Our world is driven by data across all industries, and the water sector is no exception. This ranges from enterprise systems that have been in place for decades to smart systems that are generating data at an exponential rate. It is increasingly important to incorporate practices to make sound decisions from these systems and implement controls to ensure trusted data. WSSC Water completed efforts to identify processes to improve their data-driven decision-making, and this abstract will present two strategies used to improve their performance across many departments through automation, standardization, and visualization of data. Strategy 1: Enterprise Data Warehousing: A large portion of the data used by decision makers resides in systems of record that are operated by their functional teams. While this data is usually accurate and up to date, it requires an expert from the team to extract it from the system or understand the data that is produced. It is also more granular than decision makers require, and the teams reporting on it consistently aggregate it to produce the intended results. To address these issues, WSSC Water automated the creation of datasets in these functional groups, all of which were a part of their Enterprise Data Warehouse. In the use case for this strategy, they will show the automated Commission Performance Report and Human Resources Dashboards. These items reduced the time spent developing recurring reports, leveraging Power Bi for automated and interactive reporting. Strategy 2: Non-Enterprise Data Management and Application Development: Unlike the enterprise data, WSSC Water identified many users who are managing critical data in their own spreadsheets or other tools. To standardize and automate some of the processes, they worked with these users to provide low-code platforms to manage data in their existing IT infrastructure. These tools included the development of SharePoint data-structures, Applications and Workflows to allow users to edit and maintain datasets in a collaborative environment, with the increased auditability that these tools provide. In the use cases for this strategy, they will show the Transition Plan Tracking Application and Community Investment/Engagement Application. These converted existing series of over ten spreadsheets into a single data source, provided a low-code application for the teams to enter data, and Power Bi Dashboards for reporting. The combination of these two strategies allows groups to take small steps into the world of data-driven decision making. Teams are beginning the process with Strategy 2 by standardizing their reporting, with the intent to be automated into an enterprise solution under Strategy 1 in the future. In the past, tools such as the ones outlined in these strategies were limited to IT Departments and professional programmers. With the advent of modern data management strategies, they are much simpler to implement and maintain, but still in line with IT standards and supported by their department once they are in production. In the end, WSSC Water identified significant time savings, data quality, and visualization capabilities as a result of taking a data-driven approach to managing some of their manual efforts.

Background Water resource recovery facilities (WRRFs) around the world are constantly faced with significant challenges 1, 2. It is estimated that WRRFs are operating at an average of 81% of their design capacity, while 15% of systems are at or have exceeded that threshold3. As the most prevalent biological nutrient removal (BNR) process, any improvements to conventional activated sludge (CAS) processes are highly desirable in our industry4. However, upgrading CAS trains is costly and alternative technologies often tend to be more energy-intensive, expensive1, and time consuming to install, commission, and operate. Thus, the use of physical selectors (e.g., hydrocyclones) for biomass densification has emerged as a front-runner for increasing secondary clarifier capacity and improving nutrient removal. Objective and Approach Despite the many studies exploring the advantages of densified activated sludge (DAS) systems compared to CAS systems, DAS impacts on microbial communities and fecal indicator bacteria (FIB) are unknown2, 5. In 2023, the Water Research Foundation funded a tailored collaboration with the Metro Water Recovery (MWR) in Denver. The collaboration aimed to investigate FIB removal and disinfection kinetics. This study focused on CAS and DAS treatment trains at three North American full-scale operating WRRFs (Figure 1). The WRF project aims to: A) Compare E. coli concentrations over a 15-month period and investigate factors influencing differences (e.g., granulation size distribution, floc/granule mass fraction, floc/granule aSRT, microscopy, COD, Turbidity, TSS, NH3, pH, Temperature, Color, UV-254, TKN, TP, TOC). B) Determine how changes in Secondary Effluent (SE) properties between DAS and CAS affect disinfection efficacy using chlorine, peracetic acid (PAA), performic acid (PFA) and ultraviolet disinfection (UV) seasonally (n=12), with the same water quality parameters listed in Objective A. C) Assess impacts of operational variables on DAS and provide utilities with recommendations. These can include how to utilize modeling and statistics to improve performance using demand and decay values and mechanistic disinfection efficacy models D) Determine if additional analyses (e.g., protozoa counts, granule sieving analyses) provide operational value to utilities adopting DAS. Results Data collected for one year at the MWR Hite Treatment Facility highlights the statistically significant difference in E. coli concentrations between the CAS and the DAS trains (Figure 2). This could be explained by a variety of variables that have not yet been evaluated. FIB counts may be impacted by the predator protozoan community5, but this has yet to be supported by data (Figure 3). While percent mass fraction (Figure 4) and seasonality (Figure 5) have been hypothesized to impact DAS E. coli counts6, this has not been shown by the preliminary data collected, which highlights the importance of a more detailed study to explain the differences observed . Summary DAS is able to be implemented with low capital cost while increasing the capacity of CAS systems. However, there is little data on how SE from DAS systems impact downstream disinfection processes. This WRF project will evaluate the impact DAS systems have on disinfection processes compared to CAS systems. Data collection and testing for this project will begin in April 2024.

