Results

Don't Forget Manhole Rehabilitation: Significant I&I Reduction Accomplished Through Asset Management Program Methods WEF Collection Systems Presentation Abstract September 2021 Johnson County Wastewater (JCW) owns and operates a collection system consisting of approximately 2,300 miles of gravity pipe, 40 miles of forcemains, and 60,000 manholes. As the JCW collection system and workforce continue to age, investments in maintenance, repair, rehabilitation, and knowledge transfer to sustain desired service levels and risk tolerances will continue to grow. Increasing investment needs, coupled with limited resources, has driven JCW to continuously improve the efficiency and effectiveness of service delivery while continuing to execute day-to-day work functions. To meet this challenge, JCW and HDR staff collaborated in the development and execution of JCW's Collection System Asset Management Program (CAMP) Implementation Plan which establishes a clear, practical, and strategic path forward. JCW has executed its asset management program through this approach which identifies, prioritizes, coordinates, and schedules continuous improvement initiatives at a manageable pace that strives to balance staff availability and continuous improvement objectives. JCW's CAMP is a comprehensive, mature asset management program that encompasses all collection system assets. The efforts completed through this program have enabled JCW to forecast maintenance, condition assessment, and renewal investment needs with a high level of confidence, justify appropriate investment levels, focus limited resources, increase operational efficiency, and facilitate knowledge transfer. The asset management principles this program is built upon, and the lessons learned during the execution of this program are applicable to utilities of all sizes. One of the major program initiatives is the Manhole Inspection and Renewal Program. This presentation will present the challenges, accomplishments, and lessons learned throughout the development and implementation of the CAMP, specifically through the lens of our manhole program. The presentation will provide a review of the manhole program development (Years 1 and 2, 2016 -2017), and provide details on the accomplishments of the program goals completed in Years 3 - 6 (2018 - 2021). The program thus far has included six phases of Tier 2 inspections (over 10,000 manholes), and three phases of rehabilitation centered on both infiltration and structural findings. Pre-rehabilitation and post-rehabilitation flow monitoring has shown the program to be successful in reducing I/I, further emphasizing the importance of not forgetting about your sanitary manhole structures. The key Manhole Program accomplishments to date include: - Assessment of historical manhole inspection and rehabilitation efforts, and development of opportunities for continued improvement. - Development of JCW specific data collection standards and best practices, which focus on collecting the right data and limiting superfluous data collection. - Development and implementation of a Tier 2 inspection process utilizing 360 videos capturing defects throughout the full sanitary structure. - Development of a rehabilitation decision model and algorithm for manholes tailored to the manholes assets present within JCW's system. This model consists of multiple decision models dependent on material, structure location characteristics, cover and frame type, and drainage area conditions tributary to the manhole. - Independent QC of the rehab decision model using over 3,000 inspection findings to refine the decision model. - Testing of JCW's standard manhole cover types to determine inflow rates for each cover type and corresponding I/I reduction strategies for cover inflow. - Targeting floodplain areas and manholes susceptible of high inflow sources within various locations in the County. - Linking decision model data and 360 videos to GIS systems across departments, supporting improved decision making by allowing easy review of rehabilitation and inspection project locations. - Integrating program results and projections with JCW's basin planning and capacity enhancement program. - Automation of these tools to help execute the program. - Scaling inspection program up to 2,500 Tier 2 inspections per year, leading to complete Tier 2 inspections of over 10,000 manholes. - Completed rehabilitation of nearly 1500 manholes. - Evolution of standard specification of rehabilitation materials consistent with industry best practices. - Initial post-rehabilitation flow monitoring efforts indicating I&I reduction levels average over 20% in program focus areas. - Continuation of historical practice of capturing Tier 1 inspection data every time a manhole is opened by JCW staff members. Attachment A: Roadmap of JCW Collection System Asset Management Program Attachment B: Example Photo Using 360 Degree Manhole Camera Attachment C: Manhole Cover Inflow Testing Attachment D: Identification of Potential Manhole Inflow Sources in Floodplain Attachment E: Manhole Rehab Logic Example (Brick Manholes)

Public water agencies throughout the United States face many challenges with extending the reliable service life of their aging buried infrastructure. The San Jose/Santa Clara Regional Wastewater Facility (RWF) has the capacity to treat approximately 200mgd, with ongoing projects expanding this number. It is located in the City of San Jose (City) and has approximately 67,000 linear feet (LF) of buried wastewater process pipes, many of which were installed in the '50s and '60s and thus have exceeded their design life. Because of the potential terminal condition for some RWF piping, the City is using this Project to increase operational reliability and mitigate the likelihood of failure of their existing buried linear assets. If selected, the purpose of this presentation would be to share BV and the City of San Jose's approach to a large-scale piping condition assessment and rehabilitation effort. The presentation would include a description of the risk tool that BV developed exclusively for this project, condition assessment methods that were implemented, and rehabilitation methods that were selected. Fortunately for these agencies, many viable pipe rehabilitation methods have been invented to date, and there are often large pools of contractors vying for the job. Unfortunately for these agencies, there is rarely a platform available to share feedback or lessons learned from prior projects, even between neighboring cities. Furthermore, it is rare for an agency to embark on such a large, comprehensive project. Therefore, the largest benefit of this presentation would be the ability to share BV and the City's approach to delivering an on-time/under budget project, which started with developing a piping inspection prioritization tool and ended with rehabilitating pipes to provide an additional 50-year service life. In 2018, the City retained Black & Veatch (BV) for the Yard Piping Improvements Project (Project) to systematically assess all buried process pipes 8 inches to 144 inches at the RWF, which equates to approximately 60,000 LF of piping. Pipes at the RWF are comprised of many materials, but are primarily made of either reinforced concrete, ductile iron, or welded steel. The focus of the multi-year Project is to repair, rehabilitate, or replace (R/R/R) pipes, or portions of pipes, that are highest priority by virtue of their criticality and/or observed physical condition. In 2015, as part of a separate project, BV developed a condition assessment plan that provided a prioritized list of critical pipes for inspection, inspection protocol recommendations, and end of life estimates. The plan used weighted risk factors to determine the LOF (likelihood of failure) and COF (consequence of failure) for each assessed pipe. Depending upon identified pipe risk, inspection protocols and desired levels of inspection detail were determined for each pipeline. The final report produced in 2015 has served as the technical basis for the current Yard Piping Improvements Project, and the recommendations provided in that initial report have largely been followed. To date, approximately 36,000 LF of primary and secondary treatment piping has been inspected. Following each inspection, BV reviews the resultant condition data and makes R/R/R recommendations based on the findings. The Project follows an annual cyclical schedule whereby pipes are inspected during the regional dry-weather season, design work based upon these inspections occurs during the wet weather season, and R/R/R construction proceeds in the next dry-weather season. There is a separate service order for each year's pipe rehabilitation design, and a design-bid-build (DBB) project model is followed for each service order. Approximately 2,200 LF of the 36,000 LF inspected to date was identified to have severe deficiencies requiring R/R/R, and these pipe segments have since been rehabilitated. The scope for the first pipe rehabilitation service order contained primary effluent 96-inch reinforced concrete pipe (RCP) and an elliptical 87x136-inchpipeline. Beginning in the '50s, the RWF has slowly expanded to add more effective treatment processes and to increase the overall plant capacity. As a result of this expansion, there are many buried crossing utilities that preclude the feasibility of applying many traditional rehabilitation methods, resulting in a trenchless method focus. Ultimately, the 96' pipeline was rehabilitated with CIPP, and the 87'x136' was rehabilitated using a combination of concrete crown restoration with geopolymer material with an epoxy top coating. The second pipe rehabilitation service order, which is currently in the design phase, contains more primary effluent RCP including 78-inch, 96-inch, and 84-inch pipeline. CIPP was selected as a rehabilitation method for both the 78-inch and 96-inch pipelines, and concrete crown repair with a with an epoxy top coating selected for the 84-inch pipeline. The overall project is scheduled to be completed in 2026, with phases completed each year. The presentation of the Project, which has never been presented at a WEF Collections Conference to date, will focus on condition and risk assessment, selection of inspection methods and applications, the criteria against which rehabilitation alternatives are compared, planning and successfully executing pipeline rehabilitation.

