positions of leadership in the water sector. Outcomes for Participants will include: - Recognition for their accomplishment within their utility/place of employment. - Assignment of new responsibility and/or a new opportunity to demonstrate leadership. - Advancement by way of promotion to a higher position. Outcomes for Utilities will include: - Opportunity to empower Academy participants to exercise leadership in areas to improve their utility in some meaningful way. - Innovative approaches from Academy participants to solving problems in the community. Outcomes for Communities will include: - Increases in the resilience and sustainability of their utility systems. -Improvements in the relationship between residents and the utility organization serving them. - Better management and protection of water and environmental resources.

The Interstate 579 'Cap' Urban Connector Project and creation of the new three-acre Frankie Pace Park provides a vital urban green space link and repairs broken community connections between Pittsburgh's historic Lower Hill District and the city's downtown business and cultural centers. Over 60 years ago, as part of 1950s and 60s national urban renewal initiatives and interstate highway expansion, over eight thousand Hill District residents were forcibly displaced by the construction of the new Crosstown Boulevard through Pittsburgh's Lower Hill District. The Lower Hill District was a vibrant and primarily Black neighborhood with a rich history of Pittsburgh born Jazz greats and the famous Pittsburgh Crawfords of the professional Negro League baseball. Access to the downtown area was significantly impacted for residents that remained adjacent to the eight-lane highway and its 40-ft deep concrete canyon. The construction of Frankie Pace park is a literal and metaphorical bridge, helping repair broken connections for the Hill District neighborhood residents and spur economic development. The $32 million park was opened to the public on November 22, 2021. The park is named in honor of longtime Hill District resident and community activist, Frankie Mae Pace. The park consists of over 250 newly planted trees, 4000 perennials and shrubs, 0.7 acres of pervious lawn, six (6) terraced rain gardens, 300 linear feet of artistic surface trench drains, and over 500 CY of topsoil placed on top of the cap structure. The 52,000 SF cap over the interstate serves as one of the largest public green roof projects in the region, if not the nation. The design of the cap structure was iterative process considering key design feature such as the weight of the engineered soil, landscaping plans, and potential event spaces on the structure. All these elements work together to capture, detain, and filter stormwater prior to entering the Pittsburgh Water and Sewer Authority's combined sewer system at the bottom of the site. Overall, an estimated 1.5 to 2.0 million gallons of stormwater is managed annually in the park and the lawns can store up to 6 inches of rain during a single rainfall event capturing a total of 2.1 acres of impervious area. In addition to the enhanced stormwater features, the park intertwines artistic and interpretive artwork from local artists allowing park users to learn the history of the Hill District and the importance of stormwater management. The presentation, if selected, will provide a brief history of the historical importance of Pittsburgh's Lower Hill District, an overview of how the project came to be, explain the design and construction of the cap and associated stormwater management features, and quantify the hydrologic and water quality performance of the site through design hydrologic and hydraulic modeling. The presentation will also highlight federal funding opportunities related to highway cap projects including USDOT's Reconnecting Communities Pilot Program. Attached are images of the before and after photos of the site and photos of the trench drain system and tiered rain gardens at the bottom entrance to the park..

Abstract Robust siting of Green Infrastructure (GI) application can achieve high reduction in peak discharge rates of runoff during storm events and improve water quality, all while creating additional green space benefits. While designing and implementing GI has become more mainstream, retrofitting GI into developed areas still poses challenges due to existing utilities and infrastructure, lack of suitable soils or suitable slopes, and several other potential surface and subsurface issues. To identify and evaluate favorable potential GI locations, we developed a four step GIS site-screening approach that reduces engineering process and leads to optimized GI application programs. Arcadis developed a GIS site screening approach that uses readily available infrastructure data. Much of this work would have previously been done by sending field staff out to inspect and gather data. The goal of this approach is to provide a tool for the planner/ designer that represents a continuum of GI suitability across the project area from which individual locations are evaluated and ranked before the sites are sent for further field confirmation. This approach reduces time in the field by prioritizing which areas may be better suited for GI implementation and as such can provide a defensible baseline for Capital Improvement Program (CIP) project selection and design. The approach was developed and used successfully in several cities across the US, in Columbus, OH, Los Angles, CA, DC and Richmond, VA. Objective The developed approach depends on 4 steps to locate most efficient sites that include flow availability, site availability, site suitability and GI performance scoring. These four steps address the sites secretion, the location of the GI (in public parcels or within the public corridor), the type of GI (Bioretention cells or pervious pavement) existing surface and subsurface utilities and project goals. The objective is to consider all the prementioned factors using readily available data and produce a short list of sites that provide highest benefits and reduces the required flied work Stepping through each phase sequentially enabled the screening of large number of potential public parcels and right-of-way sites and reduce to a viable number of sites with the highest benefits. The evaluation process also enabled the GI Ranking approach to provided results at a faster rate as lesser number of sites are being evaluated in each new phase. Finally, the process helped to simplify reviews for each phase and prevented re-examination of sites that were already excluded if/when the performance criteria was modified Figure 1 shows the workflow diagram of the selection phases and the objective/target of each step. Methodology The GI Ranking Tool evaluation and analysis process includes the following steps: 1. Flow Availability. The flow availability process involved locating runoff catchments and city owned parcels with adequate surface runoff. The process included identifying flow routing mechanisms and calculating directly connected impervious area (DCIA) within both City owned parcels and runoff catchments. 2. Site Availability. In this step, the availability for adequate space for various GI types within sites with high flow runoff identified in step 1. Site availability analysis depends on the minimum requirements for each of the considered GI types. In public parcels, pervious pavement, Bioretention cells in open spaces, and/ or converting part of the parking lot to bioretention are considered. In public corridors within the right-of-way, permeable pavement is considered for low traffic areas, like local roads, collector roads, and alleys with curbs. Bioretention sites are considered along sidewalk away from intersections and driveways 3. Site Suitability. Steps 1 and 2 determine the availability of flow to mitigate and space to place GIs. In step 3, sites are then screened for suitability based on potential conflict with surface functions and potential conflict with subsurface structures like tress, utilities, etc. 4. Score GI Performance. The fourth step is ranking the GIs using scoring criteria that meet the study target goals. Criteria include amount of runoff/flow reduction, impervious area reduction, maintenance of the selected GI types, socioeconomic benefits, minimization of known local flooding condition, improvement of urban tree canopy and improvement of water quality. Different benefits could be used for the ranking based on the project goals Case Study Results The siting procedure was applied to different cities including