Results

INTRODUCTION Anaerobic digestion is utilized by water resource recovery facilities (WRRFs) to stabilize wastewater residuals and recover renewable energy in the form of biogas. Recently, anaerobic co-digestion of wastewater residuals with high strength organic waste has gained much popularity in the wastewater industry due to it's potential to improve methane yield. Fats, oils and grease (FOG) is one of the desirable co-substrates due to its higher methane production potential and degradability (compared to wastewater residuals) (Salama et al., 2019). However, some studies (Amha et al., 2017; Wu et al., 2018) have shown that higher FOG loadings can be inhibitory to the digestion process or the complex consortium of microorganisms involved. Therefore, it is critical to explore and understand how FOG impacts the co-digestion process and evaluate methods to avoid inhibition. One of such methods examined in this work was to evaluate if microbial acclimation through stepwise introduction of the co-substrate can avoid inhibition during FOG co-digestion. The goal of this study was 1) to determine the impact of co-digestion of waste activated sludge (WAS) with FOG on methane yield and microbial communities using short term Biomethane Potential (BMP) tests and long-term bench-scale reactors; and 2) to determine if microbial acclimation through stepwise introduction of FOG can be implemented to avert inhibition by comparing step-load and shock-load conditions in bench-scale reactors. METHODOLOGY Substrate and inoculum collection: Anaerobic inoculum was obtained from the Nashville Metro Biosolids WRRF's anaerobic digester which treats primary sludge and secondary scum. The WAS was obtained from City of Cookeville WRRF. The FOG used in this study was pure fats and grease obtained directly from a pork roasting grill at a local restaurant. BMP tests design and operation: Three experimental phases were carried out in 160 mL serum bottles at 35 °C. Phase 1 involved mono-digestion of WAS, as well as the co-digestion of WAS with FOG fractions of 25%, 50% and 75% (volatile solids basis). Phase 2 involved the co-digestion of 50% FOG with the 25% FOG digestate from Phase 1 as inoculum, while Phase 3 involved the co-digestion of 75% FOG with digestate from Phase 2 as inoculum. Phase 1 lasted for 20 days, while the phase 2 and 3 lasted for 13 days each. Bench-scale experimental design and operation: The experiments were conducted using two identical 10 L bench-scale reactors with a working volume of 6 L and operated at 35 °C. During the startup phase, all the reactors were fed with 100% WAS until they reached steady state. The designated control reactor was fed with WAS throughout all experimental phases, while the test reactor received various fractions of FOG. Phases 1 to 3 were conducted at volatile solids loading rate (VSLR) of 2 g-VS/L/d, and involved co-digestion of 25%, 50% and 75% (VS basis) of the co-substrates, respectively. Due to digester failure in Phase 3, Phase 4 was experimented as a recovery phase by feeding the test digester with only WAS. Phase 5 involved the co-digestion of 75% co-substrate at higher VSLR of 4 g-VS/L/d without prior exposure to the co-substrate, and therefore without prior microbial acclimation. Reactors were operated at 20 days SRT and each experimental phase was run for 3 SRTs. The digesters were monitored weekly by measuring parameters such as biogas volume and methane content, pH, and VS removal. The methanogenic community present within the different experimental phases were also examined through 16s rRNA gene sequencing to understand the impact of the FOG fractions on the methanogenic communities. RESULTS & DISCUSSION Results from the study revealed that compared to the mono-digestion of WAS, co-digestion with FOG can improve specific methane yield (i.e the total methane volume per gram VS added) up to 16.5-fold. The specific methane yields of all the tested FOG fractions were higher at the BMP level than the ones observed in the bench-scale as shown in Table 1. In the BMP study, inhibition was not observed even at the 75% FOG fraction; however, 75% FOG was found to be inhibitory in the bench-scale experiment as seen in the decline in weekly average biogas production rate in Figure 2. The BMP tests were loaded only once, which made it less likely to cause inhibition as compared to the continuous loading in the bench-scale experiment which resulted in organic overload and subsequent inhibition. At the microbial scale, the overall methanogenic community was dominated by Methanolinea, a hydrogenotrophic methanogen, and its abundance remained similar across all the tested FOG fractions at the BMP level. However, significant reduction of methanogenic population was observed during the inhibitory conditions at 75% FOG fractions in the bench-scale experiment, as shown in Figure 3. The results suggest that bench-scale experiments provide more realistic methane yields with detectability of inhibitory thresholds of FOG as well as reveal methanogenic community response to different FOG fractions under stable and unstable conditions. The bench-scale experiment also showed that step-wise increment of the FOG could not achieve microbial acclimation to avert inhibition in this study. Further, FOG co-digestion was only viable with up to 50% FOG addition at the 2gVS/L/d loading rate. At the higher loading rates, inhibition occurred due to accumulation of volatile fatty acids above 2,000 mg/L and decline in pH. It should be noted that the 50% FOG threshold observed in this study may have been influenced by the inoculum, the FOG characteristics or lack of continuous pH adjustments within the experimental phases. CONCLUSION The study shows that FOG can be used as a co-substrate to improve methane yield when up to 50% FOG fraction is used at an organic loading of 2gVS/L/d. The study also provides insights about the influence of operational modes and stepwise acclimation strategy on FOG co-digestion and highlights the need for other strategies to avoid inhibition in FOG co-digestion systems.

