Conference Papers

Introduction: The San Antonio Water System (SAWS) is investing over $1.2 billion dollars in its wastewater collection system, targeting over 5,200 miles of sewer main repairs, in response to city-wide sanitary sewer overflows (SSOs) and infiltration and inflow (I&I) issues. This work is under mandate from an Environmental Protection Agency (EPA) Consent Decree and is on target to be completed by 2025. One result of this Consent Decree has been an increase in package rehabilitation projects aimed at improving the worst performing sewer main segments in 'scattershot' groupings. SAWS has identified over 200 of these package rehabilitation projects to maintain the schedule of the Consent Decree. Plummer Associates Inc. (Plummer) was selected to perform the design of five small diameter package projects, together totaling over 43,000 LF of gravity sewer mains. These projects included the rehabilitation of more than 130 small diameter (8'-21') sewer main segments by various rehabilitation methods including cured-in-place pipe (CIPP), pipe bursting, open cut replacement, abandonment, and open cut rerouting. Purpose: This presentation will focus on successful project management and lessons learned for five multi-method package rehabilitation projects from preliminary design through construction. Package rehabilitation projects present a high level of risk to design and construction schedules due to the number of unique project sites, each possessing its own set of requirements for successful design and timely rehabilitation. Early design stages included data collection, condition assessment, planning for field investigations, determining agency coordination required for each site, identifying real estate conflicts, and classifying items with the highest risk to the project schedule. Methods used for organizing, classifying, and clearly presenting the overwhelming amount of data collected during these early stages was widely successful and will be discussed in detail. Subsequent design phases emphasized the prioritization of critical path activities. Critical path sequencing for these package rehabilitation projects can often be complicated due to the number of unique project sites and it may change several times during design as additional information is gathered. Successful management of these critical path activities, as well as lessons learned and unforeseen complications, will be discussed. Finally, bidding and construction administration of these projects highlighted other lessons learned and our experiences with material delays, rapidly changing material prices, real estate complications, third-party utility coordination, and contingency quantities will be discussed. Benefits of Presentation: Attendees will learn about key items to consider in the design of package rehabilitation projects, important points for successful construction administration of such projects, and how to implement big approaches to the management of small diameter sewer repairs. Owners, design engineers, and contractors will gain insights to successfully manage future package rehabilitation projects though design and construction. Status of Completion: The five package rehabilitation projects discussed in this presentation are in various stages of completion as stated below. - SAWS BPC Central Small Diameter Package 4A: Construction completed March 2022 - SAWS BPC Central Small Diameter Package 4B: Construction is substantially complete with final completion scheduled for January 2023 - SAWS BPC Central Small Diameter Package 4C: Project is currently under construction with final completion scheduled for January 2023 - SAWS Multiple Sewershed Package 17A: Construction is substantially complete with final completion scheduled for December 2022 - SAWS Multiple Sewershed Package 17B: Project is currently under construction with final completion scheduled for November 2023 Conclusion: This presentation will highlight the project approach, challenges, and lessons learned in the management of design and construction for five small diameter (8'-21') sanitary sewer package rehabilitation projects from preliminary design through construction.

