This study investigated the performance of a flow-through UV-LED POE system for disinfecting municipal wastewater secondary effluent. Pilot-scale tests were conducted to determine optimal operating conditions in terms of flow rate and UV wavelength combinations. The inactivation of total coliforms, E. coli, bacteriophage MS2, and HPC bacteria was monitored to evaluate the disinfection efficacy. Results revealed that the inactivation performance was significantly affected by UV transmittance and flow rate. UV wavelength had a minor impact on disinfection performance. The study also estimated the specific energy consumption and cost implications for meeting E. coli limit in wastewater discharge permit. The findings provide valuable insights for the design and optimization of UV-LED POE systems in municipal wastewater treatment, emphasizing the importance of hydraulic residence time, UV wavelength selection, and energy efficiency considerations.

This study investigated the influence of solid retention time (SRT) and aeration on the efficiency of the high-rate contact stabilization (HiCS) process. Decreasing SRT from 3 to 1.3 days favored carbon capture, peaking its efficiency at 47%, but negatively impacted total Chemical Oxygen Demand (COD) removal. Lowering SRTs peaked protein and polysaccharide concentrations in EPS production at 176.2 mg protein/g VSS and 44.5 mg polysaccharide/g VSS respectively. Polyhydroxybutyrate (PHB) dominance in polyhydroxyalkanoates (PHAs) production was observed due to high wastewater acetate concentrations. Furthermore, extended aeration significantly affected treatment efficiencies and microbial community composition. Aquabacterium, being the most abundant species at 20.12%, could have a putative influence on the reactor's performance. These findings offer valuable insights into optimizing HiCS processes for wastewater treatment and advancing sustainable, energy-positive facilities.

Potable reuse commonly employs reverse osmosis (RO). However, RO has high energy requirements and generates a brine waste, making it better suited for coastal locations that allow for oceanic brine discharge. Carbon-based advanced treatment (CBAT) offers a more favorable option for inland regions, with lower capital costs, energy requirements, and no brine waste. This study quantified carbon emissions over a 50-year operational period for three configurations: RO with oceanic brine discharge, RO with zero-liquid discharge (ZLD) brine handling, and CBAT. Results showed that RO and pumping energy accounted for over 80% of Scope 2 emissions in RO trains, and ZLD brine treatment increased emissions by 60%. Alternatively, CBAT had 3x lower Scope 2 emissions, but Scope 3 emissions could be substantial depending on the type and replacement frequency of the granular activated carbon. By understanding carbon emissions, decision-makers can balance meeting potable reuse requirements while minimizing the carbon impact

A detailed review of sediment performance for existing and future storm tunnel operations in London was undertaken. This included considering predictions from various analytical methods and modeling, and comparison with real-world observations of sediment. From this, modeling refinement was applied to achieve improved validation, and strengths and limitations of prediction methods were identified. At the conclusion of this work, the insights gained aided in developing robust predictions of the future operation of the tunnel system, and in successfully undertaking future system level projections of sediment behavior.

Facing a number of drivers related to disinfection performance and redundancy, the Stamford Water Pollution Control Authority (SWPCA) retained Hazen and Sawyer (Hazen) to evaluate alternatives for upgrading and expanding the existing ultraviolet (UV) disinfection system at the Stamford Water Pollution Control Facility (WPCF). This technical paper will review the following: National Pollutant Discharge Elimination System (NPDES) permit limits at the Stamford WPCF; Field sampling conducted to understand bacteriological reductions required of the plant’s disinfection process; Bench-scale collimated beam testing for two indicators to inform UV disinfection design dose requirements; Design considerations to ensure compliance with bacteriological limits for fecal coliform and Enterococcus and with a continuous minimum UV dose requirement; and An approach to construction that allowed the plant to maintain continuous operation of the UV disinfection process during replacement of the existing UV system.

Applications of anaerobic biological processes and technologies have the potential to invert energy demands of municipal wastewater treatment. One of the major barriers to widespread full-scale implementation of anaerobic technologies in mainstream wastewater treatment is the need for modern design parameters to guide utilities’ decision making. Anaerobic technologies are underutilized in wastewater treatment, mistakenly perceived to exclusively treat high strength (e.g. industrial) wastewater or primary and secondary solids in municipal treatment. To contradict these misperceptions, a pilot-scale (720 L) anaerobic baffled reactor was operated by the Colorado School of Mines, continuously treating raw domestic wastewater for 7 years.

