Conference Papers

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

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.

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.

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.

Microplastics (MPs) are a kind of pollutants that have attracted widespread attention in recent years. Previous research shows that the vast majority of MPs will be intercepted by sludge after the wastewater enters the wastewater treatment plant (WWTP) 1), and will enter the soil with the subsequent utilization of sludge. Before the sludge enters the soil, it is usually subjected to a series of treatments such as high-temperature composting and methane fermentation. Methane fermentation is an energy conversion of sewage sludge, and its use will expand in the future. Recent study found that the shape, quantity and size of MPs in methane fermentation or high temperature composting of sewage sludge changed 2) but the reason and the MPs' characteristics was not deeply studied. This research study and summarized the characteristics of MPs in the sewage sludge before and after methane fermentation in Japan. We sampled sludge before and after methane fermentation at WWTP A and B in Japan several times in 2022 from June to December. Both WWTP A and B use methane fermentation for sludge treatment. WWTP A uses mesophilic fermentation while WWTP B uses thermophilic fermentation. After organic matter removal using H2O2, ultrasonic treatment, and density separation steps, the sludge sample will be screened for particles suspected to be MP using microscopy and their chemical composition will be determined using μ-FTIR (AIM-9000; Shimadzu.Corp.). This study is focus on non-fibrous MPs with particle size greater than 100 μm. The size (long axis and short axis) and the plastic type of every MPs were recorded, concentration by dry weight and monthly discharge of MPs were calculated. With the above information, the characteristics of MPs before and after methane fermentation of sludge were summarized. In the sludge samples in this research, the concentration of MPs ranged from 0.72×104 to 1.8×104 pcs per kg dry weight. (Figure 1.) Overall, WWTP A had a higher concentration of MPs than WWTP B. The sludge from both WWTPs showed 2.9%-37.1% of decrease in MPs' concentration after methane fermentation. The concentration of MPs in samples from the same WWTP did not show great fluctuations from month to month. If the change in the amount of MPs in the methane fermentation system is calculated from the input and production of sludge, the amount of MPs was reduced by 50.1%-71.1% after the methane fermentation. For the plastic type, PE was found in all of the samples, accounting for 9.1%-21.7%. The detection rates of PP, PP-PE, acrylic and ABS were higher than 75%, PVC, PMMA and EVA were higher than 50%. Some particles with the spectral characteristics of MPs but with an ambiguous spectral information, or with the spectral characteristics of several MPs at the same time were founded. These particles may have been subjected to degradation or may be a mixture of plastics. Although it was not possible to determine the exact type of plastic, these particles were determined to be MPs in this study. The maximum size of MPs observed in this study was 1637.5 µm. 86.5% of the MPs in the sludge were smaller than 500 µm, 8.8% of the MPs were between 500 and 1000 µm, and only 4.7% of the MPs were larger than 1000 µm. (Figure 2.) The particle size of MPs became smaller after methane fermentation in WWTP A. Before digestion, the range of 200-300 µm had the most MPs. After digestion, the range of 100-200 µm had the most MPs. In WWTP B, the range of 200-300 µm had the most MPs but after methane fermentation, the percentage of MPs in this range has decreased significantly. After methane fermentation, there was a decrease in MPs' quantity. The degradation of MPs may have occurred during methane fermentation. Since there is a lower limit of detection of MP size in the analytical and detection methods, the accuracy of analysis decreases near this lower limit, and effective analysis is not possible for MPs smaller than the lower limit of size, 3) the possibility that the decrease in the number and size of MPs was caused by physical effects still cannot be excluded in this study.

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.

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.