[Introduction The City of Kelowna Wastewater Treatment Facility (WWTF) is a biological nutrient removal (BNR) plant with capacity to treat approximately 70 MLD of raw wastewater. The facility produces both primary (fermented) solids and secondary (waste activated sludge) solids. The two (2) solid streams are thickened and blended to produce a mixed sludge, which feeds dewatering centrifuges. The undigested dewatered cake is hauled to the Regional Biosolids Composting Facility (RBCF) located near Vernon, BC for composting. The RBCF is jointly owned by the City of Kelowna and the City of Vernon and operated by the City of Kelowna. Undigested solids (including feedstock from Kelowna, Vernon, North Okanagan Regional District, Silver Hawk Utilities), and Lake Country Wastewater Treatment Plants (WWTP) are received at the RBCF and mixed with hog fuel or clean wood chips and composted to produce an organic soil amendment called OgoGrow that meets the BC Organic Matter Recycling Regulation (OMRR) Class A compost criteria. OgoGrow is used by the municipalities and marketed for sale to the public. The total annual processing capacity at the RBCF is capped at 27,000 wet tonnes per year and the City of Kelowna allocation is 18,000 wet tonnes. The current volume of undigested solids production at the WWTF exceeds the City's allocation at the RBCF and solids above 18,000 wet tonnes are sent to an alternative overage facility. As the City's population continues to increase an alternative biosolids management strategy is being considered. Diversion to off-site facilities would be part of a portfolio of biosolids management options. In addition, the City is actively pursuing infrastructure options that will reduce GHG emissions, and biosolids is one important avenue being considered. This paper discusses the feasibility of biosolids management options based on variations and enhancement of anaerobic digestion (AD), which might help address capacity concerns at the RBCF. Different options were analysed for biosolids volume reduction, energy generation and use, life-cycle cost, including sensitivity to select input parameters. A structured decision-making process, using a simplified triple bottom line (TBL) approach, is also included to provide a comparative evaluation of the options and inform the City on a number of important corporate considerations. Anaerobic digestion conceptual design The City defined the objectives of a new digestion facility in a previous study completed in 2020. A preferred AD alternative was identified and proposed to be located on a new site approximately two (2) kilometres away from the current WWTF. Fermented primary sludge (FPS) and thickened waste activate sludge (TWAS) would be pumped from the WWTF through a forcemain. The envisioned new AD Facility would be constructed in phases. In the first phase, the digesters would operate as mesophilic digesters and generate Class B biosolids. With approximately 50% removal of volatile solids through mesophilic digestion, capacity issues at RBCF could be alleviated. In the second phase, the digesters would operate as thermophilic digesters and flow-through vessels would be added for extended thermophilic anaerobic digestion (ETAD). Class A biosolids would be generated due to the thermophilic digestion process, allowing for an additional outlet for the beneficial use of biosolids. The digested biosolids would be dewatered, with cake being hauled to the RBCF for composting or directly to land application, depending on the project phase and operational needs. The initial phase costs were estimated at $78.1M at midpoint of year 2024 construction; the full buildout was estimated to cost $100.4M at midpoint of year 2024 construction. Advanced digestion options Concerns with the estimated high costs of the new Digestion Facility allowed for an additional review of options or variations of the preferred concept that could still generate either Class A or Class B biosolids, promote further reduction in volume (thus freeing up more space at the RBCF), and at the same time generate more biogas to help offset the operational costs of the new Facility. Five (5) options with different digestion configurations that could satisfy the City needs were developed with the 'delayed' ETAD option that was previously developed used as the 'control' option, as follows: -Option 1 - Mesophilic digestion that would generate a Class B biosolids product; -Option 2 - Thermal-hydrolysis process (THP) followed by mesophilic digestion (Full THP) that would generate a Class A biosolids product; -Option 3 - Thermophilic digestion that would also generate a Class A biosolids product; -Option 4 - Delayed ETAD that would initially generate a Class B biosolids product, and later a Class A product (control option); -Option 5 - Mesophilic digestion followed by THP that would generate a Class B biosolids product (but also eventually a Class A product after composting). The two (2) TH options (options 2 and 5) are based on CAMBI's TH technology and configurations. CAMBI has significant TH experience, with a high number of operating facilities in North America and around the world, hence their systems were selected as representative technologies for the purposes of this study. Table 1 provides detailed information on process parameters for each option. Technical comparison A high-level comparison of the five (5) different options will be presented at the full Conference paper, focusing on advantages and disadvantages of each. Financial comparison The five (5) options were compared financially in terms of capital, operation and maintenance (O&M) and life cycle costs. All options were evaluated with and without biogas upgrading to better understand its impact on O&M costs. It was assumed that all biogas produced would be sold to Fortis BC for the biogas upgrading option. Class D (-30% to +50%) cost estimates were prepared for the