Conference Papers

As we await the Biden administration's review and approval of the Lead and Copper Rule Revisions (LCRR) promulgated on December 22, 2020, it is time to start familiarizing yourself with the proposed revisions, which seek to better protect children and communities with more effective requirements. At a glance, the revisions will require water suppliers to identify the most impacted areas by conducting a Lead Service line (LSL) inventory; strengthen drinking water treatment and corrosion control practices; replace LSLs; increase sampling reliability; improve risk communication; and better protect children in schools and childcare facilities. Through exploring how three communities proactively addressed the risk of lead in drinking water, attendees will gain a better understanding of what to expect when the LCRR is in effect, what are federal mandates, and how to get a head start. New York City Parks and Recreation Department conducted a robust testing program to sample more than 3,500 interior and exterior drinking water fountains at its public spaces across the city's five boroughs, within 3 months. Existing asset data allowed the project team to leverage GIS and compatible mobile applications to identify fountain sites, track stagnation, and manage testing and results in real time. The extensive data management required for this project provides valuable insight for managing LSL inventories and workflows around the find and fix philosophy as proposed by the LCRR. In 2017, the Massachusetts Department of Environmental Protection (MassDEP) assisted the city of Lynn in mapping facilities and conducting baseline sampling for lead and copper at more than 600 fixture locations in 25 public school buildings. After receiving the baseline sampling results, a phased approach was developed to address fixtures with elevated lead levels on a priority basis. Beginning in late 2019, the city entered the second phase of their program addressing lead in school drinking water and began replacing more than 400 drinking water and non-drinking water fixtures throughout its schools. School closures due to COVID-19 proved beneficial to this project as it allowed for school-wide water shutoffs that resulted in an accelerated replacement program. Approaches to comply with LCRR in absence of readily flushable connections which is often the case within schools will be addressed. California's El Dorado Irrigation District (EID) conducted a bench study to proactively evaluate alternatives for their drinking water corrosion control treatment. The district added zinc orthophosphate (ZOP) at its three water treatment plants to reduce in-house plumbing lead corrosion. The study assessed the feasibility of converting to a phosphoric acid corrosion inhibitor in lieu of ZOP to reduce zinc loading to the distribution system and subsequently to wastewater. This included development and implementation of a distribution system monitoring plan designed to assess potential impacts to distribution system corrosion with a particular focus on areas with asbestos cement piping. The results of the study were utilized by EID, in collaboration with the California Department of Public Health, to improve the District's overall corrosion control strategy to specifically address the upcoming LCRR requirements. Participants in this session will learn how these three entities with different goals and limitations approached comprehensive investigations to reduce lead exposure to consumers and worked proactively to make changes that improve water quality in advance of the forthcoming LCRR. The presentation will also provide brief insight on the impact of 'potential revisions to the microbial and disinfection byproduct rules' from the LCRR, with emphasis on proposed minimum oxidant residuals and common measures to control lead, microbial levels and DBPs.

Introduction
The Harris County Flood Control District (District) initiated a comprehensive asset management (AM) program that is changing their approach to operating, maintaining, and investing in infrastructure assets that reduce the risk of flood damage to Harris County, Texas. The AM program requires business transformation throughout the District's organization that will drive operations and maintenance (O&M) and capital investment decision-based activities. The program is intended to be a living and actionable strategy that allows for continuous improvement as the organization grows and the program matures. The District is using a phased approach for the development of the AM program. The initial phase (Phase I) of the project, which was completed between March 2021 and August 2021, developed interim AM program components and demonstrated the AM program approach applied to concrete-lined channels (Figures 1 and 2) which are a subset of the District's overall asset portfolio. Phase I formulated and documented the District's AM Policy, formulated elements of a first-generation Strategic Asset Management Plan (SAMP) and developed preliminary long-term maintenance and capital renewal estimates for concrete-lined channels included in federal and non-federal Channels Inspection Reports. The project team documented the Phase I efforts and findings and outlined anticipated future efforts in an interim report. The second phase of the project (Phase II) is focused on further developing the AM program while approximating long-term maintenance requirements for as many District assets as possible to support the District's maintenance budget request for the upcoming two fiscal years. Phase II will be completed by September 2023. AM program development is following best practices established through the International Organization for Standardization (ISO) 55000 series of standards for AM. This presentation will provide a summary of the Phase I efforts and results. The presentation will also provide a detail the planned Phase II efforts and status to date which is anticipated to include a discussion of asset inventory, inspection methods, and the District's current approach to long term maintenance cost estimating. Phase I - Interim Development As an initial step to implementation, the project team developed interim policies and strategies, initiated cross-organizational buy-in, developed an improved asset hierarchy (Figure 3) and created an asset registry associated with concrete-lined channels (Figure 4). A cornerstone of AM program, the risk framework, was also developed. The risk framework is anticipated to be used in the District's decision criteria to prioritize major maintenance projects, where, with all other factors equal, assets with a higher risk will be first in line to be repaired or replaced. The interim framework was based on five risk criteria for promoting an equitable application of maintenance funding: social vulnerability, historic structural flooding, channel level of service, development age, and development intensity. These five criteria were used to measure risk and to apply a total risk score to assets associated with concrete-lined channels (Figure 5). Phase I - Results For the interim phase, program outcomes were demonstrated by performing life cycle cost modeling for the District's approximately 140 miles of concrete-lined channel. The estimated cost to replace these District-owned assets 'in-kind' was approximately $1.098 billion as determined by planning-level replacement costs using attributes from the asset registry and District pay items and unit costs. The life cycle cost modeling simulated the concrete-lined channel assets over a 100-year period with funding scenarios that included major maintenance, vegetation management, and end of life renewal. Four different funding scenarios were simulated to demonstrate funding requirements needed to achieve various average long-term performance levels (conditions) of the concrete-lined channel assets in the model. The interim results (Table 1) demonstrated that while an annual O&M budget of $14M will maintain the concrete-lined channel assets in a 'Very Poor' condition, an annual $34M O&M budget will maintain the concrete-lined channel assets in a 'Good' condition over the long-term. The interim results provide an example of life cycle cost modeling results that are anticipated to be used to both optimize available O&M funding and to routinely evaluate various O&M budget levels and their resulting long-term effects on the condition of the District's asset portfolio.

Phase II - Current Activities
The project team is currently evaluating District assets associated with their open channel network for three watersheds: Little Cypress Creek, Halls Bayou, and Vince Bayou (Figure 6). District assets associated with these open channel networks include channel, outfall, manhole, inlet, conduit, and control structure assets. For these watersheds and associated open channel assets, the project team is developing a detailed AM register of assets, preparing a condition assessment framework based on industry best practice, conducting field inspection/condition assessment activities, developing long-term maintenance estimates, and identifying maintenance projects for 2 fiscal years. The current effort will test and further define future approaches to the District's AM program. The presentation will provide a detail the planned Phase II efforts and status to date which is anticipated to include a discussion of asset inventory, inspection methods, and the District's current approach to long term maintenance cost estimating.

Results and Conclusions
The AM program is shifting the District's current approach of estimating future maintenance costs based on past expenditures to a forward-looking approach based on accurate and up-to-date District asset data. The approach allows the District to optimize application of available O&M funding to achieve the best long-term condition of District assets. The program also provides a method to routinely evaluate various O&M budget levels and their resulting long-term effects on the condition of the District's asset portfolio. The results of the program will allow decision makers to plan future O&M budgets based on desired asset condition and available funding.

