The City of Portage la Prairie lies 50 miles west of Winnipeg, in the heart of Manitoba's farming belt. As the global population increases, food processors increase production to meet the global demand, which subsequently generates more wastewater. To meet pre-treatment requirements associated with existing food processors in the aera increasing production and new food processors developing new plants in the area, the city of Portage la Prairie needed to build a new anaerobic treatment system prior to their existing aerobic treatment system to handle wastewater from different food processors, such as potato and peas. In 2017, the city decided to partner with Evoqua (now Xylem) to build an anaerobic wastewater treatment system to replace an existing BVF reactor previously operating on-site. This treatment system was designed to treat 8,400 m3 of wastewater per day from potato and pea processing plants, totaling 32,800 kg/d of COD. Pairing an anaerobic system with a downstream aerobic system minimizes the energy consumption of the overall wastewater treatment plant, which algins with global sustainability efforts aimed at reducing carbon footprint. Not only does the anaerobic system reduce electricity consumption associated with aeration, mixing, and sludge dewatering in the aerobic system, but it also generates biogas from industrial wastewater, providing renewable energy for the wastewater treatment plant. For this anaerobic wastewater treatment system. Evoqua decided to use a low-rate anaerobic treatment system which consists of a lead ADI-BVF reactor, followed by a lag ADI-BVF reactor to clarify the effluent to meet pretreatment requirements. The entire anaerobic wastewater treatment system (i.e. BVF reactors) significantly digests the soluble COD, BOD, and TSS, and coverts the biodegradable organics into valuable biogas. As part of a future project, biogas will be utilized in a dual fuel boiler to meet heating demands around the plant. Technology Description The anaerobic ADI-BVF(R) reactor is an earthen basin with a concrete perimeter wall lined with a geomembrane liner. Specially designed influent piping evenly distributes incoming wastewater throughout the front-end of the reactor, where the majority of the biologically degradable organics are digested and converted to biogas. A supernatant recycle (SREC) pump is used to mix clarified liquid from near the top of the reactor through the influent distribution system, and a return anaerobic sludge (RANS) pump is used to periodically return settled sludge from the back end (sedimentation zone) of the reactor to the front-end. The lag BVF reactor is also an earthen basin covered with a geomembrane system (same material as lead BVF reactor cover). Further anaerobic pre-treatment and solids clarification is conducted in the lag BVF reactor. The lag BVF reactor has the ability to withdraw RANS and return settled solids to the lead BVF reactor influent and sludge blanket using the RANS pumps. The supernatant from the lag BVF reactor flows by gravity to the existing aerobic system. The BVF reactors are covered with a multi-layered, flexible, insulated geomembrane cover which allows for the reactor to operate under a slight vacuum. Biogas generated in the system migrates to the reactor cover perimeter, and speed-controlled blowers transmit the biogas to a waste gas incinerator. The wastewater treatment plant has been operational for 4 years since its commissioning in January 2020. The BVF reactors have effectively treated the incoming wastewater and produce high quality effluent. The ADI-BVF reactors have consistently removed over 95% of the wastewater COD load, discharging anaerobic effluent with an average COD concentration under 200 mg/l, and an average TSS concentration under 100 mg/l.

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been widely used in various industries and products, such as firefighting foams, non-stick coatings, and textiles. Due to their high stability and resistance to degradation, PFAS can persist in the environment and accumulate in living organisms, posing potential risks to ecological and human health. Therefore, there is an urgent need for effective and efficient methods to remove PFAS from different sources of contamination, such as industrial wastewater, landfill leachate, and Aqueous Film Forming Foam (AFFF). This presentation will introduce and demonstrate a novel approach that combines two established technologies, foam fractionation (FF) and supercritical water oxidation (SCWO), to achieve the concentration and destruction of PFAS from various waste streams. FF is a separation technique that uses air bubbles to capture and enrich PFAS from dilute solutions, resulting in a concentrated PFAS-rich foam. SCWO is a thermochemical process that uses water at high temperature and pressure to oxidize organic compounds, such as PFAS, into harmless products, such as carbon dioxide, water, and salts. By applying FF and SCWO in tandem, PFAS can be effectively removed from contaminated water, leaving behind PFAS-free water that can be safely discharged or reused. The main objective of this presentation is to share the practical experience and results of operating a commercial-scale SCWO unit that has been treating PFAS concentrate from various sources. The presentation will provide analytical data and performance indicators from the treatment of PFAS concentrate derived from raw leachate and industrial wastewater that have been pre-treated with FF. Moreover, the presentation will discuss the process and outcomes of treating AFFF concentrate and rinsate that have been generated from fluorinated foam replacement projects. A key aspect to be highlighted is the benefits and challenges of the integrated FF and SCWO approach, covering design considerations, operational conditions, and field outcomes from full-scale implementation. Attendees will also learn about the prerequisites and steps for field deployment and the regulatory compliance issues related to air and water emissions. The following are the learning objectives of this presentation: 1. To gain an overview of the capabilities and readiness of FF and SCWO technologies for treating PFAS-impacted waste streams. 2. To learn about the best practices and strategies for working with state and municipal regulators to ensure compliance with air and water quality standards. 3. To acquire valuable lessons and insights from the deployment, commissioning, and ongoing operation and optimization of a full-scale SCWO unit.

