Results

In the context of biosolids management, for a process to be truly sustainable it must respond to the critical issues facing our industry today; removing contaminants, reducing carbon emissions, and creating circular economies from our most basic and unavoidable waste stream. According to the EPA, in 2018, 15% of the methane emissions generated in the United States came from organics breaking down in landfills. While this number alone is overwhelming, it doesn't capture the total emissions released during the processes of drying and transporting solids from wastewater treatment. Furthermore, land application of biosolids runs the risk of leaching contaminants into ecosystems. Bioforcetech rethinks the entire life cycle of organics, diverting organics from landfill or land application and transforming them into a carbon negative material at net zero energy. Our submission for the 2022 WEF Residuals conference focuses on the technical details that allow our two-step process to run at net-zero energy and transform contaminated 'waste' into a clean and valuable biochar. The abstract also details new partnerships for this biochar, called OurCarbon, that replace fossil fuel based ingredients in commercial products and a life cycle assessment conducted using the BEAM Model that concludes the production of OurCarbon prevents 10 tons of CO2e from entering the atmosphere for every one ton of OurCarbon produced assuming diversion from typical landfill. BFT's proprietary two step process of drying and pyrolyzing biosolids utilizes our patented Bioforcetech BioDryer and P-Series Pyrolysis machines. These two technologies work together to reduce material mass by 90% and lock available carbon in place for centuries all while generating the energy necessary to run both processes. Managing biosolids efficiently requires managing water and energy efficiently. While competing industrial drying processes employ large amounts of external energy (belt and drum drying) or require perfect weather and lots of time (solar drying), Bioforcetech takes a different approach to producing Class A Compliant biosolids. We leverage the living energy that is already within a feedstock to dry biosolids quickly and efficiently. Much like the control of oxygen, heat, and bacteria for sludge digestion, the Bioforcetech BioDryer uses air and bacteria to dry biosolids in a three phase process. This living process is so effective that our BioDryer system is able to process biosolids from 20% to 90+% solids in as little as 48 hours with only 50% and 30% of the thermal energy and electricity that belt and drum drying require. In the first phase, air is pushed through the biosolids to cultivate thermophilic bacteria, microorganisms that create heat. As these microbes release heat into their environment, the BioDryer chamber increases in temperature to 150°F and the water in the biosolids begins to evaporate. During Phase 2, the thermophilic bacteria flourish, generating large amounts of heat. This causes the bulk of the moisture in the chamber to evaporate without any external heat source. What is normally the largest energy toll on other dryers is completely passive in the BioDryer. Finally, in phase 3 the passive heat has evaporated so much moisture that the bacteria are not able to proliferate further, reducing their energy output. To compensate, the BioDryer introduces an external hot airflow to finish off the drying process, usually taken from the excess heat produced by our P Series pyrolysis unit. The BFT BioDryer is able to receive multiple feedstocks, has a modular construction that makes installation and expansion easy, and is run on a fully automated software and hardware suite to reduce O&M well past industry norm. Once the biosolids feedstock has been dried, it moves into our P-Series pyrolysis where the material is separated from contaminants and the carbon present is locked in place. The P-Series Pyrolysis machine transforms waste without wasting any energy. By carbonizing organic material through the application of heat in an oxygen-deprived environment, our process separates syngas from organics and utilizes it to produce high quality clean OurCarbon biochar. Available energy created in this system is circulated to be reused, allowing for a self sustained 24/7 heating system with no external energy required and with no open flame. Thanks to our proprietary flameless combustion chamber, all thermal energy is safely and fully utilized at a controlled combustion temperature. Our flameless burning system boasts extremely low NOx emissions, is the first pyrolysis process approved by the US EPA for biosolids, and is also the first system to meet emission requirements for both California and US EPA regulation. There is absolutely no tar associated with our combustion process or its byproducts, only thermal energy is left. Though designed for biosolids treatment, our reactor is able to treat a wide range of materials or a mix of multiple feedstocks. The P-Series system can process digested/undigested biosolids, manure, green waste, wood waste, food waste, and any combination of these feedstocks. During this presentation we will take the audience through the details of our full scale operational system in Redwood City California and discuss three new contracts under development in Redding, California, Ephrata, Pennsylvania and a third location on the east coast. In 2019, Bioforcetech initiated testing of our drying and pyrolysis process to determine our ability to eliminate CEC's from biosolids. To do this, Bioforcetech isolated a single large batch of biosolids and tested samples of this batch for PFAS, PFOA, and PFOS at each step of our drying and pyrolysis process. An initial sample was taken of anaerobically digested biosolids at 17% solids content, a second sample was taken of 91% solids content after the batch was dried in our patented BioDryer, and a third sample was taken after the batch was carbonized in our P-FIVE pyrolysis machine. The analysis of these three samples conducted by Vista Analytical Laboratory showed the reduction of 38 PFAS, PFOA, and PFOS compounds to below detectable levels after pyrolysis from a significant presence in both of the biosolids samples. In May of 2020, an EPA PFAS Task Force representative contacted Bioforcetech as part of a search for technology that could solve the PFAS crisis. The tests conducted on our biochar samples by the EPA Task Force in August of 2020 confirmed undetectable levels of 41 PFAS, PFOA, and PFOS compounds that the task force tested. The results from the EPA's analysis, including methods involved, will be formally published in November of 2021. The results of multiple tests conducted and confirmed to remove CEC's by different constituents shows great promise for the ability of Bioforcetech's system to remove PFAS, PFOA, and PFOS from biosolids completely. While more rigorous testing must be completed, we are motivated and inspired by the results thus far. Because of the unique processes of our P-Series pyrolysis machine, the biochar we create is of exceptional quality. While biochar is best known for its application as an agricultural soil amendment, OurCarbon has been developed as a sustainable replacement for petroleum based pigments and additive materials that close the loop on waste streams in local municipalities and in globally sold products. In a pigment application, OurCarbon has the ability to replace a toxic colorant called Carbon Black, which is made by burning fossil fuel based hydrocarbons. For every one ton of Carbon Black that is produced, 3 tons of CO2e are emitted into our atmosphere. We are excited to announce that we have recently replaced this pigment formally in screenprinting inks through a recent exclusivity agreement with Quaglia, an Italian screen printing ink producer. The Quaglia team has replaced Carbon Black with OurCarbon in a new commercially available, 80% biobased screen printing ink to be used in a wide range of applications including textiles, automotive applications, hard goods, and packaging. This partnership is a unique opportunity to show the entire world how valuable our 'waste' can be. We are actively engaging with paint companies and bioplastic producers to replace Carbon Black with OurCarbon in their production process and look forward to announcing more collaborations at the 2022 conference. In addition to replacing fossil fuel based materials in industry, a Life Cycle Assessment (LCA) conducted by Northern Tilth using the BEAM Model confirms that every ton of biochar created from the Bioforcetech system prevents 10 tons of CO2e from entering the atmosphere as compared to typical landfill practice. This 1:10 LCA ratio allows OurCarbon to calculate not only the carbon fixed in the material itself, but also the emissions that have been prevented by diverting organic waste from breaking down anaerobically in landfill and emitting as methane.