Since it was founded in 2013, Bioforcetech has been working to rethink biosolids treatment at every step of the process. Our work has culminated in a deeply sustainable system that harnesses the energy already available in biosolids to dry and carbonize it with little to no external energy. Our patented Bioforcetech BioDryer (designed in house) and P-Series Pyrolysis machines (licensed and engineered in partnership with Pyreg GmbH) work together to reduce material volume and weight by 90%, lock available carbon in place for centuries, and produce a valuable biochar material all with 99% less external energy requirement than a standard paddle dryer. The Bioforcetech system is modular, capable of handling 80% of all US plants by linking units together in series, so that a plant can begin processing now with room to build as their capacity grows. At present time, we are proudly the only commercially available functioning pyrolysis project in the USA, and are running our units under some of the most stringent permitting conditions in the world (We have received an SSI exemption from the EPA and have received full permitting from BAAQMD). At Bioforcetech, we know that change is possible through collaboration across sectors and industries, which is why we are also investing in finding new applications for biochar that will lighten the carbon footprint of other industries and help grow the market for the material across the world. Our wastewater treatment is of utmost importance to human health. The accumulation of PFAS, PFOA, and PFOS in wastewater effluents puts our industry in a unique position to aid in the removal of these substances from our population.At Bioforcetech we have taken the PFAS issue as a personal challenge to overcome, and we are now proud to share that testing conducted on our technology shows considerable promise for its ability to successfully eliminate these harmful substances from input materials completely. When continuously applied, these CEC's bioaccumulate into the soils we walk on, the groundwater we drink, and the plants that we eat. As described by the EPA, high accumulations of PFOA, PFAS and PFOS can cause serious health effects including increased cholesterol levels, issues with infant birth weights, adverse effects on the immune system, cancer (for PFOA) and thyroid hormone effects (for PFOS). While the production of these chemicals has been phased out in the United States, similar chemicals like GenX have taken their place and continue to be created. The presence of PFAS, PFOA and PFOS in biosolids makes even the most beneficial land application of the material a serious risk to human and environmental health. In September 2019, we at 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 biosolids after the batch was dried in our patented Biodryer, and a third sample was taken after the batch was put through 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 issue. We were happy to work with the EPA to further test our technology, and found the results promising again. 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 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. PFAS, PFOA, and PFOS have permeated every part of our planet. Wastewater effluents provide a unique context where these chemicals can bottleneck together and appear at relatively high volume. It is therefore our responsibility as an industry to leverage this context and destroy PFAS, PFOA, and PFOS before it accumulates further in our soil, food and within our bodies. Solving this challenge is crucial to completing the Bioforcetech mission; to protect nature and human health by providing technologies that deliver a zero waste future, transforming organic waste into sustainable products. We are looking forward to continuing this work.

High hydrogen sulfide (H2S) concentrations are commonly seen in biogas produced from anaerobic digestion process in municipal water resource recovery facilities (WRRFs). These H2S concentrations cause the corrosion of concrete and steel, increases biogas conditioning costs, compromises the functions of cogeneration units, and leads to sulfur dioxide emissions. In addition, elevated dissolved sulfide levels in the sludge can inhibit the overall digestion process. Traditional methods of removing the sulfide have relied on chemical dosing into the digesters or biogas scrubbing, both increasing the costs of biogas utilization, often maintenance intensive and can present relatively high environmental impacts. This may lead to other issues including unnecessary adverse odours and less efficient operation of power generating assets. Biotechnologies (i.e. aerobic or anoxic biotrickling filtration) have recently emerged as cost-effective and more environmentally friendly alternatives (Munoz et al. 2015). Nevertheless, these biotechnologies are still limited by their high investment costs and their generated byproducts such as sulfuric acid and/or elemental sulfur slurry that need further processing or disposal (Kraakman et al. 2019). This paper explores the full-scale implementation of a relatively new process called 'micro-aeration' (MA). MA is a process integrated technology that employs a very small amount of air introduced into the anaerobic digester to raise the redox potential to partly oxidize the sulfides to elemental sulfur and remove it from the digester together with the digested sludge. Traditionally, exposure of the anaerobic digestion process to oxygen has been avoided due to its perceived negative effects on growth and activity of obligate anaerobes, especially methanogens. However, in recent years numerous studies have reported the potential beneficial effects on anaerobic digestion in terms of digestion process stability and digested sludge dewaterability when a small volume of air or oxygen is injected into the sludge (Jenicek et al., 2014). The MA process has been shown to reduce H2S in the biogas and sulfides in the waste stream by more than 90% (Ngheim et al., 2014, Jenicek et al., 2017). For this reason, MA has the potential to revolutionise sulfide removal in anaerobic digestion. However, the basic mechanisms involved in micro-aerobic sulfide oxidation are not fully understood and control strategies for MA are still being optimised. Complex biological and chemical interactions occur between sulfur, oxygen, iron, and phosphorus throughout the anaerobic digestion processes, which are well characterized in literature (Batstone, 2006). Despite recent developments in whole plant process simulators (Hauduc et al., 2017), and modifications to the anaerobic digestion model (ADM) (Flores-Alsina et al., 2016), the implications of these interactions, including within the MA context, have not been fully explored. This paper presents an increased understanding of the MA process by specifically reviewing the performance of a full-scale MA application by Sydney Water and by proposing a process model capable of representing the performance observed at full-scale MA and considers biological and chemical interactions. A review of other full-scale MA applications is also presented. METHODOLOGY This investigation comprised the following steps: Literature review of the existing MA process configurations and performance. Including recently reported full-scale pilot testing (Kraakman et al, 2019). Critical review of over three years of process data for a Sydney Water installation including MA conditions, solids and biogas balances and analysis of the sulfur balance around the digestion treatment process. Development of a process model for an existing installation using the SUMO platform with integrated sulfur chemistry. This involved developing an anaerobic digester process unit with capabilities to set up aeration conditions and calculate oxygen transfer for uptake by digester biomass and use in oxidative processes such as sulfide oxidation by Sulfur Oxidizing Organisms (SOOs). Figure 1 shows the Sumo process schematic of the modelled installation. RESULTS Analysis of the process data on the MA trials showed that normal H2S concentrations in the biogas of approx. 