various options to provide a comparative basis for the evaluation and detailed charts will be included in the full Conference paper. Simplified triple bottom line approach A simplified Triple Bottom Line (TBL) 'plus' approach for structured decision making was used to make a comparative evaluation of the five options. The framework was based on the overarching perspective of 'sustainability' and uses a simplified multi-criteria analysis to integrate technical, environmental, social and economic factors such that a complete picture of the alternatives under evaluation can be provided. Weights were used for each criterium to reflect the City's values and provide a sensitivity analysis of the rankings. The following criteria and factors were selected based on discussions with City staff: -Technical: Biosolids volume reduction and dewaterability, complexity of operation -Environmental: GHG emissions, pathogen regrowth -Social: Odour emissions, Class A versus Class B biosolids -Economic: Life cycle costs GHG emissions and life cycle costs scoring were based on estimates assuming the City would consider two (2) different management strategies: -Generate Biosolids Growing Medium (BGM) from Class A biosolids and Class A Compost from Class B biosolids (emissions shown in Table 2); and -Generate Class A compost from either Class A or Class B biosolids (emissions not shown in this abstract but will be included in the full Conference paper). An initial scoring was conducted using the same weight for the technical, environmental social and economic criteria. Scoring was also conducted using different weights to look at the importance of both economic and non-economic factors and better reflect the City's concerns related to biosolids management. Table 3 shows the scoring and ranking with higher importance given to non-economic factors. Similar scoring tables will be presented in the full Conference paper for increased importance given to economic factors and also to social and environmental factors. Summary and conclusions Based on a simplified TBL 'plus' decision-making analysis, the rankings obtained, and sensitivity analysis conducted, both THP options were found to consistently be the highest scoring or ranking options for each of the management strategies evaluated. Addition of conventional AD as a subsequent step to reduce the volume of biosolids is an appropriate technology for the City to consider. There are a host of issues to consider when contemplating a thermal hydrolysis facility associated with AD. Some municipalities are considering this process as an entirely new facility that would include TH/digestion and related infrastructure. Others are examining options to modify their existing anaerobic digestion process to accommodate TH pre-treatment and to expand or alter the energy producing elements of a facility. Post-digestion THP ranked consistently in first when composting was considered for all Class A and Class B biosolids.

Odor detection threshold determination following international standards, ASTM E679 and EN13725, is the primary odor parameter of choice used in odor assessments worldwide. While this is a tool that, when coupled with air dispersion modeling, provides an understanding of the first layer of odor impact in the community and is commonly used for odor regulation around the world, the assessment of odor threshold is only one parameter of odor. Odor intensity and characterization (odor profiling) provide more important information related to true receptor impact from the perspective of when these odors will be a nuisance. Odor profiling, through descriptive analysis, is a sensory science term used to describe methodologies utilizing a panel of trained assessors to identify and describe specific sensory attributes about a test sample (qualitative) and scaling the intensity of these attributes (quantitative). The food, beverage, and consumer product industries have formally use descriptive analysis to obtain critical information about the appearance, aroma, flavor, and texture of products for over 70 years. These methods can be used to document odor profiles of samples collected from facility odor sources. As described by other researchers, further considering odor descriptors with dilution methods will help to understand how the odor profile may change from the point of emission from the stack to point of impact at the stakeholder as it dilutes in the air. The odor profiles of odorous sources are the perceived response of a complex mixture of chemicals in the air. While hydrogen sulfide is targeted (as the Celebrity) in work at water resource recovery facilities, there are many other compounds present from multiple chemical families, e.g., organic sulfur compounds, organic acids, amines, VOCs. Many of these compounds (the entourage of the Celebrity) have extremely low odor thresholds below the low ppb levels of hydrogen sulfide. State-of-the-art molecular odor analysis by SIFT-MS provides quantification at these sub-ppb concentration levels utilizing the same samples submitted for odor perception evaluation. This combined analysis including odor threshold, odor intensity, odor descriptors, and molecular analysis on the same sample provide access to direct relationships not available before for a broad range of wastewater issues and studies. This paper will present examples comparing the full odor profiles from multiple emissions sources. Inlet and outlet sample comparisons show one case where odor descriptor profiles are similar even with reduction in odor threshold and molecular concentration values and in another case, odor descriptors shift significantly with lower reduction in odor threshold values. A review of odor characters and molecular concentrations of other samples show how data relationships provide a deeper understanding of the odor sources and thus provide direction for improving in odor impacts in the community.