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.

Utilities around the world have navigated the challenges of the global pandemic by working collaboratively and taking new approaches to delivering on their organizational mission. Some are seeking ways to shift from near-term agility to long-term resiliency and sustainability. Washington Suburban Sanitary Commission's (WSSC Water) Strategy and Innovation Office (SIO) worked with their cross-departmental New Normal Taskforce (Taskforce) to think beyond the current challenges to examine emerging challenges and opportunities. Using scenario planning and virtual forums, the SIO and Taskforce identified six key business opportunity areas for investment that build from pandemic-driven insights and will position WSSC Water for success across a variety of potential futures. This effort demonstrated WSSC Water's ability to leverage crisis-based momentum and internal partnerships to move beyond near-term shocks to build resiliency for the future. WSSC Water is currently among the largest water and wastewater utilities in the nation, with a network of nearly 6,000 miles of water pipeline and over 5,600 miles of sewer pipeline. Their service areas span nearly 1,000 square miles in Maryland's Prince George's and Montgomery counties. They serve 1.8 million residents through approximately 475,000 customer accounts. Guided by their vision to be the world-class water utility 'where excellent products and services are always on tap' and commitment to ethical, sustainable, and financially responsible service led WSSC Water to form the Strategy and Innovation Office (SIO). The SIO is charged with accelerating organizational performance through strategic planning and execution, knowledge management, and organizational effectiveness. The SIO is made up of the Office of Innovation and Research, Strategic Performance Office, and Enterprise Risk Team. The Office of Innovation and Research is responsible for finding and accelerating new technologies and processes that reduce operating expenses, increase safe work practices, improve sustainability and create new revenue opportunities. The Strategic Performance Office leads strategic business planning, data analysis and process improvements. Enterprise Risk spearheads business risk assessments and mitigation planning to minimize challenges to implementation of WSSC Water's strategic business plan. The New Normal Taskforce was formed as a cross-departmental team to identify and address challenges associated with the global pandemic and operational challenges. The Taskforce included the SIO as well as representatives from human resources, asset management, diversity and inclusion, police and homeland security, finance, production and utility services departments. Throughout the pandemic, the Taskforce reviewed working conditions, business practices, and technologies to identify concepts to permanently adopt into post-pandemic operations. Arcadis was retained to facilitate a series of virtual sessions to engage the SIO and Taskforce in examining the emerging opportunities and challenges post-pandemic recovery plus ten years. This longer view was used to move beyond the current context and challenges of the pandemic to identify and to better position WSSC Water for long-term success. A key tactic in this exercise was scenario planning. Scenario planning is a method of using uncertainty in plan development and decision making. By using this tactic, leaders can make decisions or adopt strategies that play out well across several possible futures resulting in more resilient business plans. The WSSC Water-Arcadis team held a series of virtual workshops built on the key steps to scenario planning. First, the team developed framing questions that identified the most pressing challenges or questions facing WSSC Water. These questions included complex long-term topics (e.g., digital transformation, affordability, workforce development, community understanding) that do not have established or discrete solutions. The framing questions were used throughout the workshops to keep discussion anchored in the practical challenges of the utility. Second, the team developed and evaluated key national and regional trends that are outside the control of the organization but impact their decision-making. This analysis involved deep dives into nine trend areas including advanced asset management, alternative energy technologies, climate change, policy and governance, contaminants of emerging concern, customer expectations, intelligent water, revenue and pricing, as well as workforce development and upskilling. From these trends, the team selected two key themes to develop a scenario compass and four alternative future scenarios for use in the idea development sessions. Using a world café format and collaborative virtual platform, the team examined each alternative future scenario and generated ideas that leveraged existing resources to address each of the framing questions. Discussions included approaches to improve infrastructure management, operational efficiency, business continuity, workforce development, customer experience, and digital transformation. From these discussions, idea themes were identified and consolidated into potential innovation investment areas. Over 600 individual ideas were contributed through the virtual sessions which were consolidated into 19 primary idea themes. These themes were later grouped into six research and innovation investment areas including customer experience, infrastructure, stakeholders, operations, sustainability, and data & digital. Within each of these areas, the specific ideas were sequenced across three priority horizons: H1 — enhancing existing core functions, H2 — adopting new functions from partner or adjacent industry, and H3 — novel function or future aspirations. These horizon maps provide a roadmap for general exploration by the SIO. Lastly, using the six investment areas, the team developed tailored roadmaps for innovation investments regarding each framing question. The SIO will use the roadmaps to develop a strategy to assist WSSC Water leadership with investment in near-term innovation with long-term impact and reduction of risk posed by uncertainty. They will use the investment areas to assess and prioritize new ideas and technologies as well as guide decisions regarding resource allocations. The horizons within each investment area help set a cadence for needs assessments and functional requirements for external partnerships. Further, the collaboratively developed focus areas identify cross-departmental support and resources needed to implement these strategies. Lastly, the exercise provides SIO with a number of tactics that will support review of trends and alternative futures. As trends change, the updated roadmaps will provide a framework to guide revisions to investment areas or sequencing to improve organizational resiliency. In this presentation, our team will walk through WSSC Water's experience and outcomes. Participants will learn the fundamentals for applying planning tactics to leverage uncertainty and lessons learned during the pandemic to identify investment areas that will support long-term organizational resiliency.

