Conference Papers

With five municipalities Burlov, Eslov, Lomma, Lund and Malmo and half a million customers, VA SYD is one of Sweden's largest agencies for water distribution and sewage collection and treatment. VA SYD need a digital solution to minimize the impact of flow variations due to extreme weather events, improve water quality in receiving water bodies, attenuate flows to the wastewater treatment plant, and reduce sewer overflows. Also, if sewer overflows could not be avoided, the agency needed to control where the sewer overflows occur in order to minimize environmental impacts. VA SYD implemented a digital twin hydrologic and hydraulic model in the city of Lund, covering the entire service area draining to the Källby wastewater treatment plant. The digital twin was developed to allow for on-line simulation and forecasting capabilities with weather adaptive control to meet the goals and objectives of VA SYD. Phase 1 of the project included implementation of the digital twin with a data connection to existing meters and gauges, SCADA system and weather forecasts. The existing collection systems model was calibrated against flow measurements both in terms of inflow components in connection to rainfall events and infiltration from groundwater. Phase 1 included forecast calculations for the upcoming 24 hours. The forecasts were carried out automatically once an hour. The digital twin system displayed measured flows and levels as well as calculated flows and levels at selected points along the collection system. The system displayed actual and calculated sewer overflow volumes, as well as water volume in the network and basins All displays were both hindcast and forecast. Finally the digital twin user interface also displayed estimated run-off from each sub-area from each type of flow components, i.e. inflow versus infiltration. Data assimilation, detailed weather forecasts and control strategies were developed and implemented during Phase 2 of the project. Data assimilation was applied to the calibrated collection systems model to deal with residual anomalies. This means the digital twin continuously analyses the deviations between measured and calculated values and compensates for them up to the time of the forecast. The deviations are interpreted and can then be used during the forecast calculation via an 'error forecast'. In this way, the digital twin model calculation is corrected both in the historical part and in the forecast. The digital twin model's weather forecasts were upgraded to include a hybrid between C-band radar and several weather models, where the most likely forecast is selected. The forecast horizon is 36 hours with hourly resolution and spatial resolution of 2 km. A new forecast is produced every hour. During the first few hours, primary radar data is used while the weather model gradually takes over. The data grid over the City of Lund was interpolated into each sub-catchment of the collection system model. This allows each catchment to get its own unique rain series in the forecast horizon, which is combined with measured rainfall data. Within the City of Lund, there are two major basins and a basin at the pumping station in Dalby. How and when to use these basins most efficiently was evaluated based on what to achieve. Based on these evaluations, decisions were made on what type of control strategies VA SYD wanted to deploy and what conditions that were available with the current control measures in place. The selected control strategies and conditions for automated selection between were programmed into Future City Flow as a scheduled separate forecast calculation. The results of these calculations were then used as setpoints in the operative control of available control equipment. Procedures for extracting setpoints and transmitting them to both VA SYD's SCADA system and directly to the PLC via OPC UA was implemented.

Industrial activities have created many brownfields throughout the Chicago metropolitan area. Brownfields are generally associated with poor soil health, inferior nutrient cycling, and attenuated soil ecosystem services, as demonstrated in low primary production and carbon (C) sequestration, low diversity of soil biota and plants, and high runoff with impaired water quality. Thus, restoration of brownfield sites not only increases the economic value of the sites, but also increases the ecosystem services the land provides. A research and demonstration site for brownfield restoration was established on Metropolitan Water Reclamation District of Greater Chicago (MWRD) land along the Chicago Sanitary and Ship Canal, which has been classified as a brownfield site due to prior use of the site for storage of petroleum and chemicals and destruction of soil horizons. Due to their physical, chemical, and biological properties, biosolids, which contain high amounts of organic matter, are an ideal soil amendment for degraded and contaminated soils. In addition to C and nutrients, biosolids contribute to an active microbial community, which is a critical component of soil ecosystem function, including nutrient cycling, C sequestration, plant symbiosis, and contaminant degradation. Research plots were established in October-November 2021 using Split Plot design with four replications. The main treatments were 1) control (no amendments to the existing soil), 2) air-dried biosolids at one-half rate (air-dried biosolids applied at 2.5 cm depth or 130 Mg ha-1), 3) air-dried biosolids (air-dried biosolids applied at 5 cm or 260 Mg ha-1), 4) composted biosolids (woodchips composted with biosolids-3:1 at 5 cm depth or 185 Mg ha-1), and 5) a blend of biochar and air-dried biosolids (pyrolyzed biosolids at 1.25 cm depth and air-dried biosolids at 3.75 cm depth or 105 Mg ha-1 pyrolyzed biosolids mixed with 195 Mg ha-1 air-dried biosolids). For the same thickness (5 cm) of soil amendment applied, the loading rate in weight basis was lower in composted than air-dried biosolids due to the lower bulk density for composted biosolids. Since composted biosolids contained more organic C (25.8%) than air-dried biosolids (19.8%) by mass, the C input from the two amendments applied in 5-cm treatments were comparable. The biochar/air-dried biosolids blend also leads to a similar C input to the 5 cm air-dried biosolids treatment, as biochar contained 21.5% of organic C, just slightly higher than that for air-dried biosolids. Subtreatments are two prairie plant communities with C4 grasses for subtreatment 1 and C3 grasses and forbs for subtreatment 2. The subplot size was 4.5 m x 5 m. The plots were hydro-seeded with native plants in November 2021. Additional seeding by drilling is still needed due to the poor germination during the first year, which is common for establishing native plants. This report will focus on assessing the impacts of biosolids on soil health in degraded urban soil, which supports plant establishment. We sampled soil in April 2022 at 010 cm depth and analyzed the key parameters for soil health, including soil organic C (SOC), nitrogen (N) mineralization potential (NMP), microbial basal respiration, microbial biomass C (MBC), and water-holding capacity (WHC). Due to the high gravel content of the brownfield soil, all results except for soil WHC are presented as 'stock' in 010 cm soil depth by using bulk density of soil materials (< 2mm). Results for two subtreatments within a main plot are pooled for this report of the soil measurement. All soil amendments drastically increased soil WHC from 53% to 100121% (dry soil weight basis), which is associated with the increase in SOC (Table 1). Soil organic C in the control plots had a mean of 17.4 kg ha-1 in the top 10 cm (Table 1) with a range of 10.026.0 kg ha-1). The C-rich soil amendments considerably increased SOC, leading to higher than 30 kg ha-1 in soil for all four amendments. Microbial biomass C measurement indicated that microbial populations were more abundant in plots with the soil amendments than the control: however, it varied depending on the amendment type (Table 1). Microbial biomass C was highest under the air-dried biosolids, followed by air-dried biosolids at one-half rate, composted biosolids, and the biochar-biosolids blend, and lowest in the unamended control soil. Microbial respiration, the CO2 output of the microbial community, reflects microbial quantity and activities and the utilization of substrates by microbes. We found that the soil microbial basal respiration in the control plots was low relative to the treatment plots (Table 1). The high biosolids rate had a higher basal respiration rate than the other treatments. The microbial metabolic quotient (qCO2), the respiration rate per day per unit microbial biomass, helps us understand the environmental stress level for microbes in the soil. High qCO2 indicates greater environmental stress for soil microbial communities. The full rate of air-dried biosolids reduced the qCO2 compared to the control, though the other soil amendment treatments had a similar qCO2 to the control (Fig. 1), indicating that air-dried biosolids can provide a less stressful habitat for microbial communities. Nitrogen mineralizing potential is important for evaluating N accessibility to soil microorganisms and plants. For the sampling period, approximately six months after plot establishment, control plots reflecting the degraded conditions of the site had a very low NMP of only 0.01 kg ha-1, compared to a range of 2.584.2 kg ha-1 in the treatment plots (Table 1). All three treatments that received air-dried biosolids had a higher NMP than composted biosolids. The results presented here showed that the use of biosolids as a soil amendment gave rise to significant improvement in the health of degraded urban soil, which will facilitate plant establishment and possibly drive interactions among microorganisms, plants, and soil components for restoring ecosystem services of the brownfield.

