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.

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.

Despite early evidence indicating that co-treating leachate with municipal wastewaters is beneficial, over the last decade more plants refusing to accept leachate for co-treatment. Leachate exhibits great temporal and spatial variations in physical and chemical properties and strength making predictions of process upsets difficult for operators. It can adversely affect water resource recovery facilities (WRRFs) biological nutrient removal (BNR) processes due to the presence of inert, nonbiodegradable chemical oxygen demand (COD) and recalcitrant dissolved organic nitrogen (rDON), which are not treated but mainly diluted increasing the difficulty of compliance with increasingly stringent discharge standards, particularly for total nitrogen (TN) limits. There is currently no framework that informs WRRF operators how much leachate they can accept without causing process upsets. Our objective was to evaluate the impacts of leachate co-treatment on a full-scale municipal wastewater treatment plan (WWTP) by comparing plant performance at varying levels of leachate contributions and hydraulic loadings. We used the K-Nearest Neighbors (KNN) machine learning algorithm to determine at which leachate volumes BNR was impacted. Leachate BOD:COD ratio was 0.08 +/- 0.07. The ratio indicated a stabilized, old matrix. Zinc, iron, aluminum, chloride, and sulfate concentrations were 0.174, 38, 1.47, 1803 and 119.1 mg/L, respectively. The average volumetric leachate ratio (VLR%) was approximately 0.01% corresponding to a daily volume of 30 meters cubed (m3) but reaching a maximum of 270 m3 (VLR% = 0.1%) and fluctuating on a daily basis. The cluster analysis revealed 5 VLR% groupings that were used for subsequent analyses: no leachate, 0 < Low ≤ 0.001, 0.001<Medium ≤ 0.02, 0.02<High ≤ 0.05, and 0.05< Very high ≤ 0.2. The completed study results showed that treated effluent concentrations of TKN, ammonia, fecal coliforms (FC), E. coli (EC), TSS and TP experienced a trend where effluent quality was improved at low and medium VLR% compared to no leachate addition, but deteriorated in high and very high VLR%. Treated effluent UVT% and EC were not statistically significantly different at varying VLR%, but FC was. Plant hydraulic had a significant impact on removal rates. Ammonia removals and nitrite concentrations improved in high flow conditions, while TP, BOD and cBOD removals deteriorated. Finally, VLR%, leachate COD, TKN ammonia, chloride and arsenic had significant relationships with plant performance. The study's findings mean that for leachate with comparable age and strength, VLR% should not exceed low to medium contributions (0 and 0.02%) during co-treatment at this WWTP.

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.

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.