Hydrogen sulfide (H2S) has long been recognized as a dominant odorant at water resource recovery facilities (WRRFs), with primary clarifiers identified as a main source of H2S emissions (Calvo et al., 2018). Liquid treatments such as chemical addition have been used to reduce primary clarifier emissions, but the efficacy of this approach and the impact of these chemicals on other plant processes can be uncertain without full scale piloting. Whole treatment plant sulfur modeling can provide a comprehensive planning tool to address both concerns regarding treatment efficacy and whole plant impacts. Some recent studies have explored sulfur interactions with iron and phosphorus using whole plant modeling (Johnson et al, 2019, Hauduc et al., 2017, Flores-Alsina et., 2016), but integrated sulfur models for whole plant process optimization and design are still not well used in practice. A recent project in Texas provides an example of how this tool can be used to support whole plant assessments of liquid stream odor treatments when nutrient removal is also a concern. The Trinity River Authority of Texas' (TRA's) Central Regional Wastewater System Treatment Plant (CRWSTP) is a 189 mgd annual average flow facility includes headworks, primary and secondary treatment, filtration and disinfection. The plant employs an enhanced biological removal process (EBPR) for nutrient removal. Plant solids processes will soon be changing, as TRA moves from lime stabilization to thermal hydrolysis pretreatment (THP) with anaerobic digestion (AD) a move that will impact recycle streams at the plant. Whole plant sulfur modeling to screen potential liquid stream treatments at the CRWSTP to: Determine sulfide removal efficiencies at the primary clarifiers Assess impacts at the aeration basins, with a focus on EBPR impacts Define impacts of both current and future recycle streams on liquid stream treatments and downstream impacts. Specific treatments assessed included: Pure Oxygen Ferrous Sulfate (FeSO4) Magnesium Hydroxide (Mg(OH)2) Combined FeSO4 and Mg(OH)2 This paper provides an overview of the modeling effort and its findings. Methodology All whole plant simulations were completed utilizing the Sumo2S package, version 2019 (Dynamita Sumo). The modeling approach included an influent waste characterization, historical data review, model calibration, and special sampling. Waste characterization of the influent and recycle stream were completed based on the Methods for Wastewater Characterization in Activated Sludge Modeling (Melcer, 2003). Results and Discussion Model Development and Calibration A model of the influent headworks through primary treatment was developed with the current plant configuration. This model was used for model calibration to historical and field pilot study data. Figure 1 summarizes the general model structure with multiple tanks-in-series representing physical infrastructure including screening, lift station, pipeline and grit removal. The model was then expanded to include THP and AD. The model was calibrated with previous field pilot data, with the following results : Baseline Figure 2a summarizes the model calibration with no chemical addition for dissolved sulfide control. Pure oxygen calibration Figure 2b/c summarizes simulated versus field data of both dissolved oxygen and dissolved sulfide concentrations. FeSO4 calibration Figure 2d summarizes the calibration of FeSO4 addition and dissolved sulfide concentrations. Mg(OH)2 validation Dose ratios per flow unit were determined with bench scale testing (pilot field data was unavailable). Model efforts identified the following parameters as critical for calibration: Airflow rates within individual reactors Low airflow rates were introduced within reactors to represent physical structures such as weirs and areas of turbulence. Organisms present within the raw influent Relative fractions of ordinary heterotrophic, sulfate oxidizing, and sulfate reducing organisms. Precipitation and dissolution rate of iron sulfide Calibration to field data resulted in reduction of both rates. Whole Plant Simulations Current and future recycle streams modeling scenarios are presented in Table 1 and 2 respectively. Both model results indicate that FeSO4 and the dual feed of FeSO4 and Mg(OH)2 addition provides the highest level of dissolved sulfide removal in the primary clarifiers. Results of the current recycle stream model are presented in Figure 3 and compared against a baseline condition that assumes no chemical addition. Downstream impacts of chemicals addition included the following: Volatile fatty acids (VFAs) decreased by 15 % (10 mg/L VFAs) in the primary effluent. FeSO4 addition contributed to alkalinity consumption and reduce the primary effluent pH to 6.7. Mg(OH)2 addition did not impact EBPR process. When the new CRWSTP solids treatment facilities are completed, TRA plans to add ferric chloride (FeCl3) addition to the ADs, and so the whole plant impact of recycle streams with this addition was assessed. Modeling of future solids conditions with no FeCl3 addition to the ADs show that dissolved sulfide removal efficiency decreased by 10 % due to recycle stream. The modeling revealed the following with respect to plant impacts: Recycle stream ammonium loading from future solids facilities combined with FeSO4 addition to the headworks for odor control purposes had a significant impact to the liquids stream alkalinity and pH. High phosphorous fixation occurred under all scenarios. The addition of FeCl3 to solid and/or FeSO4 to the influent forms 10 percent more precipitates within the solid's facilities due to vivianite production. The addition of Mg(OH)2 results in a negligible increase to the relative precipitate formation. Overall results are presented in Figure 4. FeSO4 addition at both the headworks (for primary clarifier control) and digesters dropped nitrification reactors pH down to 6.6. Simulations showed a gas phase H2S concentration of 2,400 ppm for baseline condition. The addition of iron to the headworks or anaerobic digestion, results in low concentration levels of H2S in the biogas. Conclusion The evaluation of odor control processes using whole plant modeling with the inclusion of sulfur interactions provides valuable insights on both the effectiveness of liquid stream treatments for odor control and the impact of those treatment processes on whole plant impacts. While all treatments studied reduced wastewater sulfides to some extent, the modeling showed that adverse process impacts could be expected for most scenarios assessed, with super oxygenation resulting in the least process impacts (and reasonable sulfide reduction in the primary clarifiers).