Vapor-phase odor control systems are often comprised of one or more cylindrical tower scrubbers, ductwork, mist/grease eliminators, fans, pumps, ladders, platforms, instrumentation & custom control panels. As these systems get larger and the layout more complicated; design engineers should be aware of the adaptability of the system, the materials they're working with, and how to improve their design for the people who will be tasked with its long-term successful operation. Functional design is crucial in tying these components together, ensuring that the end-user will work in harmony with the equipment and not against it. Consider the 'payback' in time & safety of a few hours spent optimizing the footpath of an operator when the equipment will be in use for 25 or more years. The following should be a priority of an odor control system design once the basic equipment selection, sizing and placement has been determined: 1.Receiving feedback from the end users, operators, and maintenance staff, understanding the feedback, and representing their needs & concerns in the design. 2.Identifying safety concerns (e.g., tripping hazards, head injuries, falls, chemical exposure or access to safety showers, confined space entry) within either planned pathways or 'desire paths' for improved accessibility, and lower O&M risk and effort level. 3.Evaluating the equipment location, orientation, points of operator or maintenance interaction in a 3D environment and identify and design the efficient pathway through these points. 4.Updating standard equipment specifications with these features to form lasting improvements as well as emphasizing the latest in robust & low-maintenance instrumentation. This presentation will provide a methodology for improving O&M in our odor control systems, specification suggestions as well as compilations of WWTP staff experiences from a few large wastewater treatment plants in Southern California. Namely, Orange County Sanitation District, whose employees possess a treasure trove of experience in operating and maintaining large scale odor control systems and their design with the operator's safety and accessibility in mind.

Odor Control Technology isn't Enough Without Effective Capture Effective odor control is not just about the technology, it is also about the capture and containment of the odor. Choosing and sizing a wet scrubber or any odor control technology is critical, however the best technologies are insignificant if nuisance odors continue to escape before they can be treated. Such issues with capture and containment of odor were present at Orange County Sanitation District (OC San) Plant No. 2 biosolids Truck Loading facility. OC San Plant No. 2 is located in Huntington Beach, California, along the Santa Ana River (which has a raised walking/bike path) and is located near residences, Huntington State Beach, a few parks, and some commercial properties. The Plant is currently treating an average wastewater flow of approximately 60 million gallons per day (MGD). The function of the Truck Loading facility is to store the dewatered biosolids and to load to the hauling trucks for offsite beneficial reuse. Newly installed centrifuges, which improved biosolids dewatering, increased odor generation at the storage and Truck Loading facilities and triggered complaints by plant personnel and community members. To address these nuisance odors, a scientific approach was implemented that consisted of four main parts: gathering data, targeted sampling, air movement monitoring, and designing a custom air capture system based on the information collected in the previous steps. This paper will provide an overview of the approach utilized and highlight key elements that aided in understanding and solving the problem. Gathering Data: A series of questions were asked to find where and when the problem was occurring. To understand and solve the problem, collaboration with the OC San Maintenance, Operations, and engineering staff was crucial. Through this collaboration, it was determined that the odor in the Truck Loading bays was caused by the centrifuge-dewatered biosolids in the truck loading operation. Odors were released when the biosolids dropped through the storage silo knife gate valves and filled the truck trailers. Odors continued to be released from the accumulation of biosolids on surfaces of the truck and Truck Loading bays from the loading process. Minor system contributors included fugitive odors where biosolids accumulate but were difficult to clean, including the floor grates associated with the truck scales, which trap biosolids from washdowns. This information determined that the central issue surrounding the Truck Loading facility was the lack of containment infrastructure. Continuous dataloggers were installed to identify the pattern of hydrogen sulfide and ammonia occurrence throughout normal operations for several weeks. Trucks generally drove into the loading bay from the north, where a door closed behind it, to prevent the wind from blowing the odor out through the facility. The original design of the building assumed that winds would dominate from the south side, and that thus air would be sufficiently contained by the door on the north while ventilation drew out the foul air. The presence of odors indicated that this design was less effective than anticipated in capturing the stronger lingering odor, and further analysis was needed to determine the best containment and ventilation approach. Targeted Sampling: Next targeted sampling was conducted to quantify the odor by pinpointing the constituents of the odor, and their concentrations so that effective capture and containment can be customized. This sampling and analysis measured a complete set of odor-causing constituents such as hydrogen sulfide and ammonia on a continuous basis as well as grab samples for other speciated reduced sulfur compounds/VOCs during the most concentrated periods of Truck Loading, at the higher areas of the loading bay, as well lower regions of the bays (Understanding that the mix of compounds present consisted of both heavier and lighter than air compounds). Air Movement Monitoring: Air movement in the Truck Loading bays was simulated using a series of smoke tests for both existing and considered future conditions. The smoke tests were conducted with smoke candles that released a large amount of smoke (up to 40,000 cubic feet) within a small period of time, to simulate the sudden release of odor while the trucks were being loaded. Each test simulated either existing or potential ventilation conditions. Potential conditions included simulating the presence of a door on the south side of the building, differing ventilation rates, and differing quantities of supply air provided. By observing the movement of the smoke during this array of conditions, conclusions were drawn about the movement of odor throughout the truck bay, including the locations of dead zones, the effectiveness of an additional door on the south side for containment, and the effectiveness of the existing ventilation system at clearing air through each region of the truck bay. The smoke tests made it clear that a second door was necessary to contain the smoke within each bay. Tests which simulated a door made clear other weaknesses with the existing ventilation system's layout, including dead zones near the ceiling. Design of a custom system: The above tests and observations indicated the specific problems that were causing issues with odor control at this particular facility. Alternatives evaluation and conceptual design of improvements to the system were entirely customized to the height and length of the building. First, a door was recommended on the south side of the Truck Loading facility, to contain the odors within the building. Positive air supply was recommended at low and high heights to move foul air with odorants heavier than air observed in step 2, and sweep dead zones found near the ceiling in step 3. A U-shaped exhaust duct layout at ceiling level was recommended to capture the most concentrated foul air on both sides, where the smoke tests indicated most of the smoke was accumulating. The above method of identification of the distinct contributors to the odor control issue at this facility was instrumental in creating a custom design to address the concerns thoroughly and efficiently. Without the observations and collaboration in the earlier steps, the conclusions that allowed for a custom solution would not have been possible.