INTRODUCTION The Aerobic Granular Sludge (AGS) and other densified processes offer the promise of biomass intensification with the added benefit of nutrient removal. A key element needed to support AGS is the selective wasting of flocculant biomass and particles from the process. Wasting occurs from the top of the settled solids or by other physical methods (e.g. hydrocyclones). While this wasting approach is essential to the AGS process, it results in waste solids (WAS) streams that differ from conventional activated sludge (CAS) with higher flow rates, lower total suspended solids (TSS) concentrations, and biological nutrient removal (BNR) activity. Therefore, the AGS WAS must be managed in a completely different way from CAS WAS. Two key WAS management challenges need to be considered. The first challenge is managing intermittent AGS WAS flows, which are on the order of 5 to 15 times higher than CAS WAS flow rates on average and approaching 100 times higher for instantaneous flow rates. The second challenge for AGS WAS management is understanding the impact of the phosphorus accumulating organisms (PAOs) on the solids handling system and managing the potential for struvite formation. The objectives of the project work are the following: *Define AGS WAS settleability characteristics *Expand the understanding of phosphorus release potential (total OP release) and rates METHODS & APPROACH Solids Settling Characterization All WAS samples were taken directly from the pipe that transfers WAS from the AGS reactors to the solids buffer tank (Figure 1). Settlability was evaluated using a 5.5-inch diameter column settler (Figure 2). The settling column was filled with 10 L of WAS sample for each test. Sample ports, located every 2 L and at the bottom of the column, were used to collect supernatant and settled solids samples. Settled WAS and supernatant samples were taken and TSS was measured in both samples. Sludge volume index (SVI) values were also estimated. Phosphorus Release Rates and Potential Phosphorus release testing has been conducted using gang stirrer apparatuses with 1.5 L samples (Figure 3) and low-rate mixing (30-50 s-1). A carbon source was added to 10 of the samples giving F:M ratios ranging from 0.0 to 0.5 g-COD/g-VSS. Additionally, the initial TSS concentration was varied by providing some initial thickening in some samples resulting in a range from 1,500 to 5,000 mg/L. The initial total phosphorus and phosphate concentrations were measured in the raw WAS sample. Samples were subsequently taken from the release tests through a 34 h time period. Samples were filtered and phosphate measured. Results & Discussion AGS WAS Settling Rates The WAS volume was recorded as a function of time by measuring the depth of the sludge layer in two separate test batches. Initial WAS concentrations were 2,500-5,000 mg/L and thickened to 8,500-10,000 mg/L by the end of the test period. The final settled volume was reached within 4-12 minutes. The maximum settling velocity was 3.9-11.9 m/hr at time 2-4 minutes and decreasing over time (Figure 4). SVI5 values were estimated in the range 110-200 mL/g, and SVI30 values were calculated in the range 100-120 mL/g. The TSS concentration in the supernatant was 8-40 mg/L. Evaluation of modeled settling in a clarifier was conducted using a BioWin simulator based on the calculated Vesilend model clarifier coefficients. Model sludge blanket height and effluent suspended solids remained within the desired range, even with the additional solids. A state point analysis from BioWinTM indicated that the AGS WAS operating condition was within the solids-flux limitation of the clarifier (Figure 5). Phosphorus Release Rates and Potential Phosphorus release testing showed phosphorus release rates varied initially in response to carbon dosing with higher short-term release rates followed by reduced long-term release rates (Figure 7). Short-term (or initial) release rates varied from 0.4 mg-P/g-TSS/h for no carbon addition to 4.0 mg-P/g-TSS/h for carbon addition (acetic acid with F:M of ~ 0.4 g/g). The long-term release rates varied from 0.1 to 0.7 mg-P/g-TSS/h for initial TSS concentrations in the range 1,500-5,000 mg/L (Table 1 and Figure 8). The effect of starting TSS concentration was more important than carbon addition for this test batch with rates normalized to volume increasing exponentially as shown in Figure 8. The overall phosphorus released varied in the range 7-22% of the initial TP measured. A follow-up test was conducted showing a release of 25-30% of the initial TP over a 72-h release period. A phosphorus mass balance on the plant aligns with maximum releasable TP observed based on the phosphorus removed from the liquid stream. An evaluation of the settling characteristics of AGS WAS showed high settling velocities resulting in WAS TSS concentrations similar to CAS WAS TSS concentrations with low DSS concentrations. Based on the results of phosphorus release testing, struvite mitigation is recommended for anaerobic digestion of AGS WAS.