APPLICABILITY Solids thickening is an indispensable unit process for process intensification of biosolids treatment. The fluctuations of feed sludge characteristics often impact the stability of the thickening process, reduce process capability, and increase operation and maintenance costs. Often, the optimization of sludge thickening is focused on meeting performance requirements as detailed in specifications. This study expands the assessment of sludge thickening by including both thickening equipment and its up- and downstream infrastructure from a process capability perspective. The presentation will benefit engineers and utility operators in better design and troubleshooting of sludge thickening processes with designed thickened sludge solids total equal to or higher than 6%. INTRODUCTION The practice of wastewater treatment is evolving to transform wastewater treatment plants into WRRFs with the adoption of advanced wastewater treatment and solids handling equipment, processes, and systems. Enhanced sludge thickening plays an important role in achieving footprint reduction, chemical and energy efficiency, and process control of solids handling [1]. Several studies have suggested that enhancing sludge thickening plays an important role in achieving energy self-sufficiency [2]. Studies showed that improvements in primary sludge (PS) and waste activated sludge (WAS) thickening significantly increased biogas production [3]. Thickened sludge with higher than 4% total solids could be sufficient for achieving a positive energy balance in two-step AD processes. Sludge thickening is taking an increasingly important role in process intensification in biosolids treatment, either through pass-through thickening prior to sludge digestion or recuperative thickening integrated with digestion processes. Centrifugal thickening is one approach to achieving high-rate sludge thickening. The control of the thickened sludge total solids (TS) usually involves the control of Relative Centrifugal Force (G-force), solids retention time, differential rotation speed between centrifuge bowel and screw, and polymer dosage. The application of an in-line density meter or pressure-indicating transmitter could provide control signals for optimizing the performance of centrifugal thickening through mechanical adjustment of the size of thickened sludge outlet [4] or adjustment of the specific gravity of thickened sludge through air injection [5]. Feed sludge characteristics have a significant impact on the performance of thickening centrifuges. The variables of the sludge characteristics include hydraulic loadings, solids loadings, and the mixing ratio between PS and WAS. The fluctuation of feed sludge characteristics could negatively affect the performance of thickening centrifuges and interrupt subsequent operations of biosolids processes. At the same time, fluctuations in feed sludge characteristics are expected and should be accommodated in the design of sludge thickening. The objective of this study is to investigate two cases of centrifugal thickening installations, respectively equipped with GEA and Centrisys thickening centrifuges. This study will provide practical recommendations for mitigating potential bottlenecks in achieving 6% TS of thickened sludge. This study will introduce the use of process capability assessment as a tool for O&M. METHODS Collection and organizing of site information. One challenge for thickening improvement is to systemically document and organize the site information associated with sludge thickening. This study investigates the design and operation of thickening centrifuges and the immediate upstream and downstream unit processes of the thickening centrifuges at two water resource recovery facilities (WRRFs). The design conditions of the two thickening centrifuges systems are summarized in Table 1. The process capability of sludge thickening is affected by both performance of the thickening centrifuges and the performance of up and downstream infrastructure, including wet wells, sludge transfer pumps, the design of process piping, and flow measurement devices. In this study, we developed a check list for a detailed documentation of the thickening unit process as well the immediate upstream and downstream processes, as shown in Table 2. Process capability assessment. Process capability assessment is a manufacturing tool to gain process performance knowledge by analyzing a measurable property of a process to the specification [6]. In this study, an easy-to-use process capability assessment tool is developed for operators to document the thickening performance as a record for understanding process performance and preventative & predictive maintenance of the thickening equipment on a monthly basis. RESULTS A scoring matrix is developed based on the assessment checklist (Table 2) for the evaluation of the positive and negative factors impacting efficient thickening for the two WRRFs. The scoring matrix is used as a survey and communication method to collect opinions from operating crew, maintenance crew, and engineers. Figure 1 shows an example of the scoring matrix. The scoring matrix will be further developed to document the progressive process improvement of sludge thickening. As it is not practical to adjust feed sludge TS in a controlled approach at WRRFs, the impact of solids loading on the performance of sludge thickening is evaluated through time series analysis and histogram analysis of feed and thickened sludges. Figure 2 shows the time series analysis of the feed sludge and thickened sludge TS. As illustrated in Figure 3, histogram analysis of the same set of data reveals the process operation in respective to specified performance (Table 1). Hydraulic loading of thickening centrifuges could be readily adjusted by throttling feed pump. The impact of hydraulic loading is evaluated in terms of solids recovery ratio under different thickened solids TS. As shown in Figure 4, a trade-off exists between hydraulic loading and the solids recovery under the same thickened sludge TS. The results of Figure 4 is based the WRRF 2. A similar curve will be developed for WRRF 1 for this study. Figure 5 shows the change of apparent viscosity as sludge is thickened to TS of 2.5%, 4.5%, 6.0%, and 8.5% respectively. The significant increase in thickened sludge viscosity leads to a higher transfer pump discharge pressure. Depending on different process piping design, the thickened sludge transfer pump's discharge pressure varies 90-110 PSI for WRRF 1 and 70-100 PSI for WRRF 2. It is necessary to size the thickened sludge transfer pump appropriately to minimize process interruption due to insufficient pumping capacity. Figure 6 provides an example of the developed process capability assessment method for monthly evaluation of the performance of thickening centrifuges. The assessment serves as a standard approach to understand the process stability and capacity in related to specified performance requirements. CONCLUSIONS This study documented the impact of sludge characteristics on the performance of thickening and subsequence sludge transfer. The significant increase of sludge viscosity when thickened from 4% to 6% TS requires a design of higher discharge pressure of thickened sludge transfer well. The findings of this study suggested that special attention is needed in the design of the process piping, pumping, and process controls to realize the capability of thickening equipment. The process capability assessment tool applied in this study provides plant operators with means to document and understand the performance of thickening centrifuges. The method developed in this study could be applied to the process capability assessment of other types of thickening technologies beyond thickening centrifuges in WRRFs. This method can serve as a communication tool between the operation and maintenance crews/departments, as the results addressed both process performance and equipment conditions. With the adoption of more advanced and sophisticated solids handling equipment, developing comprehensive process capability assessment tools for respective unit processes may lead to improved performance and reduced life cycle costs of solids handling at WRRFs. This study adopts process capability assessment in evaluating the performance of sludge thickening based on two types of centrifugal thickening machines with different control mechanisms. Attendance at this presentation will benefit design engineers interested in designing centrifugal thickening as part of the process intensification of solids handling in WRRF. The presentation will provide practical suggestions for understanding the process capability of installed thickening equipment for performance improvement.