The Inflation Reduction Act (IRA), signed August 2022, brought sweeping changes to how water and wastewater utilities evaluate project opportunities as United States continues to push the energy transition.The IRA is the largest energy incentive legislative effort in U.S. history, providing unique opportunities for public and private utilities. For the first time, tax-exempt organizations can obtain tax credit funding through direct payments - for qualifying clean energy or efficiency projects. These tax credits can total as much as 50% or more of the qualifying project costs. Many utilities are already taking advantage of these tax incentives which can reduce local funding requirements. Qualifying project examples are solar for water or wastewater treatment plants, waste energy recovery for wastewater treatment plants and more. Sustainability projects for utilities which qualify for the IRA tax credits include biogas, solar, clean hydrogen, wind, hydro, electric vehicles and more. In certain circumstances the cost of the equipment, such as biogas at wastewater treatment plants, is only a small portion of the eligible property for the tax credits. This presentation will provide an overview of the IRA, the utility sector's approach and general trends related to the IRA in the early stages including the significant requirements related to maximizing the credit amount. Relevant lessons learned and case studies in the first year of this impactful legislation will also be shared. [u]Learning objectives[/u] Participants of this educational session will be able to: 1. Outline current tax incentive opportunities pertaining to utilities 2. Understand examples of qualifying projects 3. Determine qualifying projects for one's utility

BACKGROUND
The Oakland-Macomb Interceptor Drain (OMID) is the main wastewater interceptor that serves nearly 850,000 customers in 25 municipalities in Oakland and Macomb Counties north of Detroit, MI, USA. The Oakland-Macomb Interceptor Drain Drainage District (OMIDDD) operates the approximately 22-mile (35.4-km) unreinforced concrete interceptor that includes piping from 3 feet (0.3 meters) to 12.75 feet (3.9 meters) in diameter, 10 metering facilities receiving flow from contributing community sewers, and the 273-MGD (1,033-MLD) rated capacity Northeast Sewage Pumping Station (NESPS). Upstream of the NESPS, the OMID also receives flow from the Macomb Interceptor Drain (MID) that collects flow from suburbs to the east and is operated by the Macomb Interceptor Drain Drainage District (MIDDD). The MID portion includes about 26 miles (41.8 km) of large-diameter unreinforced concrete interceptor piping, 23 metering facilities, and 2 pump stations. There is corrosion in some locations of the OMID due to sulfuric acid (H2SO4) formed from hydrogen sulfide (H2S). The H2S released from the sewer also results in recurring odor complaints. Hydrogen sulfide release is greatest at turbulent vertical drop manholes where community sewers at higher elevations discharge into the deeper OMID and when control gates are operated during the OMID's unique 'storage and release' practice of flow control. Odor and corrosion issues extend back to the 1970s when the OMID was constructed. Since 2011, the OMIDDD has taken steps to study these issues and initiate mitigative improvements on behalf of ratepayers.

OBJECTIVES
Through both comprehensive studies and mitigation strategies, the OMIDDD seeks to accomplish the following key objectives for the interceptor: -Reduce the rates of corrosion -Cost-effectively extend its operating life -Minimize odor complaints throughout the system Though this paper focuses on the efforts of the OMIDDD, the MIDDD maintains similar objectives with their interceptor. Together, both Districts are working toward complete odor and corrosion control coverage of their combined systems. The Districts currently have active interceptor grouting and lining operations; however, the size of the interceptors makes Contractor mobilization, access, and liner installation a costly effort. With appropriate odor and corrosion control, these lining operations could potentially be limited to specific problematic segments and result in a significant cost savings.

METHODOLOGY
Characterizing the impact of sulfide generation, H2S release, and sewer corrosion required a comprehensive approach. This included reviewing past studies and completing field sampling, sewer process modeling, air dispersion modeling, and fan testing. The extensive data collection program at 17 locations throughout the OMID included liquid-phase dissolved sulfide grab samples and about four weeks of continuous monitoring of sewer differential pressure and vapor-phase H2S concentration using digital monitors. The same sampling effort was completed at 19 locations in the MID; thus, allowing for complete characterization of the large diameter tunnel network. Field sampling, wastewater quality, and hydraulic modeling data were used to develop and calibrate a complete system sewer process model. With this model, multiple conditions that might influence odor generation and sewer corrosion were evaluated: -Dry weather (low flow), -Wet weather from inflow and infiltration (high flow), -'Storage and release' operations -Future phased rehabilitation (e.g., adjusting gate operation frequency/duration for routine Contractor access) -OMID realignment Rates of concrete corrosion predicted by the sewer process model were correlated to prior condition assessments completed using the Pipeline Assessment Certification Program (PACP) ratings and used to approximate remaining pipe life based on the long-term operating strategy of the system up to a maximum allowable concrete loss of 1 inch (25 mm). Concrete loss plots (see example, Figure 1) for the various conditions were created to identify locations along the interceptor alignment most susceptible to deterioration. Process modeling also accounted for 'storage and release' operation, where wastewater is stored in the OMID using flow control (gate) structures. Storing wastewater either for flow management or downstream maintenance access increases detention time, thus generating sulfide. When released either by raising the low-flow sluice gates or overtopping the divider walls in the flow control structures turbulence results in H2S stripping (Figure 2). This pressurizes the H2S-containing odorous air in the interceptor headspace, often leading to off-gassing through ground-level manhole cover pick holes. Sensitivity of ground-level receptors to sewer off-gassing under average dry weather flow and at drop connection manholes was evaluated through air dispersion modeling. The OMID system has relatively few venting locations. Manholes along the interceptors that are spaced relatively far apart (about 1,000 feet, or 300 m) result in low natural ventilation rates. Assuming that the ambient odor impact criteria should be at or below a 7-D/T for 1-hour of community impact 99.5% of the time, air dispersion modeling results characterized the likelihood that an odor control strategy would affect ground-level impacts through management of sewer pressure, H2S, or both. Finally, once the most appropriate odor and corrosion mitigation locations and vapor-phase treatment technologies were identified, field fan testing with sewer pressure monitoring was completed to right-size the future odor control system (Figure 3).