The Stormwater Management Program (SMP) is a Johnson County, Kansas program which partners with the 20 cities in the County to manage stormwater and is funded by a 1/10th of one percent, county-wide sales tax. It administers these funds on behalf of the Cities, historically by providing matching funds to Cities for eligible projects, including study, design, and construction projects. SMP has invested significantly on StormWatch Alert 2 systems (www.stormwatch.com) over the past 30 years to implement real-time early flood warning systems. SMP has funded the installation and maintenance of many of the sites throughout the region and has utilized the data generated from the system for SMP-sponsored studies and projects. SMP also funds a portion of the cost to maintain and improve the website. Johnson County owns 68 of the 108 sites in the system. In addition, City of Overland Park, Kansas Department of Transportation, and City of Kansas City, MO owns several sensors. Currently, SMP with the help of City of Overland Park uses manual process of forecasting flooding conditions and implements emergency management procedures within the county based on existing stream level and National Weather Service's forecasted weather information. However, this process is very tedious, time consuming and not reliable to accurately forecast future flood conditions. Given these challenges, SMP engaged with NEER for the pilot study to utilize its cloud-based Machine Learning (ML) solution to automatically forecast early flood warning system (up to 24 hours) for the Watershed Organization 1 using existing hydraulic models and StormWatch real time datasets. NEER obtained existing HEC-1 and HEC-RAS models from FEMA for Watershed Organization 1. After verifying the integrity of the models, NEER converted existing HEC-1 and HEC-RAS models into EPA-SWMM model. During the conversion process, NEER followed the standard engineering practices to update the existing hydrology (subbasin and storage data) and hydraulic (open channel geometry, culverts, and bridge data) characteristics. After updating all the parameters, the hydraulic model was calibrated using StormWatch gage data collected during 2016 to 2020. There are a variety of statistical measures used to measure the goodness-of-fit between a long term continuous measured and a modeled hydrograph. For this study, statistical measures Integral Square Error (ISE) and Nash'Sutcliffe efficiency (NSE) were used as a single, non-subjective, statistical measure of model calibration (https://www.chijournal.org/C414). Generally, calibration results showed very good to excellent NSE and ISE range for all the gage locations. After the calibration, NEER set up a continuous real time and forecasting stormwater simulation model. In this step, StormWatch gage data (rainfall and stage collected every 5 minute) was obtained and stored in a Time Series Database. In addition, the 24-hour forecasted rainfall data obtained from the National Weather Service was also used in forecasting the stage and water surface elevation along the Brush and Turkey Creek. This real time and forecasting model that is scheduled to run every 6 hours, provides a predicted and forecasted floodplain boundary, depth grid, water surface elevation grid, velocity grid, and flood severity grid. that can be used for operational decisions. The total number of buildings and roads flooded, and operational recommendations (such as closing of roads, and evacuation of buildings) for every 6 hours is stored and displayed in the dashboard.