Water and wastewater utilities are facing many challenges in the twenty-first century, including aging infrastructure, climate change, population growth, and regulatory compliance. One of the most pressing issues is the looming talent gap and the retirement of experienced staff. This poses a risk to the continuity and delivery of quality service. To address this challenge, utilities need to adopt innovative solutions that can enhance the operational resilience and safety of their systems and personnel. One of the emerging technologies that can offer such benefits is extended reality (XR), which encompasses virtual reality (VR), augmented reality (AR), mixed reality (MR), and assisted reality (aR). XR can provide a unique and immersive experience. It can help utilities overcome the talent gap by offering a new way of training and retaining staff. XR can also help utilities improve their operational resilience and safety by providing a more realistic and interactive environment for training and simulations. XR technologies can create immersive and interactive environments that simulate real or imagined scenarios and overlay digital information onto the physical world. These technologies can be used for various purposes in the water sector, such as training and education, asset management, inspection and maintenance, emergency response, remote assistance, and even stakeholder engagement. For example, VR can provide realistic and cost-effective training for new and existing staff, especially for complex or hazardous tasks that require high levels of skill and safety. AR can enhance the situational awareness and decision-making of field workers by providing them with real-time data and guidance on their smart devices or wearable headsets. MR and aR can enable remote collaboration and communication among utility staff, contractors, regulators, and potentially customers, by creating a shared virtual space that integrates both physical and digital elements. This presentation will discuss how XR technologies can help water and wastewater utilities address the talent gap and enhance the operational resilience and safety of their systems and personnel. The presentation will provide an overview of the current and potential applications of XR in the water sector, and highlight the benefits, challenges, and best practices of implementing these technologies. The presentation will also showcase some of the successful case studies and lessons learned from utilities that have adopted XR solutions and provide recommendations for future research and development. To determine the efficiency of task guidance and training using XR technology, CDM Smith conducted a research and development (R&D) project with a wastewater client. The project's primary goal was to train new staff to complete common tasks using an XR system and measure the results. Nine employees were provided basic training in using the XR technologies. Then, they were run through four different task guidance procedures.

*Cleaning the Reclaimed Total Suspended Solids (TSS) Meter

*Titration Analysis for chlorine residual

*Hach composite sampler

*Belt Press Operation The procedures averaged 13 steps each and the employees were able to follow the instructions and complete the tasks. XR technology training time averaged 9:05 minutes and employees rated the training experience at 7.88 out of a scale of 10. Employees rated ease of use at 8.66 out of a scale of 10. Eight out of nine employees said they would like to use this type of task guidance training in the future. This presentation will include more information about this project and other case studies using XR technologies to enhance operational resilience and safety. We will conclude with a Q&A session, where the audience will have the opportunity to ask questions and share their feedback.

INTENDED OBJECTIVE: Biosolids from water resource recovery facilities (WRRFs ) are increasingly used for agricultural and recreational land purposes due to their sustainable means to replenish macronutrients. However, the relatively high phosphorous content of biosolids limits certain applications. This study aims to identify optimal locations for recovering vivianite and subsequently phosphorus, to allow class A biosolids reach ideal phosphorus levels. INTRODUCTION: Global consumption rates of synthetic fertilizers per unit of cropland have increased 3 to 8 times over the past half century (Lu et al. 2017). Class A biosolids are increasingly explored as an alternative to commercial fertilizers due to their effective means to replenish carbon and macronutrients (Gilmour et al. 2013). However, the N:P ratio of biosolids is typically lower than commercial fertilizers which can cause an accumulation of phosphorus when applied to soil, increasing risk for eutrophication (Penn et al. 2002). Therefore, it is critical to implement efficient phosphorus-removal technologies/techniques within the biosolids treatment train to improve the N:P ratio and limit the amount of phosphorus that result in the cake. Therefore, this study aims to analyze the P mass balance of the Blue Plains advanced wastewater treatment plant in Washington, DC as well as its vivianite characterization in full-scale. The process sampling, modelling and analysis led to identification of potential locations for vivianite recovery, and initial estimations on how much the P content in our class A biosolids might be reduced by recovering vivianite upfront. MATERIALS AND METHODS: Sampling campaign: Samples were collected in DC Water Blue Plains over a 3-month period (Mid-February to Mid-May 2022). Quantitative analysis: Phosphorus is measured by the EPA 365.1 method. Scanning Electron Microscopy with Energy Dispersive and Mossbauer Spectroscopy: Prepared by method in Prot et al. 2021. Modelling method: Visual Minteq version 3.3 with DOC SHM model RESULTS & DISCUSSION P mass balance at Blue Plains and P content in biosolids product Blue Plains advanced WWRF achieved a 98% incoming TP removal over its primary (enhanced-chemical phosphorus removal) and secondary systems through iron dosing. The removed P is diverted to the solids fraction and results in a Class A biosolids product (BLOOM) with 2.88% P (dry weight basis) and 28-32%TS (Fig.1A). The P:N ratio of our product is 1:1 and thus higher in P content than the target of 1:2 P:N for typical fertilizers. Decreasing P content in BLOOM by 50% or thus recovery 60% of vivianite would increase the value and applicability of BLOOM. Vivianite formation and formation potential along the Solids Treatment Train A total Fe/P molar ratio of 1.5 or greater allows for optimal vivianite precipitation (Cong et al. 2017) which is reflected in DC Water treatment flow diagram (Figu 1). Vivianite was detected in primary thickened sludge, blend of thickened primary (PS) and waste activated sludge (WAS), and digested sludge b ased on sequential extraction method in Wang et al. 2021. This was also further supported by the clear co-location of Fe and P in SEM images (Figure 2A and 2B). These locations are consistent with the vivianite scaling seen in primary sludge gravity thickening lines and centrifuge lines in the facility. Through quantitative analysis, the vivianite mass flow in thickened primary sludge, blended PS/WAS and digested solids accounted for 8%, 52%, and 49% of the incoming P to the plant (Fig. 1). These vivianite ranges are like those reported by iron-dosing plants in Prot et al. 2021 and Wilfert et al. 2016. Estimation of P recovery potential needed to impact Class A biosolids P content Based on the current vivianite-P levels in the three identified locations (Fig. 1), sludge after anaerobic digestion contained the highest level of vivianite-P. This is likely due to higher orthophosphorus levels after thermal hydrolysis treatment which allows for additional vivianite formation with Fe(II). This notion is supported by the low levels of Fe(II) concentrations after anaerobic digestion indicating that most of it is bound (Fig. 1). We estimated how much vivianite recovery efficiency we might need to decrease the P content in the BLOOM with an ideal target of ~0.014 kg P/kg TS and acceptable target of 0.022 kg P/kg TS. Given the highest vivianite levels in digested sludge, a recovery efficiency of at least 40% with ideally 70% is sufficient to meet our targets (Fig. 3). Utilizing vivianite recovery technologies such as magnetic separation (80% of vivianite recovery in digestates according to Wijdeveld et al. 2022), and other alternative options could provide the potential recovery target needed to improve BLOOM. CONCLUSIONS Based on current vivianite-removal technology efficiencies, removing vivianite will significantly impact the phosphorus levels in BLOOM. Results suggest that after anaerobic digestion is a preferred and feasible option to implement recovery technology due to its high vivianite content as well as the opportunity to recover vivianite in a fraction of the digestate to produce low P BLOOM rather than the whole biosolids treatment train. Future testing will explore recovery efficiencies of P and vivianite to confirm feasibility and setup a path towards pilot testing approaches.