Columbus Ohio, Los Angles California, DC and Richmond VA. The Richmond, VA GI Master Plan is used in this presentation to detail the procedure. The objective was to identify opportunities to incorporate green infrastructure in public parcels and in the right-of-way to reduce stormwater quantity and improve water quality. The key objectives that are critical to the project's success include: - Reduce stormwater volume in the combined sewer system. - Reduce impervious area and increase green space. - Reduce amount of nitrogen, phosphorus, and sediment delivered to James River. - Address existing drainage/flooding concerns where possible. - Implement easily maintainable GI where possible to minimize future maintenance (since maintenance in perpetuity will be required of any GI). The study area included over 500 public parcels and the impervious area within the public corridor was more than 3,860 acres. The final site selection show that Bioretention in open areas of public parcels and the space between curb and sidewalks in the public right-of-way had the highest number of qualified sites for incorporating GI, while bioretention in parking lots and green alleys had significantly smaller numbers of qualified sites. The public parcels contained 169.75 acres of DCIA. The applied procedure identified the top 110 parcels with the highest score. GI application to these 110 parcels would control up to 154 acres (91%) of the public parcels DCIA. The public corridor contained 3,862 acres of DCIA. The applied procedure identified the top sites with the highest score that would control 536 acres (14%) of the DCIA within the public corridor. Tables 1 through 6 show an example of the siting procedure results for each step and Figures 4 and 5 show an example for the final site selection and ranking.

The 60-mgd F. Wayne Hill Water Resources Center (FWHWRC) is Gwinnett County's largest and most advanced wastewater treatment plant. The FWHWRC utilizes enhanced biological phosphorus removal (EBPR) and chemical polishing to meet a stringent effluent total phosphorus limit of 0.08 mg/L. The liquid treatment train is comprised of influent screenings, grit removal, primary clarification, activated sludge (biological reactor basins (BRBs)), secondary clarification, tertiary filtration, pre-ozonation, biological activated carbon (BAC), and post-ozonation. Solids handling includes co-thickening of primary sludge and WAS, anaerobic digestion, and sludge dewatering. The facility also utilizes the OSTARA Pearl process with WASSTRIP (i.e. Nutrient Recovery) for controlled harvesting of struvite and the reduction of phosphorus recycle loadings on the liquid treatment train. The FWHWRC is a high-profile, complex facility with numerous process components and five operating odor control systems, the largest of which is a 256,000-cfm chemical scrubber system. Despite GCDWR's attempts to work with its on-call contractors and engineers to identify and remedy several known odor sources, odor complaints persisted. An odor study was therefore recommended to fully characterize odors from various parts of the plant. This paper discusses the recommendations from the odor study conducted at the treatment plant, as well as the outcome from implementing the recommended changes in full-scale. Optimization Effort The odor study included an odor source survey, odor sampling and sample analysis, and development of an Immediate Action Plan; odor source prioritization, and development of a Long-Term Action Plan. The Immediate Action Plan was intended to identify issues that could be addressed in the short term to help alleviate any odor complaints originating within the boundary of the treatment plant. This task began with a site visit by a team of odor and process experts, who conducted an operational review of the facilities in the plant. The site visit included visual inspection of all existing odor control systems to identify improvements that can be made to the operation of the systems, in addition to a review of operational practices that may be contributing to off-site odors. As part of the site visit, all potential odor sources were identified, and a detailed sampling plan was developed with more than 40 sample locations. Grab samples were collected and analyzed for sensory samples (odor threshold, intensity, and dose-response), sulfur speciation, and ammonia/amines (at select locations). In addition, several OdaLog units were installed to determine diurnal trends for hydrogen sulfide gas. Results D/T Highest D/T values were observed near the influent distribution box, followed by the solids odor control system. Odors observed near the solids disposal truck bay were determined to be stationary. D/T values measured near the FOG receiving station were also observed to be low. D/T values measured at the exhaust of all other odor control systems were lower than 250 o.u. Sulfur compounds- The highest concentrations of reduced sulfur compounds were detected at the Solids Odor Control System inlet (350 ppb H2S) and exhaust (210 ppb Dimethyl Sulfide); and the Influent Distribution Box (180 ppb Dimethyl Disulfide). The remaining sample locations had concentrations of reduced sulfur compounds that were either non-detectable (ND) or at low ppb levels. H2S concentrations across the range of sample locations were considerably low or not detected, except for occasional spikes at the Influent Distribution Box due to diurnal flow variations at noon and midnight. Amines and Ammonia- With the exception of one sample at the solids disposal truck (17.5 ppm), all ammonia concentrations detected were below the detection threshold (17 ppm). The highest concentration of trimethyl amine (TMA) compounds was detected in the Truck Loading Bay, which had a high concentration of 11 ppb. All other locations sampled and tested, including the Nutrient Recovery Facility and its associated odor control system and solids disposal trucks had relatively low levels of TMA. Odor Emissions The primary odor source on site was determined to be the large chemical scrubber system. Although the measured H2S values were low (0.09 0.9 ppm), D/T values in the scrubber exhausts were higher than expected, ranging from 250 to 1,900. Combined with the high exhaust rate of 256,000 cfm, these scrubbers were determined to be a clear source for off-site odors. In addition, the removal efficiencies for D/T through the chemical scrubbers averaged only about 90%, which is below the expected removal efficiency of 99%. Based on the sampling and emissions rate data, this source was deemed a high-priority source. The Immediate Action Plan helped identify and prioritize odor improvements into three categories: high, medium, and low priority. The highest priority items included refurbishment of the existing 256,000 cfm chemical scrubber system, including: rebalancing of the ductwork system-a 2-month long process that included over 250 individual take-off points, adjustment of chemical feed setpoints, adjustment of chemical feed/sampling locations, operational procedure improvements (including packing cleaning procedures, fan operation, etc.), fine-tuning of automatic controls for fans and chemical feed pumps, and replacement of scrubber packing and spray nozzles for increased efficiency. In addition, other operational improvements were identified, including: adjustment of operation of splitter boxes to minimize fugitive emissions, addition of a new carbon adsorption system to serve the equalization splitter box, recommendations for improvements to the operation of the solids process, and reducing sludge blanket levels in the secondary clarifiers. Conclusion Based on the results of the odor study, many of the Immediate Action Plan recommendations were successfully implemented by GCDWR which in turn has led to mitigating any odor complaints since. Modifications to sampling location and operating parameters such as pH and ORP set points on the chemical scrubbers has also led to significant cost savings from reduced chemical usage (>50% reduction in chemical usage). The other modifications implemented for the chemical scrubbers have increased scrubber removal efficiencies, reduced fugitive emissions from the plant, and reduced scaling in the chemical scrubbing process. In addition, the recommended improvements have increased the reliability of the existing odor control systems and reduced odor emissions from the facility. Completion of the odor study allowed GCDWR to prioritize odor improvements and zero in on the most problematic areas of the plant prior to making any major capital investments.