RESULTS AND CONCLUSIONS
This comprehensive approach to evaluating OMID-specific operating conditions enabled the design team to identify the most effective locations and methods to address odor and corrosion. Both liquid-phase and vapor-phase technologies were evaluated through sewer process modeling. Three locations for activated carbon vapor-phase odor control systems were identified. Two systems one actively ventilated and the other passively will be located at flow control gate structures. The third system will be actively ventilated and located at the drop manhole downstream of a community sewer metering facility. Together these systems are expected to address odors and corrosion across most of the OMID. During storage conditions, the vapor-phase systems will not provide continuous control due to headspace constrictions. Likewise, the sizes of the recommended vapor-phase devices will not be large enough to depressurize the sewers for some storage and release events when the release rates are relatively fast and the stored wastewater volumes are relatively high. Process modeling showed that if storage and release events were to be conducted frequently-such as every day-the pipe life could be significantly reduced. However, under normal dry weather conditions, these systems will effectively depressurize the sewers and odors will be effectively mitigated. Corrosion will also be greatly reduced in the main interceptor but may persist at some locations lacking continuously wetted surfaces. These areas may be appropriate candidates for lining. Design has begun at each location, providing unique challenges related to aesthetics, visibility, and site constraints for which unique solutions are being pursued. For example, the community metering station is surrounded by residential homes, therefore requiring concealment that closely reflects the neighborhood (Figure 4). Facility designs will be completed in 2023.

PURPOSE The purpose of this research is to demonstrate the concept of thermal destruction of nitrous oxide as a technology that fits into the current goal of resource recovery and utilization at wastewater treatment plants while simultaneously providing increased flexibility with which to operate a given treatment process. This paper will present the computer simulated results indicating the thermal decomposition of nitrous oxide emissions from a biological nutrient removal (BNR) process. INTRODUCTION Two separate sources of gaseous emissions at wastewater treatment plants are those from the aeration basins for the biological treatment and from the combustion processes within the facility. The combustion processes may include one or more of the following: boilers, operating on fossil fuel or natural gas, combined heat and power (CHP) units, operating on digester biogas or a sludge incinerator. The objective of this research is to link the gaseous emissions of the biological processes to the air intake of the existing combustion processes with the net effect of reducing the total emissions of harmful gases from the facility. The emission of nitrous oxide (N2O) from wastewater treatment plants is of concern due to its impact as a greenhouse gas [i.e 298 times that of carbon dioxide (CO2)] and is a consideration in the ongoing research regarding the nitrite shunt and Anammox processes. By using the emissions from the biological reactors as the inlet gas stream to the combustion process the nitrous oxide is removed by thermal decomposition; see Figure 1. Thermal decomposition of N2O occurs at approximately 565 ºF (296 ºC), well below the combustion temperature, as N2O splits to nitrogen (N2) and oxygen (O). The oxygen is consumed as an oxidant. Thermal decomposition of nitrous oxide has been implemented to reduce the unavoidable N2O emissions from the manufacture of adipic acid for the nylon industry (Reimer et al. 1994 and Shimizu, Tanaka and Fujimori 2000). In addition to the reduction of nitrous oxide, any hydrogen sulfide (H2S), methane (CH4) or VOCs that may be emitted is also removed. A secondary benefit of using the gaseous emissions from the biological processes as the inlet to the combustion process is that the CO2 acts as a thermal sink thereby reducing the thermal NOx emissions produced by the combustion process. This technology removes any constraints on how the biological process may be operated because it eliminates the need to consider the N2O emissions. For example, the goal of maximum pollutant removal, lowest energy consumption or resource recovery may be pursued without concern for the gaseous emissions that result. For this study, gaseous emissions from the aerobic portion of a BNR process treating a flow of 30 million gallons per day (MGD) with influent parameters of biochemical oxygen demand (BOD5) = 250 mg/l and NH3-N = 35 mg/l were estimated. Six cases, for which, the nitrous oxide emissions were estimated as a percentage of the influent ammonia value were simulated. The values of 0.2, 0.5, 1, 2, 5, and 10% were chosen based on published literature (Kampshreur, et al. 2009). Methane, hydrogen sulfide and VOCs emissions were also estimated. Estimates of methane emissions were based on data from a municipal plant treating wastewater at a rate of 1 MGD that showed the average annual emission rate from the aeration tanks was 2.2 x 105 g-CH4/year (Czepiel, Crill and Harriss, 1993). Hydrogen sulfide emission estimates were based on data collected from three municipal treatment plants (Devai and DeLaune, 1999). The VOC emissions were estimated based on the EPA 40-City Study, (1982) and the Joint Emissions Inventory Program (JEIP), (1993). Computer simulations using STANJAN© to run chemical equilibrium calculations were conducted (Reynolds 1986). Each of the six cases (i.e. the gaseous emissions with different concentrations of N2O) was run at different fuel to air ratios (equivalence ratios). The primary objective of the study was to determine the fate of the nitrous oxide emissions from the biological process. The secondary objective was to determine the effect of carbon dioxide (CO2) and nitrogen gas (N2) on the production of thermal NOx (i.e. NO and NO2) formed in the combustion process. The formation of nitrogen oxides (NOx) primarily nitric oxide (NO), by the oxidation of atmospheric nitrogen is a function of flame temperature and is termed thermal NOx (Turns 1996 and Warnatz, Maas and Dibble 2001). The final objective was to determine the fate of several other gaseous constituents that may be present: methane (CH4), hydrogen sulfide (H2S) and ten of the most common VOCs found in municipal treatment plants. RESULTS In all six cases nearly complete thermal decomposition of N2O was achieved. Equilibrium conditions were assumed given the adiabatic flame temperature of methane is approximately 2000 K. In Figure 2 the influent and effluent mass flow rates of N2O, for three of the gas streams, (those with 0.1, 0.2 and 0.5% of NH3-N as N2O) are plotted against the equivalence ratio. The effluent mass flow rate (shown in red) is negligible indicating significant thermal destruction of nitrous oxide. The results are similar for the higher concentrations, not shown. In Figure 3 thermal NOx produced, for each of the individual gases, the complete gas stream and the standard gas stream (air) is plotted against equivalence ratio. The results indicate that combustion with the gas stream from the biological process, (i.e. complete gas stream) reduces the thermal NOx emissions by 18.4% over combustion of methane with air (i.e. standard gas stream). The reason for this is that the carbon dioxide (CO2) produced from the biochemical reactions acts as a thermal sink. This is analogous to exhaust gas recirculation (EGR) technology used to reduce NOx emissions from internal combustion engines. Figure 3 also indicates that the nitrogen gas (N2) produced from the thermal decomposition of the N2O had no effect on NOx emissions when compared to the standard gas stream. This is due to the small quantity of N2 compared to the amount of CO2 produced by the biological reactions. Figure 3 also indicates that the equilibrium concentration of NOx is high at temperatures near stoichiometric combustion and decreases rapidly from that point (Flagan and Seinfeld 1988). Most combustion process used for power generation are operating slightly at an equivalence ratio between 0.8 -0.95, near the peak of the plot in Figure 3. CONCLUSIONS The results indicate that the thermal decomposition process reduces N2O emissions as well as methane, hydrogen sulfide, and VOC emissions (results, not shown here). A secondary benefit is the reduction in thermal NOx emission from the combustion process. This process mitigates greenhouse gas emissions without significant impact on the existing WWTPs. It also provides more flexibility in the process decisions by removing the constraints that results when considering the gaseous emissions that result from the biological process.