Introduction Membrane Aerated Biofilm Reactor (MABR) and Densified Activated Sludge (DAS) employ different mechanisms to deliver process intensification, both of which are applied independently at full-scale (Astrand 2023). Coupling MABR and DAS (MABR-DAS) is an area of opportunity to bring more value for WRRFs. The first opportunity is to combine the individual features of the technologies to de-bottleneck plant operations where MABR intensifies the biological reactor and DAS intensifies secondary clarification (Donnaz 2020; Roche 2021) and uncouples SRT -- floc and granules which helps with even further intensification of BNR. The second opportunity is to exploit synergies between the technologies to enable intensification that is greater than the sum of the parts and expand the range of WRRF plant configurations that can benefit from intensification. MABR and DAS Process synergies The hybrid MABR-DAS process offers several unique features that enhance biological selection compared to conventional BNR. These features promote a virtuous cycle with densification. Maximize Substrate Gradient in the Feast Zone A high substrate gradient in the feast zone favors the growth of densified biomass. MABR maximizes substrate gradient by reducing recycle flows that dilute substrate concentration. SND in the anoxic zone of an MABR enables nitrate recycle to be eliminated or reduced. Densified sludge enables RAS rates to be reduced. Enhance Anaerobic Conditions and Bio-P MABR enables and improves bio-P and the biological selection of PAOs and GAOs by enhancing or creating anaerobic conditions. Elimination or reduction of nitrate recycle by MABR increases anaerobic HRT. SND and complete denitrification in the MABR zone reduces NOx return in the RAS. The MABR anoxic zone can serve as an extension of the anaerobic volume due to: An ORP gradient along the length of the MABR zone enabled by the attached biofilm, Use of the unaerated volume below the MABR cassettes for fermentation, BNR intensification by MABR enables aerobic volume to be cannibalized for anaerobic and/or anoxic fractions. This allows CAS plants with no or small unaerated volumes to increase the unaerated volume fraction necessary for biological selection. Reduce rbCOD Bleed into the Famine Zone SND in MABR consumes rbCOD for denitrification, preventing it from entering the famine zone. MABR enables increased F/M compared to conventional BNR systems. The seeding effect of the nitrifying MABR biofilm enables operation at lower suspended growth Aerobic SRT and thus higher total F/M for the system. Full-Scale Implementation at the Yorkville-Bristol Sanitary District A full-scale implementation of MABR-DAS has been in operation at the Yorkville-Bristol Sanitary District (YBSD) since 2023. The YBSD MABR-DAS upgrade has occurred in the following stages (Figure 1). (1) Nitrifying CAS. Prior to 2017 the plant was a nitrifying CAS system rated for 3.62 MGD with the biological reactor arranged as ten aerobic tanks in series. (2) MABR. In 2017 the plant was upgraded to MABR and Enhanced Biological Phosphorus Removal (EBPR) to increase the biological capacity by 25% and meet a new phosphorus limit. The biological process was reconfigured to A2O with one reactor anaerobic and one reactor anoxic with MABR cassettes. The plant does not have nitrate recycle. (3) MABR-DAS. In January 2023 densification was implemented to increase the hydraulic capacity by 40% to 5 MGD and improve bio-P performance. In the future, MABR cassettes could be added to increase biological capacity by an additional 20% (145% total). Results from 11 months of operation of the MABR-DAS system are provided below. Sludge Settleability During the first 11 months of MABR-DAS operation, SVI30 decreased from 100 mL/g to 60 mL/g and SVI5 decreased from 250 ml/g to < 100 mL/g. The granule fraction (GF, fraction of solids > 250 µm in size) increased from 35% to 55%, see Figure 3. Figure 4 summarizes the correlation between SVI and GF. The gray data points are from before implementation of MABR-DAS and the blue points are after implementation. The data suggests two phases in the transition of the plant. Phase 1 indicates densification, with selective wasting and washout of filaments when SVI30 decreased from 110 mL/g to 60-75 ml/g with no corresponding change in GF. During Phase 2, GF increased from 35% to around 55%, and this was coincident with a further decrease in SVI. Figure 5 summarizes phosphorus removal performance before and after operation of the MABR-DAS system. Phosphorus removal is achieved by a combination of bio-P and chem-P with bio-P limited by a 10% anaerobic mass fraction. A decrease in coagulant dose since the start of MABR-DAS indicates that bio-P performance has improved with MABR-DAS. Phosphorus release profiles from a kinetic & CFD model demonstrate that the MABR anoxic zone serves as an extension of the anaerobic volume (Figure 6). Alternative mixing strategies in the anaerobic zone improve phosphorus release by a further 15-30% (Duchi 2023). Knowledge Gaps & Opportunities Physical Selection of Nitrifiers Sloughed from MABR Biofilm Adding a Third Dimension to SRT Uncoupling MABR introduces another form of biomass (biofilm) in the activated sludge process. This brings an additional lever to the principle of SRT uncoupling, control the SRT of the biofilm independently from the SRT of the suspended growth