The Port of Long Beach (Port) is the second-busiest seaport in the United States and committed to improving the environment. Capturing and using stormwater can offset potable water demand, result in reduction of pollutant discharges, and enhance regional drought resiliency. Therefore, the Port and its consultant, Stantec, conducted the Stormwater Harvesting Study to prioritize stormwater harvesting options for the Port. The following three scenarios for stormwater capture were examined: Onsite use, wherein stormwater would be captured, diverted, treated to meet Department of Health standards to use as an alternative water supply, and then provided to select Port tenants for use, with excess water being diverted to sanitary sewers or outfalls. Diversion to the sanitary sewer, wherein stormwater would be captured and diverted to the sanitary sewer for treatment and use off-site. Diversion to Long Beach Municipal Urban Stormwater Treatment (LB-MUST), wherein stormwater would be captured and diverted to the LB-MUST facility for treatment and use by the City of Long Beach. To prioritize locations for stormwater harvesting and onsite use, a pass/fail screening was applied to the Port's drainage basins, followed by a weighted screening criteria and ranking value. Top scoring drainage basins were linked to specific tenants within the Port to determine the final scenarios. A general concept for these projects is shown in Figure 1. Twenty-two Port-owned stormwater pump stations were analyzed for diversion to the sanitary sewer. Locations were prioritized based on the pumping capacity, and screened if located upstream of a drainage basin, in a crowded area, or not located near a viable sewer for discharge. A general concept for these projects is shown in Figure 2. Diversion to LB-MUST considered the available treatment capacity at the LB-MUST facility and the design capture volumes of drainage basins within the Port's Pier B. Two alternatives, a below ground tank and a detention basin, were considered to store the diverted stormwater within the City of Long Beach prior to diversion to LB-MUST. A general concept for these projects is shown in Figure 3. A Triple Bottom Line Cost Benefit Analysis was performed to prioritize the projects. This analysis integrates the broader social and environmental perspectives into decision making, and enables project proponents to objectively justify a project. A ranking of all projects is in Table 1.

Purpose and Findings: When designing a pump station, most engineers follow state and local standards, many of which relay upon guidelines set forth in the 10 States Standards Recommended Standards for Wastewater Facilities. In fact, the successful design of a pump station includes the detailed analysis of several different elements of the pump station facility including the wet well, force main and pumps. Occasionally, these facilities are designed as part of master plan developments, and sometimes are designed to account for future flows. Traditional design methodology involves identifying a pumping rate and system curve, then selecting a pump with a curve that shows the pump can meet the flow demands as shown in the figure below. Figure 1 The graphs are used to select a pump that meets the required design operating duty point. In most cases this method is successful and these facilities go into operation with little to no problems. We now are tasked with a new host of challenges while rehabilitating existing and designing new pump stations. This is where things can go 'off the curve'. Rehabilitating existing stations: - Inadequate wet well or piping sizing - Underperforming or mis-sized pumps - Changes to operation upstream and/or downstream of the pump station Designing new pump stations: - Connections to existing pressure systems - Extreme topographical changes and high pressures - Potential for mixed flow and negative pressures in the line This presentation will focus on the benefits of using Pipe-flo hydraulic modeling software to help with these challenges the traditional methodology struggles to address. Case Study 1 – Bay Street Pump Station The Bay Street Pump Station (BSPS) is in the City of Pontiac and is owned and operated by the Oakland County Water Resources Commissioner (OCWRC). The pump station lifted flow to a gravity sewer that was beginning to corrode and was in an easement through private property. A conceptual project was developed to redirect the 20- inch BSPS force main to the recently constructed 36- inch Perry Street Pump Station (PSPS) force main. Preliminary hydraulic analysis determined that the existing pumps at the