PURPOSE City of Atlanta Department of Watershed Management (DWM), through its Clean Water Atlanta (CWA) Program, is required by the ongoing First Amended Consent Decree (FACD) to develop Remedial Measures Reports (RMRs). RMRs are planning and conceptual design documents providing the basis of design for detailed design and construction plans for capacity relief and sewer structural rehabilitation projects. In parallel, DWM developed Watershed Improvement Plans (WIPs) for major watersheds in the City. The WIPs identified stormwater projects to improve water quality and reduce the volume of stormwater discharged to the city's creeks. Custer Avenue, Clear Creek, and Intrenchment Creek are three of Atlanta's combined sewersheds that collectively are served by more than 707,000 linear feet (134 miles) of combined sewers. To reduce CSOs and minimize urban flood risk, the RMRs identified approximately 164,000 linear feet of sewer requiring either capacity relief or sewer rehabilitation with an estimated capital cost of $201.1 million. The RMR defined projects were collectively referred to as 'gray' infrastructure projects. Concurrently, approximately 1,100 stormwater water quality and control infrastructure projects were identified city-wide, through the WIP process, at a total estimated capital cost of approximately $600 million. Collectively WIP projects were termed 'green' infrastructure projects. Considering the significant capital costs of the identified green and gray projects, DWM requested that the Program Management Services Team (PMST), under the lead of Stantec Consulting Services, undertake a project to answer three simple questions: 1. Would it be possible to integrate green infrastructure with the planned gray infrastructure projects to address combined sewer overflow (CSO) and sewer flooding problems in three combined sewersheds? 2. Would it be possible to reduce the capital cost of current RMR plans without impacting future levels of service? 3. Would solution optimization modeling present an opportunity to increase environmental and community benefits in line with wider DWM 'One Water' objectives? METHODOLOGY To answer the questions all applicable green and gray projects to DWM's existing InfoWorks ICMTM hydraulic and hydrologic models. Green projects that would not directly influence combined sewer flows were omitted. Only green projects, if implemented strategically, that could have a beneficial outcome in reducing CSO activations and reducing urban flood risk were included. PMST and DWM have utilized the hydraulic and hydrologic models for a wide range of engineering planning and design activities for more than 20 years and, as a result, the models are well populated, reliable, detailed, and were able to provide an excellent level of detail to start the optimization. The updated InfoWorks ICMTM models were then imported into a cloud-based optimization software, OptimizerTM. OptimizerTM is a genetic algorithm software designed to solve complex multi-criteria problems faster and more efficiently favoring speed of process over absolute accuracy. For this project OptimizerTM was applied to analyze hundreds of thousands of green and gray project combinations to establish the 'best outcome'. After establishing a baseline plan, OptimizerTM varied the size, scale, and combination of all possible solutions to create new plans for comparison against the baseline using three metrics: capital cost, hydraulic performance, and non-cost benefit. Each metric was applied as detailed: Capital Cost. The incremental capital cost of each project was calculated and entered OptimizerTM as a lookup table. During optimization, as project scales and sizes adjust, so do the costs. For gray projects, the increments related to pipe diameter, pipe depth, storage tank volume, etc. and where applicable, construction technique. For green projects, the increments related to the relative size of the solution based on its ability to capture an amount of rainfall runoff volume using rainfall depth and contributing area. Hydraulic Performance. Hydraulic performance was measured by applying hydraulic penalty scores to threshold exceedances in the model's predicted hydraulic grade line (HGL) and flood volume. Penalties were proportional to the exceedances and applied to to every combination of gray and green projects, OptimizerTM tried to achieve the best hydraulic performance by converging on the lowest total hydraulic penalty score. Co-benefits. Infrastructure value is an important criterion for DWM, this metric was designed to evaluate the value of all gray and green infrastructure to ensure OptimizerTM decisions considered the value of all projects. Co-benefits ensured consideration of social, environmental, and economic indicators were included in determining the best outcome. The principles applied to all projects was consistent with DWM's Triple Bottom Line (TBL) categories across all watershed initiatives. With all project information, including metrics uploaded to OptimizerTM, the optimization process was repeated more than 100,000 times to continually seek convergence, each time attempting to find a 'better' green / gray plan based on the metrics. RESULTS Unlike many models, OptimizerTM creates several potential outcomes and there were many combinations of green and gray plans that offered a broad range of possibilities. Some plans performed hydraulically better, some less expensive, and some realized much greater co-benefits; however, no single plan was deemed to be 'optimal'. Results were presented in the form of a three-dimensional (3-D) Pareto graph from which a subset of potential plans were selected. The dimension axis representing capital cost, hydraulic performance, and co-benefits. The 3-D Pareto graph showing possible plans is depicted in Figure 1. DWM were able to select a preferred plan for each combined sewershed. The selected plans and their relative costs are summarized in Table 1. CONCLUSIONS In conclusion, the Green/Gray Optimization project was able to positively answer all three stated questions. 1. Would it be possible to integrate green infrastructure with the planned gray infrastructure projects to address CSO and sewer flooding problems in three combined sewersheds? Yes, it is possible. The project demonstrated there were effective green alternatives for all three combined sewersheds with WIP projects making up 4% of the total capital cost in Intrenchment Creek, 6% in Clear Creek and 31% of the total capital project cost in Custer Avenue. 2. Would it be possible to reduce the capital cost of current RMR plans without impacting future levels of service? Yes, in all three combined sewersheds, cost estimates were lower. Custer Avenue's selected plan was 39% less expensive; Clear Creek's was 16% less expensive; and Intrenchment Creek's was 52% less expensive. In all cases, the hydraulic performance of the selected plans was better than the original RMR plan. 3. Would solution optimization modeling present an opportunity to increase environmental and community benefits in line with wider DWM 'One Water' objectives? Without question, the inclusion of green projects adds enhanced environmental and community benefits to the overall outcomes for DWM and better aligns with City wide objectives to move to a 'One Water' approach that values all water. Further, these co-benefits are added without compromising sewer system performance.

Introduction
The Morrisville Biosolids Gasification Pilot Project (the Project) demonstrated that Ecoremedy's Fluid Lift Gasification technology can reliably dry and gasify industrial volumes of dewatered biosolids without bulking agents or fossil fuel. The Project garnered international interest and was lauded by industry experts during tours.

This case study explores how a public-private partnership enabled piloting of this innovative technology. After briefly reviewing design, construction, permitting, and commissioning, this presentation will summarize key accomplishments, including a summary of "lessons learned" during this historic project.

Design and Construction
The Morrisville Municipal Authority (MMA) is developing a new wastewater treatment facility (WWTF) at a nearby industrial park to replace the existing WWTF. The goal of the Project was to demonstrate Ecoremedy's FLG technology at the existing WWTF for potential inclusion at the new WWTF.

The MMA provided a greenfield site and waste supply to the Project through a pilot agreement signed in July 2018. Within one year, Ecoremedy completed design, construction, and Phase I permitting. The Project was self-financed by Ecoremedy under a Build-Own-Operate-Maintain model and operated on a tip-fee basis. Startup extended from July 2019 through February 2020, after delays from COVID-19. After commissioning, the Project operated until August 2021.

Ecoremedy completed engineering design in only three months. This was possible by leveraging decades of past success with high-ash, high-moisture manure-based feedstocks, including a week-long demonstration with composted biosolids. The Project was a 7x scale-up from past commercial projects.

A single process train was designed to operate for both Phase I loading (up to 4,536 wet metric tons/yr of undigested cake at 18-22% solids from the MMA's filter belt press) and Phase II loading (18,144 wet metric tons/yr of regional merchant capacity, with 22,680 wet metric tons/yr of total system capacity). It was designed to convert cake to three end-products without shutting down or retooling: concentrated minerals (ash fraction), carbon-rich biochar, and dried Class A product (permitted as an EPA recognized "Alternative Fuel").

The Project was housed in a single-story post and beam, metal-clad building (30 m long x 15 m wide with an eave height of 8 m) adjacent to the MMA's dewatering building. Pumping was not possible, so a receiving building was added to accept roll-off containers from MMA and cake hauled in from off-site. The building was selected for easy deconstruction due to the temporary nature of the pilot location.

Permitting
For Phase I, Ecoremedy submitted a Request for Determination of eligibility for a Permit By Rule (PBR) as a captive waste processer with de minimis air emissions. The PA Department of Environmental Protection (PA DEP) granted the PBR permit, with additional flexibility for R&D activities. Without previous biosolids gasification air data, air emissions were modeled using stack data from Ecoremedy poultry litter gasification projects. The elemental analysis of biosolids is similar to poultry litter for energy comparison.

Phase II air permitting required stack testing to validate emissions modeling as a minor source status, or potential de minimis source.