The North River Wastewater Resource Recovery Facility ('WRRF') provides secondary treatment for 170 million gallons per day dry weather flow primarily residential wastewater for a population of approximately 500,000 residents in the New York City's Borough of Manhattan. The facility is unique in that a heavily used, 28 acre urban Riverbank State Park is located on top of the plant. New York City Department of Environmental Protection ('NYCDEP') conducted dispersion modeling analysis to evaluate the potential impact of the North River WRRF's emissions. Typical sources of airborne formaldehyde in an urban environment include direct formaldehyde emissions from incomplete combustion (oxidation) products, from motor vehicle exhaust byproducts, or indirectly from formation of formaldehyde in the ambient air from photo-oxidation of hydrocarbon precursors, also emitted from motor vehicle exhaust and other combustion sources. The NR WRRF has compression ignition reciprocating internal combustion engines for its raw sewage pumps and blowers and is thus a potential source of formaldehyde emissions. NYSDEC Air Guide 1 dispersion modeling analysis estimated the potential impact of formaldehyde emissions from the facility's compression ignition reciprocating internal combustion engines (RICE) may be >10 times of the NYSDEC Annual Guidance Concentration of 0.06 µg/M3 around the engines' exhaust stacks within the plant's rooftop Riverbank State Park. NYCDEP executed a stationary ambient air formaldehyde monitoring program at a location by the engines' exhaust stacks for a year started in September 2015 as follows: Stationary Formaldehyde Monitoring Using EPA TO-11A Method -- Two 12 hr samples at one location every 6 days -- Started 09/25/2015 and concluded 09/25/2016 The initial formaldehyde monitoring registered unexpected ambient air formaldehyde concentrations as high as 84 µg/m3, much higher than published results of a previous survey conducted in New York City. NYCDEP staff performed a top-down assessment of the sampling program and the elevated concentrations observed with the assistance of NYSDEC. NYSDEC installed a separate set of sampling equipment side by side with the NYCDEP sampling equipment to collect same samples on two days and sent the samples to a NYSDEC laboratory for analysis. The NYSDEC sampling and analysis results verified the NYCDEP monitoring data. The NYCDEP monitoring program was expanded to conduct portable sampling at up to 13 remote locations in and adjacent to the Riverbank State Park and the surrounding community: Additional Remote Locations Formaldehyde Sampling Using Modified NIOSH Method 2016 -- Two 1 hr samples per day and two days per week at initial 11 but expanded to 13 locations -- Started 12/15/2015 and concluded 09/22/2016 NYCDEP performed data analysis including spatial and temporal analysis and revealed the following: The stationary monitoring station data show an apparent correlation between measured formaldehyde concentrations, ambient temperatures and ozone concentrations The stationary monitoring station data show very limited difference between formaldehyde concentrations for day and night time sampling events The portable sampling data didn't show a correlation between measured formaldehyde concentrations, ambient temperatures and ozone concentrations, The portable sampling data show marginally higher concentrations at the east side of the park that is closer to the nearby NY 9A Henry Hudson Parkway The portable sampling data show no significant difference between average formaldehyde concentrations between locations The portable sampling data show that the highest formaldehyde concentrations at each locations were all registered when the wind was blowing from a southerly direction The portable sampling data and Pollution Rose analyses didn't show apparent impact contours of any point source NYCDEP has continued performing the stationary monitoring, and also performing the remote locations sampling at reduced effort. The data show a seasonable variation pattern of the ambient air formaldehyde concentrations, demonstrating that the elevated concentrations are likely due to formation of formaldehyde in the ambient air from photo-oxidation of hydrocarbon precursors, and emitted from motor vehicle exhaust and other combustion sources.

The call to meet industry standards and operate according to best practices is one which all industry professionals can appreciate, but where standards are clearly outlined best practices is far less concrete. Within the residuals and biosolids treatment industry, that which constitutes best practices can vary greatly across facilities depending on a number of factors. In the spirit of diminishing this ambiguity, three case studies examining industrial dewatering and thickening systems at separate facilities will be presented. Two of the featured case studies will focus on dewatering; the first facility produces primarily inorganic residuals while the second facility's dewatering process treats starch-laden residuals. The third study also focuses on organic residuals and biosolids treatment, however their overall treatment involves a thickening process for relatively unique biosolids disposal which could be mutually beneficial for manufacturers and municipal processors alike. This presentation will include analysis of the technical aspects in each case study and a discussion of related findings. STUDY 1 DEWATERING INORGANIC RESIDUALS The subject of the first study is a facility which manufactures paint and coatings for electronic devices. In many treatment systems, flocculation is a vital step in dewatering solids. While this facility integrates flocculants, the waste stream composition poses additional challenges. Treatment begins in reactor tanks with coagulants, flocculants, and precipitants before being transferred to a clarifier. However, because this facility's residuals are predominantly inorganic, these residuals cannot effectively form the floc structure which renders a more manageable sludge suitable for common technologies like the belt filter presses or screw presses. Because popular technologies are ill-equipped to process this facility's distinctly tacky sludge, operators rely on a plate and frame filter press for dewatering (see Figure 1). Plate and frame filter presses are comparatively inexpensive, but despite cost-efficiency this press is subject to drawbacks which would typically disqualify its utilization in other facilities. These drawbacks, including reduced processing capacity and specific labor demands, are non-issues for this facility as operation occurs at a smaller scale. Because this sludge has a challenging consistency, the plate and frame filter press allows this plant to meet municipal limitations for proper disposal. Data obtained onsite reflected 2.0% feed solids was easily able to be dewatered to 28% cake solids, with a capture rate of 96%. STUDY 2 DEWATERING ORGANIC RESIDUALS The second study highlights a food processing facility which prepares potato chips. This facility's waste stream is marked by its high concentration of starch and starchy residuals. Due to the starch and water binding at an infinitesimal level, pressing alone cannot sufficiently dewater residuals. Therefore, this facility has incorporated a technology that may not adhere to wider perceptions of best practices. After its initial biological treatment in aeration basins, the waste solids are directed to a volute press. Onsite sampling reflected 2.1% feed solids was able to be dewatered to 17% cake solids but with a capture rate of only 79%. Figure 2 shows the cake from the volute press of this process. While volute presses may not meet high capture rates (see Figure 3), the resulting sludge does meet minimum requirements for municipal disposal. This choice could be seen as a failure to meet industry standards or best practices; however, this case study offers a fair example of a facility achieving balance between efficient operation and regulatory compliance. STUDY 3 THICKENING ORGANIC RESIDUALS The final case study features a second food processing plant. This plant, which produces a variety of sauces and condiments, has a waste stream with a high concentration of fats, oils and greases (FOGs). Processing FOGs can create undue strain on equipment, leading to wear and potentially shortening its operational lifespan. In this case, a complex system of treatment and retreatment is employed to maximize separation. The waste stream processing begins with an oil and water separator. After undergoing a biological process to remove contaminants, the waste stream moves to two dissolved air flotation devices (DAFs) which take 0.98% feed solids and thickens it to a 9.10% thickened solids product. Skimmed floatate, a gel-textured product shown in Figure 4, is transferred to a hopper. But what occurs next makes this study particularly noteworthy. Rather than disposing the end-process gel, this facility stores it in a silo onsite. Daily, the material is transported offsite to a nearby farm where the gel is applied as crop fertilizer. This stands out as an instance beneficial reuse, which is rare for industrial biosolids. This practice results in lower disposal costs for the facility. This beneficial reuse simultaneously benefits the municipal processers because the receiving POTW need not process FOG-laden wastewater or fine the facility for exceeding allowable effluent pre-treatment parameters. At a time when manufacturers in all areas are finding new and creative ways to meet corporate and social demands for sustainability, this type of process is an exemplar. However, as the previous case studies demonstrated this may not be in other manufacturer's' operational capacity or best interests. CONCLUSION Ultimately, the combination of unique waste streams, facility production capacity and local disposal options function in concert to outline best practices on an individual basis. The value of efficient operations cannot be overstated, but to truly thrive facility operators must be able to achieve maximum efficiency while also complying with oft-changing regulations. Failure to achieve this balance risks company resources and a cooperative relationship with municipal waste processors. By examining and comparing facilities' pre-existing treatment systems to post-upgrade systems against prevalent norms in the wider treatment landscape, we gain greater insight regarding the fluidity of best industry practices. This comparison will also yield a greater technical understanding for industry professionals as we compare capture rates and efficacy of various techniques across diverse waste streams' compositions. Finally, in addition to generating insights through analysis, this presentation will highlight how residuals and biosolids treatment systems impact municipal treatment facilities and vice versa. This discussion is intended to help reposition municipalities as a cooperative partner with a vested interest in the treatment process and industry.