Dynamic olfactometry (ES 137225) is the standard and well-established technique for odor intensity measurements, however it is not adapted for big industrial sites which need continuous monitoring and fast results. Additionally, these sites need to have odor sources identification solutions to ensure proper remediation actions. In the city of Ventspils, (Latvia), the harbour can welcome up to 20 petrol tankers, and the Baltic wind can push the gas and odors towards the city. The municipality does not have the tools neither to quantify nor to identify the sources of pollution and nuisances. In the experiment with the port authorities, an array of WT1 devices was deployed on different sites close to the sources and at the fence line. During the initial training period, the devices were trained with four different types of samples at different dilution levels (black fuel oil, solvent naphta, petrol, kerosene), and a successful correlation model was established following the 13725 standard between sensory measurements with dynamic olfactometry and the WT1 outputs, allowing the quantification of odors as well as the identification with an accuracy superior to a 0,85 R2. Additionally, a PCA (Principal Component Analysis) and a LDA (Linear Discriminant Analysis) were built and the WT1 modules proved to differentiate accurately the different sources of odor and pollution. The RUBIX WT1 gas and odors sensing modules allow not only on-line monitoring of Odor Unit and various gas emissions, but also allow odor fingerprint identification. The paper will present the methodology that combines a range of smart sensors with AI statistical data processing techniques, allowing for the odor sources identification. The experimental plan, including the training with dynamic olfactometry will be described.

Enormous quantities of pharmaceutical and personal care products (PPCPs) are used worldwide every day. Significant amounts of these PPCPs reach wastewater treatment plants (WWTP) where they are primarily concentrated within biosolids in the solids treatment train and are not completely treated (McClellan et.al., 2001). Approximately 60% of the biosolids generated in the United States (US) are land applied. As a result, the US Environmental Protection Agency (EPA) has recognized the need to evaluate the occurrence, fate, and potential risk of unregulated pollutants in biosolids considering that land-applied biosolids may result in introduction of these pollutants to the environment via transport to soils, surface, and ground waters, as well as edible crops and animal products (Gerba et. Al., 2009, US EPA 1999). The 40 CFR Part 503 Sludge Rule provide us confidence and a framework on how to best manage risks from unregulated emerging pollutants in biosolids (National Academic Press, 2002). Additionally, Section 405(d) of the Clean Water Act (CWA) requires EPA to periodically review sewage sludge regulations to identify any additional pollutants that may occur in biosolids, and to set regulations if sufficient scientific evidence shows they may adversely impact human health or the environment. The emergence of analytical methods to measure increasingly lower concentrations of pollutants, combined with new data on the potential for human health and environ-mental impacts, requires the EPA to evaluate these newly detected compounds. With the universe of compounds that must be considered under this paradigm, the EPA is working to modernize, standardize, and streamline the risk assessment process for risk assessment of these constituents of emerging concern in biosolids. The EPA's Office of Water has developed a draft Biosolids Chemical Risk Assessment and Biosolids Screening Tool (BST) and a User's Guide to identify pollutants, pathways, and receptors of greatest interest and inform decisions regarding the need for refined risk assessment of land-applied biosolids, which is currently under review by a Scientific Advisory Board. Additional information can be obtained on EPA's website. In context of this issue, the EPA Recently funded nearly $6M to four institutions for research to support states, municipalities, and utilities in determining the potential risk from pollutants found in biosolids. Results from this research will be used to inform the development of standards and policies for biosolids management. One of the four funded projects, being led by Michigan State University, Colorado State University, University of Georgia Research Foundation, and the Great Lakes Water Authority is focused on PPCPs and PFAS as representative pseudo-persistent emerging contaminants (due to continuous discharge despite relatively rapid dissipation in soils). The teams aim to improve knowledge of occurrence, transport, fate, plant uptake, livestock, and human exposure to pollutants in land-based biosolids. The study will generate scientific information that will be important in risk management and in informing beneficial use management strategies. As an extension to this interdisciplinary, multi-institutional, multi-state, and university-industry collaborative partnership, including an initial 12 wastewater utility partners, the team has funded additional sampling to expand the study to 28 individual WRRF sites in North America (Figure 1). The objective of this surveillance study is to understand the range of concentrations of these compounds in biosolids, and to determine correlations of concentrations as a function of treatment processes. Participating Utilities were contacted in the summer of 2022 to complete a 102-question survey about their operations and process trains. After analyzing the survey data, samples were collected. Currently samples collected from the 24 WWTPs and remaining will be collected by end of 2022. Samples were collected as solids entered the solids treatment train (e.g., blended primary and waste activate sludge entering the anaerobic digesters) and at the compliance point of the stabilized biosolids product leaving the WWTP, regardless of end use or disposal method. WWTPs where the solids treatment trains were complex or had multiple outputs, more than two samples were collected and assessed. The samples were analyzed for 57 PPCPs (Table 1) by SGS AXYS according to method MLA-075 (EPA 1694). In addition to PPCP analyses, general characterization of the sludge was also conducted which included: pH, alkalinity, total solids, total volatile solids, and chemical oxygen demand (COD) and other parameters. To maintain anonymity, with respect to potentially sensitive data, WWTPs are not named, and data is presented to analytical laboratories and universities according to facility codes. Results from this surveillance study will be presented to provide an initial overview of the range of PPCP concentrations that enter solids treatment processes, percentage treated/removed by the various solids treatment trains, and the final concentration present in the biosolids. The data is invaluable in supporting an understanding of what utilities throughout North America could expect and can support an understanding of how PPCPs are removed through biosolids treatment processes, which can support decisions on management practices and strategies for biosolids disposal/beneficial reuse.