Introduction Partial nitrification/denitrification coupled with anaerobic ammonia oxidation (PdNA, PANDA) process has the potential to result in capacity, chemical and energy savings at water resource recovery facilities (WRRFs). In this process, ammonia oxidation is controlled to achieve a specific NO3/NH3 ratio. Partial denitrification driven by supplemental carbon addition (e.g., methanol) is then used to stably generate NO2--N accumulation. Anaerobic ammonia oxidizers can then remove both nitrite and ammonia to achieve effluent NH3 and TN limits. Successful PdNA/PANDA has been documented in pilot and full-scale. This work documents advancement and implementation of PANDA at the Fairfax County Noman M. Cole Pollution Control Plant (NCPCP) to achieve TN limits less than 3 mg/L. Specifically, the work will discuss full-scale results demonstrating effective anoxic ammonia removal via the PANDA mode of operation Materials and methods Full-scale reactor setup. The full-scale MBBR system was commissioned in 2013 and is comprised of six trains, five of which are currently equipped with fixed-film media and ancillary equipment. Each train includes two anoxic denitrification cells (approximately 2.4 MG in total volume) in series followed by a single re-aeration cell (approximately 0.6 MG in volume). The anoxic denitrification cells are equipped with mixers and flat screens for media retention. The re-aeration cells are equipped with medium bubble aeration diffusers and cylindrical screens. All cells are equipped with K1 media, which provide the surface area necessary for attached growth of nitrifying and denitrifying bacteria. Methanol dosing was controlled via feed-back nitrate paced addition. Ammonia and nitrate for the tertiary MBBR PANDA demonstration was provided via process control adjustments to the secondary process, including changes to step-feed configuration, DO and airflow setpoints, load paced equalization and methanol feeding. Results and discussion Full-scale results — Full-scale demonstration testing of PANDA mode commenced in Q3 of 2022 and is ongoing. Results indicated:

*Anoxic ammonia removal between 1 and 2.0 mg/L has been observed since startup and the full-scale facility has been able to maintain weekly effluent ammonia concentration below 0.5 mg/L, monthly effluent TN concentrations of between 2 and 4 mg/L and an average annual effluent TN of 2.9 during the past 12 months of operation (2023).

*Unit methanol use at the facility has decreased by approximately 20% and unit energy demand at the facility has decreased by approximately 5% relative to 2021-2022 plant operations since operating in PANDA mode.

*Full-scale demonstration has confirmed that partial denitrification/anammox is sensitive to the NO3/NH3 ratio in the MBBR influent. Optimal performance (greater than 90% anoxic ammonia removal, COD to Nitrate removed less than 4.0 and influent ammonia above 1.1 mg/L) has been observed at NO3/NH3 ratio of 3.1 to 5.1.

*The FFX NCPCP has historically observed intermittent spikes in secondary effluent ammonia concentration. Potential causes of these spikes may be attributed to load peaking and/or suppressive compounds in the wastewater. A recent ammonia spike resulted in secondary effluent ammonia of 3.6 mgNH3-N/L to the MBBR. The PANDA mode of operation reduced 2.7 mgNH3-N/L to achieve a MBBR effluent ammonia of 0.9 mgNH3-N/L and MBBR effluent TIN of 2.5 mgTIN/L at a NO3/NH3 ratio of 1.5.

*NCPCP operators have easily shifted from PANDA to conventional mode of treatment when necessary to manage outside factors that might interfere with normal operations. Cumulatively, this work is the first to effectively demonstrate full-scale deammonification via PANDA while meeting stringent nutrient limits. Ongoing efforts are focused on optimizing the NO3/NH3 ratio, stabilize phosphorus removal while continuing to reduce energy and methanol associated with nutrient removal at the NCPCP.