PA DEP granted a general waste permit for Phases I and II, as well as a Phase III expansion to multiple process trains (99,790 wet metric tons/yr). Following precedent from past FLG projects and similar technologies, the Project was deemed a non-incineration technology in PA, and later by the United States Environmental Protection Agency.

Operations
The Project was designed for continuous round-the-clock operation. Due to site-specific conditions and circumstances caused by COVID-19, Ecoremedy operated the facility with daily startup and shutdown on a five-day work week for two years. Automated operations were overseen by two operators per shift.

Project Results and Lessons Learned

Major successes of the Project include:
• Autothermal gasification of biosolids with temperatures across the gasifier and oxidizer ranging from 815 C - 1093 C and natural gas used only during start-up
• Fully automated biosolids drying with temperature drop across of 400 C across the dryer
• Sustained throughput of over 1.4 wet metric tons per hour with two-shift operations and daily shutdown
• Incoming PFAS levels ranged from 1 - 400 ppb per compound in pressed biosolids. 36 PFAS compounds were each reduced to non-detect (<2 ppb) in concentrated minerals after gasification.
• Non-detect odors from Ecoremedy process discharge during steady-state operations
• Consistent production of granular Class A biosolids > 90% TS with low-dust, suitable for land application and use as an EPA-recognized Alternative Fuel
• Consistent production of concentrated minerals suitable for land application or landfill
• Technology-wide determination from US EPA that FLG is not subject to the Sewage Sludge Incineration (SSI) Rule

Lessons learned include:
• Upgrades were needed for the mixer, material handling, bucket elevator, and odor control systems
• When possible, excess thermal energy recovered from the biosolids should be used to preheat the stack for plume abatement due to negative public perception of steam
• To prevent overnight freezing of a carbon filter, 24-hour operations and a condensing venturi scrubber are preferred with a targeted RH of 60%
• Direct pumping of dewatered biosolids to the mixer is preferred to avoid overworking the cake during material handling

Project Completion
On August 23, 2021, when the plant was offline for the weekend, a fire started in the receiving building. No one was injured. The fire marshal's official report ruled the cause of the fire as accidental. There was insufficient time left in the pilot agreement to rebuild and resume operations. Ecoremedy and the MMA agreed to conclude the pilot.

Next Steps and Conclusion
As a result of the Project's successes, the MMA remains interested in the potential of Ecoremedy's gasification technology to halt the rising costs and environmental hazards associated with biosolids disposal. The industrial park where the new MMA WWTF is being constructed has changed ownership and now requires the new WWTF to be completed (estimated 2026) before Ecoremedy can begin construction. At the time of this writing, Ecoremedy is evaluating project sites near Philadelphia for a regional merchant facility, with a general waste permit already granted for 99,790 wet metric tons/yr.

Knowledge gained from the Project, including the Lessons Learned above, were applied to the design of the Edmonds Project near Seattle, WA. The Edmonds Project has a design capacity of 12,927 wet metric tons/yr of dewatered biosolids, with co-gasification of all grit and screenings, and will be installed in 2022.

This paper will present the challenges overcome and advancements made by this historic project, including the operations data in the figures and tables following this abstract.

Wastewater treatment plants (WWTPs) were considered to be the biggest microplastics (MPs) source in urban environment (Carr, S.A., Liu, J., Tesoro, A.G., 2016.). Most of MPs in wastewater removed and transferred to sewage sludge (Magnusson, K., Noren, F., 2014.), on the other hand, evidence shown that lager plastic pieces might break apart into small pieces due to the physical or chemical factors in environment (Murphy, F., Ewins, C., Carbonnier, F., Quinn, B., 2016.), some of them will become secondary MPs, therefore, sewage sludge plays the most important role in MPs pollution. In this study, a WWTP in western Japan (we call it as WWTP A here) was the research target. Fig. 1 is the diagram of the sewage sludge treatment system of WWTP A, in this research, all 7 kinds of sludge in WWTP A (marked in red numbers) including primary sludge (raw and thickened), waste activated sludge (raw and thickened), mixed thickened sludge, digested sludge and dewatered sludge were sampled, and all non-fiber MPs larger than 100 μm in those sludges were analyzed. The size, plastic type and color of every MPs were recorded, concentration and annual discharge of MPs were calculated. The sampling will be conducted in some seasons and finally MPs flow in WWTP A was built. Since there are no standard analyzing method of MPs, an analyzing method for sewage sludge was examined and established in this research. Firstly, the pretreatment, if the sludge was in solid state, then dissolved it into milli-Q water until the water content was 96%, after that, all sludge was homogenized by ultrasonic (TOMY, 90% power output of 100 W, 80% duty) for 1 hour. Secondly, every gram (in dry weight) of pretreated sludge was digested by 60 mL of 30% H2O2 in 55 „ƒ for two days, the H2O2 was divided into two parts equally and used in the beginning of each day. After digesting, gravity separation using NaI was used to separate MPs from the solid remains. Finally, micro FTIR (Shimadzu, AIM-9000) was used to analyzing the suspicious MPs. In the summer sample of 2022, Fig. 2(a) shows the MPs concentration in different sludges, MPs concentration was 0.83×103 pcs/kg dry sludge in thickened primary sludge, 2.3×103 pcs/kg dry sludge in thickened waste activated sludge, 1.7×103 pcs/kg dry sludge in mixed thickened sludge, 2.7×103 pcs/kg dry sludge in digested sludge and 3.3×103 pcs/kg dry sludge in dewatered sludge. The MPs concentration in thickened waste activated sludge was much higher than thickened primary sludge, this indicates that more MPs were removed in secondary sedimentation tank in this WWTP, the conclusion here is different in other researches, some report that in some WWTPs, the majority of MPs was removed during primary treatment (Carr et al., 2016; Murphy et al., 2016; Talvitie et al., 2015), while another researcher report that the MPs concentration in primary and secondary treatment was basically the same level (Li et al., 2018.), that's may because the specific treatment method and discharge standard is different between WWTPs. In digesting and dewatering process, the MPs concentration raised 60% and 100% comparing to the mixed thickened sludge, there were two possible explains, one is that lager plastics may break apart into smaller ones due to the physical or microbial factors, the other is the loss of total solid cause the increase of the MPs concentration, combining the MPs amount data in Fig. 2(c), the break apart of MPs might be the major factor since the MPs amount also increased substantially in digesting and dewatering process. Table 1 shows the MPs concentration in this and some other researchers, we can see the MPs concentration varies greatly between WWTPs, the WWTP itself, seasonal reason, analyzing method, target MPs size or other detail cause this difference, overall, the MPs concentration in this Japanese WWTP was in the middle-lower level. Comparing between sludge types, it seems the MPs concentration in primary sludge was the lowest and highly related to the target MPs size, the target MPs size was set smaller, the more MPs would be found, this may indicate the widely existence of smaller size MPs in primary sludge. In waste activated sludge, digested sludge and dewatered sludge, the difference of MPs concentration between WWTPs became even lager and hard to find a pattern, thus it is critical to collect more data to provide some reference for governments to make MPs related policies. Fig. 2(b) shows the particle size of the MPs in different sludges, all MPs found in those sample was smaller than 1,000 μm, the percentage of 100-200 μm MPs was decreasing during the sludge treatment process, those MPs might loss with the separate water during thickening and dewatering. The percentage of 300-400 μm MPs increased significantly, this might because the fermenting bacteria or methanogens are somehow able to decompose MPs partially, it may make lager plastics become fragile and break into 300-400 μm MPs. Fig. 2(c) shows the MPs amount different sludges. The MPs amount in thickened primary sludge was 5.0×109 pcs/y, also much lower than thickened waste activated sludge which was 18.4×109 pcs/y, in mixed thickened sludge the amount was 24.0×109 pcs/y, in digested sludge the amount was 18.6×109 pcs/y and in dewatered sludge the amount was 21.9×109 pcs/y. Different to the concentration, the amount of MPs didn't increased during the sludge treatment process, instead, comparing to the mixed thickened sludge the amount decreased about 23% in digesting and increased 10% in dewatering, the decreased MPs may break apart and become smaller than 100μm thus can not be extract in this research, or possibly drain with the separate water during dewatering. In this research, significant number of MPs was detected in the whole sludge treating process in WWTP A in Japan, evidence also shows that sludge treating process was not able to have a proper treatment of MPs. The final fate of MPs must raise our concern, if those MPs were not treated properly, serious environmental pollution may occur in sludge utilization like compost or agriculture use.