Antimicrobial resistance (AMR) makes diseases more difficult to treat and has been spreading worldwide. It is considered a major public health concern. Over the last two decades, numerous projects investigated the occurrence of AMR, especially antibiotic resistance, in wastewater. In 2023, several papers (e.g., Berglund et al., 2023; Wang & Smith, 2023; Zhao et al., 2023) reported the detection of antibiotic-resistant genes (ARGs) and mobile genetic elements (MGEs) in wastewater, resulting in negative news stories and media inquiries at water resource recovery facilities (WRRFs) about AMR and potential risks from wastewater or biosolids (Wigglesworth, 2023). In addition, the Centers for Disease Control and Prevention (CDC) has expressed interest in including wastewater-based surveillance (WBS) of AMR targets in its National Wastewater Surveillance System, which will lead to continued focus on AMR. This presentation is intended to help inform the water sector as attention to this complex topic grows. It provides a summary of concepts related to antimicrobial and antibiotic resistance and the current state of the science related to antibiotic resistance at WRRFs. It highlights the following take home messages:

*Antibiotic-resistant bacteria (ARB) and ARGs are widely detected, including in natural environments and food, but their associated human health risks remain poorly understood and inadequately characterized.

*The risk of getting infected by ARB is not greater than the risk of getting infected by the same antibiotic-susceptible bacterium. Humans are exposed to millions of microbes with antibiotic-resistant traits every day via natural and necessary activities, such as the ingestion of water and food (Pepper et al., 2018). Most of these exposures do not cause infections.

*Antibiotic-resistant bacteria and ARGs are detected at WRRFs, but treatment processes, including coagulation, clarification, filtration, disinfection, and anaerobic digestion, generally reduce their levels.

*The Global Water Pathogen Project (2019) estimates that conventional WRRFs reduce the types of ARGs observed and their numbers in raw wastewater by approximately 33% to 98%. Though some ARGs and mobile genetic elements (such as integrons) are not reduced.

*Current practices for wastewater and municipal drinking water treatment are adequate to prevent enteric bacterial infections from ARB via drinking water.

*Workers at WRRFs could be exposed to ARB and ARGs through contact with wastewater, solids, and bioaerosols. The associated risks are uncertain but can be mitigated by following the worker safety recommendations of the CDC (n.d.-a) and WEF (2020).

*Wastewater-based surveillance is an emerging approach to complement public health data, but is not intended to inform risk assessment from wastewater exposure.

*Water resource recovery facilities are important critical control points and are one of the most effective means of removing or reducing the occurrence of ARB and ARGs in wastewater and the environment.

Over the past decade, increased attention has been placed on enhanced biological phosphorus removal (EBPR) configurations that include fermentation of a portion of the activated sludge biomass. Often this is accomplished in a sidestream reactor, and thus is referred to as sidestream enhanced biological phosphorus removal (S2EBPR). Recent research suggests that S2EBPR configurations promote more stable and lower effluent orthophosphate concentrations due to a more diverse microbial ecology compared to 'conventional EBPR' configurations. Such research suggests that S2EBPR encourages the selection for a larger prevalence of fermentative phosphorus-accumulating organisms (PAOs) which can metabolize a wide range of carbon sources in addition to volatile fatty acids. This scenario may improve process performance by reducing the reliance of the EBPR process on influent carbon in the form of VFAs. Four S2EBPR configurations that promote biomass hydrolysis and fermentation include: (1) sidestream RAS fermentation, (2) sidestream RAS fermentation with supplemental carbon addition, (3) sidestream mixed liquor suspended solids (MLSS) fermentation; and (4) mainstream unmixed in-line MLSS fermentation (UMIF). A Water Research Foundation (WRF) project (Project 4975) studied S2EBPR configurations to provide practical design guidance, operating tools, and modeling best practices for EBPR processes using biomass fermentation. Results of a UMIF full-scale pilot conducted at the Geneva WWTP in 2020 as part of this Project will be presented. The 5.0 mgd Geneva (Illinois) Wastewater Treatment Facility (WWTF) completed a major process improvements project in 2019, including modifications to the conventional activated sludge process to provide EBPR to meet tightening discharge permit requirements, including a total phosphorus limit of 1.0 mg/L. Bioreactor upgrades were recently completed to promote EBPR to meet this limit. The bioreactor design provides the flexibility to operate in either a 'conventional EBPR' design using an A2O configuration, or to operate with A2O in a UMIF configuration by turning off mechanical mixers in the second of two anaerobic zones and only operating them for 15 minutes per day. The retained sludge ferments at the bottom of the tank and generates VFAs. This sludge is continuously pumped at a rate of about 10 percent of the forward flow from the UMIF zone to the first anaerobic zone. This internal return flow distributes VFAs into the mixed liquor, where they become available to PAOs. During the commissioning of the EBPR process, the secondary treatment process was operated in three configurations: A/O, A2/O with nitrate recycle to Anoxic Zone A, and A2/O with nitrate recycle to Anaerobic/Aerobic Swing Zone B. Ortho-phosphorus profiles through the bioreactors are shown in Figure 1 for each of these configurations before operating in a UMIF configuration. Note that in this figure, each color reflects a different operating configuration, and the two lines for each color reflect the two individual bioreactors used in the study. The phosphorus profiles in each bioreactor were similar for each BNR configuration sampled, with effluent averaging about 0.6 mg/L in each. Following the commissioning period, the operators began piloting the UMIF mode to increase the anaerobic SRT, provide seed biomass for downstream anoxic/aerobic treatment, and encourage hydrolysis and fermentation of the settled MLSS which can be recycled to the head of the anaerobic zone with a recycle pump. The plant operated a UMIF pilot train in parallel with a conventional A2O train to compare their performance. Ortho-phosphorus profiles through the bioreactors under UMIF conditions are shown in Figure 2, with effluent averaging about 0.06 mg/L. The following observable trends were noted:

*Significant decrease in ortho-phosphorus concentration in the anoxic zones. This is primarily attributable to dilution by the nitrate recycle stream, though it may also be possible that some phosphorus uptake may occur by denitrifying PAOs due to the introduction of nitrate.

*A sharp decline in the ortho-phosphorus concentration in the first oxic zone. This is attributable to the sheer size of the Oxic Zone A, which is the single largest zone in the bioreactor, allowing for the longest hydraulic retention time in which phosphorus uptake can occur in an aerated zone.

*Operation with UMIF has resulted in excellent EBPR performance, with UMIF resulting in significantly lower orthophosphate concentrations in the final aerated zones in the bioreactors. This UMIF pilot demonstrates how a simple operational modification, like turning mixers on and off, can improve phosphorus removal with no capital improvements or time-consuming operational modifications. The UMIF configuration has positioned the WWTF well for upcoming further tightening of the TP limits to 0.5 mg/L. This presentation will provide not only a description of the anaerobic zone mixer operating strategy and how it improved EBPR performance, but will also include lessons learned and guidelines for operators to consider to fine tune the mixing strategy for their plant to avoid unintended negative consequences, such as increased ammonia release and resulting nitrite accumulation in the aerobic zones.

Introduction As population growth, urbanization, and climate change intensify pressures on water resources, utilities are faced with an increased urgency for advanced water treatment (AWT) solutions and a need to enhance resilience against evolving climatic conditions. Concurrently, wastewater resource recovery facilities (WRRFs) are faced with increasingly stringent nutrient discharge limits that surpass the capabilities of conventional treatment methods. Consequently, utilities are compelled to adopt innovative approaches to address the quality and quantity of water supplies while ensuring regulatory compliance and sustainability. In this work, we highlight case studies of two forward-thinking utilities, distinguished by geographical contexts and unique drivers, yet united by a commitment to advance climate change adaptation strategies, achieve ultra-low nutrient limits, and integrate holistic one water initiatives. Metro Water Recovery (Denver, CO): Upcoming Colorado water quality regulations are set to impose stringent stream standards, notably 2.01 mg/L for total nitrogen (TN) and 0.10 mg/L for total phosphorus (P) on WRRFs, including Metro Water Recovery's Robert W. Hite Treatment Facility (RHWTF) and Northern Treatment Plant (NTP). AWT technologies like carbon-based advanced treatment (CBAT) schemes (e.g., coagulation/flocculation/sedimentation (floc/sed), ozone (O3), biofiltration (BAF), and granular activated carbon (GAC)) may address stringent nutrient limits while also aligning with Direct Potable Reuse (DPR) requirements. A study was initiated to: 1) assess the treatability of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and soluble non-reactive phosphorus (sNRP) using CBAT technologies; and 2) discern the capabilities of CBAT in concurrently achieving nutrient limits and DPR compliance. Evaluation of nutrient removal through tertiary CBAT processes spanned full-scale applications (floc/sed at NTP and BAF/floc/sed at RHWTF's Denver Water Recycling Plant (DWRP)) and pilot-scale (O3 only, BAF only, and O3/BAF at RHWTF), supplemented by bench-scale floc/sed (jar testing) and GAC evaluations (rapid small-scale column tests). Parameters such as O3 dose and empty bed contact times aligned with potable reuse standards. While full-scale floc/sed/filtration at NTP (Figure 1; Figure 2) and DWRP (Figure 3, Figure 4) (~20 mg/L alum) effectively managed particulate P and sNRP removal, it did not meet DOC and DON targets for Direct Potable Reuse (DPR) applications. CBAT testing showed potential for control of DOC and DON, albeit with the need for multiple potentially costly unit processes. The GAC runtime (up to 3,500 Bed Volumes for DOC and DON targets) was notably extended through enhanced upstream treatment. While floc/sed processes achieved comparable DOC and DON removal rates (up to 40% each) at the expense of elevated coagulant doses (80 mg/L Ferric chloride), O3/BAF treatments realized a modest 26% reduction in DON. Future pilot efforts aim to assess the efficacy of a comprehensive CBAT treatment train, inclusive of tertiary denitrifying BAF, to fulfill TN requirements and optimize DPR suitability. AWT Utility (Midwest): A midwest AWT utility has seen significant population growth in recent years and is estimated to double by 2040. Rapid growth and a desire improve the health of the receiving water body have urged the utility to consider alternative water supplies. Subsequently, the utility commissioned a CBAT pilot consisting of O3, two-stage BAF, GAC, and UV advanced oxidation process (UVAOP). The objective of this study was to pilot CBAT technologies to demonstrate the ability of AWT process trains to produce high quality finished water that meets stringent water quality targets. This study utilized a multi-barrier scheme of O3/two-stage BAF (aerobic/anoxic) to meet low TN limits. Filters were operated in several phases (Table 1) until effluent quality targets were met (TOC < 3 mg/L, TN < 2 mg/L, contaminants of emerging concern (CECs)- meet MCLs) and steady-state was achieved. Select operational parameters were varied during each phase and the resulting water quality surrounding the first anoxic BAF (BAF 3) is shown in Figure 8. Table 2 shows the effluent DO, nitrate (NO3-N) concentrations and corresponding % NO3-N removal achieved across each anoxic BAF. Results indicate that when supplemental carbon and upstream feed DO levels were controlled, anoxic BAF 1 established and maintained anoxic conditions and achieved NO3-N removals up to 60% with anoxic BAF 2 acting as a polishing biofilter (%NO3-N removal ~30%). When supplemental carbon and upstream DO quenching chemical doses were reduced, anoxic BAF 1 turned into a sacrificial BAF, consuming excess DO and displaying poor nitrate removals (~15%), while anoxic BAF 2 became the dominant anoxic biofilter (> 60% NO3-N removal). Piloting efforts demonstrate how a modified CBAT train may simultaneously meet low TN targets (< 2 mg/L) and produce high quality product water. Conclusion Case studies at Metro Water Recovery and a midwest AWT utility demonstrate CBAT's potential for improving finished water quality for reuse and meeting ultra-low nutrient discharge requirements. Project findings provide first guidance on how WRRFs can adjust operational setpoints using CBAT process infrastructure to meet DPR or discharge water quality requirements in ecologically sensitive and drought-prone watersheds.