1,000 ppmv can be reduced by up to 92%. However, there is a clear trend when studying air flow rates and H2S removals where a normal removal of around 50% was achieved at air flows of 177 NL/m3 reactor volume-day or higher, with a maximum observed oxygen consumption of 6.65%/m. Moreover, increasing the oxygen to sulfide ratio did not necessarily increase H2S removal. Results for biogas H2S removal and impacts on methane content due to the dilution mostly by the nitrogen in the MA air injected are summarized in Table 1. These sulfide removals translate in an increased biogas quality for energy recovery in WRRFs with potential to lower costs of biogas conditioning. In terms of digestion performance, no statistical differences were observed in total solids reduction, biogas production and cake solids achieved when the MA was performed compared. General process model calibration was performed following the International Water Association's Good Modeling Practices Unified Protocol and the SUMO Process Simulator (Dynamita, Lyon, France). Calibration of the sulfur chemistry in the raw sludge and the digesters without MA was first achieved by estimating the particulate fraction in the influent sulfur speciation, and by considering the collection system operation in terms of iron addition, discharge of biological sludge from a neighboring treatment plant, and internal sulfur recirculation from a chemical scrubber targeting H2S. To calibrate the process model, model parameters needed to be adjusted to match the observations from the MA trials. Most critical seems the affinity constants and its related rate of sulfide oxidation in the model compared to default microbial and chemical kinetic parameters when applied to full scale digestor systems. Two sulfide oxidation pathways are identified for oxidation of H2S, one mediated by SOOs and another chemically mediated in the presence of a metal. From literature in the subject, it is still unclear which pathway would dominate, and simulations using the developed model in this project showed that both mechanisms have the potential to yield the oxidation rates needed to match results obtained. Given the research conducted by Van der Zee et. al. (2007), Jensen et. al (2009), and Ruan et. al. (2017), the MA model currently considers the biological oxidation as the most significant mechanisms for sulfide reduction during air injection. A better understanding of the residual iron-ion levels in the digester feed sludge and actual mass of the different sulfur species will be useful to refine the model. CONCLUSION This investigation presented a process model for a better understanding of the sulfur chemistry during the digestion process, with biological oxidation likely to be the most significant mechanisms for sulfide removal during the MA process. MA is a promising technology for sulfide control in anaerobic digesters; this investigation showed that up to 92% H2S removal can be achieved, although the performance to date has been variable for various reasons. Lower H2S level in the biogas decreases biogas treatment cost for energy recovery thus contributing to the economical and sustainable performance of the energy recovery process of waste sludge digestion at wastewater treatment facilities.

Introduction Per- and polyfluoroalkyl substances (PFAS) encompass a wide range of compounds, numbering in the thousands. These compounds, because of their properties, have been used in a variety of consumer and industrial products and, consequently, are widely distributed in the environment (Buck et al., 2011). Research focused on understanding the sources of PFAS in drinking water and have identified municipal wastewater reclamation facilities (WRF) as an important pathway (Clara, Scheffknecht, Scharf, Weiss, & Gans, 2008). Because PFAS are concentrated in wastewater solids (Rainey, 2019), WRFs introduce these compounds to the environment through land application of biosolids, potentially allowing PFAS to enter surface water and groundwater (Lindstrom et al., 2011). What has not been well studied is the potential for sewage sludge incinerators (SSI) to introduce PFAS to the environment or destroy it. The extent of PFAS thermal destruction (i.e., thermal degradation by-product formation or complete mineralization) is poorly understood. No published data currently exist on the fate of PFAS through an SSI, although limited information from other industries can be referenced. This paper documents the current understanding on the fate of PFAS through SSIs and the research currently underway to further our understanding. PFAS Thermal Behavior For a combustion process to achieve complete PFAS thermal destruction (mineralization), PFAS compounds would have to be driven to their thermodynamic endpoints of CO2, H2O, HF, or sulfur compounds, if present. Residence time, turbulence (mixing), and stoichiometry (the relative mixture of waste to fuel, oxygen, and other gas-phase constituents) within the flame zone impact the completeness of combustion (Lewis, 2008; Niessen, 2002). Published research and industry guidance indicate that complete destruction of PFAS requires high temperatures (Table 1) which exceeds typical temperatures in SSIs. Notably, this guidance is based on limited conceptual or laboratory-scale experiments and precedence on previous guidance established for hazardous waste incineration. The baseline research for these recommendations stems from USEPA and other international environmental agency activities. Taylor & Yamada (2003) published results of a simulated hazardous waste incineration experiment with limited air to account for non-ideal combustion conditions. Experiments showed less than 0.4% and 0.05% of the PFOS fed to the reactor were detected in the exhaust at tests conducted at 600°C and 900°C, respectively. Yamada, et al., (2005) published a similar laboratory-scale study that considered combustion of PFAS-impregnated textiles. Neither PFOA nor PICs were detected under non-ideal combustion performance. Taylor et al. (2014) found no PFOA emissions after combustion of gasified fluorotelomer-based polymers. Full-Scale Incineration Studies A few full-scale studies have been published on the fate of PFAS through incineration systems with only two considering an SSI. Loganathan et al. (2007) investigated eight PFAS through a wastewater treatment facility. PFAS were measured in dewatered solids fed to the incinerator and in the ash. No mention was made on the operating conditions or whether the bottom or fly ash was sampled. Findings indicated a significant transformation of the measured compounds (26 & 97 percent); however, some PFAS were still detected in the ash. A second study is currently underway at an SSI facility employing an fluidized bed (MacGregor, 2020). Samples were taken at all inputs and outputs of the SSI system and analyzed quantitatively for 28 PFAS. Preliminary results show that mass flows were reduced through the SSI processes for all quantitated PFAS, with the exception of 6:2 fluorotelomer sulfonate. The authors also noted that the inorganic fluoride content of the wet scrubber discharge water was over 10,000 times that of the influent flow plus the measured PFAS fed to the furnace, assuming mineralization. No other studies have been published on SSIs, but limited information can be found in literature investigating incineration in other industries. Lemieux et al. (2007) reported on the USEPA's study of feeding carpet treated with fluorotelomer products into a pilot-scale rotary kiln furnace. The emitted PFAS detected, primarily PFOA and PFHxA, did not change when feeding PFAS contaminated carpet or not. Aleksandrov et al. (2019) investigated emissions from a pilot-scale rotary kiln incinerator. No significant PFAS emissions were detected. Thermal By-Products Bench- and pilot-studies have examined decomposition of specific PFAS congeners and by-product identification; several studies documented thermal PFAS degradation by-products (Table 2). These studies show that PFAS will decompose at temperatures relevant to operating conditions of SSIs although by-product formation will be a concern. Funded Research The USEPA (2021) has recently sampled an SSI as part of a broader sampling program at a WRRF. Samples were taken from all major input and output streams of the multiple hearth for PFAS characterization. The samples are currently being analyzed for targeted, non-targeted, and total organic fluorine. Winchell et al. (2021b) provide a detailed discussion on these analytical techniques. A separate study led by Brown and Caldwell with support from the Water Research Foundation's Tailored Collaboration program will sample two SSIs, one multiple hearth and one fluidized bed. This study mirrors the USEPA from a sampling and analytical standpoint. The full-scale sample will take place during the winter and spring. Initial work has included site selection and workplan development. Including, estimating PFAS emissions at various destruction and removal efficiencies (DREs) based on targeted PFAS measured in initial dewatered cake samples. Figure 1 shows the PFAS emissions from one of the test sites remain above the reporting limits for the analytical method at relatively high DREs. This suggests specific PFAS will be detectable unless achieving high DRE, a question highly sought after by the industry. Conclusions Thermal treatment of PFAS through SSIs represents a potential wastewater solids process for destroying PFAS; although, significant questions remain regarding both the destruction efficiency and potential formation of undesirable by-products. Temperature is only one of the three key operational parameters that should be considered when assessing destruction capacity in combustion systems. The other two important factors include residence time and turbulence. A well-functioning SSI will submit PFAS to greater residence times and mixing (or turbulence) than the laboratory-scale research performed to date, further promoting PFAS destruction.