Problem Since the startup of the three fluidized bed incinerators (FBIs) at the Northeast Ohio Regional Sewer District (NEORSD) Southerly Wastewater Treatment Center (Southerly WWTC) in 2014 greater than expected auxiliary fuel, that is natural gas, usage has been observed. The original FBI design assumed no auxiliary fuel would be necessary during typical operations. This abstract updates the paper submitted for the 2020 RBC, which was unfortunately cancelled due to the pandemic, with additional data obtained during the interim. Background The NEORSD owns and operates three FBIs at the Southerly WWTC, each design to process 100 dry tons per day (dtpd) at 28 percent solids and 68 percent volatile solids. The FBIs are fed dewatered sludge cake consisting of primary and waste activated sludges generated at the Southerly WWTC. Sludge from the Easterly WWTC managed by NEORSD, discharges into the headworks at the Southerly WWTC for ultimate processing by the FBIs. Typically, FBIs do not require auxiliary fuel when operated near the design condition. Auxiliary fuel is required during startup and sometimes during shutdown operations. Continued use of auxiliary fuel throughout all operations indicates the system is not operating as designed. Objective This study evaluated the existing conditions the FBIs operate under to determine which parameters might be adjusted for more efficient operation. NEORSD can then adjust, as possible, to reduce auxiliary fuel use. Historical Operation Evaluation NEORSD originally provided one year of hourly (average) data from April 2016 to March 2017, see Table 1 for the operational averages. The data was evaluated to determine which parameters impact autogenous operation. The screened parameter set included the following six which were likely to have the greatest impact on autogenous operation. Sludge feed Sludge percent solids Sludge percent volatiles Windbox temperature (preheated air from heat exchanger) Bed temperature Fluidizing airflow All these parameters statistically correlated with autogenous operations at specific levels per the t-test results in Figure 1. So, BC further evaluated this list using NEORSD's existing operating strategy as a guideline. In the end, BC determined the sludge feed rate was the most readily adjustable parameter to achieve more reliable autogenous operation. The sludge feed provides all the heat, when operated close to design values, to heat the combustion air and evaporate the water from the sludge without natural gas addition. When averaging all three FBIs the average sludge feed rate is 1.2 wet tons per hour (wtph) higher during autogenous conditions. It should be noted that the average sludge feed rate, during these autogenous conditions, was roughly 64 percent of the incinerator capacity (13.9 wet tons per hour at 30 percent total solids [TS]). The data suggests that operating the FBIs at higher feed rates will result in autogenous conditions more often. Operational Alternatives Two distinct operational changes could increase the sludge feed rate per FBI. Each option increases the number of thermal cycles, that is the frequency the system goes from operating temperatures to a significantly cooler level. Revised Operations — Option 1 - The first option utilizes storage capacity to provide consistent incinerator operations. Each storage tank holds approximately 1.5 days' solids processing capacity of one incinerator. There are three storage tanks available for operational storage with a fourth one for emergency storage. This option uses one sludge storage tank with one FBI to handle the solids with excess flowing into a second sludge storage tank. When the second sludge storage tank becomes half full and climbing a second FBI can be brought on line to help deplete the incoming and stored solids until one FBI can again handle the solids production. This option includes some concerns about placing additional thermal cycles on the equipment. Revised Operations - Option 2 - The second option operates two FBIs at a higher capacity. This is accomplished by placing one of the operating FBIs in hot standby mode for 6 to 8 hours every day. Though the FBI internals would likely see a relatively small thermal cycle, downstream equipment will undergo a larger cycle or temperature range. Option 2 would also likely not yield the same natural gas savings due to heating if the standby FBI required intermittent heating during downtime. Revised Operation Implementation An industry survey was conducted to better understand thermal cycling on sewage sludge incineration systems and impacts on equipment. Based on the survey Option 1 would likely result in less thermal cycle impacts due to relative infrequency compared to Option 2. Furthermore, discussions with the key equipment supplier (primary heat exchanger and waste heat boiler) indicated the equipment was designed for far more thermal cycles than practical over the anticipated service life of the equipment. After reviewing the two options NEORSD selected and began planning to implement Option 1. NEORSD operates three sludge storage tanks, two are normally used with a third for peak demands. At an assumed 5 percent solids concentration each tank holds roughly 230 dry tons of solids. Each cycle from 1 FBI to 2 FBIs and then back to 1 FBI should take approximately 30 to 40 days, depending on the sludge generation rate, the sludge incineration rate, and the sludge solids concentration achieved in thickening and storage. Based on this approach the FBI sludge feed rate will exceed 80 percent of the design capacity, greatly increasing the chances for autogenous operation. NEORSD conducted multiple full-scale trails, with a month-long campaign in April of 2019 providing the most representative operations of the selected option. Other trials in May 2019, September/October 2019, and August 2020 resulted in shorter durations and experienced other complications resulting in higher energy consumption. Table 2 presents the comparison between the trials and historical costs spanning 2016 through 2018. Costs in the table represent annual values. The trial values were projected to annual operations for comparison. The results of the trials indicate energy and economic savings will result from the revised operating strategy. The April 2019 trial most represents the anticipated revised operating strategy and would result in an annual savings of $390,000. Conclusions This study initially investigated the alternatives to minimize the use of auxiliary fuel during normal operations. This effort identified that recommended increasing the sludge feed rate reduces auxiliary fuel demand and presented two options to achieve a higher FBI throughput. NEORSD opted to manage the sludge in the SSTs to operate the FBIs at a higher sludge feed rate which requires alternating between one and two FBIs in service. The recent April 2019 full-scale trial showed significant energy reductions from the revised operating strategy. Based on this effort NEORSD will continue to pursue operating in the revised manner full time. NEORSD will also continue to closely monitor equipment condition to prevent unplanned outages and whether the slight increase in thermal cycles have any effect. Status NEORSD continues to test the revised operating strategy to verify the operational savings and gain experience. Ultimately the strategy will be implemented as the standard operating procedure.

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.