PROBLEM STATEMENT/PURPOSE: Prince William County Service Authority (PWCSA) owns and operates the H.L. Mooney Advanced Water Reclamation Facility (AWRF) in Northern VA. The AWRF is nestled in a residential community with parks and a walking path along the property line. The AWRF first implemented odor control in 2001, and subsequently upgraded the system in 2011 to provide odor control for preliminary treatment and solids thickening processes. To further reduce odors at the AWRF's property line and beyond, PWCSA is completing a design-build project that includes the assessment of odors at the AWRF through sampling and dispersion modeling, evaluation of odor control technologies, and the design and construction of the chosen system. The purpose of this abstract is to present the odor sampling, monitoring, and extensive dispersion modeling that led to the current design (2022) and future construction (2023) of a 95,000 CFM centralized odor control facility at the AWRF.

BACKGROUND:
The AWRF is located in Woodbridge, VA, approximately 30 miles outside Washington, DC and is in close proximity to several livable communities, nature parks, and walking paths. The AWRF is designed to treat 24 million gallons per day (mgd) average daily flow with current flows in the 14 to 16 mgd range. The AWRF has an existing packed tower chemical scrubber odor control system that treats odors from preaeration, screening, grit removal, and gravity thickening processes at the AWRF. Odorous air from solids dewatering and incineration are routed out of a high stack for improved dispersion. However, odor control improvements are needed to reduce odors within the AWRF site and reduce odor excursions into neighboring residential communities and walking paths outside the AWRF property line.

METHODOLOGY:
In the summer of 2021 odor sampling was conducted at various source locations throughout the AWRF to characterize the odors onsite coming from untreated sources and assess the treatment of the existing odor control facility. Odor sampling was completed during summer months to obtain samples under worst-case conditions (warm weather, higher anticipated odors). The sampled untreated process sources included the equalization basins, primary clarifiers, aeration basins, solids processing building odor exhaust (untreated odors routed to the high stack), and the incinerator exhaust stack. In addition to the untreated odor sources, sampling was also completed on the chemical scrubber inlet and outlet to assess the system performance. The odor sampling completed included: -US EPA Surface Emission Isolation Flux Chamber -Grab samples collected for olfactory odor analysis by ASTM E679 -Odor speciation using ASTM D194 -Reduced sulfur compounds using USEPA Method TO-15 (GC/FPD detector) -Field measurement of H2S using Acrulogs and Jerome 631X H2S meters -Ammonia, Amines, and Dissolved Sulfide with Colorimetric Detection Tubes -Temperature and pH Sampling data was evaluated and used to characterize the types and concentrations of odor species present at the AWRF, and to determine the odor emission rates from each odor source for use in the dispersion model.