Introduction Sludge generated from wastewater treatment typically goes through a series of handling processes such as thickening, stabilization and dewatering, before its final use or disposal. Anaerobic digestion is widely applied in medium to large water resource recovery facilities (WRRFs) for sludge stabilization. In anaerobic sludge treatment, fugitive methane emissions can occur from digesters (due to aging infrastructure), downstream storage, from associated pressure relief valves and pipework, and also due to methane slip through combined heat and power (CHP) engines and biogas upgrading. For example, work in Denmark over the past few years has quantified methane emissions at 69 biogas facilities and shows methane emissions account for up to 7.5 percent of the gas production at WRRFs (Fredenslund, A.M et al., 2021; Scheutz & Fredebslund, 2019). Large leakage of methane may negate the positive climate impact from biogas energy recovery and contribute significantly to the facility's operational carbon footprint. A portion of the methane generated is dissolved in the digestate, which can also be released during the downstream dewatering or sidestream treatment processes. In addition, long-term sludge drying (e.g., in lagoons) is commonly applied in many countries, such as Australia, due to its ease of operation and low operational costs. Methane generated from sludge drying lagoons is typically not captured and can be a significant greenhouse gas (GHG) emission source. In the US, a country-wide standard methodology for quantifying GHG emissions from the wastewater sector does not exist. Among the available reporting protocols, methodologies for quantifying fugitive methane emissions from sludge treatment and biogas handling are limited to combustion of biomass and biogas, which essentially assumes zero methane emissions from anaerobic digestion and biosolids dewatering processes. The latest Biosolids Emissions Assessment Model (BEAM 2022) has recommended a minimum of 1 percent of methane in biogas as fugitive emission and allows a user-input value if site-specific data are available. The lack of consistent methodology and lack of facility level measurement result in significant risk to facilities in the estimation of their fugitive methane emissions through the sludge treatment and biogas handling processes. This paper presents an overview of challenges and issues in quantifying fugitive methane emissions from sludge treatment and biogas handling, impacts on GHG inventory and practical tips for reducing methane emissions based on global experience to date across a growing number of case studies. Benchmarking Fugitive Methane Emissions Methodologies and Key Considerations In the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, a three-tier method is described for quantification of methane emissions from WRRFs. Tier 1 provides global activity and emission factors; Tier 2 provides for local in-country activity factors and/or emission factors and Tier 3 methods require facility level monitoring. Accurately quantifying fugitive methane emissions requires Tier 3 facility level measurement using methods such as differential absorption lidar (DIAL), tracer gas dispersion (TDM) and inverse dispersion modelling (IDM), which may be combined with point source leak detection or other process unit methods to determine location of leaks. This practice remains emerging with significant work ongoing in Europe to provide facility level quantification and mitigation at WRRFs. Elsewhere, Tier 2 methods are common. The UK Carbon Accounting Workbook is used by Utilities to report on operational emissions and includes country-specific (Tier 2) theoretical emission factors associated with the most common sludge and biosolids processes in the UK, with emissions based on mass of methane per unit of tonnes dry solids of raw sewage sludge (UKWIR, 2020). In the Australian National Greenhouse and Energy Reporting (NGER) framework, methane process emissions are indirectly estimated using sampled influent and/or effluent streams and application of assumed biogas generation and percentage biogas utilization to calculate the net tonnes of CO2 equivalent released to the atmosphere. This approach considers facility level data but does not require direct measurement of the GHG, hence still considered Tier 2. Emissions from biogas flaring is based on best practice flow rate measurements of the flared biogas and its methane concentration. Different facilities may have a range of approaches to sampling process streams for operational, planning or reporting requirements. Sampling locations, frequencies and methodologies can result in inaccuracies in estimating the fugitive methane emissions. The recently published IWA book 'Quantification and Modelling of Fugitive Greenhouse Gas Emissions from Urban Water Systems' includes additional information on fugitive methane emissions from a range of wastewater treatment, sludge and biogas handling processes, estimated through facility level monitoring (IWA, 2022). Table 1 provides a summary of key methane emissions from global case studies including both those which directly monitor methane emissions and those which use various alternative GHG accounting methodologies, generally aligned with Tier 2 level approaches. A more complete table will be provided in the full paper. In the absence of global full scale monitoring data to estimate fugitive methane emissions, existing methodology estimates may be beneficial for benchmarking emissions from sludge treatment and biogas handling processes however, Tier 3 level facility monitoring is required to accurately estimate methane emissions and to validate any mitigation efforts. Monitoring and Reducing Fugitive Methane Emissions Whilst published literature studies of methane mitigation are limited, practical examples of programs for monitoring and mitigation across European countries show the criticality of direct methane emissions monitoring, and operational approaches to mitigate methane emissions through regular survey, proactive leak detection and repair and independent certification. Table 2 summarizes some of the key sources and (limited) mitigation approaches from work to date; further details to be provided in the full paper. In future planning, it is critical that decisions regarding anaerobic versus aerobic sludge digestion consider fugitive emissions from existing and proposed assets. Conclusions Fugitive methane emissions from sludge treatment and biogas handling processes are a significant source of GHG emissions which must be monitored and mitigated by utilities taking action to reduce their carbon footprint. These emissions are particularly critical for WRRFs with anaerobic digestion and open anaerobic systems such as sludge drying ponds. There is lack of consistent methodology for quantifying and monitoring these emissions in North America, which could lead to over- or (more likely) underestimation of their contributions to the overall GHG footprint for the WRRFs. As shown by ongoing work in Europe, facility level measurement is critical in quantifying the fugitive methane emissions. This paper will provide practical recommendations to WRRF operators to guide best practices for methane monitoring and mitigation throughout the facility life cycle.