Purpose:
CHA Consulting has been involved in the design and installation of water and sewer mains using the trenchless method of Horizontal Directional Drilling (HDD) in South Florida. A total of 30,000 LF of pipe has been installed using this technology and includes 21 separate projects in last 10 years. Pipe sizes for these projects vary from 8' to 54', including a world record of the longest 54' pipeline installed by HDD. The main purpose of this presentation is to share our experience and lessons learned with utility managers in other parts of the country.

Benefit of the Presentation:
This information will benefit all professionals involved in pipeline projects by providing in-depth analyses of the HDD method and its various applications, an overview of the technical design process, and a concise yet informative study of the challenges, both technical and non-technical, faced during the design, permitting, construction, and certification of pipelines installed with this technology. The goal is for professionals of all experience levels to gain a comprehensive understanding of the HDD method and its benefits, especially as it pertains to the use of this technology in South Florida. Design and Construction Challenges: Some of the critical design and construction challenges observed, are listed below.

Design Challenges:
- Entry and Exit Angles: These angles were generally kept between 8 and 12 degrees based on equipment limitations, ground conditions, and to facilitate breakover support during pipe pullback.
- Minimum Curvature Radius: For most projects, this was usually between 1,500' and 4,000' to minimize pulling forces during pipe installation. Bending radius outside the drill were between 40 to 50 times OD.
- Installation Loads: Pipes are subjected to tension, bending and external forces. HDD installation loads were determined during the design phase. A safety factor of 2 was used to determine pipe material and thickness.
- Pipe Material Selection: Pipe Material for HDD installation should be smooth, flexible, and must have sufficient strength to resist the installation, working tensions and any transients that may occur during operation. Types of pipes considered for these projects Included Fused Polyvinyl Chloride (FPVC), High Density Polyethylene (HDPE), and Steel.
- Utility information: Accurate utility information is critical for HDD projects. Subsurface Utility Engineering (SUE) was performed to confirm utility locations at critical areas of the project.
- Subaqueous installation: Installation under water bodies required maintaining clearances of 15' below the canal's cross section as well as minimum clearances from bridge piles.
- Connection to other type of pipe materials: HDD installation requires special pipe materials to connect to other types of pipe materials. Flange adapters, couplings, and restraints were used for these connections.

Construction Challenges:
- Staging: Staging Areas are typically 35' by 70'. Contractors needed to coordinate with property / business owners and reach agreements thru Public Relations Firms.
- MOT: Although HDD avoided the need for MOT along pipe alignment, traffic control around the entry and exit pits was required. The location of these pits determines the complexity of the traffic control required. This may be anywhere from simple lane closures/merges to entire intersection closures.
- Geological Conditions: Most of South Florida is characterized by sandy/clay conditions (medium to dense Brown Silty Sand, Gray Sand, and Silty Clays), medium to high density Brown Sandy Limestone area, and combinations of these conditions. These ground conditions were challenging for HDD installations.
- Existing Buried and Overhead Utilities: Detailed as-built records of the lines and other utilities in the areas were requested to avoid conflicts with designs and installations.
- Frac-out: The inadvertent return of drilling fluids to the surface during the drilling operation, frac-out can occur as a result of a variety of factors. This can be critical due to the proximity of environmentally sensitive areas. Frac-out plans were developed during the design phase and were part of the permit package.
- The projects included several canal crossings (Intracoastal Waterways, Miami River, Biscayne Canal, Biscayne Bay, etc). Close coordination with permitting agencies was required to obtain the approval of these crossings.

Permit Requirements:
Several environmental agencies have jurisdiction over the project locations; therefore, the permitting process has been very intense and challenging. Permits required for the HDD Installation in South Florida include: US Army Corps of Engineers (USACE), Florida Department of Environmental Protection (FDEP), South Florida Water Management District (SFWMD), Miami Dade County Department of Regulatory Environmental Resources (RER), Broward County Environmental Protection and Growth Management Department (BCEPGMD)

Status of Completion:
All of the 19 HDD installations covered in this presentation have been completed in the last 10 years in South Florida, mostly within the Miami-Dade County and Broward County. A summary of the most relevant projects of our experience is depicted below: 20' WM & 16' FM Las Olas Blvd, Ft Lauderdale, FL (4,300 LF, completed in 2017): Design/Build services for the design, permitting, and construction inspection of a 20-inch H.D.P.E. water main (2000 LF) and 16-inch H.D.P.E. force main (2300 LF). 54-inch HDPE/PCCP Force Main Miami Beach, FL (4,450 LF, completed in 2016): Design and installation of a 54-inch force main. 42' FM North Miami Avenue from NW 36th St. to NE 62nd St. (7,500 LF, completed in 2019): Design and installation of High-Density Polyethylene (H.D.P.E.) pipe, valves and fittings. 54' FM HDPE Redundant Bypass Line, FT Lauderdale, FL (8,400 LF, completed in 2020): Design-Build for the Installation of New Redundant 54' Bypass pipe. 12' FM on Brickell Key Drive, Miami FL (1,500 LF, completed in 2022): 14' H.D.P.E. F.M. Emergency Installation Underneath Brickell Key Bridge.

Conclusions:
A successful HDD project carefully considers the challenges described above and many other factors to ensure constructability, feasibility and project safety. Our experience during the last several years in the design of these pipelines has resulted in the adoption of several design characteristics as standards for effective designs. These include best entry and exit pit locations, optimum entry and exit angles, acceptable bending radii, and feasible pipe materials and dimension ratio (DR)s. In addition, installations in different jurisdictions and environmental locations have proven to create a robust repository of permitting information that has been useful when permitting and certifying these projects. The knowledge and information exhibited in this presentation is done so with the intention of communicating our experience and lessons learned designing HDDs in South Florida to our colleagues around the country.

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.