This presentation is intended to convey the design concepts, efficacy of rehabilitation methods, and construction challenges for the Guam Waterworks Authority (GWA) Interceptor Sewer Refurbishment Project. The project included the rehabilitation of a large diameter interceptor sewer by UV cured-in-place pipe (UV CIPP). Design of the UV CIPP was based on ASTM F2019 - Rehabilitation of Existing Pipelines and Conduits by the Pulled in Place Installation of Glass Reinforced Plastic (GRP) Cured-in-Place Thermosetting Resin Pipe (CIPP). Design criteria for the project included the calculation of dead loads based on the actual depths of cover above the top of the existing pipes as well as live loads based on AASHTO HS25 for sewers both inside and outside of the roadways. Guam is a U.S. Territory in the Western Pacific with a population of almost 170,000. The island is approximately 10 miles wide by 32 miles long. It is located about a quarter of the way between the Philippines and Hawaii, approximately 900 miles north of the equator, and it sits atop the western rim of the Marianas Trench. The island is strategically important to U.S. military operations because of its location, its land areas suitable for major airports, and its naturally deep harbor is a safe port for ships and submarines. U.S. military bases, including Naval Base Guam and Andersen Air Force Base cover approximately 39,000 acres or 29% of Guam's total land area. To accommodate the increased wastewater flows expected with the transfer of 5,000 or more U.S. Marine Corps families from Okinawa to Guam in late 2024, the Guam Water Authority assessed the condition of about 8.4 miles of 18-inch through 42-inch diameter interceptor sewer to reliably carry wastewater. The interceptor sewer extends from Andersen Air Force Base on the north end of the island along Guam Route 9 and thence along Guam Route 3 to the Northern District Wastewater Treatment Plant. The existing interceptor sewer was constructed in the 1970s. An assessment of the condition of the sewer was conducted in 2010, and a report of the findings was completed in 2015. The report noted significant corrosion of the inner walls of the sewer and recommended rehabilitation of its entire length. Additional assessment in 2017 noted that most of the sewer was constructed using Techite Reinforced Polymer Mortar Pipe and Asbestos Cement Pipe. Both materials can be problematic. Techite pipe is a thin-walled fiberglass composite pipe that was manufactured in the 1970s. It was removed from the market in about 1980, because it was found to be subject to catastrophic failures. Because of the concerns to health caused by the handling of AC pipe- especially the risks of inhaling asbestos dust when cutting the pipes - it is no longer produced or allowed in many countries, including the United States. Guam Waterworks Authority utilized a progressive design-build delivery process to procure a contractor (design-builder) for the project and contracted with our design-build team in September 2019. The design-build team included Core Tech-Hawaiian Dredging (CT-HD), as the general contractor; Michels for the UV CIPP lining; Mocon Construction for manhole rehabilitation; Dueñas, Camacho and Associates for bypass pumping and civil design; and Gresham Smith for rehabilitation design. The project was funded by the Department of Defense (DoD) for the U.S. Marine Corps redeployment of families from Okinawa to Guam. GWA and CT-HD determined that UV CIPP was the best solution for the pipeline rehabilitation. Previous attempts to install conventional CIPP on Guam USA had achieved mixed results at best. This was partially due to the remote location of the island, which makes the installation of conventional CIPP logistically difficult. Essentially, the conventional liner manufacturer must either build a wet-out facility on the island, or the installation crews must wet out the liner on the job site. On-site wet-out is difficult for even small pipe diameters. It is impractical if not impossible for larger diameter liners. Therefore, UV CIPP was selected because the liners could be impregnated at the manufacturer's wet-out facility, then properly stored and transported by container ship to the island. The obvious conclusion is that UV CIPP is ideally suited for sewer rehabilitation in a remote location such as the island of Guam. Almost all the existing manholes on the interceptor were PVC lined precast concrete. Significant portions of the PVC manhole liners were defective and in need of repair. In lieu of repairing the PVC liners with similar products, our Design-Build team proposed rehabilitating the defective manholes using an epoxy lining system. The $23 million project, which included the rehabilitation of approximately 44,350 LF of 18-inch through 42-inch diameter sewers, necessary pre-lining point repairs, and the refurbishment of approximately 100 manholes, was successfully completed in July 2020. Although the project was completed on schedule and with minimal change order costs, our team had to overcome significant challenges. These challenges included: - Scheduling of all phases of the work, including long delivery times for the liners from the manufacturer. - Numerous bypass pumping setups, which were complicated by required minimum cure times for cementitious repairs before lining the existing manholes with Raven epoxy. - Detailed traffic control plans and coordination with highway construction along Guam Route 3. - Scheduling and permitting work on Federal Lands. - Protection of Endangered Species such as the Common Mariana Moorhen. - Archeological Review. - Constructability issues such as:
a manhole and sewer segment that were partially under a multistory apartment building.
removal of jagged edges of failed
Techite pipe without a robotic cutter, which was not available on the island. It is felt that the information provided in this presentation will be of value to the engineering community, especially for future projects with large diameter sewers, extensive bypass pumping, remote installations, and stringent design requirements.