The City of Des Moines, Iowa (the City) awarded a contract to CDM Smith for development of a comprehensive city-wide stormwater master plan (SMP). This session will communicate the value of applying a risk-based asset management framework to the City's SMP development. Municipalities will benefit from this discussion by learning about risk-based asset management principles for stormwater systems. This framework is adaptable, eases prioritization efforts, and enhances communication with stakeholders. The SMP was developed to provide a systematic, prioritized, and proactive framework for addressing the City's stormwater management challenges. To date, the SMP has consisted of two phases with the first focusing on a needs assessment and programmatic framework, and the second phase began implementation of the city-wide risk analysis and the more detailed application in the initially selected watersheds. The needs assessment and programmatic framework phase (Phase 1) was conducted by completion of a program audit, review of best practices, and identification of new practices to enhance the City's stormwater management program, including the initial development of a risk-based asset management framework. During the subsequent implementation phase (Phase 2), processes identified during the initial needs assessment were applied to characterize the existing stormwater system and provided insight for short- and long-term financial planning. Overall, the SMP informs future strategies by providing actionable recommendations and processes to manage assets more efficiently. Continued evaluation of level of service objectives, public engagement, and process refinement bring life to the SMP, allowing for future application and adaptation by the City. During Phase 1, a risk-based asset management framework was developed to prioritize stormwater asset inspections, maintenance, renewal, and capital projects. Under this structure, the Likelihood of Failure (LoF) and Consequence of Failure (CoF) are used to calculate the Risk associated with each asset. Each of these parameters ' LoF, CoF, and Risk ' range in value from 1 to 5, with 5 being the worst. LoF is based on the assessment of an asset's condition and performance, while CoF is based on an asset's significance to the stormwater system and the impact severity of failure. Condition may be evaluated through field investigations or estimated using a surrogate parameter easily obtained through analysis of asset properties, such as age and material. The preliminary LoF based on surrogate parameters may be used in conjunction with CoF to determine an initial Risk score and inform inspection priorities. This assessment allows itself to be conducted with limited field investigations to provide an initial estimate of system risk and needs. Initial estimates of system risk may then be used to identify priority catchments for detailed investigation and recommended capital improvement projects (CIPs). Specific processes for this purpose were developed as part of Phase 1. Phase 2 of the SMP applied the processes identified during Phase 1 to the City's stormwater system. A desktop analysis was performed to determine the LoF, CoF, and resulting Risk score of each asset. Surrogate parameters were used to determine LoF, because inspection data was not widely available. GIS-based algorithms were developed to calculate these LoF, CoF, and Risk scores for each asset. From this, three priority catchments were identified in the City. Upon review of priority catchments with City stakeholders, the project team deployed for field investigations to fill data gaps and determine a more accurate LoF condition score. Investigations included pole camera and CCTV of pipes and adjoining structures and visual inspections of stormwater basins. Parallel to field investigations, SWMM models were created for the priority catchments. Inspection-based LoF condition scores and LoF performance scores from the SWMM models were used to identify assets that should be included in a capital improvement project (CIP) due to the need for renewal, either by rehabilitation (lining) or replacement. Conveyance improvements and opportunities for additional storage were modeled to provide a preliminary CIP approach. Results of the desktop analysis used to inform priority catchment selection were also used to identify potential CIPs in non-priority areas. These projects were identified by focusing in areas with the highest LoF and Risk scores. Although these CIPs require additional design, the preliminary analyses results in short-term financial planning data. The necessity and reach of these identified CIP locations will be confirmed through final field investigation and detailed design. In additional to the risk-based asset management framework and identification of potential CIPs, other key outcomes of the SMP included: - Development of level of service (LOS) objectives - Development of a public outreach plan - Development of white papers regarding policy development to support the asset management framework - A summary of recommended operation and maintenance activities per asset type - Creation of Lucity-based asset management dashboards, improved asset inventory, inspection forms, and other tracking resources, as well as staff education on use of Lucity resources - Development of an Excel-based tool to estimate asset inspection and renewal needs based on surrogate parameters of age and material for use in long-term planning - A strategy for implementing SMP recommendations and processes, including identification of staffing needs - Short- and long-term financial planning recommendations Final deliverables of the Phase 2 Des Moines SMP are currently under review and will be finalized in early 2023. As the City implements SMP recommendations, the assessment methodology, data collection approach, and other processes may be refined to better support the City's system. Efforts should focus on ramping up proactive inspections to help shift asset management from reactive to proactive, further developing the asset inventory and understanding of the system's current condition. Moving forward, the developed risk-based asset management framework provides a clear path for asset evaluation and CIP prioritization, while providing flexibility for future iterations.