RESULTS:
The results of the sampling showed the solids processing building exhaust to have the highest dilution to threshold (D/T) value, followed by turbulent zones of the primary clarifiers, anoxic stages of the aerobic basins, and quiescent zones of the primary clarifiers. The chemical scrubber exhaust results showed the system to be effectively reducing odors from the treated sources. The speciation sampling resulted in the detection of four odor compounds including hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide. Ammonia was also detected in samples from the solids processing building. D/T results were used to develop the odor emission rates (OERs) for each odor source. OERs were developed by translating sampled values into odor units per second (OU/sec) based on airflow and odor magnitude. The OERS were used as inputs for the baseline emissions model, also known as the AERMOD dispersion model. Meteorological data for the AERMOD dispersion model was sourced directly from the National Oceanic and Atmospheric Administration archives for representative observation sites. The most recent three years of available data (2018–2020) were used in this analysis and surface data was obtained from the Quantico Marine Corps Airfield, which is 8 miles south of the AWRF. The resultant impacts calculated by AERMOD are expressed in odor units per cubic meter of air (OU/m3) and can be compared directly to the sampled D/T values. Several scenarios of modeling were completed to evaluate existing conditions, identify the most impactful sources of odor dispersion, and assess potential treatment solution results for the sources. The baseline dispersion model, or existing conditions scenario, showed the predicted impacts from the sampled odor sources on site and their impact outside the AWRF fence line. Figure 1 provides the baseline scenario potential impacts. The worst-case D/T concentrations predicted to reach a given area are shown with the color/label. Based on the baseline scenario, the odor source impacts of the AWRF would be noticeable, and potentially a nuisance, for all areas above 7 D/T (shown in yellow in Figure 1). This includes the communities to the north and east of the AWRF, which have maximum odorous impacts of 7 to 10 D/T. The wide impact of the 3 D/T contour extends beyond the frame of this view, which suggests that the AWRF could potentially contribute to ambient odors greater than 1 mile from the fence line. Individual sources were modeled and showed the solids processing building exhaust and the aerobic basin anoxic zones to have the greatest D/T dispersion impact. Before additional treatment options were evaluated, an odor impact criterion, or D/T fence line goal, was developed with PWCSA during several workshops. Virginia odor criteria are plant-specific, and a survey of Virginia plants showed criteria generally range from 5 to 10 D/T with different averaging time requirements. It was determined that the impact goal should be one that minimizes the risk of negatively impacting neighbors but is balanced with controlling increased cost that will be incurred if goals are excessively tight. For PWCSA, the recommended goal of 100 percent compliance with 7 D/T (1-hour impact goal) at the fence line was used for the evaluation of the model. Once the odor impact criterion was determined, six (6) additional modeling scenarios were developed to evaluate the impacts from treating/reducing odors from the untreated sources. The scenarios were as follow: 1.Treatment of solids processing building exhaust (assumed 90% D/T reduction from solids processing) 2.Coverage and treatment of the primary clarifier odors (assumed 95% D/T reduction from solids processing) 3.Combination of 1 and 2 (treatment of solids processing and primary clarifier odors) 4.Combination of 2 and treating EQ basin odors (assumed 50% D/T reduction from EQ basins) 5.Combination of 2 and covering and treating odors from the aerobic basin anoxic zones (90% reduction of odors from anoxic zones) 6. All control alternatives combined The different modeled scenarios showed the greatest odor reduction results for control scenario 6 (all sources treated), followed by control scenario 3 (primary clarifiers and solids processing building treated). Although control scenario 6 reduced the 7 D/T line impact slightly more than control scenario 3, both scenario results show benefit and bring the 7 D/T line close to the fence line. The model predicted dispersion results from scenario 3 are shown in Figure 2. All six of the scenario results will be shown in the presentation.

DISCUSSION/CONCLUSIONS:
The sampling and modeling results were used to identify the primary clarifiers and solids processing building as additional sources for odor control treatment at the AWRF. Once the sources were determined, a capacity assessment was completed on the existing system which showed it did not have sufficient capacity to treat the additional sources. A complete treatment technology evaluation was completed for the AWRF based on the airflows, odor species present, and required treatment for dispersion. Ultimately, the team decided to move forward with a new centralized chemical scrubber facility re-using the existing vessels and a new vessel to meet the design capacity of 95,000 CFM. Chemical scrubbers were chosen based on the sampling results, odorous airflow capacity requirements, and site space constraints. The presentation will provide insight and potential project path solutions for other utilities looking to evaluate the odor impacts from their treatment facilities on neighboring communities, experiencing odor complaints, or wishing to evaluate dispersion modeling uses.

Autogenous Biochar Production from Municipal Wastewater Biosolids Feedstock at the Ephrata Borough Authority WWTP #1 in Lancaster County, Pennsylvania, USA Lead Authors: Charles Winslow, GHD, charles.winslow@ghd.com Stan Chilson, GHD, stan.chilson@ghd.com Key Words; Pyrolysis, Volatile Organic Compounds (VOC), Biological Contamination, Synthesis Gas, Carbon Fraction, Carbon Dioxide, Greenhouse Gas, Biodryer, Dried Biosolids, Biochar EXECUTIVE SUMMARY The Ephrata Borough Authority (EBA) owns and operates two municipal wastewater treatment plants in Lancaster County, Pennsylvania. The biosolids produced from the 4 MGD WWTP #1 are unstabilized and currently disposed of at local landfills. As a result of rising landfill costs, reduced landfill availability, and concern about future PFAS regulations associated with municipal wastewater biosolids, the Authority engaged GHD to design a new innovative, carbon negative biosolids handling and processing system to produce biochar, a nutrient and carbon rich material with no detectable biological contaminants or PFAS compounds in the final end product, as well as resale value in several markets. This presentation evaluates EBA's decision making process in selecting biodrying coupled with pyrolysis versus other alternatives under consideration. The presentation also includes a summary discussion of pyrolysis fundamentals, including mass and energy balances. THE CHALLENGE One of the challenges many municipalities face is the prospect of doing something new. EBA was confronted with the challenge of upgrading their existing biosolids processing and handling system in the context of uncertain financial and regulatory factors. While they had an outlet for the anaerobically digested, unstabilized biosolids produced at their WWTP #1, they were concerned about this outlet's long-term viability and cost. With an eye on the future and the goal of producing higher quality biosolids and minimizing the amount of material for disposal, they began the process of evaluating their options. Ultimately two upgrade options were selected for final consideration. The first option was conversion of the existing digesters to a two-phase anaerobic digestion (TPAD) system consisting of both thermophilic