Abstract Description Loudoun Water's Project Support Office (PSO) has undertaken an innovative, yet practical, approach to establishing guidance documentation for the initiation, execution, and closing of projects across its many groups and needs. The resulting Project Delivery Guidance documentation avoids the common pitfalls of standardization efforts to provide accessible, actionable guidance to project managers across the organization. Abstract Located in the westernmost suburbs of Washington, D.C., Loudoun Water provides public water, reclaimed, and wastewater services to one of the fastest-growing areas of the country. As a result of recent growth, over half of Loudoun Water's infrastructure was installed in the last twenty years. The rapid growth will not stop- over the next thirty years, the area's population is expected to increase by another 125,000. Loudoun Water's capital planning assessments show that over one billion dollars in capital infrastructure is needed to serve future customers. Loudoun Water's responsibility to implement capital projects at such a hurried pace coupled with the need to update the two decades old project delivery system led to a strategic initiative of establishing a Project Support Office (PSO). The PSO works with various departments/divisions, supports to implement the capital and O&M projects, and carries out portfolio and program management level activities. The PSO led many tasks during its initiation to establish and ensure that optimal and required project management practices were followed across the organization to implement capital projects. The PSO assists project managers and project teams with their efforts to improve project definition, schedule, cost, and quality performance for their projects by defining minimum expectations and providing guidance and oversight. A primary goal of the PSO is to provide support documentation to aid project managers across the various divisions and departments to successfully initiate, execute, and close projects. As part of this goal, the PSO embarked on the development of a series of guidance documents aimed at providing project managers with a common understanding of the key deliverable components at typical design milestones, including preliminary engineering, 60% design completion, 90% design completion, and bid-ready design submittal. The Project Delivery Guidance documentation details the expected components (mandatory and optional) and completion level of specifications, design drawings, permitting, and coordination items at each design milestone. This presentation will describe Loudoun Water's approach to developing and implementing their new Project Delivery Guidance. A key focus of this process was soliciting input and generating buy-in and acceptance of the various stakeholder groups across the organization through collaborative workshops and guideline review cycles. The presentation will detail how Loudoun Water solicited feedback and insight into the processes and approaches of similar utilities and navigated the common pain points and pitfalls often associated with efforts to standardize an approach to critical processes across such a large organization. This work resulted in guidance documents that were broad enough to meet the varying needs of projects across Loudoun Water will be specific enough to provide actionable information to assist in the execution of projects.