Rising chemical and sludge disposal costs, an uncertain future for biosolids disposal, and operator shortages; are some issues shared by many wastewater utilities today. The Kalamazoo Water Reclamation Plant (KWRP) dewatering upgrade case study presents a road map for other utilities on how to address the pressing issues many utilities face today by incorporating pilot testing, and utilizing operations and maintenance staff input in the equipment selection and design process, selecting the equipment to produce the driest cake, configuring equipment in a way to minimize odor and maximize the potential for future expansions, and by visualizing data to fast track the operator training process. This presentation presents a history of the plant, its past and present concerns related to biosolids, and an overview of its dewatering facility commissioned in 2022. KWRP, located in western Michigan, serves approximately 190,000 people. KWRP previously used sludge incineration, but the incinerator was abandoned in 1999 due to the implementation Title V EPA, a stringent air quality regulation for flue gas from incinerators. Until the most recent upgrade discussed here, the gravity-thickened primary sludge and waste-activated sludge from the biological nutrient removal (BNR) process were combined and dewatered together using four belt filter presses. Because a sizable pharmaceutical production plant is in the service area, activated carbon is added to the BNR process to absorb micropollutants. In 2001, because of the closure of the incinerator, KWRP started to produce Class A biosolids using the RDP lime addition and pasteurization process. This class A sludge production process did not last long. The plant experienced too many difficulties with operating and controlling the installed RDP process for the required sludge production throughput. Michigan's rising costs for land application fees were another factor for discontinuing that process. In 2008, the utility moved to 100% landfilling sludge, taking advantage of relatively low disposal cost: $17.5/wet ton. From 2008 to the present, the plant has faced a steady rise in disposal costs, on average 13.0% /year; cake dryness requirements (%TS) have also tightened. Maximizing the dryness of the dewatered cake and reduction of disposal volume became a priority for the Dewatering Facility Upgrade. Additional objectives for the upgrade included minimizing the odor source and improving the operational environment in the sludge dewatering facility, designing a flexible set up to adapt future changes in post-dewatering solids-handling, and to ensure the selected equipment is intuitive for operators to dial-in and maintain. KWRP believes pilot testing provides the most accurate data for decision-making and solidifying the facility design. The city opened an invitation for paid pilot testing to all interested manufacturers in 2014. Eleven manufacturers and six technology alternatives participated. After testing was completed, centrifuges were selected as the equipment of choice, for being the lowest annualized cost option in present-worth with the possibility for simple future expansion. (Figure 1). Figure 1: Annualized Total Cost for Kalamazoo Sludge Dewatering Options After receiving proposals from vendors, the city organized operators' visits to other water reclamation facilities and equipment manufacturing and equipment service facilities to gather KWRP staff input during the selection process. Among the equipment evaluated, Centrisys was selected for several reasons: The central location for repairs was fundamental for the centrifuge manufacturer choice, along with access to their top technical and optimization leaders in the company. Simple operation and maintenance of the hydraulic scroll drive, in comparison to a gearbox drive, was also a critical factor for the equipment selection. The hydraulic scroll drive was also preferred for its ability to generates higher torque than gear box to maximize the cake dryness. Three Centrisys CS26-4 units were installed in 2021 and successfully started up in 2022 (Figure 2). The project design includes the necessary infrastructure to support the current installation along with the possibility of an additional fourth Centrisys CS26-4 if needed. The upgrade resulted in the immediate improvement in sludge dewaterability: before the upgrade a 2-meter Andritz belt filter press was generating 16-17% cake; after the upgrade, the centrifuges now generate cake in the range of 21-24%, which translates to a disposal sludge volume reduction of 20-30%. The timing was just right: When pilot testing began, disposal costs were $30.90 per ton. In 2022, it was raised by 44% over the previous year to $92.71/wet ton, making it one of the highest in the region. Figure 2: Centrisys CS26-4 Installation at Kalamazoo Water Reclamation Plant Working through the volatility of disposal costs and uncertainties in the regulatory climate, KWRP has selected ancillary equipment to accommodate future changes better. Instead of open-top conveyors, cake piston cake pumps are now used to move the dewatered biosolids. The piston pumps can generate operating pressures up to 1,500 psi. In the case of either future regulations of emerging contaminants like PFAS, or increasing disposal costs, where further processing of the dewatered cake by means of sludge drying are required, facility additions can be accommodated by a simple reconfiguring of the pipes. The selection of the cake pumps over open conveyors minimizes the source of odor. The small amount of odorous gas generated from the decanter centrifuges and the cake pumps is now treated through activated carbon filters to improve the operator environment. Another design consideration for ease of operation is the addition of Valmet total solid meters to the centrifuge feed lines (Figure 3). The centrifuges have forward control of the polymer dosing systems: taking the measurements from the TS meter and the flow meter and pacing the polymer rate by specifying the polymer dose in lb/dry ton, rather than just a pump speed, in the control panel. This setup makes training new operators easier by giving real-time trends for the operators to learn about the plant and specifically dewatering operations. Additionally, having the polymer dose input (lb./ton) at the centrifuge which resembles what the operators learned for the operator training exam aids staff in being able to visualize the data. This in turns helps KWRP to shorten the initial training period for dewatering operations and more quickly move operators to the next level of training: tuning the centrifuges and to take on tasks such as selecting better polymers to get more out of their new equipment. Figure 3: Installed Valmet Meter KWRP addressed these challenges via a data-driven, and operator-centric approach for their biosolids dewatering facility upgrade. The primary pieces of the KWRP story are: the support from the community in funding the pilot testing piece of the dewatering equipment evaluation, the operator site visits to learn about the equipment, and the inclusion of innovative technologies such as real time solids measurement and visualization. In close collaboration with the equipment suppliers, KWRP found the winning ticket for navigating uncertain regulatory market conditions and preparing the plant for the future.

With the advent of powerful sewer process modelling tools, the range of physical, chemical, and biological processes occurring within sewers can reliably be tracked across large sewer networks and over changing conditions. These processes include:
Heterotrophic Growth,
Particulate COD hydrolysis,
Fermentation,
Sulfate conversion to sulfide,
Carbonate cycle chemistry,
Sulfur cycle chemistry/biochemistry,
Denitrification, Sulfide precipitation by metals, Natural ventilation,
Air emissions, and
Sulfide corrosion of concrete.

Heretofore, sewer process modelling has focused on sulfide generation and fate for the purpose of mitigating problems related to odor and concrete corrosion. Recently, the development of powerful and complete sewer process modelling tools has expanded to include additional capabilities such as tracing wastewater plant upset conditions upstream to identify industrial discharge release events attributable to the plant upset and anticipating the fate, transport, emissions, and exposure to the public of chemical warfare agents within a sewer network. These modelling capabilities represent a new field of inquiry designated 'forensic process modelling'. Forensic process modelling implements sewer process modelling in combination with treatment plant process modelling and atmospheric dispersion modelling to address such challenges as busting industrial pre-treatment permit violators and averting terrorist attacks. This paper illuminates the topic of forensic process modelling by demonstrating its application in two case studies. Tracing an Acid Spill to its Source The Albuquerque Bernalillo County Water Utility Authority's main water reclamation facility faces challenges related to their lower effluent pH limit. In general, the problem is kept well in hand through careful dosing of magnesium hydroxide to the collection system which, in addition to improving plant effluent pH, augments sulfide control in the collection system. Recently, a sudden pH drop at the plant was detected and the drop appeared unrelated to any process or chemical in the control of the water authority. It was suspected that an industrial discharger caused the event. To test this hypothesis and identify the culprit, the Water Authority's WATS model (Wastewater Aerobic/anaerobic Transformations in Sewers), which was developed as part of their recent sewer odor and corrosion control master plan, was adapted to represent influent conditions corresponding to the measured pH upset. Then, each industry discharger was screened to identify those which deal with acidic waste streams. WATS model scenarios were then run to represent an acid spill from each of the short-listed industry dischargers. These scenarios allowed quantitative comparison of an acid spill which could cause the plant upset to the acid waste streams of potential culprits. WATS modelling scenarios resulted in identification of the industry discharger which could be attributed to the pH upset. This forensic inquiry culminated in actionable evidence toward enforcement of the violator causing the pH upset. Anticipating a Phosgene Attack Owners of civil infrastructure have long been charged with protection of public health and safety. Unfortunately, owner responsibilities have of late expanded to include anticipating and mitigating against terrorist attacks. In the case of water treatment plants, nuclear facilities, or other facilities enclosed within a defendable fence line, attack preparation may include target hardening and increased site security. But what of sewer networks for which there is no fence line and little separation between the public and the facility? Every household has anonymous access to the sewer system through its lateral connection. Also, the sewer headspace ventilates to the ambient atmosphere with serious implications for exposure to the public. The situation represents a uniquely intractable security problem in the face of a terrorist attack seeking to use the sewer network as delivery mechanism for a chemical weapon attack. DC Water in particular, due to its symbolically important location, must anticipate terrorism. Also, they own a number of odor control systems which force ventilate air from the sewer headspace to the ambient environment. For these reasons the trajectory of a chemical attack on their sewer network is of particular interest. In this case study, a phosgene attack was simulated using the WATS model. Phosgene is a chemical warfare agent which also has wide application in the plastics industry meaning that it is potentially obtainable by individuals (as opposed to foreign governments). Phosgene degrades the pulmonary tissues and victims may not be aware of receiving a lethal dose before it is too late. The DC Water WATS model, which was developed as part of their corrosion control and asset management program, was adapted to represent the chemical and physical properties of phosgene which determine fate and transport within a two phase (liquid stream and gas headspace) sewer network. The scenario tracks a 200-gallon release into a lateral clean-out connection upstream of one of the interceptor odor control stations. Dispersion modelling was used to estimate public exposure at a neighboring facility based on WATS model predicted concentrations from the odor control stack. The case study culminates on an assessment of the possibility of lethal exposure to the public based on this relatively small poison gas attack.