Disposal of high-salinity concentrate generated from municipal facilities and industries (e.g., energy, semiconductor facilities) can have adverse environmental impacts. To address this issue, concentrate treatment seems to be a promising option to eliminate the wastewater discharge, while recovering extra water and valuable materials such as salts. This can be achieved through concentrate minimization and zero liquid discharge strategies. This paper presents six case studies that were implemented in the industrial and municipal sectors across the country to minimize concentrate, increase water recovery, and extract valuable resources.

Utilities are increasingly frequently resorting to real-time control systems that intentionally block the flows in interceptors to take advantage of available in-line storage during storm surges events to combat sewer overflows from sewers. Many utilities are also increasingly frequently extending their pump station’s wet wells into the sewers feeding the wet well to raise net positive suction head to improve pump performance and to effectively enlarge their wet wells, improving pump performance. When hydraulic grade lines subside to normal (open channel) operating levels, the any sewage pushed outside the pipes through defects and failed joint seals/gaskets pours back into the pipe, bringing bedding fines that eventually result in pipe bedding envelope failure and pipe collapse. This paper identifies the causes, mechanisms of failure, evidence of failure caused by surcharges, inspection techniques to identify pipes at risk if surcharged, and rehabilitation methods once a pipe is thus compromised using the case study of the Howard Rossa Interceptor in Evansville, Indiana as an illustration of cause and effect.

This research studied integrated fixed film activated sludge (IFAS) technology to simultaneously remove N and P in real municipal wastewater by combining anammox biofilms with flocculent activated sludge for enhanced biological P removal (EBPR). The study was conducted in a sequencing batch reactor (SBR) operated as a conventional A2O (anaerobic-anoxic-oxic) process with an 8.8 h hydraulic retention time. After achieving steady-state operation, the reactor showed robust performance, with average removal efficiencies of 91.3±4.1% for total inorganic nitrogen (TIN) and 98.4±2.4% for phosphorus (P). Denitrifying polyphosphate accumulating organisms (DPAOs) were responsible for 15.9% of P uptake during the anoxic phase, while biofilms showed anammox activity in the aerobic step. The IFAS configuration with a low solid retention time (SRT) of 5 days prevented the washout of biofilm anammox bacteria and allowed selective washout of unwanted organisms. The results demonstrated the successful coexistence of anammox bacteria with other bacteria for efficient nutrient removal in real wastewater conditions.

To address the problem of eutrophication in the marine environment caused by excessive nutrient release and meet stringent nutrient discharge limits (e.g., TIN < 3 mg/L), a costeffective BNR (biological nutrient removal) technology is needed for equipping coastal wastewater treatment plants (WWTPs) with nutrient removal capacity. This pilot work was aimed to demonstrate how a conventional “A2O + tertiary MBBR” process can be easily modified to collectively achieve EBPR, endogenous denitrification, and Partial nitrification/ denitrification and anammox (PANDA) in one combination under novel system automation control. Nutrient discharge limits (average TIN < 3 mg/L) were met. Large amount of carbon and oxygen can be saved throughout the secondary and tertiary treatment innovation. The volume of aeration tank can be reduced.

Sludge processing plays a key role in the energy balance (i.e., energy consumption; energy generation) of a sustainable water resource recovery facility. To this end, several advanced sludge conditioning technologies are increasingly being considered to improve this balance and to facilitate offsite management of the biosolids. This paper summarizes the evaluation of two of advanced sludge processing technologies, thermal and microbial hydrolysis processes, as part of ongoing efforts to further optimize the energy profile and overall sustainability of a large WRRF required to meet stringent effluent nutrient requirements.

This paper presents a techno-economic analysis of Advanced Water Treatment (AWT) Systems for partial Reverse Osmosis (RO) treatment schemes for potable reuse applications for inland utilities. Treatment process design considerations for two scenarios of partial RO treatment schemes for potable reuse are explored and expected produced water quality was identified. Capital and operating costs for each treatment scenario are presented and compared with baseline advanced treatment alternatives using RO-based Advanced Treatment (RBAT) and Carbonbased Advanced Treatment (CBAT). This study shows a partial RO treatment train can be used cost-effectively to provide inorganics removal required for some inland communities. Treatment trains decisions can be dependent on social, environmental, technical, economic, and regulatory considerations. This study informs decision-making about potable reuse treatment trains by comparing the planning level cost estimates and technical performance of partial RO potable reuse treatment scenarios for inland communities.