BSPS would not be capable of pumping the flow thru the redirected 20-inch BSPS force main and the 36-inch PSPS station. New pumps were needed at the BSPS, Fishbeck used Pipe-flo software to model the system, because the new pumps had to also be capable of pumping when PSPS was operating. The impacts to the hydraulics of PSPS also needed to be understood before making the connection in the proposed location. See below for the Pipe-flo model developed for BSPS. Figure 2 The Pipe-flo software allows for the development of 'lineups' which are different steady-state conditions calculated in the system at any given point. Like the traditional methodology, where we calculate for a peak flow rate, Pipe-flo allowed for the evaluation of the system when one or both pumps were on and with either facility operating. Multiple lineups under dry- and wet-weather conditions were run in Pipe-flo and both the proposed BSPS and existing PSPS pumps still met the design flow requirements for each facility. This output data was used to demonstrate to the Michigan State Department of Environment, Great Lakes and Energy (EGLE) that both facilities could satisfactorily utilize the same force main in our proposed configuration. This project has been fully permitted and is awaiting easements before bidding for construction fall 2021. Case Study 2 – 8 Mile Pump Station The 8 Mile Pump Station (8MPS) was built in 1965 as a lift station, which brought flow from an incoming 60-inch gravity sewer 50+ feet deep up through a recirculation chamber to a shallow 60-inch outlet. There are 5 pumps of various sizes to accommodate different levels of flow, and all 5 pumps run during wet weather events. When the 60-inch gravity outlet is at capacity, the flow overtops a weir in the recirculation chamber back into the PS wet well. This has historically led to rising water upstream of the PS and overflows to local waterways. A 30-inch relief force main was added later due to help reduce overflows, with 2 of the existing pumps piped to be able to discharge to it. Overflows continue even with the relief force main and additional improvements are needed at 8MPS. The current proposed solution is to convey more flow downstream to the system outlet and bypass the existing bottleneck at the 8MPS by eliminating the recirculation chamber and slip-lining the existing gravity sewer for 4,000 feet so it could act as a force main. The original concept as proposed intended to utilize existing pumps, but during the basis of design stage, the existing pumps were found to be underperforming. Fishbeck modeled the existing station using Pipe-flo and conducted flow verification testing in the field and found many of the five pumps to be operating well below capacity. The pump manufacturer assisted in developing degraded pump curves. These new curves were imported into Pipe-flo and the results showed that the existing pumps would not be acceptable and would fail to meet the goals of the project. Fishbeck then modified the Pipe-flo model to reflect a new 4-pump configuration. Pipe-flo was used to quickly assess the characteristics of the system using each set of pumps under dry- and wet- weather conditions, as well as how the pump station will operate under interim conditions during construction with different pumps or discharge outlets out of service. Pipe-flo was also used to assess the pressures and velocities in the existing piping where flow was being increased to verify that existing air and surge relief valves would meet the new service requirements. Had the existing methodology of using the manufacturer's pump curves and a new system curve been used, the existing pumps may have been assumed capable of meeting the project requirements only to realize the shortcomings during construction. Completing the modeling allowed for several configurations to be easily evaluated and potentially significant design decisions made earlier in the project schedule. This project is under design and moving forward with anticipated construction in 2022-24. Figure 3 Table 1 In each case presented above, using traditional methods of calculating the system curve and selecting pumps may have produced a satisfactory pump selection, but did not allow for deeper evaluation of some of the fringe operational conditions. It is during those unusual conditions when pumps are most susceptible to running off their curve and potentially incurring damage. if these conditions are identified, they can be mitigated through design by the selection of different pumps, addition of air/vacuum relief or throttling valves or even adjustments to wet well operating levels.