Background The Los Angeles County Sanitation Districts (LACSD) own and operate Tulare Lake Compost (TLC), a biosolids composting facility in the San Joaquin Valley of California (Figure 1). TLC was permitted to process up to 500,000 wet tons of biosolids per year, sufficient for all biosolids generated by LACSD wastewater treatment plants. During the composting process, volatile organic compounds (VOCs) and ammonia (NH3) are generated and may be emitted to the atmosphere. Emissions must be controlled to meet the requirements of TLC's air quality permit issued by the San Joaquin Valley Air Pollution Control District (SJVAPCD), which caps emissions of both VOCs and NH3 on a mass basis. Since the SJVAPCD is in non-attainment for ozone and PM 2.5, extremely stringent emissions limits are placed on their precursors, specifically VOCs and NH3, respectively. The original design of windrow composting piles with fabric cover emissions control technology for TLC did not perform adequately during the summer season. Through a series of test piles, LACSD has evaluated an alternative composting technology with the extended aerated static pile (eASP) configuration. Its emissions control device is a biofilter cover layer, composed of previously finished compost, which treats VOC and NH3 emissions from the active compost below it. To satisfy permit requirements at TLC's design capacity, lifecycle emissions from eASPs must be kept below emission factor targets of 0.20 lbs-VOC and 1.79 lbs-NH3 per ton of active compost mix. TLC produces Class A exceptional quality compost, with requirements to meet the Process to Further Reduce Pathogens (PFRP) and Vector Attraction Reduction (VAR). PFRP requires maintaining a core temperature of 131 °F for 3 days for pathogen removal, while VAR requires a core temperature of 104 °F for 14 days to reduce vector (e.g. rats, flies, mosquitos) attraction. Methodology and Implementation Baseline eASP Configuration eASP design was generally based on literature, experience from emissions testing consultants, and site visits to an existing facility utilizing the process. The active compost portion of the baseline eASP consisted of multiple adjoining rows with overall dimensions of 150' long, 140' wide, and 7' high (Figure 2). The active compost was topped with 2.5' of finished compost to form the biofilter cover layer. That 2.5' layer consisted of 1' of screened finished compost above of 1.5' of unscreened finished compost. The coarser unscreened material was intended to distribute emissions laterally across the pile, while the finer screened material above would be more effective at VOC and NH3 removal. Each row within the baseline eASP was aerated through an air header; block walls were placed on two sides of the eASP to limit uncontrolled air intrusion and retain heat (Figures 2 and 3). Sprinklers on top of the eASP irrigated the biofilter cover layer to maintain adequate moisture content in the biofilter cover for emissions control (Figure 4). Aeration Testing Adjustments to aeration timing and spacing parameters were tested. The intended purpose was to (a) improve the reliability of meeting PFRP/VAR temperature compliance, and (b) reduce capital expenditures (CapEx). More air was provided early in the composting process lifecycle in comparison to the baseline eASP (Table 1). The additional aeration was intended to increase biological activity to promote faster heating of the pile and meeting PFRP and VAR temperature requirements sooner in the eASP lifetime, thereby reducing the risk of non-compliance. The spacing between air headers was increased, only providing air beneath every other row as shown in Figure 5, while using the increased early aeration schedule from part a. This was to simplify construction and operation of the eASP by eliminating the need to reroute air headers. Irrigation Testing Decreased irrigation was tested to determine the relationship between irrigation applied to the eASP versus the amount of leachate produced and VOC emissions. Irrigation is critical to maintaining moisture to support the biology in the biofilter cover on top of the eASP, but too much irrigation leads to excessive leachate production. Leachate treatment or disposal is expensive so it's important to minimize the amount of leachate produced during the composting process while providing enough irrigation to not exceed the emissions limits for the facility. Temperature Monitoring eASP core temperatures were monitored continuously with online temperature probes (ReoTemp EcoProbes). Core temperatures were measured at 38' and 40' depths for PFRP and VAR compliance. Emissions Monitoring VOC emissions were monitored with SCAQMD Method 25.3 for total non-methane non-ethane organic carbon (TNMNEOC) and helium was used as a tracer gas for air flow measurement. Ammonia emissions were monitored by both manual GASTEC tube readings and SCAQMD Method 207.1. Results Baseline eASP Configuration VOC and NH3 emission factors were 0.05 and 0.04 lbs per ton of compost mix, respectively, well below the targets previously discussed. The eASP biofilter cover technology was able to control emissions during the composting process well below levels required for full capacity use of the facility. With respect to core temperature requirements, all zones in the baseline eASP passed the PFRP and VAR criteria, but one zone significantly lagged others. The average time for all zones to meet PFRP for the pile was 7.5 days with a minimum of 4 days and a maximum of 23 days. VAR was met at an average of 18.5 days. Such a cold zone increases the risk of non-compliance, which would require re-composting that zone. In response, aeration adjustments were implemented in the subsequent eASP to promote faster heating through increased biological activity. Aeration Optimization to Reduce PFRP/VAR Compliance Risk Four piles were tested with increased early aeration. The VOC emission factors ranged from 0.12 to 0.20 lbs per ton of compost mix, either below or just meeting the emission factor target. NH3 emissions were negligible for the two test piles that relied on solely Gastec tube measurements and 0.03 lbs per ton of compost mix for the test piles utilizing Method 207.1, well below the target threshold. With respect to core temperature requirements, all zones passed the PFRP and VAR criteria. The average time for all monitored zones to meet PFRP was 3.5 days with a minimum of 3 and a maximum of 4 days. VAR was met at an average of 14.5 days. There were no lagging zones and the faster heating is apparent in Figure 6, in which the four eASPs with increased early aeration shown as the gray lines have higher core temperatures early (days 1-10) in the composting process relative to the baseline aeration schedule shown as the blue line. Providing more air early in the eASP lifecycle can yield consistent temperature compliance throughout the eASP, but also yields higher VOC emissions. Aeration Optimization to Reduce CapEx for Implementation With wider air header spacing (aeration 'b'), the VOC emission factor was 0.08 lbs per ton of compost mix; NH3 emissions measured with Gastec tubes came back with minimal readings. All zones passed PFRP and VAR requirements. The average time for all monitored zones to meet PFRP was 3.2 days with a minimum of 3 and a maximum of 4 days. VAR was met at an average of 14.2 days. As shown in Figure 7, temperatures are similar between the four eASPs with air headers under every row (aeration 'a') shown as the gray lines and the eASP with wider air header spacing (aeration 'b') shown as the green line. Thus, the wider air header spacing did not appear to adversely affect VOC emissions control or compost temperatures, so an eASP can operate with fewer blowers and twice the distance between air headers as reported in literature. This is a major benefit for TLC as it allows for simplified eASP construction without the need to reroute air headers and avoids the expense of a future capital improvement project to install permanent air headers in-between the existing air headers. Irrigation Optimization to Minimize Leachate Production The relationship between irrigation rate versus leachate production and VOC emissions is shown in Figure 8. More leachate is produced with increased irrigation rate. Lower VOC emissions correlate with increased irrigation. Establishing these relationships is significant as it provides a valuable tool to balance leachate production and emissions for the facility. Conclusion eASP with biofilter cover is a viable technology for controlling composting emissions at TLC. Changes to the aeration schedule improved temperature to meet PFRP/VAR requirements and the operation with wider air header spacing was successful. Establishing the relationship between irrigation/emissions/leachate production helps with striking a balance for operati