and mesophilic digesters, which was capable of producing Class A biosolids. The second option was to scrap digestion altogether and to design a new biodrying and pyrolysis system capable of producing Class A biochar. Facing a similar scenario, many in our industry would arguably select the more well-known and established TPAD technology because familiarity breeds a certain comfort level, and our industry is generally risk adverse. THE SOLUTION EBA is a forward-thinking municipality, and they realized that the biodrying and pyrolysis system alternative offers a number of advantages over the two-phase anaerobic digestion option, including lifecycle cost savings and a more favorable construction sequence and schedule; however, if EBA selected this option they would be only the second operating biodrying and pyrolysis facility processing municipal wastewater biosolids in the USA. There are five known biodryer installations operating on wastewater biosolids only feedstock worldwide at the time of this writing. Biodryers are a tried and proven yet relatively new technology that produces Class A biosolids. The biodrying option does not require the addition of any new tanks, thus allowing for repurposing the existing digesters as liquid storage tanks. The biodryer solution also eliminates the need to recycle high strength nutrient loads, as required with TPAD, negating the need for side-stream treatment and mitigating potential impacts on the liquid side of the treatment plant. Coupling a pyrolysis reactor on the back end of the biodryers further reduces the amount of end product by another 60% on a mass basis, and produces a high-quality biochar, which is of such exceptional quality that it is no longer considered a biosolid, and that testing has shown to be devoid of PFAS compounds. More importantly, the inclusion of a pyrolysis reactor allows for the combined system to run autogenously, negating the need for external fuel sources after it is brought to temperature. The Authority was excited about the prospect of bringing this innovative technology to Ephrata, but conventional wisdom would suggest that the TPAD solution was the safer option. However, that being the case, the EBA made the bold move of selecting a new biodrying and pyrolysis process because of the long-term benefits in the face of regulatory uncertainty. PROJECT SUMMARY The project scope consists of new dewatering, biodrying, and pyrolysis equipment housed in a new building, as well as conversion of the existing primary and secondary digesters to aerated and covered sludge storage, including a biofilter for odor control. Construction is anticipated to begin by the end of 2021. At design the new solids handling system will process 8,400 dry lb per day of undigested biosolids through what is best described as a continuous / batch process. Centrifuges will be utilized to process liquid biosolids to produce 22% to 24% total solids (TS) dewatered cake. Dewatered sludge cake is fed to each biodryer drum and, once filled, the biodryer undergoes a batch process lasting 48 to 56 hours. At the conclusion of the biodrying process the material is about 80% dry and classified as a Class A biosolid. The dried material is stored in a hopper, which is used to continuously feed a pyrolysis reactor. The pyrolysis reactor strips the volatile organic compounds from the solid mass and further dries the material to about 95%, producing nutrient- and carbon-rich biochar in the process. The syngas resulting from the pyrolysis reaction is combusted to produce heat energy that is recovered and used to kickstart the biodrying process and maintain the pyrolysis reaction. The new carbon negative biodrying and pyrolysis system will operate autogenously after initial startup and heat up, requiring no external fossil fuel to maintain system temperature and operation. The amount of biochar produced represents a 90% reduction by mass relative to dewatered cake entering the biodryers. Biochar is a marketable product with no detectable PFAS, which Ephrata plans to sell for a small profit at the completion of the project. CONCLUSION The situation facing EBA is one that many municipalities will likely be confronted with in coming years as the disposal of municipal biosolids comes under increasing scrutiny. It is always a challenge to do something new because many municipalities hesitate at the thought of being an early adopter of a relatively new technology. In general, our industry is very risk adverse and, arguably, needs to become risk smart to evolve. The story of EBA and their evaluation and selection of innovative biodrying and pyrolysis technology can serve as a model and an inspiration to others considering a similar journey.

INTRODUCTION Despite the fact that MPs can be removed from wastewater with an efficiency of up to 90 %, still 105108 microplastics (MPs) are released from WWTPs each day (HatinoÄŸlu & Sanin, 2021). Indeed, more than 90% of the removed MPs accumulate in sludge during treatment (Okoffo et al., 2019) reaching an abundance varying from 510 to 495,000 MP particles/g DS (HatinoÄŸlu & Sanin, 2021). Studies reveal that MPs have harmful impacts on organisms; they may act as a vector of hazardous pollutants such as pharmaceuticals and heavy metals with an absorption mechanism onto their surfaces. Moreover, they provide sustainable surfaces for pathogens to colonize and form biofilm. Even though pathogens can be removed by WWTPs to a great extent, MPs can offer a safe environment for them to survive during the treatment process. MPs themselves, together with the hazardous chemicals and pathogens they can accumulate on their surfaces, pose a new concern for the land application of biosolids. Anaerobic digestion (AD) is a sustainable stabilization system with renewable energy generation and good-quality biosolids production for land application. Thermophilic digestion (TAD) is well known to be more effective in stabilization compared to mesophilic AD (MAD) due to its effective pathogen inactivation and Class A biosolids generation. Recent studies have shown that the presence of MPs can affect AD, and in addition, MPs themselves seem to be affected during the process. Yet, all these studies investigating MPs in AD are conducted under mesophilic conditions. TAD has not been investigated so far to reveal the fate and effect of MPs during the process. Polyamide (PA) (nylon) with amide groups (-CO-NH-) having the strength and fatigue resistance is one of most commonly encountered type of MP in sludge (El Hayany et al., 2022). Its high abundance and leaking potential of its monomer caprolactam (CPL) during MAD (Chen et al. 2021) creates interest for PA6. This study aims to comparatively investigate the effect of PA6 on methane production with MAD and TAD while evaluating this MPs' fate during these processes. This work is unique for identifying the behavior of MPs in TAD and specifically evaluating the fate and effects of PA6 comparatively in MAD and TAD processes. MATERIAL & METHOD For the simulation of MAD and TAD, biochemical methane potential (BMP) test was conducted at 35oC and 55oC, respectively. Waste activated sludge (WAS) (substrate) and anaerobically digested sludge (ADS) (inoculum) were sampled from a conventional WWTP designed for a population equivalent of 4 million with a capacity of 765,000 m3/day. The seed was used as sampled for MAD BMPs but was acclimated for the TAD study. As PA6, a fishline with a diameter of 0.5 mm was cut into sizes in the 425-500 µm range and used. Each mesophilic and thermophilic BMP tests had 13 sets of triplicate reactors comprising biotic, abiotic control and seed control groups. Each biotic and abiotic set included six different PA6 doses in reactors, 0, 10, 30, 60, 100, and 200 MPs/g TS. Reactor TS values were adjusted to 2% with an F/M of 1 (g VS of WAS/g VSS of seed). All reactors were purged with 99% nitrogen gas, and were incubated for 60 days. Biogas