The City of Windsor (City) owns and operates two municipal wastewater treatment plants; the Lou Romano Water Reclamation Plant (LRWRP) and the Little River Pollution Control Plant (LRPCP). These facilities provide secondary level treatment for municipal and industrial wastewater from the City of Windsor, ON and the neighboring Municipalities of Tecumseh and LaSalle. The LRPCP and LRWRP produce approximately 2,400 and 8,500 dry tons per year of residual wastewater solids, respectively. Under the current management strategy, the residual solids at each facility are dewatered by centrifuge (to a dry solids content of ~ 28 %) and transferred to the City-owned Windsor Biosolids Processing Facility (WBPF). At the WBPF, the dewatered sludge cake is thermally dried and pelletized to produce a fertilizer product which is registered under the Canadian Federal Fertilizer Act and sold throughout Southwestern Ontario, Canada. The WBPF has multiple drawbacks including utilizing an energy intensive drying process, aging infrastructure and equipment, and is not expected to be capable of accommodating future wastewater residual projections. In recent years, there has been increasing attention paid to managing the organic fraction of municipal solid waste. In an effort to divert organic material from the landfill, many municipalities have integrated organics management programs, which involves co-processing wastewater residuals with the diverted municipal organic wastes. In addition to the environmental and cost benefits of diverting and combining these waste streams, this process maximizes the recovery of their remaining value in the form of electricity, thermal energy, and/or fuel. Environmental benefits of diverting organic materials from landfills include reduced methane emissions, decreased leachate discharges, and opportunity for energy recovery from waste. Similar to the California program, the Ontario Ministry of the Environment, Conservation and Parks requires 70 percent of organic waste to be diverted from Ontario landfills by 2025. The City of Windsor does not currently have an organic waste collection program in place; therefore, a program is in development. The source separated organic waste materials which may potentially be accepted through this program include municipal food and organic waste; institutional, commercial, and industrial food and organic waste; agricultural organic waste; and high strength waste (HSW) such as food processing waste, dairy waste, and fats, oils, and grease. To address future biosolids management needs and comply with regulatory requirements for organic waste diversion, the City of Windsor completed a comprehensive study to develop an Integrated Biosolids and Organics Management Strategy. This study presents the complete planning and evaluation process for the Integrated Management Plan including the identification of the opportunity and evaluation of alternatives as well as a review of biogas potential, energy savings, and GHG reductions through anaerobic digestion and biogas utilization. To select the recommended management strategy, the following three alternatives were compared: (1) improvements to the existing WBPF, (2) composting, and (3) anaerobic digestion. The evaluation included social and cultural environment criteria, natural environment criteria, technical / suitability criteria, and economic criteria. Anaerobic digestion was identified as the preferred alternative as it provides the ability to process wastewater residuals in a less energy intensive way for improved energy recovery from waste, biogas production, and reduced GHG emissions. Additional benefits of an anaerobic digestion facility includes: that it has smaller land area requirements; proven and reliable process operation; higher potential for federal and provincial grant programs; is consistent with the City of Windsor's Community Energy Plan and Climate Change Action Plan; and results in the production of a well stabilized finished product suitable for farmland application. Under this strategy, the wastewater residuals and organic waste would be processed at a centralized anaerobic digestion facility with biogas utilization via a combined heat and power (CHP) unit. Figure 1 outlines the proposed process schematic for this alternative. Table 1 shows the feedstock quantity, volatile solids (VS) loading, and biogas production for each feedstock material. Feedstock quantity for the LRPCP and LRWRP is presented based on historical mass of wet dewatered sludge cake measured from 2016 to 2020. It is estimated that an average of 10,300 wet tonnes of source separated organics (SSO) and 22.7 m3/day of HSW could be collected throughout the City of Windsor and processed at the proposed facility. The biogas production from digesting sludge is estimated to be 2,050 m3 biogas/day and 6,950 m3 biogas/day for LRPCP and LRWRP, respectively. Co-digestion would increase the total biogas production by approximately 50% with 1,350 m3 biogas/day from HSW and 3,600 m3 biogas/day from SSO. Table 2 shows the energy balance for the LRWRP and LRPCP with the projected energy production from anaerobic digestion and biogas utilization. The energy consumption presented incorporates the historic energy consumption at the LRWRP and LRPCP and projected energy consumption required for thickening, dewatering, and anaerobic digestion. The energy produced from anaerobic digestion of sludge would amount to 40% of the energy required to operate LRWRP and LRPCP. Co-digestion with HSW and SSO would increase this contribution to 62% of the total energy required to operate both plants. In addition, Table 2 shows the effect that anaerobic digestion and biogas utilization had on GHG emissions for LRWRP and LRPCP. Anaerobic digestion of sludge reduced GHG emissions by 1,400 tonnes CO2e/year and 400 tonnes CO2e/year at the LRWRP and LRPCP, respectively. Co-digestion would reduce GHG emissions further to 3,300 tonnes CO2e /year, which corresponds to approximately 36% reduction in GHG emissions. Based on this evaluation, significant energy savings and GHG reductions can be achieved through anaerobic co-digestion of wastewater residuals and organic waste. This solution would move the LRWRP and LRPCP towards a net-zero energy future, provide energy savings to the City of Windsor, and reduce GHG emissions via onsite energy generation and biogas utilization. This integrated management approach will allow the City to meet the regulatory organics diversion requirements and address biosolids management needs for the two wastewater treatment plants. The operation and maintenance cost for the facility would be approximately $1,400,000 CAD/year; however, this would be offset by fertilizer revenue (~ $1,400,000 CAD/year) and electricity savings ($3,000,000 CAD/year). The opinion of probable cost for such an anaerobic digestion facility is approximately $151,000,000 CAD (inclusive of contingency and engineering allowance; exclusive of taxes). There are several government rebate programs available which help to facilitate municipalities implementing waste diversion programs and adopting technologies that generate clean affordable energy.

The Napa Sanitation District (NapaSan) oversees a sewer collection system in Napa, California consisting of 270 miles of mains, including a 66-inch diameter trunk sewer that parallels the eastern bank of Napa River for about three miles through wetlands and threatened species habitat. This pipeline connects the City to NapaSan's Soscol Water Recycling Facility (SWRF), is the backbone of the collection system, and conveys up to 58 MGD peak wet weather flow. That is more than 90 percent of the wastewater flow generated within NapaSan's service area. Installed in the 1960s, the trunk sewer is constructed entirely of reinforced concrete pipeline (RCP) without a protective lining or coating and the system has no redundancy for this asset. NapaSan partnered with Woodard & Curran to conduct an inspection and condition assessment of the three-mile stretch of 66-inch diameter trunk sewer. The project team performed CCTV and sonar inspections, assessed the data, and developed remaining useful life projections, project prioritization and recommendations for repair. The team identified more than one mile of the inspected trunk sewer had reached the end of its useful life and required structural rehabilitation. With pertinent data on hand, the project team identified rehabilitation alternatives and developed a preliminary and final design to rehabilitate the compromised section, including the design challenge of routing more than 20 MGD through a bypass pumping system along the Napa River. The design opted for use of trenchless technology in the form of cured-in-place pipe (CIPP) lining. Navigating an environmentally sensitive project site The inspection, assessment, and resulting rehabilitation of this sewer trunk was inherently challenging due to its location along the Napa River, in an area which is critical habitat for 15 special-status plant species and 14 special-status wildlife species. This required Woodard & Curran's experts to collaborate with eight different environmental agencies to ensure all permitting was procured for the project to move forward. In addition, the Woodard & Curran team acquired State of California environmental clearance (CEQA) to perform the work. The design plans detailed distinct areas at each manhole site where contractors could safely work without impacting sensitive environmental areas along the existing alignment. This helped the contractor identify where best to deploy their crews for the CIPP work while still meeting stringent permit requirements. Certain manholes located within highly sensitive environmental areas were designated as lining reception locations so as to minimize or totally avoid impacting environmentally sensitive habitats. Another critical environmental consideration the design team had to account for was the large volume of cure water necessary for the rehabilitation project. Given the drought status in California, this was a significant demand on water resources. However, the team worked with the client to leverage recycled water resources produced by NapaSan to help avoid exacerbating drought conditions. A mobile filtration system was used for the cure water prior to discharging to the sewer system to comply with the maximum allowed styrene concentration levels at NapaSan's treatment plant. Minimizing impact to a heavily trafficked area In addition to sensitive environmental habitat, the trunk sewer's alignment also follows the Napa River Trail, a paved walkway providing area residents with recreation access, such as hiking, birdwatching, and fishing. The project team collaborated with a myriad of stakeholders and the construction crew to reduce impact to the trail for both public access to the resource and public safety. The bypass required to ensure sewer service was not disrupted for ratepayers met an additional hurdle with an active railroad crossing. The bypass piping had to be manifolded and truncated to one 22-inch diameter HDPE bypass pipe. This allowed the bypass to fit inside an existing 24-inch diameter storm drain to cross through a wetland area and travel under active railroad tracks so as not to disrupt rail service. Similar measures were taken to reduce impacts to area vehicular traffic. Receiving industry accolades The complexity of this $5.6 million project was featured by Trenchless Technology Magazine in October 2022. It will also be recognized during the 2023 NASTT No Dig Conference in Portland, Oregon, as the 2022 Trenchless Rehabilitation Project of the Year - Runner Up.