Flow Metering -- A Powerful Tool to Build Smart Sewer Systems Benefits and Objectives Measuring real-time flow rates in a sewer collection system is like a doctor taking a pulse for a patient. Rapid advancements in flow metering and data gathering technologies have led to substantial improvements for real-time operational support and decision-making systems. This study undertook a review of current available flow metering technologies to optimize the operation and maintenance (O&M) of sewer collection systems, and also to identify potential methodologies and applications where flow metering provided significant insights and benefits to system evaluation. This paper provides a summary of the results from this study, and covers the following specific objectives: - Summarize the uses of flow metering techniques to reduce infiltration and inflow (I&I) and sanitary sewer overflows (SSOs), improve level of service, and reduce O&M costs - Provide general guidance and lessons learned for municipalities and utilities to develop and conduct flow metering programs for sewer collection systems - Equip operators, regulators, engineers, and scientists with tools to accurately characterize sewer flows and assess a sewer collection system's capacity and performance - Present several unique case studies of flow metering and flow data analysis. Methodology Flow metering principles and technologies -- Area/velocity flow meters typically utilize pressure or ultrasonic sensors to measure flow depth and doppler-type velocity sensors to measure velocity. The flow rate is determined through depth (from which area is calculated) and velocity measurements. Metering location selection -- The selection of flow metering locations is fundamental to assuring accurate representation of flows throughout the system. Flow meters are typically located along trunk sewers near major confluences. For inflow and infiltration studies, flow meters can be focused in the areas with known high I&I. Data analysis -- Dry weather and wet weather average and peak flows are calculated using flow metering data. Sanitary sewage flow, base infiltration, rainfall-derived infiltration and inflow (RDII) are calculated as well. The rainfall data from a rain gauge is also analyzed. General Applications Hydraulic model calibration -- Flow monitoring is often conducted to support hydraulic model calibration for master planning. Hydraulic models can be calibrated using both dry weather and wet weather flow metering data. Capacity assessment -- Simulations of dry weather and wet weather scenarios based on flow metering data provide information for capacity assessment, which ultimately can be used to identify alternatives for addressing capacity limitations. I&I study -- I&I analysis using flow metering data is able to identify areas of concern that need to be addressed. Design wet weather flow projections -- Flow metering and rainfall data could be used to develop a model to predict the wet weather flow for a 2-year or a 5-year storm event at a specific basin. Unique Case Studies Sewer Clogging -- A section of sewer pipe upstream of a lift station in a coastal city in New Jersey often experienced surcharges during high flow events. A level sensor (Telog) and a HACH Flodar meter were installed to evaluate the issue (Figure 1). A hydraulic model for this section of sewer was developed and calibrated using level sensor data and HACH Flodar data. The modeling results demonstrated that a clogged bar screen at the lift station appeared to be the cause of the sewer backup. The hydraulic modeling with flow metering data is a powerful tool to illustrate the impact of hydraulic restriction and head loss on upstream water levels. Plant influent flow meter validation -- A temporary flow metering study was conducted to verify the accuracy of an influent flow meter at a wastewater treatment plant in California. The comparisons of temporary flow metering data, plant influent, and effluent flow data are shown in Figure 2. It was found that the influent flow meter readings were higher than the temporary flow meter results. Recommendations were made to improve the accuracy of the existing plant influent flow meter. Hurricane event -- A major hurricane occurred during a temporary flow metering study in a coastal city in New Jersey in 2011. The flow metering data and the hydraulic modeling simulation provided a unique scenario for the hurricane event (Figure 3). Because of the magnitude of the storm and the regional power outages that transpired, all sewer lift stations were disabled during the hurricane. However, the monitoring and modelling revealed that the collection system handled the high flow very well, with only a small area of flooding due to the lift stations off-line. Pump station design flow determination -- A linear regression model (Figure 4) was development by plotting RDII volume against rainfall precipitation and used to predict wet weather flows under a 5-year storm event for a pump station. Lessons learned Field verification -- Before installation of flow meters, field verification should be conducted to validate the actual locations of the manholes for installing flow meters, as well as size, slope, invert elevation, and condition of the pipes. Meter maintenance -- Routine maintenance and regular inspection of flow meters (e.g., routinely check for clogging, meter cleaning, replacement of desiccants and batteries, etc.) is required to keep meters functioning properly. QA/QC -- The Manning equation can be employed to conduct QA/QC of the flow metering data. A scatter graph (velocity vs. depth) for a flow metering study in Indiana was created to compare the differences between metered flow and theoretical flow (Figure 5). Further field inspection found that a nearby lift station had experienced occasional back flow issues causing erroneous meter readings. In addition, the scatter graph indicated that the sewer experienced surcharges or potential overflows at this location. Rainfall data -- It was recommended to install a continuous-recording rain gauge for future studies. Conclusion The paper shows how adoption of a flow metering program enables wastewater utilities to improve productivity for inspection, condition assessment, optimizing sewer O&M efforts, and more effectively implementing asset management programs. With anticipated future advancements in sewer flow monitoring, utilities will be even better able to identify solutions to address capacity limitations or performance challenges.

Purpose: This is a case study of a sewer replacement that transformed into a strategic development initiative to enhance the image, character, and economic vitality of an urban center. Benefits of this Presentation: This presentation will benefit our industry by outlining the integrated approach to planning, building, and funding that made this complex project possible. It will present the challenges and the keys to success. Successful integrated infrastructure projects like this provide value to our industry by enhancing public perception of large-scale sewer work. Above-ground improvements offer citizens a solution they can see and touch while upgrading buried utilities they might not otherwise recognize as needing repair. Status of Completion: The construction was completed in 2018.