Transforming a utility's culture to embrace innovation requires redefining behavioral norms and recruiting stakeholders into the innovation environment. Often, utilities struggle with establishing innovation cultures due to ineffective change behavior techniques as well as complex and inflexible supply chain relationships. Peer scanning, informative interviews, and design thinking are all effective tools that can assist utilities with breaking down these barriers. Our team used these tactical approaches to serve as the catalyst for understating how to leverage innovation for the Birmingham Water Works Board (BWWB). BWWB sought out ways to use innovation for financial impact. It began by conducting a survey to determine ways that peer utilities have reduced operating expenses, reduced/delayed capital expenditures, generated revenue, experience economic development, or 'delivered value' to the customer. 17 utilities were surveyed to understand how they utilize innovation to improve their financial bottom line. Through exploring ways to reduce operating expenses, generate revenue, and optimize capital expenditures, utilities are using innovation to overcome financial hurdles. Insights emerged, detailing that utilities have felt real financial benefits from implementing innovative ideas, technologies, and business processes. 100% of the utilities experienced reduced operating expenses. While 47% experienced reduced capital expenses, only 29% of the utilities experienced increased revenue. Most utilities reported benefits were long lasting and were not one-time. 12 of the surveyed utilities participated in informational interviews to gather further details on their approaches. From conducting interviews, BWWB gained insight on items for possible implementation. Over 20 suggestions were mentioned; it included ideas such as regionalizing services to leveraging assets to partnering with vendors to develop technology. Overall, the initiatives mentioned were aligned with alternative revenue, economic development, cost savings, and management of customer expectations. To determine the feasibility of implementing some of the innovation approaches discovered, BWWB vetted the unique ideas. Since BWWB had already implemented several strategies similar to peer utility initiatives, those opportunities were not considered further. BWWB ultimately selected to vet 4 opportunities through the design thinking process. Tim Brown, the president of the design house IDEO, defines design thinking is defined as 'a human centered and collaborative approach to problem solving, using a design mindset to solve complex problems.' By bringing together diverse stakeholders and perspectives to engage on strategic opportunities, design thinking places the human at the front and center of a problem. Our process followed 3 themes: -Learn: Examine opportunities through the lens of all stakeholders involved and consider the jobs done by key players. -Inspire: Explore innovation approaches that have been successful in other utilities. -Create: Generate ideas that addressed opportunities identified in the Learn session and then developed an actionable roadmap to bring the ideas to fruition. Our team will present BWWB's case study approach to building its innovation culture as well as detail lessons learned along the way. BWWB recognizes that a culture of innovation is born when everyone can play. By using tactical approaches, BWWB focused on fostering new behavioral norms and engage key stakeholders in the organization as building blocks for developing its culture of innovation.

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.

The Metropolitan Water Reclamation District of Greater Chicago (MWRD) is a special-purpose district responsible for treating wastewater and providing stormwater management for residents and businesses in its 882-square-mile service area, which encompasses Chicago and 128 suburban communities throughout Cook County. The MWRD works diligently to protect Lake Michigan, the source of their drinking water, and to ensure the health and safety of residents and area waterways. In 2020, the MWRD embarked upon a strategic planning process to establish the vision and goals that would guide its work over the next five years. The MWRD engaged Arup and Civic Consulting Alliance to conduct the strategic planning process in collaboration with its Board of Commissioners and Executive Team. We brought expertise on structuring comprehensive stakeholder engagement for water utilities along with experience working with institutions to embed an equity-focus across their work — two strategic priorities for the MWRD in this round of planning. This new Plan built on the accomplishments of their 2015-2020 Strategic Plan. The goals were to: - Articulate the mission, vision, and strategic goals for the MWRD for the next five years - Identify a set of strategic initiatives to achieve those goals - Provide a framework for measuring progress and reviewing/updating the Plan on an annual basis The planning process began in September 2020 and was completed February 2021. The Strategic Plan was formally effective on June 3, 2021. We undertook a comprehensive, staged approach that consisted of four consecutive phases: - Phase 1: Led an intensive and iterative engagement effort to assess the MWRD's current state and identify its desired future state. That engagement effort included MWRD leadership and more than 500 MWRD staff, as well as approximately 50 stakeholder organizations that participated in a stakeholder workshop — including the Chicago Metropolitan Agency for Planning, the Metropolitan Planning Council, and a range of environmental and community-based organizations — and members of the general public who participated in public-facing surveys. - Phase 2: Conducted a workshop with the MWRD's strategic planning Steering Committee, which identified five strategic goals: resource management; stormwater management; workforce excellence; community engagement; and enterprise resilience. The strategic goals were formulated based on information and opinions collected during Phase 1. - Phase 3: Facilitated working groups for each strategic goal and developed a Strategic Roadmap for the MWRD to implement, including 150+ sequenced initiatives and metrics to measure progress. - Phase 4: Finalized the Five-Year Strategic Plan, which includes 5 overarching strategic goals, 32 strategies (that support the goals), and initiatives and a framework for the MWRD to update the plan annually. We presented on global best practices and industry trends to help guide the visioning process, and facilitated external stakeholder workshops to bring perspectives from environmental organizations, local communities, and regional planning groups into the planning process for the first time in the MWRD's history. Our Strategic Planning team leveraged industry frameworks from organizations such as the National Association of Clean Water Agencies (NACWA) and Water Environment Federation (WEF); and augmented with other trending research such as City Water Resilience Approach (by Rockefeller Foundation, Stockholm International Water Institute, Arup) and Circular Economy principles (Ellen MacArthur Foundation) to create a context-specific Strategic Plan for the MWRD. This resulted in a Strategic Plan that is innovative, responsive to key trends such as the growing threat of climate change, and the racial and social inequity in Cook County. As a result of this process, the MWRD is equipped with a Strategic Plan guided by the principles of engagement, collaboration, innovation, equity, and resilience. The MWRD's vision for its future state has been updated, and given the racial and social inequity in the communities served by the MWRD, its core values have been expanded to include equity and diversity. Moreover, these values are reflected in the specific strategic initiatives outlined in the new Plan. For example, one key focus is to identify and eliminate barriers to participation for disproportionately impacted areas (DIAs) — low-to-moderate income areas that may be more susceptible to flooding, and that often have less capacity to partner with the MWRD to implement stormwater solutions and alleviate local flooding. The benefits and significance of the Strategic Plan will be far-reaching for the MWRD to give a positive social impact to the communities it serves. These include: - Integration of an equity lens into the District's vision and strategies, to reduce the disproportionate impact of flooding and other water management challenges on low-to-moderate income areas in Cook County - District is equipped with a robust, collaborative, and community-informed strategic planning process that will guide it to a path to a more sustainable future The presentation will provide the following: - An overview of the overall strategic planning process - Steps to make the process more inclusive, and how staff at all levels were engaged, and how external organizations and the public were engaged - Identify the industry related frameworks that were used to develop the Strategic Plan - A review of key themes and initiatives identified in the Strategic Plan - Key outcomes that will forge stronger and more equitable connections with the communities the District serves - Lessons learned from conducting this process remotely and in virtual environments