Introduction Per- and Polyfluoroalkyl Substances (PFAS) have been an increasing focus of the public, legislative bodies, and the regulatory community, and recent EPA activities highlight this focus with respect to biosolids(1). In October 2021 the EPA released its PFAS Strategic Roadmap, outlining EPA actions with respect to PFAS for 2021-2024: these activities include a risk assessment of PFAS in biosolids to be completed by 2024(1). EPA also announced its intent to pursue the classification of PFAS under the Resource Conservation and Recovery Act (RCRA). While it is no means certain that federal PFAS regulations for biosolids are forthcoming, some utilities have faced - or might face - increasing pressure to consider either i) reducing PFAS and microconstituent loads in biosolids, or ii) processes that provide an alternative product for land application. Conventional treatment processes such as anaerobic digestion or composting do not mitigate PFAS concentrations(2). Pyrolysis is an alternative solids process that is gaining interest as a possible approach to mitigate PFAS and microconstituents. Current literature is contradictory on the impact of pyrolysis on PFAS, with removal(3) and no removal(4) being reported. Thus, new experiments were conducted to determine the fate of PFAS during pyrolysis of biosolids, and results will be presented at the conference. In addition to knowing the impacts of pyrolysis on the fate of PFAS, practical considerations of pyrolysis such as generation of difficult-to-handle byproducts and side streams, dryer operations and costs, and product management need to be evaluated holistically. To approach this topic of PFAS removal via pyrolysis holistically, this presentation has three main objectives: 1. Define pyrolysis and the pyrolysis products generated from municipal biosolids 2. Determine the impact of pyrolysis on microconstituents, including PFAS, using novel, unpublished pyrolysis batch studies that investigate the fate of PFAS in biochar, pyrolysis-liquid, and pyrolysis-gas 3. Understand practical considerations for implementation of pyrolysis Objective 1: Define pyrolysis and pyrolysis products Pyrolysis is a thermal decomposition process that occurs at high temperatures (normally over 450ºC) under limited or no oxygen. Pyrolysis of biosolids generates solid, liquid, and gaseous products. The solid product, called biochar, is a carbon-rich product similar to charcoal that can be used as a soil amendment because it retains moisture(5). It can also adsorb nutrients from thickening filtrate and be used to improve grass growth(6). The non-condensable gases produced, called py-gas, contain energy rich constituents such as methane and hydrogen(7). The pyrolysis liquid can be composed of two phases: light non aqueous phase called bio-oil and an aqueous phase known as aqueous pyrolysis liquid (APL). The bio-oil, which can be used as a renewable fuel upon upgrading, is corrosive during combustion and difficult to handle, whereas the APL also contains organic compounds and sometimes high concentrations of ammonia that can be toxic to biological processes such as anaerobic digestion(8). Objective 2: Determine the impact of pyrolysis on PFAS and microconstituents Novel Research Approach Experiments will be conducted in a lab-scale batch pyrolysis system as described elsewhere(9). Dried municipal biosolids will be used as the influent feed, and effluent biochar, pyrolysis-liquid, and pyrolysis gas samples will be collected for PFAS analysis. In total, 37 PFAS compounds will be analyzed by PACE Analytical® in the solid, liquid, and gas phases to determine the impact of pyrolysis on the removal of PFAS from biosolids. These experiments will be completed by the end of 2021 and the analysis will be completed by March 2022. This experiment will be the first study to investigate the presence of PFAS in all three product phases (solid, liquid, gas) following pyrolysis. Results from Previous Lab-Scale Studies These results will be presented in light of Dr. McNamara's previously published data that found 3 possible fates of microconstituents during pyrolysis of biosolids: a. No removal: microconstituents reside with solids (e.g. metals) b. Volatilization: microconstituents leave solids and reside with pyrolysis liquid c. Transformation: microconstituents are chemically transformed Batch pyrolysis experiments revealed that pyrolysis removed triclocarban (Figure 1), triclosan, and nonylphenol from biosolids(10). Triclosan and nonylphenol volatilized away from the biochar and into the pyrolysis liquid; triclocarban was chemically transformed during pyrolysis. These results indicate that, while pyrolysis might likely remove PFAS from the solid biochar phase, PFAS might still likely reside with pyrolysis liquid requiring further downstream processing. The experiments and analysis to be completed by March, 2022 will confirm this hypothesis. Objective 3: Practical considerations for implementation of pyrolysis Pyrolysis has been extensively used for non-biosolids feedstocks but is not yet mainstream for biosolids applications, partly because of the overall operational complexity of these systems and cost considerations. Compared to biosolids land application, pyrolysis technologies represent a significantly higher capital investment for utilities since feed to pyrolysis must contain only 5 to 15% moisture, requiring thermal drying as a pre-requisite for pyrolysis. The capital and operational costs for drying could be very high depending on the moisture content of the influent biosolids(7). Including drying within the system boundary also makes the overall energy balance of a pyrolysis system less favorable. The energy available in pyrolysis gas and liquid products is approximately equal to the energy required for drying and pyrolysis of biosolids that are 20% solids. Based on anecdotal evidence from some of the demonstration facilities, phase-separation, i.e., separating the various pyrolysis products, downstream from the pyrolysis reactor can also be a challenge that could impact the quality of pyrolysis products for downstream applications. The bio-oil that is produced can be difficult to handle and potentially hazardous. To address the handling concerns with bio-oil, pyrolysis systems either need to run hot enough to not produce bio-oil or utilities need other plans for handling bio-oil post production. In short, while a potentially promising method for biosolids treatment, long-term operational viability of these systems for biosolids applications, sidestream characteristics, and emissions control requirements for these systems are yet to be proven. The potential benefits of pyrolysis include solids destruction resulting in less hauling costs, generation of pyrolysis-gas that could be co-combusted with digester gas or landfill gas, and generation of biochar which has potential as a value-added product and the potential to reduce PFAS. Biochar improves the soil characteristics by not breaking down readily, providing carbon sequestration and improving moisture-holding capacity of soils. Utilities considering pyrolysis have to weigh the potential benefits of the technology alongside costs and other operational considerations to determine the overall feasibility of the technology for full-scale implementation. Any government subsidies or credits to support PFAS removal, that might make pyrolysis more affordable to utilities, will also be reviewed and presented in this paper.