Introduction Partial-Nitritation/Anammox (PN/A) processes are increasingly being selected as energy and carbon positive options in the treatment of ammonium-rich side-streams from digestate. Two-stage, sequential PN/A systems were the first to be developed and subsequently, single-stage PN/A (where PN and Anammox reactions occur simultaneously in a single reactor) processes were developed. Although the later possesses the advantage of footprint reduction, these processes have lower HRT and require a balance in aeration and loading such that DO concentrations remain high enough to drive nitritation, but low enough to avoid inhibiting Anammox metabolism, which proves to be a persistent challenge. In general, the highly sensitive nature of the anammox process requires that all plausible inhibiting factors (such as heavy metals, sulfate, etc.) are curbed within practical thresholds. A Two-stage PN/A (AMX(R)) process recently reported by Jung et al. (2019) reduces the HRT required in dedicated PN reactors and improves the system's resilience to high ammonium, COD and solids loads. This technology was therefore employed for the reject water treatment within B City's N-treatment plant in Korea, making it the first and only full-scale domestic application in Korea. This paper discusses the resilience of this AMX technology and adopted strategies in overcoming unforeseen high levels of Sulfate (SO42-) in the influent streams. High sulfate concentrations inhibit anammox and reduces nitrogen removal efficiency (E. Rikmann et al., 2016). Therefore, the exact effects of high strength sulfate on a full-scale PN/A process and the resulting steps to long-term operation to stabilize nitrogen removal efficiency in a practical, economical, and innovative way is presented in this work. Methods Fig. 1.1 shows the industrial treatment processes at B City's N-WWTP with a capacity of 184,000 m3·d-1. A combined 778 m3·d<sup?-1 of concentrated sludge and food waste sludge are introduced into the anaerobic digester. After approximately 30 days in the digester, the sludge is further dewatered into 123 m3·d-1 of sludge cake. Meanwhile, the 817 m3·d-1 of filtrate from the dewatering process, is channelled to the Two-stage AMX(R) (Fig. 1.2) process, which is tailored for treating digester effluents with elevated nitrogen levels. Highest measured sulfate levels exceeded the reported anammox threshold by 90%. Results and Discussion The operation for the full scale PN/A process was segmented into three distinct phases: seeding and SO42- control, continuous nitrogen load increase, and performance validation phase. In Table 1.1, the summarized key operating factors and performance results for each phase is tabulated. In Phase I, the unforeseen high sulfate concentration wastewater (Fig. 1.3) fed into the Two-stage AMX(R) process prevented a quick start-up and acclimation of the anammox. According to S. Zhou et al, 2022, in the absence of sulfate reducing ammonium oxidizing bacteria (sulfammox), sulfate levels exceeding 100 mg/L can instantly inhibit any species of anammox bacteria. Therefore, to prevent complete microbial activity loss and intuitively introduce additional biomass, the energy currency of all living cells, ATP was quickly monitored alongside the specific anammox activity (SAA). By measuring SAA, intermittent biomass was gradually added in a timely and economically manner to prevent further SO42- shock and activity loss. SO42- control was simultaneously carried out. Consequently, the anammox reactor HRT was extended beyond its design, while the NLR dipped far below its design value of 0.87 kgN·m-3·d-1. By phase II, as the sulfate concentration in the influent was controlled and kept below 300 mg·L-1, the nitrogen load in the Anammox reactor was gradually increased. HRT was shortened to 2.1 days (design HRT: 1.5 days). This led to an average NLR of 0.57 kgN·m-3·d-1, with a nitrogen removal efficiency of 81%. In Phase III, the NLR reached its design value of 0.87 kgN·m-3·d-1, and performance was evaluated over roughly a month. The operating HRT and average NLR during this phase stood at 1.5 days and 0.89 kgN·m-3·d-1, respectively. The nitrogen removal efficiency averaged 84.6%, surpassing the operational goal of 82%.By analyzing the data of the existing S-WWTP and K-WWTP, provided by B-City, the N-WWTP was identified to have reduced operating costs by 83%, capital expenditures by 64- 93%, and process footprint by 70-90% by applying the Two-stage AMX(R) technology, compared with conventional technologies. In monetary terms, energy costs were reduced by 60%, chemical costs by 99%, and sludge treatment costs by 49%, saving more than KRW 1.5 billion ($1.15M) per year in OPEX. Construction costs were reduced by KRW 1 billion to up to KRW 7.5 billion ($5.73M). Conclusion This paper summarized the effects of high strength sulfate on the full-scale anammox process and the resulting long-term stable nitrogen removal efficiency by simultaneously counteracting the sulfate and phasing the nitrogen loads in a pragmatic but intuitive and repeatable manner. By employing innovative techniques like direct ferric addition and microbial specific activity monitoring at specific intervals, anammox reseeding was done to prevent complete activity loss in a unique but economical fashion. The resilient AMX technology achieved the designed NLR of 0.87 kgN·m-3·d-1 and exceeded the nitrogen removal performance target of 82% reducing nitrogen loads.

Ozone is well known as an effective disinfectant and oxidant and has been operated for drinking water treatment in combination with biofiltration or biologically active carbon filtration for more than 50 years. Its versatility makes ozone/BAC a powerful tool for non-potable and potable water reuse applications. It is frequently applied as major barrier for pathogens and chemicals in carbon-based indirect potable reuse projects, especially for inland applications with limited options for sustainable management of reverse osmosis concentrates. In addition, most recent regulation for California includes ozone/BAC as an important barrier for control of chemicals in direct potable reuse (DPR) projects. In Europe, pilot- and full scale ozonation systems are currently installed in several countries with the aim to mitigate the discharge of chemicals of emerging concern (CECs) into receiving surface waters. Recent regulatory changes are expected to accelerate the implementation within the European Union: In October 2022, the European Commission published a draft of the amended Urban Wastewater Treatment Directive, which for the first time includes requirements for mitigation of organic micropollutants. In addition, EU has defined minimum requirements for agricultural water reuse that came into force on 26th June 2023 and provoked pilot studies testing ozone/BAC also for water reuse applications. This presentation will discuss experiences with ozone/BAF design and operation in Europe and the US, identify key parameters for design and process control, and outline potential concepts for future design. Ozone/BAC for water reuse in the US is designed for simultaneous removal of chemicals and pathogens, often applying ozone to TOC ratios >1 g O3/g TOC. Efficient disinfection (> 6 log inactivation) was confirmed in various spiking tests with bacteriophages at pilot scale. In contrast, ozonation of secondary effluents is designed for CEC removal and recent applications often apply ozone/TOC ratios as low as 0.3 g O3/g TOC. However, even at higher doses around 1 g O3/g TOC only limited inactivation of abundant indicator bacteria was observed in different studies, which often results in the conclusion that disinfection of wastewater by ozone is not effective. While ozone alone is effective for the removal of many contaminants, its combination with post-treatment in BAC filters is typically recommended to remove easy biodegradable oxidation by-products generated during ozonation and thereby lower effluent TOC and adverse effects in downstream processes. Besides, adsorption in BAC filters may serve as additional barrier for CECs if the carbon is regenerated on a regular basis. In our presentation, we will highlight similarities and differences in process design, control and operation in the US and in Europe, discuss potential reasons for deviating results, and outline solutions for an optimized design of ozone-BAC including effective removal of CECs and pathogens as well as the control of by-product formation. The presented results are based on own research (pilot and full-scale studies in Europe and the US) and literature studies including previous work for the WRF project 4832.