Many New England communities are undergoing flow restoration efforts to improve the health of impaired waterbodies. One such waterbody is Englesby Brook, which drains an area of approximately 605 acres in Vermont's Burlington Bay watershed before flowing into Lake Champlain. Englesby Brook was designated as a stormwater-impaired watershed on the 2006 Vermont 303(d) list due to multiple impacts associated with excess stormwater runoff [1]. A Total Maximum Daily Load (TMDL) target was subsequently released, requiring an 11.2% increase in stream flows during low flow conditions and a 34.4% reduction in flows during the 1 year 24 hour storm event. To improve stream health in Englesby Brook, the City of Burlington Department of Public Works planned a number of stormwater projects. One such project was the retrofit of a stormwater basin called '08 Pond', a wet detention pond collecting runoff from 131.5 acres (21.7% of the Englesby Brook watershed). The proposed retrofit would have included expanding the existing pond footprint, excavating below the pond bottom, and creating additional storage above the existing permanent pool at an estimated 2015 cost of $400,000. This proposed project was estimated to reduce peak discharge from the pond by 63.4% for the 1 year storm [1]. However, recent advances in communications and control technology provided an alternative to this traditional expansion retrofit. To optimize flow through the 08 Pond, the City of Burlington decided to enhance the basin with continuous monitoring and adaptive control (CMAC) technology. CMAC systems leverage real-time site data, the weather forecast, cloud-based software, and flow controls (e.g., actuated valves) to predictively control the timing and rate of flow through stormwater facilities [2]. At 08 Pond, CMAC automatically draws down the pond below the normal pool in advance of storms, allows the pond to fill up targeting zero discharge during events, and performs a post-storm release. Model results show an up-to 80% reduction in peak discharge during the 1-year storm is possible through the use of CMAC at 08 Pond. Anticipated CMAC costs in early 2020 totaled $98,000. Following the retrofit completion in May, 2022 the City will have invested $105,000 to facilitate the installation of this innovative CMAC system. Data from a set of storms totaling 1.63 inches of rainfall in seven days at 08 Pond is shown in Figure 2. Englesby Brook 08 Pond is the second CMAC system in the City of Burlington. The first was the enhancement of an underground detention vault at the Greater Burlington YMCA in 2020. During an analysis period of 3/1/2020 through 11/1/2020, this project retained 70.2% of the stormwater volume during critical wet weather periods, compared to only 16.8% stormwater capture simulated for an identical passive detention system. This presentation will discuss how Burlington is working towards stormwater impaired waters flow restoration and parallel water quality requirements, the background for the Englesby Brook 08 Pond project and highlight aspects of the design, construction, and software configuration. Performance results will be shared for both the 08 Pond and YMCA CMAC projects.

There is an increasing emphasis on the impact of volatile gaseous emissions from area sources such as anaerobic treatment ponds, biosolids treatment processes, feedlot pads, compost windrows, and municipal wastewater sites, due to the concerns related to malodors, greenhouse gases, micropollutants, or bioaerosols. The estimation of emission rates are critical to support the assessment of environmental and social impacts such as nuisance and human health as well as climate change. Emission sampling is an essential stage in determining emission rates, where sampling methods seek to simulate the real emission scenarios. In a previous review (Liu et al. 2022), the benefits and disadvantages of a series of sampling methods (flux chamber, wind tunnel, static chamber, headspace methods) were compiled. The review showed there was lack of the understanding of the role of sampling methods, creating difficulties for industries or users in the analysis and interpretation of the emission data. Flux chambers are a commonly used method, due to the presence of standards, ease of operation and perception as a method that simulates real-world emissions. During method development, flux chambers were extensively tested to assess the impact of operational factors such as flushing rate and placement depth, however, experimental implications of different designs of flux chambers were limited. Based on the finding by Hudson and Ayoko (2008), 19 called flux chamber cylindrical devices were found out of 76 dynamic devices, while only 5 of 19 shared the same design in terms of dimension and operating system (Gholson et al. 1991, Sarwar et al. 2005). Such differences in design, limits the comparison of data and the establishment of an emission model for evaluating emission from area sources such as biosolids storage and application sites. In this research, four different flux chambers were used to measure the volatile emission rate from porous media using typical operating conditions (Table1). The comparison of flux chambers took into account inlet gas distribution system, chamber materials and variations in hood dimensions. The sweep gas flow rate in the chamber was varied from 1 L/min to 5 L/min. The results were interpreted using the relationship between gas velocity, turbulence intensity and the physical design of the device. Chamber II was set up based on the U.S. EPA flux chamber design (Kienbusch 1986) and tested as a benchmark. The emission rate measured using chamber III, which was duplicated from chamber II, showed 20%-60% variations, indicating the necessity of calibrations for each flux chamber before use. Compared to chamber II, variations of sweep air flow rate in chamber IV showed less effect on changes in the emission rate. However, the overall emission rate from chamber IV was higher, e.g. 103% higher at 1L/min flow rate. This difference was attributed to altered sweep gas jet direction which affects the circulation of sweep gas over the area surface and generated turbulence. To verify the hypothesis that sweep gas direction can affect the emission rate, axially vertical jets of sweep gas were used in chamber IV resulting in a higher emission rate compared to chamber II, while the increased number of jets further increased the measured emission rate (chamber I). The study findings emphasised the importance using a standardised flux chamber configuration, while linking the inlet gas distribution setups to recirculation motion in the chamber as well as the effects on emission rates from porous media. This is in agreement with prior studies conducted using CFD on liquid surfaces (Andreao et al. 2019). The outcome of this study will contribute to the more consistent use of flux chamber within which consistent, reproducible conditions could be established.