There are many challenges with keeping water and wastewater infrastructure functioning and serving the public. The physical challenges are readily understandable but another challenge no less formidable involves the human element -- keeping our facilities staffed with adequate numbers of trained individuals who can function as an effective team. During the past 50 years Niagara Falls has endured a staffing evolution accompanying its evolution in governance and infrastructure. Faced with a mix of common and unique staffing issues, some measures have worked well while others have had only limited success. The current Niagara Falls Water Resource Recovery Facility (WRRF) was built under the federal Construction Grants Program of the 1970s and 1980s. Generous staffing from the start, hirings required by a federal Consent Decree, and the phasing out of operating aid from the state began the financial squeeze on the city. By the mid-1990s pressures grew as federal pretreatment regulations forced local industrial customers to sharply reduce their discharges. While rejecting an independent engineering assessment and holding off privatization overtures, the city administration permitted the plant staff to pursue a self-guided effort to improve and streamline the department. The effort achieved some modest success, but substantial changes to staffing levels and the associated costs were not among them. Entering the new millennium, financial attention shifted to the city's water utility. Declining consumption and rising debt service was creating its own funding crisis. A new mayor formed a Utilities Task Force to evaluate options and make recommendations. The three options considered were the status quo (with a 75% rate increase), privatization, and transferring water and wastewater assets to a newly formed authority, allowing refinancing of debt that the city could not undertake. The authority option was ultimately recommended and accepted, resulting in the Niagara Falls Water Board (NFWB). In 2004 the first Executive Director initiated a competitive assessment (CA), which determined that a 27% gap existed between the NFWB and the best-run utilities of similar size. Several strategies were identified for narrowing the gap. The CA also elevated the sense of urgency of the approaching silver tsunami. The CA consultant was retained to assist with a Best Practices Program (BPP), intended to close the gap in an expedited manner. While some changes did occur, many were not long lasting. Revenue shortfalls in 2006 threatened to reopen the budget mid-year to further increase user charges. Averting this required a workforce reduction, impacting most divisions in the utility. This had a predictable impact on the effectiveness and enthusiasm for the BPP. During this same period the CBAs were renegotiated, creating two tiers of employees. Newly hired employees would receive lower starting pay, fewer holidays, and a lower level of medical coverage. The cost-saving impacts of these changes upon attracting new employees would become evident later. The retirement of the long-standing WRRF Chief Operator in 2004 presented its own problems such as disinterest among subordinates and a culture clash with hiring from the outside. The problem has been addressed by returning retirees, part-time licensed operators, and process control assistance by a consultant. Other retirees are also assisting in the areas of plant maintenance, sewer maintenance, engineering, water treatment operations, and the distribution/collection systems. These positions are termed 'temporary part-time appointment.' More formal means have been used to capture and preserve collective staff knowledge while they're still available. One is a PowerPoint orientation specifically structured for new employees. An electronic O&M manual was developed to simplify and expand staff access to many varies resources, including construction plans, procedures, 3D imaging, and manufacturer literature. Team building efforts have taken several forms. Myers-Briggs personality assessments and leadership training facilitators are examples. 50 years have provided a string of lessons in maintaining a viable and effective workforce. Many have revealed their clarity only in hindsight. Following is a distillation of the more important ones: oYour workforce is like a living creature: growing, learning, backsliding, and changing in ways not obvious. oAn employer has rights, just as the employees do. The vehicle to memorialize these rights is the CBA, which is intended to serve all. oAttrition and consolidation have their limits. As Albert Einstein observed, 'Everything should be made as simple as possible, but not simpler.' oBe proactive in capturing and documenting the valuable knowledge the staff has amassed, individually and collectively. Encourage mentoring and shadowing. oIf your collective institutional knowledge has already waned, don't neglect the huge resource your recent retirees represent. o'Consultant' is not a dirty word. They are plentiful, with varied experience and talents to help you when you don't have the in-house abilities to help yourself. oBeware the temptation to diminish the compensation package for new hires. oSenior staff should frequently remind themselves that the day will come when the utility continues operating with none of the current employees remaining.