In the past two decades, wastewater treatment plants (WWTP) have been undergoing a dramatic transformation from solely focusing on wastewater treatment to resource recovery of valuable byproducts from waste. Utilities are increasingly realizing the benefits of biofertilizer production, nutrient recovery, energy production, and water conservation and the value it brings to the overall bottom-line for the end user. Wastewater utilities are also uniquely positioned to bridge the demands of renewable energy production as well as reducing organic solid waste from ending up in landfill, both regulated in many states in the US. The US EPA has identified more than 1,300 facilities in the US that rely on anaerobic digestion to reduce organics from wastewater, however, per the American Biogas Council, an estimated 40% of all anaerobic digesters in the US are being underutilized. Digesters with excess capacity are energy sinks, requiring just as much heat and electricity when operated at under capacity as they do while fully optimized, but with very little return in the form of energy production (as biogas). This unused digester capacity can be utilized to anaerobically codigest landfill diverted organics to produce biogas, which in turn can be converted to biomethane or heat and electricity using a combined heat and power system. Increased biogas production is just one of the many benefits of introducing high strength biodegradable wastes from commercial and industrial establishments into municipal anaerobic digestion systems. Digestion systems can also be designed to produce Class A or exceptional value (EQ) biosolids that is returned to the market as biofertilizer or soil amendment. In anticipation of an upgrade from 5.0 to 7.7 MGD, Hermitage Municipal Authority in Pennsylvania undertook a major upgrade of their solids handling facility to increase treatment capacity. The facility only has secondary treatment, meaning there is no easy-to-digest, high calorific value primary sludge as a feed to the new anaerobic digesters. As part of the upgrade, one of the goals was to boost biogas generation and use it as the primary fuel in a combined heat and power (CHP) cogeneration system to offset process heat and generate renewable electricity. This lead to a solids management plan specifically design to address high strength codigestion of source separated organic (SSO) wastes imported to the facility, mostly focused on pre-consumer expired or contaminated food waste, all while still able to produce a US EPA approved Class A biofertilizer. A new two phased digestion system was built using two existing anaerobic concrete tanks on site and one new steel tank. This system includes a first stage thermophilic hydrolysis reactor to acidify high strength waste, followed by high rate mesophilic digesters. A new biogas collection and treatment system and a combined heat and power unit was installed. Subsequently, a second CHP system was installed to maximize biogas utilization with minimal downtime. A new depackaging system, capable of handling dairy/liquid waste was included as part of this initial upgrade. This limited use process justified the needs of the time since only one regional dairy had agreed to divert their pre-packaged, expired dairy waste to the wastewater plant for organics recovery. Subsequently, a second depackaging system was installed to widen the imported source separated organics profile, specifically to include the capabilities to extract organics from various packaged solid food waste. The design of the facility also include a staging area to receive imported packaged organic waste from grocers, large food manufacturers, dairy and other organic waste generators. More recently, a new innovative depackaging process was installed to improve organics removal efficiencies, reduce contaminant level in extracted organic slurry, and manage increased throughput of imported waste at the facility. The three depackaging units are now capable of handling both solids and liquid waste effectively. Since January of 2013, the facility has grown from having just one dedicated organics waste supplier to now receiving food waste from over a dozen major sources. The facility has since processed over 8,000 dry tons of solid waste and over 12 million gallons of high strength liquid waste. The facility utilizes a custom organics feed staging strategy in the advanced anaerobic digestion system, that allows an applied organics loading rate (OLR) in excess of 12 kg/m3 (0.75 lb/ft3) in the first stage thermophilic acid digester. The second stage mesophilic gas digester is fed at a rate of 3 kg/m3 (0.19 lb/ft3), which is typical of conventional digesters, but is capable of higher OLR input. The phased digester feed is a combination of secondary municipal sludge and depackaged organic high strength slurry, in some instances pre-heated prior to introducing it to the thermophilic digesters. The organics loading ratio on a mass basis for municipal sludge to imported waste ranges between 1 to 0.6 and 1 to 1, with 20 tons of municipal sludge for every 12 to 20 tons of organic slurry. The phased digestion system is a US EPA's Process to Further Reduce Pathogens (PFRP) equivalent process, designed to achieve Class A biofertilizers as the final product. The current bioenergy system is capable of treating over 125,000 cubic feet of biogas and generates up to 13,400 kilowatts hour of power. The goal is to convert the biogas into compressed natural gas (CNG) to capitalize on the renewable energy credits to improve the cities renewable energy portfolio. In addition to increasing the bioenergy and biofertilizer production, the authority collects tipping fees from food waste generators that offsets ratepayer contributions. Renewable bioenergy production using landfill diverted organics all occurs within this resource recovery facility. This synergistic approach will benefit the solid waste industry from having to find new ways to manage organic food waste, the energy industry from having to build new renewable energy facilities, and most critically the wastewater industry in maximizing existing infrastructure to produce biofertilizer, recovery nutrients, produce bioenergy, and conserve water all while generating revenue from tipping fees. The paper offers a concise methodology that illustrates this synergetic approach to a growing problem. The paper aims to cover the nuances of source separated organics pretreatment, anaerobic codigestion and related processes.

For more than 30 years, technical standards and criteria have been developed to quantify odor concentrations, odor characteristics such as intensity, hedonic tone and odor impacts. Within these 'traditional methods', and most of the odor regulations around the world, the capacity and knowledge of citizens are largely excluded from the analysis. However, involving citizens in gathering data about odor nuisance can significantly reduce the cost of odor studies, while giving citizens the knowledge and tools to address the odor pollution that affect them. WEFs MOP 25 also mentions citizen monitoring as part interactive community outreach programs that could collect data to represent real conditions in the community that also might help understanding the strength at which an odor becomes a nuisance. In classical psychometry, there is a certain consensus on the four basic factors that affect the sensitivity of individuals: experience, expectations, motivation and the degree of alertness of the receiver. Sensitivity of groups is also affected by these four parameters. In the case of people exposed to odor impact, there are however other factors that affect group sensitivity such as: the amount of population affected (city, town, scattered houses, etc.), the land-use where the receptors are located (industrial, rural, hospital, school, etc.), the housing uses (continuous, occasional, fortuitous, etc.), or even the type of environmental protection that the impacted area may have. Weighting receptor sensitivity may be assessed using traditional psychometric tools. Psychometry is a science that deals with theory and techniques to measure psychological perceptions. The contents of psychometry are usually built upon two blocks: Theory of surveys/questionnaires/tests and, scaling, methods to perform scales, rules. Key concepts in psychometry are validity and reliability. These two parameters can be measured statistically. Odor managers have a nice tool box when they want to assess odor impact by using traditional psychometry. The most common techniques used are interviews, surveys, odor diaries and analysis of records of complaints. However, there are many limitations of these psychometric approaches, being the main one that the odor timestamp record is not accurate and thus, there are more difficulties in assessing the reliability of the odor observations recorded. Advanced psychometry, uses citizen odor observations in real time to asses odor impact in a community. There several initiatives dealing with this new way of evaluating odor impact. The European Union Horizon 2020 Science with & for Society Call funded Distributed Network for Odour Sensing, Empowerment and Sustainability (D-NOSES) project aims to develop a methodology based on participatory strategies, collaboration of different stakeholders using an extreme citizen science approach. Building on action research and participatory design (Foth et al., 2006), the goal of the project is to support and guide a collaborative journey to tackle odor pollution with the active involvement of key stakeholders from the public sector, business, civil society, and academia. In the D-NOSES methodology (Balestrini et al, 2018; Arias et al., 2019), citizens are part of this process by framing odor issues in their affected areas. This is done through identifying local odor problems, collective data collection, collective analysis of the results and co-designing measures to tackle odor pollution. Data collected by citizens shows a real, local understanding of the problem, and reduces costs of odor pollution measurements at the same time. As part of the D-NOSES project, a pilot study has been conducted in Los Alamos, Chile (15,000 inhabitants). Modifications to the 20 year old WWTP were introduced in 2018, including a technology shift from SBR to Activated Sludge and scrubbers and biofilters for odor abatement. Still, the WWTP impacts three neighborhoods (Villa Caupolic¡n, Villa Esperanza and Kintupi Ruca), which are located in the dominant wind direction. The case study started in June 2019 with an odor annoyance assessment questionnaire as described in VDI 3883 part 1. The aim of the odor annoyance assessment was to have a clear, not biased, image of the affected areas, in order to have an improved focus of the citizen engagement strategy. Results indicate a plausible relation between odor annoyance values measured with the verbal and the thermometer scale. The latter ranges from 0 (not annoyed at all) to 10 (extremely annoyed). Arithmetic means for Villa Caupolic¡n (close to source) was 5.7. Kintupi Ruca averaged 3.4, while Villa Esperanza and Villa Caupolic¡n (distant to source) 1.7. Field inspections are carried out since December 2018 by trained assessors to determine the impact frequency of recognizable odors in terms of odor hours, using the grid method described in VDI 3940 part 1 (EN 16841). The assessment area covers the three neighborhoods with 17 assessment squares. No odor impact was observed for Villa Esperanza and distant to source zone at Villa Caupolic¡n. Close to the source zone at Villa Caupolic¡n and Kintupi Ruca largely have odor impact characteristics below the 10 % threshold value, but two assessment squares located nearby a pumping station exceed this threshold. Citizen data collection started at the end of November 2019 and was suspended in May 2020 due to the corona pandemic. In addition to random observations, a group of local residents were trained as panelists to realize twice a day a predefined 1.8 km track covering 17 of the 29 measurement points considered in the field inspections, reporting odor observation by using the OdourCollect app. The app enables to report types and sub-types of odors, intensity, hedonic tone, and comment on the duration of the odor episode and the potential source. Geographic coordinates and a timestamp are automatically recorded. Data analysis of the citizen monitoring comprises more nearly 3,000 individual observations. Therefore, new indicators are developed, adopting those proposed by traditional technical standards: Observations frequencies are calculated for each assessment zone, using the grid method evaluation described in VDI 3940 part 1 (EN 16841). Citizen had not been trained on VDI 3882 part 1 (odor intensity) nor on VDI 3882 part 2 (hedonic tone), but both characteristics can be reported with the OdourCollect app. The observed relation between hedonic tone and intensity can be described as linear functions. Finally, a weekly annoyance index is calculated for each assessment square and observation week using the equation given in VDI 3883 part 2. Therefore, the reported odor intensity is related to an annoyance category. The aim of this study is to identify drawbacks and potentials of combining different approaches in which citizens take an active role. It will also present advances in the development of a new standard based on the construction of collaborative odor maps through citizen science. The development of the standard is being promoted by the International Environmental Association of Odor Managers (AMIGO) and a handful of other groups and experts.