Summary--Using a sewer process model to predict extensive collection system parameters related to odor and corrosion, e.g., sulfide and pH, the Albuquerque Bernalillo County Water Utility Authority (WUA) better understands its own system. The WUA has adopted and used the model in-house to address and resolve, quickly, confidently, and with documented, analytical justification, a wide range of operational, design, and planning issues. This model allows chemical feed optimization and assurance that appropriate wastewater is delivered to the Water Resource Recovery Facility (WRRF) to meet performance requirements. The model is complex and a significant undertaking, yet the WUA has been more effective and efficient since its adoption. This paper describes how to integrate these tools into the Utility's operations, including practical issues of structuring staff, growing the team with consultant support, and developing depth of staff. This paper also describes specific studies performed by WUA staff utilizing the model. Introduction The WUA owns and maintains over 2,400 miles of pipes in the collection system to convey approximately 50 MGD wastewater from the service area to the WRRF. The WUA has implemented various methods and technologies for controlling odors and corrosion in the collection system, resulting in significant institutional knowledge and experience in this engineering science. As part of the 2019 Collection System Odor and Corrosion Control Master Plan, Jacobs Engineering (Jacobs) and the WUA implemented a systematic approach to address odor and corrosion issues by developing a sewer process model of the WUA system. The model was created using WUA ArcGIS piping assets, hydraulic data, and wastewater characteristic data. The model used is the Wastewater Aerobic/Anaerobic Transformations in Sewers (WATS). The WATS model simulates sewers' complex chemical, biological, and physical processes through extensive mass balances and differential equations. The WATS software can predict hydrogen sulfide odor generation, concrete asset corrosion, chemical management, analyze wastewater characteristics at inflows to wastewater treatment plants, etc. The WUA's objective in using the model is to respond in real-time to unexpected-immediate, near-term predictable, conceptual design-phase and routine chemical feed considerations. The Collection Section operates and utilizes the model successfully for a wide range of tasks. Methods The framework for developing and running the WATS model in-house is shown in Figure 1. We identified an in-house engineer (Engineer) with strong technical skills but minimal previous experience in sewer odor control and assigned the responsibility of learning and utilizing the model. We provided a learning environment with adequate resources, strong support, and reviews. Technical support was provided by the modeler's direct supervisor and, under a contract established to provide training and related support, the lead process engineer (Consultant) for developing the WATS model of the WUA system. As noted in Figure 1, per typical WUA practice, the Engineer created a Standard Operating Procedure (SOP) that provides specific documentation and procedures for using the WATS model. The Engineer's knowledge is solidified through the process of writing the SOP. It serves as the Engineer's reference document and a training guide for staff assigned to assist or even to learn to operate the WATS model. After the Consultant provided basic training, it was time for the assigned Engineer to learn by performing or 'doing' repeated model use cases. This WUA Learn-by-doing approach is shown in Figure 2. Results Our first use of the model was to develop specific proposed locations, on three interceptors, for ferric chloride and magnesium hydroxide stations proposed by the Master Plan. Specific locations were found based on land availability, truck access, and other criteria. Chemical feeds were simulated with a target of 0.2 mg/L free iron downstream. Reports were developed in-house and provided to WUA Engineering for consultant design of the new facilities. The next use was to develop flow times from each permitted industrial user to the WUA's only significant WRRF. The WUA's WATS network is based on export data from the WUA's InfoSWWM model, including lengths and average velocities. In the typical use of the WATS model, upstream and downstream pipes are connected, establishing the line being evaluated. The model provides the flow time and multiple parameters pertinent to odor and corrosion control. A report was delivered to Pretreatment, providing a total flow time for each user. Pretreatment has used the report data once for a high BOD spill, but there were no obvious spill impacts to the WRRF influent. An ongoing use is managing the WUA's chemical feed program to prevent odors, manage corrosion, and deliver appropriate wastewater to the WRRF. The WUA utilizes six liquid-phase chemicals: ferric chloride, calcium nitrate, calcium hydroxide, magnesium hydroxide, hydrogen peroxide, and residual iron from the surface water treatment plant (SWTP). The WATS model is the tool used to optimize these feeds. In two studies, the model has been used to protect the WRRF. First, a calcium nitrate tank was to be replaced, and the tank had to be quickly emptied. The model indicated the nitrates would be consumed and would not reach the WRRF. Second, a low-pH Fluorosilicic Acid needed to be disposed of at the SWTP. The model indicated the pH impact at the WRRF would be minimal. In both cases, the model matched the actual results and provided confidence for the action taken. Recently, the model network was extended in two locations to study lines in design or under construction. One was a new gravity line subject to very high BOD. The network extended downstream included an existing gravity, a lift station, and a force main. Results indicated H_2 S levels in the gravity lines would be acceptable, but the unexpectedly high force main discharge would be investigated. The other is a proposed lift station and force main discharging to a gravity line unavailable for service connections. Figures 3 and 4 show results indicating the sulfide levels reached minimal levels well before a location where service connections could result in odor issues. We plan to use this 'free treatment' in the gravity line and not include liquid phase odor control but to provide managed airflow in the gravity line and construct corrosion resistance pipes and manholes. The WUA is currently designing a future satellite WRRF. The service area includes a calcium nitrate station that is to be replaced by a ferric chloride station at an upstream location. We are currently utilizing the model to estimate the increase in BOD when calcium nitrate is no longer fed, to optimize the ferric chloride feed and to estimate the resulting decrease in pH and alkalinity. Lessons Learned Modeling proficiency requires regular use. Once the designated Engineer has learned the model basics, the time allocated to the model may average 15% full-time employment. Naturally, some weeks may require nearly full-time efforts. We observed increased task requests as other groups within the WUA became aware of this new in-house capability. The WATS model has proven effective, but the utility investment and commitment must be recognized. The designated Engineer will ideally have a background in process engineering, but many of these subjects can be taught and learned over time. Sustaining depth of staff requires additional employees to be competent in the model. Writing a basic training SOP helps create and maintain the depth of staff. SOPs should be written with new advancements in the model and should be updated regularly. Benefits and Significance A utility benefits from operating a tool such as the WATS model in several ways. First, should anyone understand your system better than the utility itself? We believe a utility should best understand its system due to ownership and continuity. A utility is best served if it is prepared for all eventualities and can respond quickly. The WATS model allows the utility to do so. A utility continuously adds facilities and systems under a consultant-designed contract describing typical responsibilities. This contract structure often cannot direct timely decisions that optimize the utility-operated sewer systems. Finally, the utility benefits in responding quickly and adequately to a wide range of occurrences that all utilities endure.