INTRODUCTION Water is key at every step of the lithium ion battery life cycle. This paper discusses four case studies involving the use of novel reverse osmosis (RO) membrane processes and energy recovery devices (ERDs) for lithium related water reuse, zero liquid discharge (ZLD), and resource recovery applications in China. The cases include several key stages of the li-ion battery life cycle including lithium brine mining, battery manufacturing, and battery recycling and how RO and ERDs are used to add value within these applications. 1. RO Related Trends for Industrial Wastewater Zero Liquid Discharge in China China has made water conservation and environmental protection key priorities and is ramping up regulations around wastewater discharge, limiting both the concentration of contaminants and discharge volumes. Industrial wastewater treatment is a crucial, but oftentimes expensive process. ZLD is becoming a requirement in many highly polluting industries. An example in the lithium industry is battery manufacturing, which includes many facilities that have been required to implement ZLD to prevent the discharge of certain contaminants and nutrients into the environment. The first case study will discuss and present data for a lithium battery manufacturing facility in central China that implemented ultra-high pressure reverse osmosis (UHPRO) operating at 1,500 psi with new UHPRO energy recovery devices (ERDs) to reduce energy use when implementing ZLD and resource recovery. The waste streams contain primarily ammonium sulfate, a valuable fertilizer sold as a byproduct. Recovering ammonium generates sufficient revenue to cover the ZLD system operating costs and eliminates a harmful discharge into the environment. 2. RO Related Trends for Lithium Mining in China Western China has significant amounts of lithium in salt lakes and in brines located in subsurface geological deposits. Some of the salt lakes in Tibet have low concentrations of magnesium and other divalent salts that can make it more challenging and expensive to extract lithium from the brine. In these locations, evaporation ponds are used to concentrate the brines and eventually precipitate out different salts into different ponds to allow the separation of monovalent salts so that when lithium bicarbonate (Li2CO3) precipitates, it is of sufficient quality for some lithium ion battery manufacturing. However, demand is growing for high purity lithium to help make higher quality cathodes. In the Qinghai province, there is more lithium in salt lakes and subsurface geological brines than in Tibet; however, the chemistry of these brines makes lithium extraction more challenging and expensive to implement with evaporation ponds, thus direct lithium extraction (DLE) is required. Novel nanofiltration (NF) and RO membranes are becoming common as tools to improve lithium quality and/or to increase lithium production in both of these mining applications. The second case study will discuss and present data from a lithium brine mining project in Tibet China that uses osmotically assisted RO (OARO) and ERDs to generate high-purity, battery grade lithium. The purity is improved by a OARO process designed to separate key monovalent salts, while also reducing by half the time it takes to concentrate lithium bicarbonate (Li2CO3) using evaporation ponds in an environment not ideal for solar evaporation. The third case will discuss and present data for a combination of low pressure RO, seawater RO, and UHPRO membrane systems with ERDs at a direct lithium extraction (DLE) facility at a salt lake in the Qinghai region of China. The RO systems concentrate lithium chloride (LiCl) downstream of an ion exchange based DLE system and upstream of a thermal evaporator used prior to conversion from LiCl to Li2CO3. UHPRO was added during a plant expansion to reduce the cost per ton of Li2CO3 from one of the first commercial DLE projects in the world. 3. RO Related Trends for Lithium Recycling in China In Europe and North America, various startups are conducting research and development (R&D) to demonstrate and commercialize recycling of lithium ion batteries to recover lithium and other key components for reuse. In China, however, the government has put the responsibility of recycling batteries onto the makers of EV materials such as automakers and/or battery manufacturers. While RO membranes are used to concentrate lithium chloride at battery recycling facilities in the US, it is not yet common and R&D is ongoing. In China, however, the use of RO systems for battery recycling is already common and a unique process has been developed to separate and concentrate lithium, nickel and cobalt with RO membranes prior to further processing to recover battery grade material. The fourth case study will be on a lithium battery recycling facility in China that is using a unique combination of pretreatment and a single RO system with ERDs designed for a unique operating strategy to recover lithium chloride, lithium sulfate, nickel sulfate, and cobalt sulfate from recycled batteries that include manganese and other challenging constituents prior to additional refining to recover lithium, nickel and cobalt for reuse in batteries.