Hydraulic models are used throughout the United States and worldwide to plan sewer infrastructure improvements and evaluate system operations. Increasingly, utilities include force mains and pump stations in the hydraulic model and use them to evaluate upgrades for existing pump stations and development of new pump stations. Modeling force mains that can be intermittently under pressure, half full, or in vacuum in the sewer system is a challenging aspect of the model build process with various modeling applications. Orange County Sanitation District (OC San) provides wastewater collection, treatment, and recycling for approximately 2.6 million people in central and northwest Orange County, CA. OC San owns, operates, and maintains 4 wastewater pump stations which are interconnected via 2 parallel force mains (Newport Force Main, NFM) along the Pacific Coast Highway (PCH) in the City of Newport Beach, CA. The NFM network, shown in Figure 1, consists of three-manifold pump stations, Bay bridge Pump Station, Rocky Point Pump Station, Lido Pump station, and parallel force mains that convey wastewater to the Bitter Point Pump Station. The Bay Bridge Pump Station (BBPS), the farthest upstream pump station of the NFM network, is currently in design for its replacement. As part of the Bay Bridge Pump Station replacement project, OC San and Arcadis (OC San's engineering consultant for this project) developed a new hydraulic model of the NFM network using InfoWorks ICM (10.0) software to select new pumps at the pump station. The Infoworks ICM modeling application has two modeling options for modeling sewer force mains. Both of these options, listed below, can result in different hydraulic profiles, which can affect the pump selection for the BBPS. - Pressure Solution: The 'Pressure' solution model uses pressurized pipe equations when the pipe is fully pressurized. The model reverts to the gravity solution whenever the pipe is not full during low flow conditions and subsequently uses gravity solution for the rest of the simulation. - Force Main Solution: The 'Force Main' model is an advanced solution to model pressurized pipes, which assumes the pipe is always full and uses the pressurized pipe equations for all flow regimes during the simulation. Thus, the 'Force Main' solution model allows suction pressures to develop in the pipes and accounts for siphoning effect during the simulation. The NFM network is relatively flat with local high points and minimal air release. Therefore the total dynamic head for pumps at BBPS is primarily correlated to headloss and can be subject to localized siphons and changes to gravity flow. To determine the potential affects of siphons and flow regime changes, OC San analyzed the NFM hydraulics using both the Pressure Solution and Force Main Solution under low flow and high flow conditions to determine most accurate representation of the NFM network. The results are shown in Figures 2 and 3. - The Force Main solution results in the lowest hydraulic grade line (HGL) during the low flow conditions (Figure 2) because Force Main Solution accounts for a siphoning effect that can happen when pipelines with local high points have HGL below the crown of the pipe. The siphon pulls the water over the high point, resulting in a lower grade line for points upstream of the high point. - The Pressure Solution results in a low HGL compared to the ForceMain solution during the high flow conditions. The Pressure Solution reverted to a gravity solution during the simulation that can happen when the pipe is not fully pressurized. The gravity solution underpredicted flow attenuation and a low flow velocity, resulting in lower head-loss and low HGL. OS San selected the Force Main Solution to model the NFM network for the Bay bridge Pump Station design. The Force Main Solution is expected to provide the most accurate model of the NFM network and is the most conservative, requiring a lower total dynamic head (TDH) for consideration during pump selection.

INTRODUCTION The Town of Cary, NC Utilities Department serves a population of roughly 175,000. Cary is a regional leader in sustainability and climate change mitigation with an ambitious goal of reducing town wide GHG emissions by 25 percent by 2025 and by 100 percent by 2040. A high-level study conducted in 2011 showed water and wastewater services account for approximately 60 percent of Cary's municipal GHG emissions. More recently, in conjunction with GHG emission accounting research led by the Stantec Institute for Water Technology and Policy, Cary developed a comprehensive emissions inventory for their three water reclamation facilities (WRF), one water treatment facility (WTF), and one major pump station to both measure progress related to emission reduction activities and to incorporate GHG impact analyses in alternative selection processes. One of the WRFs included in the inventory is the 18 million gallon per day (MGD) Western Wake Regional Water Reclamation Facility (WWRWRF), commissioned in 2014 and discharging to the Cape Fear River. The WWRWRF solids handling facility includes belt filter press thickening of waste activated sludge (WAS) and thermal drying via two BioCon dryers with a combined capacity of 1,489 wet pounds per hour. The dried biosolids are processed through a pelletizer and distributed as a Class A product for land application. The facility's original design included an energy recovery system (ERS) that would combust dried biosolids to generate heat for the drying process, thereby offsetting natural gas consumption. The ERS was removed from the design with the intent to revisit installation in the future. In October 2022, Cary commissioned Stantec to assess the GHG emissions impact of installing an ERS using the newly developed GHG inventory tool. The purpose of this paper is to provide an overview of Cary's GHG emission inventory tool, understand is applicability for utilities of all sizes and treatment technologies, present the results of the GHG emission impact analysis and provide considerations for incorporating GHG evaluations in facility planning and alternative selection processes. METHODOLOGY Cary's GHG was developed for a baseline year of 2021 and is an Excel-based calculator specifically focused on water and wastewater facility emissions. The calculator sources reference data and equations from the Local Government Operations Protocol, IPCC Guidelines, EPA GHG Emission Factors Hub, EPA Waste Reduction Model, and the Biosolids Emissions Assessment Model (BEAM). The tool was developed with a user-friendly interface and can be quickly updated annually to monitor emissions over time or applied as a decision-making tool by comparing capital improvement or operational optimization alternatives. Energy recovery systems accept and combust dried biosolids from a dryer and recover the waste heat from the combustion process for dryer operation. The end product is ash, which can either be disposed via a landfill or beneficially reused as a construction material amendment. The heat produced by the ERS offsets the natural gas required to heat the dryer. WWRWRF's 2021 GHG inventory was used to assess the theoretical GHG impact of installing an ERS. Installation of an ERS is anticipated to impact GHG emissions in five areas: 1.Reduced natural gas combustion by the dryer 2.Reduced GHG offset from biosolid land application 3.Reduced end-product hauling 4.Increased electricity consumption from ERS equipment motors 5.Increased direct emissions from combustion processes There are several energy recovery technologies available to WRFs. However, this evaluation assumed the Veolia ERS system would be installed as it is designed to integrate with the BioCon dryers already in operation at the WWRWRF. The design criteria assumed a throughput of 1,489 lb/hr, consistent with the existing dryer system nameplate capacity and energy consumption estimates were provided for the full system capacity and are summarized in Table 1. The GHG impact from the ERS was assessed for 2021 only and during that year the WWRWRF dryer throughput averaged 636 lb/hr. Electricity consumed by the ERS system was estimated by multiplying the expected energy draw at design capacity by the ratio of the actual and design loads. The ash production rate is approximately 40 percent of 2021 dried biosolids production rate and the average hauled distance for ash disposal was assumed to be 30 percent of that of biosolids land application. Based on Veolia-reported values, the ERS is assumed to provide 68 percent of the dryer's heat demand and the remaining is provided by natural gas combustion. While the ERS does require some consumables for flue gas treatment such as urea, emissions associated with its transport were not included as consumption is estimated at less than one tote per year. In addition, no changes in facility or administrative costs were assumed. There is not current guidance on GHG emission estimates from an ERS. Therefore, solids combustion emissions were calculated using the 'Combustion' tab in BEAM, which is specifically intended for solids incinerators. BEAM calculates Scope 1 emissions from solids combustion as well as the biogenic CO ‚‚ emissions that arise from the conversion of the organic matter in the solids to CO ‚‚. Per LGOP and IPCC guidance, biogenic emissions can be estimated and monitored but do not need to be included in a facility's inventory. RESULTS Results of the analysis are presented in Table 2 and Figure 1 and show the existing and theoretical (with ERS) emissions in 2021. The results of this analysis show that installation and operation of the ERS system would have increased 2021 solids handling related GHG emissions by 36 percent. Nearly all of the ERS combustion emissions are as nitrous oxide, which is particularly difficult to estimate, with significant variability in emission factors. As such, actual emissions may vary based on how well the energy recovery system is maintained and operated. The difference in GHG emissions is also heavily influenced by the elimination of land application practices, which currently provide Cary with a significant emission offset. This is demonstrated in Figure 1, which shows there would not be any 'negative' emissions without land application practices. As previously mentioned, Cary may beneficially reuse the ash product for construction materials, but this practice is not expected to provide the same magnitude of offset since it does not directly increase carbon sequestered biomass. While a more complete evaluation of all financial, environmental, and social impacts of the technology alternative is recommended, this work demonstrated Cary's ability to quickly and effectively quantify the GHG emission impact of a technology alternative. In addition, this evaluation revealed the tradeoffs within the circular economy as an alternative intended to reduce reliance on fossil fuels may result in reduced production of value beneficially reused biosolids.