volume was measured routinely with water displacement and its composition was determined by Gas Chromatography (GC) with a thermal conductivity detector (TCD). Solids were measured using Standard Methods and COD was measured with the US EPA-approved digestion method. Mass, size, and morphology of PA6 before and after digestion were evaluated with scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC) to comparatively assess the changes in MPs during digestion. RESULTS & DISCUSSION The cumulative methane productions of MAD and TAD reactors are shown in Figure 1 and Figure 2, respectively. In both groups, methane production started immediately and increased steadily as time went on. In the thermophilic reactors different than the mesophilic reactors, methane volume increased in two distinct steps; second step coming about 10 days after the first. In both mesophilic and thermophilic reactors, the highest methane production has been observed in the reactors containing the highest dose (200 PA6/g TS), with the lowest dose, 10 PA6/g TS, following. However, for the mesophilic group, reactors with all other doses of PA6 produced lower methane than the control set (R0M). Even though one-way ANOVA test showed a significant difference between the sets (p<0.05), a further test of post hoc (TUKEY test) demonstrated that the significant difference was only between the R30M and R200M sets. As a consequence, when compared to the control set, PA6 addition seemed to have no effect on methane production. In TAD reactors however, while no pattern between dose and methane production is seen (Figure 2), the outstanding results reveal that all PA6-added reactors produced significantly higher methane than the control set (R0T), as validated by One-Way ANOVA results (p<0.05). Additionally, the post hoc test (TUKEY test) found that except R100T, all the PA6 added sets have significantly different methane production compared to the control set (R0T), indicating PA6 affected methane production positively in TAD. This is thought to be due to leaching of monomer CPL. Chen et al., (2021) claims that CPL attaches to enzyme molecules, changing the enzyme's active site and other conformations, increasing the enzyme's affinity for the substrate and catalytic activity. The distinct second step of increase in methane production may hint the leaching of CPL providing additional affinity for enzyme-substrate system, which is currently under investigation. SEM images were captured to examine the changes in the shape and surface of PA6 during the MAD and TAD processes. Figure 3 depicts the SEM results of biotic and abiotic controls from the mesophilic BMP test. Images exhibit minor changes on the borders of PA6 after digestion. In order to better understand the changes experienced by PA6, FTIR and DSC analyses for both mesophilic and thermophilic reactors are currently underway. ACKNOWLEDGEMENT This study is supported by METU-BAP with a grant number of BAP-GAP-311-2021-10613.

NEW Water, the brand of the Green Bay Metropolitan Sewerage District, has completed a program, with initial planning starting in 2008, to replace its biosolids management system at the Green Bay Facility (GBF) in Green Bay, Wisconsin. The facility is permitted to treat 49 MGD of wastewater and process biosolids from the GBF and waste activated solids from their other wastewater facility, the DePere Facility (DPF). The GBF was constructed in 1975 and included a thermal conditioning system (TCS), belt filter press dewatering and two multiple hearth furnaces (MHFs) to process wastewater solids. This process train was chosen because agricultural land application in Wisconsin was deemed not to be practical. Subsequently, the TCS was shut down and in 2008, NEW Water took over operations of the DPF. The almost 40-year-old GBF did not have sufficient treatment capacity into the future and the equipment required replacement due to its age and increasing maintenance costs. In addition, the existing MHFs would not meet the pending federal Clean Air Act Maximum Achievable Control Technology (MACT) air pollution regulations for sewage sludge incinerators (SSIs) that became effective in 2016. Between 2008 and 2011, NEW Water and CH2M (now Jacobs) developed a Solids Management Facility Plan that evaluated numerous solids processing technologies and process trains to respond to these issues. Seventy-three solids unit processes were considered, some were eliminated and the remaining 52 unit processes were used to develop 17 process configurations. Of these 17 configurations, six alternative configurations were selected and evaluated in detail. The Digestion with Thermal Processing and Electrical Generation alternative was selected and later named the Resource Recovery and Electrical Energy Project, or R2E2. The R2E2 process flow configuration, shown in Figure 1, is an integrated solids processing system comprising mesophilic anaerobic digestion (MAD), dewatering and fluidized bed incineration with waste heat recovery (WHR). MAD was chosen as a first processing step to generate biogas for combined heat and power (CHP). High strength liquid organic wastes are co-digested in the MAD process to enhance biogas production and maximize power production and waste heat utilization. Dewatering using centrifuges, followed by fluidized bed incineration was selected as the most efficient method of managing the biosolids, given there is not land within economical distance of Green Bay for agricultural utilization. The fluidized bed reactor (FBR) is equipped with a partial scalping dryer, utilizing waste heat recovered from the FBR and using thermal oil to ensure autothermal combustion. Phosphorus is recovered from the dewatering centrate to produce a fertilizer product. In addition, beneficial uses of the residual ash are being pursued. The CHP, dewatering and FBR equipment trains were purchased and the balance of plant design completed in 2014. Construction commenced in August 2015 and commissioning and performance testing were completed by the end of 2018. Figure 2 shows operating data from the startup of the two digesters through August 2019. The system has been operating since November 2018, as an integrated system. Figure 3 shows a summary of the system energy distribution and usage at the design year of 2035 at annual average wastewater flow conditions. The R2E2 project is expected to generate more than 65% of the GBF projected electrical power requirements in 2035 using biogas only and up to 85% using supplemental natural gas to the full CHP loads. With the system thermal efficiency of about 60% based on heat recovered, the R2E2 project will meet NEW Water's goal of producing electricity in the most efficient way while maintaining autothermal combustion. The paper will discuss the energy recovery and production performance of the facility during the two years of full operation, including the Covid-19 period. Since operation of both digesters commenced, NEW Water has initiated its program of importing high strength organic waste (HSW) and has been increasing quantities to achieve design quantities. Biogas production has increased, with increased electricity production of green energy. The monthly biogas and natural gas electricity production, together with the monthly HSW imported quantities and generator run times in the first year are shown in Table 1. As part of the energy management system, SCADA options allow determining when is the optimum time to operate the CHP and the number of units to operate to reduce demand and other electrical charges. NEW Water continues to optimize energy production with waste heat recovery and matching plant heating requirements. The presentation will be of interest to municipal plant operators, wastewater utility managers, planners and design engineers who are considering integrated biosolids processing systems to maximize energy recovery and provide resource recovery opportunities.