The purpose of this paper will be to present recent advances and techniques along with proper application of proven methodology to rehabilitate two structurally compromised reaches of the Northwest Interceptor Sewer (NWI) in the City of Detroit, Michigan. The NWI is one of the major interceptor sewers in the Great Lakes Water Authority (GLWA) system and serves hundreds of thousands of residents and businesses in Detroit, Redford, Livonia, and Westland, Michigan. As part of the asset management initiative GLWA inspected the NWI using remote operated vehicle (ROV) video techniques in absence of flow control, preventing the lower half of the NWI to be inspected or observed. The ROV inspection revealed several reaches of the NWI along Trinity Avenue and Pierson Street at Warren Avenue that appeared significantly distressed and required emergency rehabilitation. Further investigation, evaluations, and designs were required to perform the required rehabilitation. Manned inspections of these NWI reaches were attempted but were extremely limited due to the high flow conditions. At that time, GLWA activated their Emergency Repair Contract CON-149 with Inland Waters Pollution Control (IWPC) to implement flow control devices and perform the required rehabilitation under a design build approach. An extensive flow control plan was developed and implemented to gain entry. This plan included new flow control gate construction, diversions to other nearby interceptors, and wet weather flow-through designs. Coordination with environmental agencies and knowledge of the GLWA system were important aspects to develop this plan. A geotechnical investigation conducted as part of the initial effort revealed silts and sands surrounding the pipe, with a static groundwater level high enough to drive soil material into the pipe through major cracking, causing concern for further degradation of the pipe. Following implementation of flow control, a manned entry was performed, which revealed more extensive deterioration than was initially apparent, including several sections on the verge of collapse. Immediately following the inspection, rehabilitation options were developed and reviewed based on the variable condition of each reach. Cured-in-Place rehabilitation was not selected due to requirements for long term wet weather flow control that would have been extremely expensive and that would have presented unacceptable risk to the environment. Slip lining methods were not selected due to the large entrance shafts that would be required and the unacceptable reduced lining diameter that would have resulted. Ultimately, a rehabilitation system was selected consisting of: 1) Stabilizing the existing host pipe by emergency support, followed by 2) restoring ground support around the host pipe, and then 3) Installing a reinforced sprayed geopolymer liner to restore the structural lining. This approach allowed for restoration resulting in maximum pipe diameter, with the least risk to the environment. Initial emergency stabilization consisted of first installing steel ribs in the most degraded reaches, followed by groundwater dewatering to minimize further loss of ground through the lining into the sewer. Geotechnical instrumentation consisting of piezometers and surface settlement points were installed to monitor the ground surface above the interceptor, followed by cement and chemical grouting to stabilize the ground around the pipe and further minimize loss of ground into the pipe. Major cracking was repaired in some reaches by installing reinforcing steel rods and anchors followed by over-patching with Eco-Cast lining materials. Following stabilization of the host pipe, the interceptor reaches considered compromised were re-lined with a steel reinforced Eco-Cast lining system. The system consisted of installing horizontal and circumferential steel to limit future cracking of the Eco-Cast liner. This presentation will discuss the emergency approach to the inspection, design, flow control, and rehabilitation methods of the NWI, during which time continuous sanitary sewer service was maintained without interruption, and no sanitary overflow occurred to the environment as a result of the project. Unique and creative methods for accomplishing this repair will be discussed, including the use of a dry weather diversions and bypass; and developing a fully structural finished and crack resistant spray-on lining with thickness of only 3 inches. The rehabilitation of the Trinity and Pierson reaches are complete and flow has been restored to the NWI in this area, with minimal surface disruption and no negative impacts to the environment. The project leaves behind a permanent flow diversion structure that will allow inspections and maintenance for years to come. As a side note, ongoing follow-on tasks for this project will provide two additional permanent flow control structures. This rehabilitation project illustrates several conclusive lessons to the industry described as follows:
Full dewatered inspection of Interceptor sewers is essential, as the initial ROV inspection of this sewer was not adequate due to high flows. Where practical, sewer owners should preemptively install flow controls within their major interceptors that will facilitate regular full-diameter inspections.
Repair methods must be balanced against available and feasible flow control options.
Distressed Interceptor reaches are often distressed due to poor soil conditions such as wet silt/fine sand conditions.
Grouting these reaches to re-establish host pipe confinement is essential usually requiring an exterior dewatering system.
Use of a reinforced sprayed liner system is an effective method to be employed for limited flow control conditions while providing a structural and flexible complete repair, with minimal diameter reduction. Reinforcing is essential for spray-lining systems where future movement or reflective cracking of the host pipe is a possibility.