Abstract: The Downtown Renovation Phase 1 Project, aptly named 'ReNewark', began as an investment to replace aging sewers and meet EPA requirements in Newark, Ohio. The project was in the heart of a historic downtown square anchored by the Licking County Courthouse. This was a main trunk combined sewer - 48-inches in diameter and 15 feet deep. The primary goal was separation of this 130-year-old brick pipe to reduce overflows and reduce the risk of it collapsing. Since the sewer work was unavoidable, Newark leveraged the opportunity to also enhance the above-ground infrastructure. An integrated approach transformed this utility upgrade into a community redevelopment strategy. Multiple disciplines were engaged to separate the combined sewer, simplify the water piping, reconfigure traffic patterns, and add green infrastructure and pedestrian-friendly features. A multi-disciplinary funding solution was also devised which offset costs for each component of the project. One of the keys to getting this sewer project off the ground was leveraging a green infrastructure loan to pay for bioswales and a portion of the stormwater system. This ambitious sewer separation would not have happened without various entities collaborating to fund the work. Engagement with the public included extensive outreach to build consensus among citizens and the local business community. It happened informally while surveying the buildings as well as during structured events. Eight stakeholder meetings and three public meetings were held over a six-month period. They were attended by more than 500 residents who contributed their ideas to the future of Downtown Newark. The results were clear. The walkable character of the downtown was identified as a critical component for the ongoing viability of local businesses. The site investigations started with dye testing on more than 130 service laterals using remote-operated vehicle camera equipment. Arcadis also entered 90 businesses and residences to survey the existing utilities and perform a structural evaluation of the basements. A portion of the basement in many of the buildings extended beyond the exterior face of the building underneath the sidewalks. They were originally used as access points for coal or other supplies and some are still in use today. Other investigations included flow monitoring, hydraulic modeling, surveying, buried utility mapping with ground-penetrating radar, and geotechnical and archaeological investigations. Where possible, combined sewage inputs within the project area were separated. This diverts stormwater inputs away from the combined sewer and reduces overflows. The sewers were replaced with fiberglass-reinforced polymer mortar pipe with open-trench construction. The selection of this pipe material over a more traditional material like concrete allowed for faster construction in this busy downtown area. The water distribution system was simplified with dual pipes consolidated to a single 12-inch diameter ductile iron pipe. The design team set forth to improve the traffic pattern rather than replace roads in-kind after the sewer construction. The intersections surrounding the Courthouse Square were changed to mini roundabouts. The roundabouts achieved safer and easier pedestrian and vehicular traffic, improved urban aesthetic, and conversion of the traffic around the Courthouse Square from one-way to two-way streets. This provided easier access to downtown businesses. Roads were narrowed and sidewalks widened. More than twenty feet of total sidewalk width was added in some areas, creating outdoor space for events, dining, and retail. Green infrastructure improvements included 35,000 square feet of low-maintenance plantings, more than 130 shade trees, and 12,000 square feet of rain gardens and bioswales that flow into the new storm trunk sewer. The construction occurred in 13 phases over three years. Flexibility during construction was fundamental to maintaining utility and traffic continuity and keeping the downtown functioning. Bypasses of sewage flows and traffic maintenance plans were tailored for each phase to ensure minimal interruptions to the public. A project website www.wedignewark.com was created to keep the community in-the-know. Informational videos were created to promote key milestones, share progress updates, and educate the public on unique elements of the project including the benefits of bioswales and the efficiency of roundabouts. The public could see the results as the project progressed. This engagement during construction was key to getting public buy-in and cooperation. Since the construction commenced in 2014, Newark's urban center has experienced tremendous gains in population, jobs, downtown living, and economic growth. The $25M investment resulted in more than $60M in new private investment that transformed the Courthouse Square into a thriving district. The downtown was reborn with a pedestrian-oriented landscape and a safer, more efficient traffic pattern. It has become a source of community pride, energy, and revenue. The area has seen more than 100 built and planned downtown residential units, dozens of new businesses, and creation of the community-centric Canal Market District. Conclusion: An integrated approach to design and funding can move a large sewer project forward and yield economic benefits. Newark implemented this methodology and realized the benefits of enhanced traffic patterns, pedestrian safety, and stormwater quality. In addition to addressing an EPA mandate to reduce combined sewer overflows, the change to the aesthetic landscape has brought real value to the city and surrounding region.

The SARS-CoV-2 virus can be shed in the feces of persons infected with COVID-19. As a result, sewer surveillance can be used to identify the presence of COVID-19 infections in a particular sewershed. This study involved monitoring SARS-CoV-2 at strategic locations within a sewershed serving about 600,000 customers in Washington County, Oregon. Sampling was conducted at the four wastewater treatment plants (WWTPs) and at 25 manhole locations within this sewershed from spring 2020 to fall 2021. Samples were concentrated using electronegative filtration and analyzed using a ddPCR system. The 25 manholes were chosen to represent a range of characteristics in their micro-sewersheds including varying numbers of medical centers, industrial sectors, and residential demographics. The reported cases of COVID-19 from the Oregon Health Authority (by zip codes and outbreaks) were correlated with the wastewater virus concentrations. The virus concentrations in the influent to each of the four treatment plants correlated well with the reported COVID-19 cases in Washington County. All four treatment plants showed similar trends of a moderate peak of virus concentrations in summer 2020, followed by dramatic peaks over the holiday season and late summer and fall of 2021. SARS-CoV-2 concentrations at WWTPs appeared to be a leading indicator, with increases in wastewater observed two to three weeks before cases rose (Figure 1). At the manhole sites monitored during summer 2020, the frequency of high positive measurements was highest for several food-processing industrial sites where known outbreaks occurred. During the outbreaks, the virus concentrations in wastewater closely correlated with reported COVID-19 cases at the facilities. Sites with the highest virus concentrations also tended to occur in the zip codes with the highest prevalence of COVID-19. The demographics of residential areas have been shown to affect COVID-19 case prevalence, and a similar trend was also observed in virus concentrations in wastewater. Specifically, neighborhoods with high LatinX and high poverty populations also had higher SARS-CoV-2 concentrations. There was a surprising lack of detectable SARS-CoV-2 in the effluents of hospitals and health centers, even with a known presence of COVID-19 patients. The number of COVID-19 cases relative to the total number of patients in the hospital should have produced a clear signal, given previous positive signals detected from whole neighborhoods and industries with only a few documented cases. Quarternary ammonium compounds (QAC) disinfectants are commonly used to inactivate SARS-CoV-2 on surfaces in hospitals, and they are known to destroy DNA and RNA. These disinfectants may be entering the hospital wastewater via routine disinfection procedures and degrading the SARS-CoV-2 signal, leading to concentrations below the detection limit. Experiments conducted with a QAC disinfectant used in the hospitals in this study showed that there was nearly total decay in the RNA targets at 0.1% concentration, equivalent to 0.128 ounces of disinfectant per gallon of wastewater. It is feasible that disinfectants in the hospital environments are entering the wastewater at concentrations at or above this level and damaging the RNA, thus making it undetectable with the current analytical method. This surprising finding has serious implications for WBE monitoring at and downstream of hospitals and health centers. WWTP influent samples with at least 10,000 N gene copies per liter were also sequenced to determine the SARS-CoV-2 variants present in the samples. Each surge in reported cases corresponded to the dominance of a new variant, and several region-specific sub-variants were identified. The most recent surge in cases during summer and early fall 2021 was associated with the near-total dominance of the Delta variant and its sub-variants. Interestingly, wastewater concentrations during the Delta surge were much higher per reported case than during previous surges, which corresponds to the known increase in viral load in patients infected with the Delta variant. This study has demonstrated that SARS-CoV-2 can be successfully quantified at the micro-sewershed level by selection of appropriate key manholes and used as a surrogate or supplement to swab testing. Such a micro-sewershed approach can be used to identify hot spots of high infections such as industrial facilities and can correlate wastewater concentrations of the virus with community characteristics such as income levels. Such data may prove to be useful to the health care community to determine areas for increased testing or outreach and can be used to optimize data collection and reduce costs.