For many years, reverse osmosis (RO)-based advanced treatment (RBAT) using membrane filtration, RO, and UV advanced oxidation process has been an established standard for treating municipal wastewater effluent to drinking water standards for potable reuse. However, most inland water service providers and others with limitations on RO concentrate disposal will require alternative potable reuse approaches. Building upon the success of the full-scale facility in Windhoek, Namibia, nearly half a dozen years ago, the City of Altamonte Springs' pureALTA project piloted the first carbon-based advanced treatment (CBAT) train for direct potable reuse using ozonation, biological activated carbon filtration (O3/BAC), UF, granular activated carbon (GAC) adsorption, and UV disinfection. This award-winning project offered a market-changing innovative solution to inland utilities looking for sustainable approaches to water augmentation. The yearlong pilot demonstrated the use of several process control measures for optimized performance, such as ozone dose control based on influent total organic carbon (TOC) and nitrite concentration, empty bed contact time in the BAC filter for maximum TOC removal, and analysis of simultaneous removal of TOC and per- and polyfluoroalkyl substances (PFAS) in the GAC adsorber. Challenge testing using non-pathogenic surrogate organisms confirmed log removal values for Cryptosporidium, Giardia, and enterovirus at 10.6-log, 10.6-log, and 12.7-log, respectively, far exceeding the site-specific goals of 3.9-log, 4.2-log, and 11.2-log, respectively. This permanent demonstration facility has also been leveraged for public education and has hosted multiple tours for other water purveyors interested in similar solutions, and the presentation will highlight the cascading effect of the City's bold vision. Similar projects are developing across the US: The City of South Jordan in Utah, and inland utility, is currently piloting a similar treatment train for DPR downstream of membrane bioreactors (MBRs) and working with state regulators to pave the path for potable reuse in Utah. Colorado Springs Utilities' PureWater Colorado Mobile Demonstration Project, a traveling DPR demonstration system, meets stringent drinking water regulations and provided valuable data to the Colorado Department of Public Health and Environment in developing DPR rules for the State. Hampton Roads Sanitation District's SWIFT project in Virginia aims at performing managed aquifer recharge for eliminating effluent discharge to the Chesapeake Bay and mitigating saltwater intrusion, and is advancing the design and construction of full-scale CBAT for over 100 mgd of managed aquifer recharge. Clay County Utility Authority (CCUA) in Northeast Florida is exploring CBAT for indirect potable reuse with groundwater injection at Project Quench to meet future water demands in this growing part of the State, and is constructing a permanent demonstration facility. Polk County Utilities' (PCU) One Water Polk project is exploring CBAT for DPR in their northwest region which has limited groundwater supply. This project is testing the need for pre-treatment for enhanced TOC removal within a CBAT train using enhanced coagulation, and their permanent demonstration facility is currently in operation. The knowledge base generated by comparing the technical and implementation experiences of these projects can be used to inform a robust foundation for wide-spread adoption of CBAT. This presentation will offer highlights for each project, compare technical similarities and differences, and discuss lessons learned in CBAT application for potable reuse. Attendees will learn about the alternatives available to RBAT if brine management is not feasible for their service area, giving them the tools needed to evaluate the feasibility of implementing potable reuse schemes for addressing future water supply challenges.

Introduction Coastal regions globally are experiencing the growing manifestation of the effects of climate change, where the intensified frequency and severity of storm events, along with the rise of sea levels, pose escalating threats to communities, infrastructure, and ecosystems. It is in this context that nature-based solutions, often referred to as 'green infrastructure,' have emerged as sustainable and adaptive measures to counter the multifarious challenges arising from coastal vulnerability. The challenges and lessons learned from three living shoreline projects from around the country includes: Lister Park Project (LPP) on the south shore of Long Island, NY; Clover Island Shoreline Restoration Project (CISRP) at the Port of Kennewick along the Columbia River in Kennewick, WA; and Miami-Dade County (MDC) Living Shoreline Project in southeast Florida. Objectives This presentation will gain insight on lessons learned from three nature-based solutions projects in three separate geographies and environments. Seamlessly integrating flood protection, habitat restoration, and public access along the Mill River waterfront, the LPP addresses multifaceted impacts of climate change with a focus on community engagement. Simultaneously, the CISRP aims to overcome ecological challenges from historical waste concrete deposition, emphasizing biodiversity and shoreline stabilization through the creation of a strategically designed submerged bank for juvenile salmon. The MDC Living Shoreline Project initiative seeks to navigate regulatory complexities, developing a Living Shorelines Guidance Document for nature-based solutions. Status Construction of the LPP was completed in December 2023, the CISRP was completed in May 2023, Methodology The LPP integrates living shorelines-a nature-based design alternative employing a blend of green and grey solutions to combat erosion while concurrently promoting the restoration of vital ecosystems along a tidal river. This 5,500 LF living shoreline was meticulously designed to encompass a variety of riverbank conditions, serve as a buffer against both routine and extreme flooding events, thereby protecting the community and its assets. The CISRP confronts substantive ecological challenges stemming from the deposition of concrete waste along its shoreline. This has precipitated adverse effects on the habitat for federally listed species including juvenile salmon, which necessitated prompt and comprehensive restoration initiatives. The project's objective is to surmount these challenges through the systematic creation of a strategically designed submerged bank tailored to the precise requirements of juvenile salmon. Concurrently, the project addresses the stabilization of the shoreline, mitigating the effects of concrete deposition, and the establishment of riparian habitats fostering biodiversity. The MDC Living Shoreline Project involves the development of a guidance document poised to assist public and private entities in securing funding opportunities, navigating regulatory complexities, and incentivizing living shoreline creation through time and cost savings. Despite the recognized ecological benefits of living shorelines, challenges arise from perceived regulatory complexities. MDC, having undertaken multiple living shorelines projects on public lands, faces concerns over onerous regulations, prompting calls for changes in relevant acts and codes. Findings and Significance For the Lister Park Project, the design team encountered challenges necessitating adaptive solutions, such as the potential impact on existing utilities, change in conditions, and constraints of budgetary allocations precipitating iterative adaptations throughout the design and construction process. Additionally, existing conditions from when the living shoreline was surveyed to when construction began drastically changed due to the continual shoreline erosion. The CISRP stands as a testament for ecological sustainability, envisioning harmonious coexistence between industrial progress and environmental conservation on Clover Island. The MDC Living Shoreline provides a valuable resource for stakeholders involved in shoreline development and conservation within the county. These three projects emphasize the significance of adaptive strategies, tailored designs, and regulatory considerations in effectively implementing nature-based solutions to combat the multifaceted challenges of coastal vulnerability.