Some of the more complex pipes that reside within the wastewater collections system are known as siphons/depressed sewers and are often referred to in the field as 'bellies' or 'sags.' Such systems typically navigate wastewater flow in pipelines that are near bodies of water, subways, tunnels, and other fixed utilities. These lines are constructed when traditional gravity design is not permissible, and a continuous grade cannot be maintained. Flow navigates the siphon pipe until it reaches pressurized flow and often creates foul odors which can be minimized by air lines. Siphon design allows for single barrel, double barrel or multi barrel and the number of barrels is typically related to the agency's requirements on hydraulic efficiency, maintenance, emergency events, and bypass requirements. Additionally, siphon design is critical for the future life span of the pipe due to its impact on operations. A poor design can lead to blockages, sediment build up and direct impacts on minimum velocities that are critical in siphons. For operations and maintenance this is critical because Siphon debris levels must be monitored closely to evaluate future needs for additional barrels, increased maintenance requirements and necessary repair work. In this abstract we concentrate on different operations and maintenance approaches on various siphons and the economic impact it can create for the utility owner and contractors. The first approach that will be discussed will be centered around cleaning siphons that have not been maintained and where minimal information is available. Secondly, the methodology of inspection and the various means that can be attempted dependent on the technology used. Lastly the combined approach of both inspection and cleaning will be discussed and evaluated. One of the most expensive approaches is often seen as is one in which the contractor blindly attempts to clean a sewer line (whether it be a siphon or not) without the known conditions of the pipeline. Not only is this a high-risk module but it is one where variables such as the structural integrity of the pipe, sediment levels, unknown debris types, and so much more are put into question. This approach will discuss a few siphons in San Bernardino that where maintained under a clean first approach. An inspect first approach can often be the least economically bearing approach because it is one that assumes it has minimal information from the start. This is because this method creates the information the owner can utilize to provide details about the siphon. Sonar and CCTV will be discussed and how the different technologies provide for varying deliverables and the limitations of each. Finally, one of the most comprehensive approaches is one in which the siphon is inspected, and the asset is assessed providing tangible details so that the line may be properly cleaned at a price that is well evaluated. This method will discuss the success of an inspect/clean siphon project in San Diego. This presentation will provide much needed information for a topic that has very limited information. This is because nationwide siphons are sometimes not maintained due to costs and or limited staff already strained by the primary collections system. The specialized work is one that is becoming more necessary and vital due to the aging assets and the imperative need to avoid emergencies on them.

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.

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.