Purpose This presentation provides information regarding the City of Omaha's (City's) successful, stepwise approach applying asset management principles to operation and maintenance (O&M) of their wastewater collection system. The intended outcome is to transfer knowledge to the audience by sharing examples of how Omaha developed a plan and prioritized a practical implementation approach based on risk. Abstract The City owns, operates, and provides wastewater utility services to Omaha and surrounding communities via collection systems, 46 lift stations, and two water resource recovery facilities. Starting in 2018, the City conducted a Capacity Management Operations and Maintenance (CMOM) Gap Analysis for the wastewater collection system as a first step toward risk-based asset management. The City identified CMOM gaps, prioritized gap closure efforts, and is in the process of implementing recommendations for improvements -- adapting their thought and work processes along the way. One of the high priority areas identified for improvement was understanding the condition of lift station assets and tracking O&M activities and performance. In 2020, the City implemented foundational elements of asset management by including their assets in GIS and updating their computerized maintenance management system (CMMS) to the current version of IBM Maximo. During this process, key City staff participated in workshops to establish an asset registry and hierarchy that was applied in IBM Maximo. In 2022, key City staff participated in a series of workshops to develop consequence and likelihood of failure risk matrices for the lift stations. These workshops spurred engaging discussions, drawing on the participants' firsthand experience with the assets and perspectives from other experiences. The City's Lift Station Superintendent provided over twenty years of practical knowledge of the condition of the assets. The City's Sewer Maintenance Division Manager incorporated his keen awareness of consequence of failure and risk management from his previous management experience in the nuclear power industry. He understood the importance of identifying asset needs, developing a business case, and escalating issues through the management decision making processes to obtain the necessary funding based on priority. Initially, the likelihood of failure (LOF) risk matrix was developed with a top-down approach based on pipe attributes (material, age, etc.) and institutional knowledge from City staff. The physical condition category of the LOF risk matrix was then updated via a bottom-up approach using field collected data from visual and predictive testing condition assessments at 41 active sanitary and combined lift stations as well as the City's 21 Federal flood and storm pump stations. The results from this assessment were used to develop risk profiles based on station type (sanitary, combined, flood, storm) to use as a basis for O&M and capital improvement planning (CIP) prioritization and planning. The 2022 condition assessment results now serve as a baseline for future assessments, putting into place key foundational elements of asset management outlined in their plan. The City now knows with more accuracy which assets they own, where they are located, their current condition, and have a plan to address issues based on their risk profile. Now that these foundational elements are complete, the City is addressing the recommended tactical actions like transferring high-risk asset-level deficiencies into IBM Maximo corrective maintenance work orders. This work will be followed by reviewing the recommended strategic actions, to consider inclusion while developing larger repair, rehabilitation, replacement projects business cases into future CIPs. In addition, the City can start creating basic Job Plans for each lift station asset in IBM Maximo as the basis for a revised lift station Preventive Maintenance (PM) program. The initial basic Job Plans in IBM Maximo can be updated and refined as appropriate over time for the asset, station location, and risk level. The City's consistent efforts for the last several years demonstrate how an initial CMOM self-assessment was used as the basis for developing a plan that is being implemented with persistence, collaboration, and constant forward progress toward a stated goal -- all achieved when faced with staffing and resource limitations. Beyond the IBM Maximo license the City already had in place, the work required no proprietary licensing fees. A key to the success of the field assessments was the City's O&M field staff's willingness to provide information and learn. Benefits of Presentation The City's progress from CMOM self-assessment to an asset management mindset for their lift stations is applicable to many utilities that may not have the perceived funding or resources to implement asset management. This presentation describes Omaha's thoughtful, stepwise progress and roadmap for future steps -- showing others a realistic approach to what can be a daunting task. While the work started with a focus on the wastewater collection system lift stations, similar principles were applied and included for assessment of the City's Federal flood stations associated with the Missouri River levee that are regulated by the US Army Corps of Engineers (USACE). This progress was critical to coordinating with the USACE, providing documentation from IBM Maximo and supporting information that the City is properly tracking O&M activities and implementing a risk-based prioritization plan to address deficiencies at the flood stations. Status of Completion The lift station risk matrix development and field condition assessments are complete and the report and supporting data are available in IBM Maximo, including detailed asset level data, tactical and strategic recommendations, and planning level cost estimates. The next step is to develop a set of system health reports populated with data from IBM Maximo and develop forms and guidance documentation for City O&M staff to self-perform subsequent annual inspections. This work will continue and evolve as the City's lift station PM program matures. Conclusion The City is addressing critical asset management needs shared across the organization, establishing several foundational elements of an asset management program through mutual understanding and a collaborative work ethic focused on positive outcomes that benefit the overall utility. These elements include: - Leveraging institutional knowledge and existing CMMS system - Asset registry validation - Realization of current asset status and deficiency prioritization - Risk based assessment and prioritization using a standardized process - Improvement of maintenance approach - Transparency with regulators - Increased data quality for reports to support repair workload, capital upgrade, and staffing projections. Asset level condition data are available, as well as asset-specific tactical and strategic recommendations with planning level cost estimates. This presentation will share the City's experiences developing foundational elements of asset management, provide an overview of how condition assessment data were converted to actionable recommendations, and describe the status of continuing phases of implementation and refinement. Attendees will gain practical knowledge from Omaha's experience developing a plan and their implementation approach based on risk assessment and using available resources.