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.

Introduction As our systems and plants age and the wealth of knowledge from the current staff is slowly being lost due to retirement, it is now more critical than ever to ensure that facilities are being brought into the digital age. One of the most efficient ways for doing this is the use of 3D scanning technology. Objectives The use of 3D LiDAR scanning technology is not necessarily new technology, however the use of this data in a real time visualization over conventional 3D modeling is. In this presentation we will propose the use of 3D LiDAR in a less conventional method to allow for a more dynamic facility management plan. Leveraging speed and efficiency facilities can be more agile in their use of the technology and better distribute the prohibitive costs of generating a true Digital Twin of their facilities over multiple projects. Status One of the projects this technique has been implemented in is a water treatment facility in Baltimore MD. They have multiple upgrade projects happening on the facility at this time, so this was an ideal solution to help manage them. The initial responses are quite positive, as the engineering design team can quickly access the data and make revisions as needed to their designs without having to go back out to the field. To date we have scanned seven areas of the facility for upcoming design projects. As work is needed in each of the areas the engineering team can digitize the parts in real time without having to redeploy a survey crew or MEP team to collect additional information. Methodology Using a combination of scanning techniques, imagery, and data fusion, a facility can generate a complete as-built point cloud of their facility inside and out. Using high resolution UAS LiDAR and imagery is one of the most efficient ways to collect the exterior elements of facility grounds. Combining this with terrestrial and indoor mobile scanning for the interior or covered areas will allow for a total site point cloud. When compared to conventional survey methods the overall cost of 3D LiDAR collection is quite comparable, however you can collect more data at the same time. For a facility to start this process the first step is identifying the current need from the final model. Are they looking for a complete Digital Twin of their facility with all data being generated in a final Revit model? Or are they just looking for a model that will aid in future facility planning and upgrades. Figure 1: On the left you can see a colorized 3D point cloud model, on the right, you have a full Digital Twin Revit model extracted from the point cloud. With the combined point cloud and imagery properly aligned and adjusted to survey control points the facility can then use this data like a living model of their facility. With software like FusionMap, Ivion, or other web-based point cloud viewing platforms a facility can interact with the data in a light weight easy to use web environment. The key to this is that the data is spatially accurate due to all the dimensions being generated from the point cloud and not just the imagery. Figure 2: Above you can see the fully colorized 3D point cloud that is generated and used as the basis for all precision measurements. Figure 3: Above you can see how easy it is to check the dimensions of this pump pad to ensure that a new pump would still fit on the pad without modifications. Using the imagery for visualization allows for a easier more informed model for engineers to extract from. This data can be shared with contractors or other project engineers to allow them to have a virtual site walk of a facility at the click of a button. Allowing a design team, the ability to quickly recheck on a clearance or even confirm the diameter of a pipe is correct in the existing facility drawings without having to schedule another site visit. The data is also valuable in retrofitting and cost proposals to help reduce the unknowns. From ensuring clearances for removal of old equipment, to clash detection in Navisworks point cloud data can help to ensure the success of the project. Figure 4: Above you can see the level of detail that is captured in the 3D point could. From the individual hoses on the generators to the overhead hangar rods for the cabling racks. When there is a need to merge a new design with the existing facility, this data can be imported into AutoCAD software's such as Revit and individual features can be digitized in real time to be maintained or replaced instead of generating a complete model all at once with a large initial cost. Findings and Significance By using 3D scanning and selective modeling, a facility can be more dynamic in their project planning and facility management plan. Having a virtual plant model allows facility managers to look the whole picture when reviewing facility upgrades and modernization projects. These 3D point clouds can be continuously updated as modernization projects are completed, and the existing data can be archived for historical data analysis. With the use if a web hosted viewing software the facility can help to reduce the need for field visits as well as use the data for emergency training drills and SOP documents along with allowing new personal a way to get familiar with the facility.