Introduction The potential for biosolids conversion into fuels and revenue-generating products has driven interest in biosolids pyrolysis and gasification for decades, yet technology adoption has been hampered by historical issues, operational complexity, and high capital outlay. A combination of market drivers, technology evolution, and an increased offering of technology manufacturers has reinvigorated interest in these technologies as a tool to address today's biosolids challenges. While previous work has been presented on the conceptual benefits of these technologies and their products, there has not yet been a biosolids pyrolysis and gasification state of the science review to provide a definitive mass and energy balance comparison among developing technologies, discuss the root cause of historical issues and define operational requirements, and outline best practices and future research for successful technology adoption. This presentation will identify key findings for each of these areas from a recent literature review and technology survey (Winchell et al., 2021) developed in collaboration with two utilities, Metropolitan Water Reclamation District of Greater Chicago (MWRD) and Great Lakes Water Authority (GLWA), who in addition provided insight into key considerations for technology evaluations in light of the evolving biosolids management landscape. Mass and Energy Balance Assessment Pyrolysis and gasification are thermochemical processes that apply high temperatures to dried wastewater solids (or biosolids when stabilized) to release organic content into a gaseous or liquid state and retain a condensed, solid product called char. The processes can be considered to proceed on a gradient with regards to oxidant mixing when assessed with a related process, incineration. While pyrolysis and gasification do produce fuel gases (or liquids when condensed) that can be considered for a variety of combustion applications, operational challenges (discussed further below), have limited current application to direct combustion in a thermal oxidizer for heat recovery and recycle to an upfront drying step (as noted below in Table 1). Consequently, the mass and energy balances, when considered with direct combustion and drying, can be compared directly to current sewage sludge incineration (SSI). Results from a technology survey of five pyrolysis and gasification manufacturers (excepts presented in Table 2) will be presented comparing targeted mass and energy balances to historical SSI operation with key insights presented regarding the amount of auxiliary fuel required and what parameters have the most critical impact (e.g. feed solids moisture content, heating value, or dryer and thermal oxidizer thermal efficiencies). Operational Requirements The primary operational concern around pyrolysis and gasification is the resulting condensable fraction of the off-gas, commonly referred to as tar, that forms as a liquid in low-temperature zones of the system (Iaconi et al., 2017). Tar is a viscous liquid that will plug downstream passages, is corrosive, and becomes increasingly viscous over time (Basu, 2013). As noted above, current operations of biosolids pyrolysis and gasification systems transfer the fuel gas at high temperatures directly into a thermal oxidizer where the volatile vapors are combusted before they have a chance to condense. However, future installations under development have proposed fuel gas or tar conditioning prior to utilization in internal combustion applications, where specialized equipment will be required to avoid the operational hazards inherent in the process. Biosolids as a feedstock also present inherent difficulties when compared to other biomass feedstocks such as woody waste, and especially fossil fuels. Example proximate analyses for a range of representative feedstocks will be compared to biosolids to demonstrate its unique qualities (comparatively high oxygen, nutrient, and ash content) and their impact on system operations. Special attention will be given to the presence of alkali and alkaline earth metals (AAEMs) which make biosolids at risk to slagging and corrosion within the system, and best practices for system operation to achieve stable temperature to avoid these issues. Variability in biosolids parameters and loading rates during operations also pose a notable challenge to pyrolysis and gasification. Coordinating operation of discreet drying, pyrolysis or gasification, and thermal oxidation parameters require upfront load leveling and adjustments to seasonal changes in solids parameters. Reactor feeding hopper and conveyor systems have been developed to address these challenges on a micro-scale and its expected that further system development will be required to optimize operational resiliency to larger changes in solids production and processing trends upstream. Furthermore, an overview of required monitoring and operational points will be presented as an indicator for operational and staffing requirements for any project. Conclusions and Next Steps The technology review findings show that pyrolysis and gasification, as deployed today with direct combustion, can address historical operating challenges, but do entail a substantial demand on operations staff. As these technologies convert all the fuel gas into usable heat onsite, they are primarily differentiated from SSI by the characteristics, and end use opportunities afforded by the solid char product. Consequently, further work to identify the environmental and economic benefits from char, and impact of upstream processing steps on its beneficial use, will be critical to determining their viability. In addition, potential exists for improved combustion conditions compared to SSI in the thermal oxidizer, but emission characterization, especially for emerging contaminants like per- and polyfluorinated alkyl substances (PFAS) will be required to verify their effectiveness. For systems considering fuel gas processing and alternative uses, such as oil production, a careful study of fundamental operating principles and requirements will be required to address challenges inherent in the biosolids feedstock. Finally, opportunities exist for process intensification, including carbon diversion in wastewater treatment, co-processing with alternative dried feedstocks, and high efficiency drying technologies. Of all these options, high-efficiency drying is shown to have the highest potential impact and further development in this area could lead to a greater breakthrough in technology adoption.

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

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

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

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

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.