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

There is a need for a framework to mainstream citizen engagement, increase Transparency and boost Communication channels in case of repeated episodes of impact in neighboring communities. When there is a conflict, most crisis communication experts agree that Engagement, Transparency, and Communication (E&T&C) are key to maintaining or regaining the neighbors' trust. The Volkswagen emissions scandal is a recent case demonstrating the negative outcome of not having an Engagement, Transparency, and Communication Policy. To promote a change in the traditional industrial opaque thinking paradigm, we have created the first E&T&C Certification. This Certification is designed to assess the performance of Water Resource Recovery Facilities concerning their relationship with communities nearby, making it the first Certification of its kind. A project's performance is verified through 'third-party' audits by an independent auditor, depending on the degree of depth of analysis. This third-party Certification guarantees independence and impartiality in the process. The ultimate goal is to score the degree of a Water Resource Recovery Facility's Transparency, Communication, and Participation.

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.

We propose a technological approach to storm response and watershed resilience based upon massive sensor networks, and present lessons learned with regards to long-term operations, real-time alerts, and data-driven visualizations. The presence of a single real-time streamgage can help response crews determine which roads and facilities most are at immediate risk (Figure 1). However, when scaling up, network maintenance can be prohibitive to ensuring the network stays fully operational while minimizing downtime. Starting in 2020, we began operating a network of 150+ wireless water level monitors in collaboration with communities throughout four states across the Great Lakes. Upon installation, high precision GPS was used to survey each site (e.g. sensor and streambed elevations), which was essential for correlating stream levels with the elevations of assets at risk of flooding. The custom enclosures were designed to be fully detached from a fixed bracket, so that in the event a monitor needed to be replaced, it could be done quickly without the need for resurveying. When compared with nearby USGS gages, the sites maintained Pearson correlation coefficients exceeding R2 > 0.95 before and after swaps. Based on over one hundred swaps across our network of 150+ monitors over the past few years, minimizing time-consuming field tasks such as resurveying has reduced the expected time at a given site from an hour (e.g. for reinstallation) to approximately ten minutes. We also explore example use cases where continuous stream monitoring has benefited local communities. In two instances, we were able to locate where ice jams built up and alert grounds crews, ensuring nearby property was protected. The monitors subsequently captured the subsequent waves as the jams broke and also provided datapoints for estimating the stream velocity of the channel. In addition, in response to an intense 30-minute 10-year storm event, we observed that a project upgrade met its design goals while crews were still on site. (Figure 2). The data has also proven useful in instances where monitors upstream and downstream have helped identify non-point sources contributing to unexpected runoff. Ultimately, when coupled with asset information and digital elevation models, there is promise for real-time visualizations such as flood maps to help users identify the setpoints at which they would like to be notified. As more data is collected, we have begun exploring the use of learning rainfall-runoff models to forecast water levels. We close by exploring these opportunities and present our preliminary results.