Introduction In general, the two options for biosolids incineration are multiple hearth furnaces and FBI units. In the 1970s, tighter emission regulations were introduced, which encouraged the replacement of multiple hearth furnaces with fluidized bed incinerators. Veolia Water Technologies & Solutions (Veolia) is an established industry leader in high temperature fluidized bed (HTFB) incineration, also known as fluidized bed incineration (FBI). Over the years, Veolia has replaced several multiple hearth furnaces (MHF) with specialized FBI units. These include: Ypsilanti (1 MHF replaced with 1 FBI), TZ Osborne Greensboro (1 MHF replaced with 1 FBI), Green Bay (2 MHF replaced with 1 FBI), Mill Creek (6 MHF replaced with 3 FBI), Southerly (4 MHF replaced with 3 FBI), and Sutton (3 MHF replaced with 3 FBI). Emerging PFAS air and solids regulations have impacted the process design of FBI systems. This presentation will review: - Drivers of multiple hearth replacement by fluidized bed incinerators - The greenhouse gas emissions quantification of a current fluidized bed incinerator and associated air pollution control compared to that of a multiple hearth furnace - Impacts of PFAS regulations on process design of FBI systems Why are Multiple Hearth Furnaces Being Replaced by Fluidized Bed Incinerators? Multiple hearth furnaces (MHF) are circular steel units with multiple hearths (shelves) where biosolids are fed. The solids are raked towards the center of the hearth where the combustion air rises. Biosolids burn in the MHF at a range of 572-1796oF (Vallero, 2008). Biosolids fall through holes in the hearths where they drop to the hearth below, until they reach the bottom of the furnace (as ash), where it is removed (United States Environmental Protection Agency, 2003). Veolia provides a teardrop shaped fluidized bed incinerator, where biosolids are fed directly into or above a fluidized sand bed. The bed is fluidized via preheated air that is injected into a windbox, which then forces the air through tuyeres that are embedded in a refractory arch dome. The tuyeres evenly distributes the combustion air through the sand bed to ensure homogenous temperature throughout the bed. Veolia FBI reactors are operated with a freeboard temperature of ~1550oF. The emissions regulation that prompted the replacement of MHF with FBIs was the Clean Air Act of 1970. Two distinct advantages that FBIs have over MHF are that there is significantly less excess air required (40% versus 75-100%, respectively) and the ability to operate autogenously (United States Environmental Protection Agency, 2003) (Winchell, et al., 2021). Greenhouse Gas Emissions Impacts on Replacements of MHF with FBIs Veolia has developed a methodology to quantify greenhouse gas emissions, utilizing ISO 14064-2 as a guide and applied it on multiple projects, including that of fluidized bed incinerators. Initially, a base case and a project case are determined. For the purposes of this presentation, the base case is a multiple hearth furnace application, and the project case is a fluidized bed incinerator application. Water, electricity, natural gas/fuel, and chemical consumption are all taken into consideration. Using emissions factors to convert these values into tonnes of CO2 equivalents per year, we can quantify the GHG impacts of a MHF replacement with an FBI. This quantification is ongoing, but results will be presented if this abstract is selected. The results of these quantifications can be used to justify selecting one unit process over another, such as choosing a granular activated carbon unit over a sorbent polymer composite unit. PFAS Regulation Impact on FBI Process Design Similar to regulations influencing multiple hearth replacements in the 1970s, emerging PFAS regulations will also influence what unit processes will be used in incinerator systems. Currently, there is limited published data on the PFAS treatment ability of a high temperature fluidized bed incinerator. There are air pollution control unit processes however, used in FBI systems that have proven effectiveness on the treatment of PFAS compounds. In the United States, if the incineration system is new, it must be designed to meet MACT LLLL requirements, which includes the removal of mercury, dioxins, furans, cadmium, lead, NOx, SO2, HCl, and particulate matter (Figure 1). The main addition in a MACT LLLL system is a granular activated carbon (GAC) unit. In drinking water applications, the use of a GAC unit for PFAS treatment is common (Winchell, et al., 2021). Using a GAC unit, PFAS treatment efficiencies can exceed 99% in water streams (Barr Engineering Co., Hazen and Sawyer, 2023). It is important to note that the efficiency of PFAS treatment using a GAC unit is dependent on the chain length and the presence of competitors (total organic carbon, volatile organic compounds) (Barr Engineering Co., Hazen and Sawyer, 2023). There is proven ability to treat PFAS in water streams using GAC units, but limited data available for the treatment in gas streams. However, there is much data on the removal of acid gases (PFAS thermally converts to hydrogen fluoride (HF)) using wet scrubbers, which are used on almost all our incinerator trains (Wang, et al., 2022). If the incinerator system is existing and a furnace replacement or retrofit is being performed, the system must be designed to meet MACT MMMM requirements (Figure 2). In this system, instead of a GAC unit, a sorbent polymer composite system (SPC) is used for mercury removal. However, the PFAS treatment ability of SPC units has not yet been studied (Barr Engineering Co., Hazen and Sawyer, 2023). Summary Multiple hearth furnaces have been replacing by fluidized bed incinerators since the early 1970s, however, the greenhouse gas emissions impacts have not been measured. Using Veolia methodology, we can quantify the impacts of these replacements, while also identifying areas where emissions could potentially be reduced (for example, selecting certain air pollution control unit processes over another). Depending on if the fluidized bed incinerator is replacing a MHF or is part of a brand new plant, the air pollution control equipment may be different. This may also impact the PFAS treatment ability of the system, as GAC units have been proven to treat PFAS, whereas SPC units have yet to be studied. It is imperative that studies be conducted to analyze not only flue gas PFAS concentration (before and after air pollution control units), but to treat PFAS-laden ash slurry as well.