Introduction and Purpose King County's 2015 Strategic Climate Adaptation Plan (SCAP) contained a variety of actions that have, or will, reduce the county's greenhouse gas emissions and help King County (KC) prepare for the impacts of climate change. To address one priority action, a study was implemented in collaboration with the University of Washington Climate Impacts Group (UWCIG) 'to assess climate change impacts on local rainfall patterns.' The results of that research were then to be used by KC to assess potential impacts on the size of required CSO control facilities, so that this information can be incorporated into future wastewater capital planning efforts. Recent research indicates that future heavy rain events will be more intense in the Pacific Northwest. The purpose of this Climate Change Impact Analysis is to understand the impact of climate change on CSO facility control volumes and peak overflow rates necessary to achieve and/or maintain compliance with the current Washington State CSO regulatory compliance criteria. This paper presents the methodology and results of the analysis and may be useful for other utilities working to incorporate climate impacts into their capital planning. King County Wastewater Treatment Division (KCWTD) is the wholesale wastewater conveyance and treatment provider for 34 component agencies including the City of Seattle. King County has 39 permitted CSO locations and the City of Seattle has 99 of their own locations. King County is obligated by a federal and state consent decree to control its CSO outfalls, meeting CSO regulations such that there will be no more than one CSO event per year, in any 20-year period, by the year 2030. Methodology King County's approved CSO long-term control plan has a combination of storage and treatment alternatives recommended for the outfalls not currently in 'control.' For simplicity of communication, the impacts of climate change in this paper are presented as the volume of CSO storage that would be required to achieve control, meeting the Washington state CSO regulatory standard. Thus, the 1-year control volume, over the worst 20-year period, is used to assess the climate change impact by the end of this century. The UWCIG used the results of two Global Climate Models (GCMs) and downscaled them using a Regional Climate Model (RCM) to produce rainfall for the period 1970 -- 2099. The two GCM models selected were: ACCESS 1-0 and GFDL-CM3. Two representative concentration pathway (RCP) scenarios -- RCP 4.5 and RCP 8.5 -- were selected from the scenarios used by the Intergovernmental Panel on Climate Change for the Fifth Assessment Report (IPCC, 2014). The RCPs represent the concentration of greenhouse gasses in the atmosphere resulting from different levels of greenhouse gas emissions. In the RCP 4.5 projection, greenhouse gas concentrations peak before 2100 and emissions decline substantially by the end of the 21st century. RCP 8.5 is the scenario in which emissions are not stabilized in the 21st century, instead continuing to grow throughout the 21st century. The intent in this analysis was to select a future climate condition representing a high climate change scenario and one on the lower side. The grid size for the GCMs was approximately 108 kilometers. Nested RCMs were run for a grid sizes of 36 km and 12 km, using the GCM model output as boundary conditions. The rainfall characteristics were evaluated for 2070 -- 2099 and compared to the characteristics for 1970 -- 1999. The change in annual rainfall amounted to an increase of 5% for the lower emissions scenario and an increase of 6% for the higher emissions projection. The change in rainfall intensities for larger, less frequent events was significantly higher. The 2-year (1-hour duration) rainfall increased by 21% and 32% in the lower and higher emissions scenarios, respectively. Rainfall also varied by season, with less rainfall falling in the summer months (June – August) and more falling during the other months. To determine sizing of CSO facilities, King County simulates historic rainfall with calibrated hydrologic and hydraulic computer models using rain data from 17 rain gauges spread throughout the City of Seattle. The MIKE Urban Software (DHI) was used for both hydrologic and hydraulic simulation of the collection and conveyance system. For climate simulations predicting future conditions, the historical rainfall was adjusted to conditions near the end of this century as reflected in the RCM results. The historical rainfall was factored to maintain the variability of rainfall across the service area and to keep the rainfall record in a minute-by-minute time scale (the RCM output is hourly). Model simulation results (without climate impacts) have been generated by KCWTD for the period from 1978 through 2018 (41 years) to estimate the CSO control volumes and peak flowrates that would be necessary to maintain CSO locations to an average of one event per year over any 20-year period during the historical record. For comparison, the same years were simulated using the factored rainfall associated with the two climate change scenarios representing climate at the end of this century. The resulting CSO control volumes were tabulated for each CSO location to show the potential impacts of climate change on control volumes. Summary of Results This research was conducted on thirty-five of King County's CSO outfalls. The results show that climate change will likely have a substantial impact on the size of CSO control facilities. Of the 18 outfalls that were simulated as 'in control' using historical rainfall, 11 would require additional projects not currently in KCWTD's long-term control plan. The total volume of storage that would be required to keep these 11 sites in control with climate projections is estimated between 2.2 and 4 million gallons (MG) for the low and high greenhouse gas emissions, respectively. Of the 27 outfalls currently not in control, additional storage (or equivalent) on the order of 64 -- 83 MG would be required to bring these outfalls into control and accommodate the impacts of climate change by the end of the century in the climate scenarios. This additional required storage volume would increase the total storage required in the KCWTD CSO program by 43 -- 55%, at a significantly higher cost than would be required without climate change. Quantifying the potential impact of climate change will help project teams and management develop strategies to adaptively manage the risks and uncertainties in sizing CSO facilities in a changing climate. The methodology and analysis can provide other agencies with an example of how Global Climate Model results can be used in long-term planning for CSO.