The criteria by which the public determines the success of a project may vary significantly from the criteria established by those who conceive, design and build the project. The odor impacts of a new project is one example of this disconnect; all too often sewer authorities have found themselves catching up with unexpected odor impacts that cause the public to deem a 'successful' project a failure. The threshold for success in managing odors is often much higher once the public perceives an odor issue. Any major change to a community's sewer system can result in unexpected and negative impacts related to sewer ventilation and odors, and the addition of a large-diameter CSO tunnel is no exception. Akron OCIT The City of Akron's Ohio Canal Interceptor Tunnel (OCIT) is currently under construction and is scheduled for completion in 2020. The proposed OCIT has a 27-foot-ID, mixed face tunnel that will capture and convey dry weather flows. The tunnel receives flow from three (3) shaft locations. In the early stages of the OCIT design, the City chose to take a proactive approach to ventilation and odor control due to the high visibility of the project and the tunnel's planned route through prominent commercial and residential areas. This paper will present a case study of the multiple proactive ventilation and odor control analyses that were performed during the design and construction of the OCIT, which resulted in changes and additions that will help the City of Akron avoid odor-related pitfalls that other cities have encountered. Methods First, a ventilation analysis was performed using field instrumentation to assess odor concentrations and airflow dynamics in the existing system to identify problem areas. This analysis was then expanded to include the proposed tunnel system to determine potential locations that would emit air from the tunnel for the purposes of evaluating odor impact risk. An empirical ventilation model was used to quantify air flow rates within the tunnel as well as near-surface sewers within a range of hydraulic conditions; these results were cross-referenced with hydraulic modeling of the tunnel and sewers in order to estimate frequency, duration and intensity of odorous air emissions at each location. The results of the ventilation analysis and modeling were used to complete a comprehensive facility plan, which provided recommendations for design changes to the tunnel and associated structures to improve control and management of air flow through the system. The facility plan also developed capital costs and footprints for potential odor control facilities. Results The outcomes of these proactive steps were several additions and changes to the design, including: below-grade ductwork at each drop shaft site for the accommodation of future potential odor control facility needs; air curtains to prevent fugitive emissions and the drawing in of additional air; an additional shaft to allow for the release of air at a less sensitive location during wet weather events; modifications to vent vault designs at each drop shaft site; and a ventilation stack at the downtown OCIT-3 site for periodic air emissions expected there. The information provided by these proactive studies allowed the City to be strategic in its planning for managing and, if necessary, treating odorous air flows. In addition to the design changes listed above, the City decided to proactively design an odor control facility at the downstream end of the tunnel due to anticipated constant air emissions at that location. HDR facilitated a technology selection workshop with the City and selected activated carbon as the best technology to meet the City's needs for this site. Conclusion In the absence of the actions taken by the City to understand the ventilation dynamics of its existing and proposed system, it is likely that a difficult odor issue would have developed soon after the OCIT began operations. Instead, through its proactive planning efforts, the City is well-placed to minimize the odor-related impacts of the new OCIT on the Akron community.

Controlling odors and managing health risks associated with possible exposure to Endotoxins has always been a high priority for ERWSD. The Avon Wastewater Treatment Facility (AWWTF) has eliminated solids handling by discharging biosolids to the downstream Edwards facility, and is in the process of expanding the secondary facility, such that energy usage for heating and ventilating as it relates to odor control and meeting ventilation guidelines for the upcoming Nutrient Upgrade Project is an important element of the design. Design of the project is complete and construction has begun. Details of the design will be presented in this paper, where odor control has been integrated into the Nutrient Upgrade Project. Historically, comprehensive odor studies were conducted during each major process undertaking at Avon, including in 2104 before the plant shut down the Autothermal Thermophilic Aerobic Digestion (ATAD) process in 2016 and in 2018 during the planning stages of the plant expansion. The facility used an extensive odor control system in 2014 including three stages of chemical scrubber treatment for ATAD exhaust air and an Ozone oxidation process for the Headworks and Primary treatment processes. For the 2018 study, after ATAD was eliminated, ERWSD's goal was to meet a new standard of 'as near to zero community odors' as possible. The facility plan called for construction of a building over the aeration basins instead of keeping the flat basin covers, which significantly increases ventilation and exhaust air flow rates, therefore higher levels of odor treatment would be required to meet the goals. The ERWSD requirements were to provide full redundancy and multiple stages of odor treatment. This paper will present data, analysis of alternatives and the methodology used to meet these objectives. The design includes replacement of the ozone treatment system, which was found to be ineffective in treating odors (50% removal efficiencies) with a multiple stage carbon treatment train and the demolition of scrubbers that had reached the end of their useful life. Ozone was injected into the Headworks Building with 12 Air Changes per Hour (ACH) of outside air and exhaust from the primary and grit tank covers were also ducted to the Oxidizer chamber. Strobic Air fans will be used for the discharge of air from the Aeration Basin Building, providing dilution and a high emission profile. Modeling used in the project is presented below, showing improvements in community odors each time changes were made or planned for the facility. These are peak odor contours (Dilutions to Threshold -DT) for the 2014 plant, the 2018 plant and for the future expanded plant, in that order, showing improvement at each stage. Total plant Odor Emission Rates (OER) for each stage are as follows, with the increase in odor emissions for the expanded plant being the result of exhausting 33,000 cubic feet per minute (cfm) from the aeration building instead of a much lower exhaust rate from the existing flat covers: ERWSD has probably done more research and testing on Endotoxins at their plants, starting in the early 1990's and in the secondary clarifier buildings than any other municipality in the U.S. and has established limits on Endotoxin exposure for the buildings where workers are present. Endotoxins are lipopolysaccharides which are found in gram negative bacteria (some of which could be pathogenic) and exist in the outer membrane of the cell wall. These substances can cause respiratory or flu like symptoms so ERWSD keeps workers safe by providing sufficient ventilation to keep endotoxins below 90 Endotoxin Units (EU) per cubic meter (m3) for an eight (8) hour exposure based on 'no-observed-effect' health risk assessments performed in Europe. This paper will present monitoring data collected by ERWSD on Endotoxin levels inside buildings and from point sources. In this case, three (3) ACH's) was selected for the Clarifier Building to dilute Endotoxin concentrations with outside air below the 90 EU/m3 guideline At one point in this study, consideration was given to providing some make up air to the aeration basin from the unclassified clarifier building to save energy, but the consensus was to be safe and not use air that may contain some level of Endotoxins as make up air to another area. Odor control at wastewater plants is closely related to the heat and ventilation systems in the same areas. National Fire Protection Association (NFPA) 820, titled, 'Standard for Fire Protection in Wastewater and Collection Facilities' calls for a variety of fire safety systems, including guidance on how to mitigate hazards by ventilating spaces where fire risks are present. Areas upstream of the Avon WWTP primaries are ventilated per NFPA 820 with 100% outside air (OA) to mitigate explosion risks and are considered National Electric Code (NEC) Class I Division 2 areas, which require properly rated electrical equipment. However, areas downstream of the primary treatment basins are not required to have fire risk mitigation by NFPA 820 requirements. While not required to be ventilated by NFPA 820 to mitigate explosion risks, the areas downstream of the primary basins that can be entered by plant staff will be ventilated at rates to reduce risks associated with indoor air quality, such as limiting exposure to Endotoxins, mitigating buildup of corrosive fumes and meeting odor control goals. Ventilation can have a large impact on energy usage because OA may need to be heated or cooled to protect personnel and equipment inside the building. In Avon, a Colorado mountain town, the winter conditions can be extreme, requiring heating of the OA to prevent freeze and cold-temperature risks. There were a variety of ways to address the energy usage associated with ventilation at Avon including: --Heat the supply air with natural gas or electricity -- Heat the supply air with an existing wastewater-effluent-source heat pump system -- Air transfer ventilation using heated air from areas that do not have air quality risks, -- Energy recovery systems that transfer heat (but not contaminants) between exhaust and supply air This paper explores the various options at the Avon WWTP and how the design team settled on OA ventilation with supply/exhaust energy recovery for post-primary areas. The discussion will also describe how the use of supply/exhaust energy recovery resulted in a variance to IBC required building envelope insulation.