A major source of pharmaceuticals in the environment is the discharge of wastewater contaminated with active pharmaceutical ingredients (API) at manufacturing facilities. API wastewaters are often segregated and trucked offsite for disposal. Electrochemical oxidation (EOx) allows onsite treatment of pharmaceutical wastewaters including stable fluorinated APIs without generating secondary waste streams, eliminating the need for offsite disposal. The EOx process can break extremely stable bonds and is ideally suited for API removal. Fundamentals of electrochemical oxidation, catalyst selection, and typical operating conditions are reviewed. EOx systems are typically operated as batch reactors with first order kinetics dominating API removal rate, and complementary processes can improve performance. Process trains integrating EOx with concentration/separation technologies are illustrated. A case study and operating data are presented of an API removal system currently operating at a Fortune 500 pharmaceutical manufacturer utilizing an integrated ultrafiltration, reverse osmosis, and EOx treatment train.

This paper presents the integrated approach by the City of Austin to address odor concerns in the Greater Walnut Creek Area and its sewershed. The project focused on the identification of the odor sources and their potential impact on the community using dispersion modeling. The project also used sewer process models to comprehend the entire collection system to determine H2S hot spots and to screen sulfide control strategies considering plant impacts. Results showed that the baseline scenario for the Walnut Creek WWTP exceeded the odor threshold set forth. The City is going through an expansion of the Walnut Creek WWTP that incorporates these findings into the design of odor control facilities to mitigate outside impacts. The resulting optimized strategy for the collection system relies on the use of pH adjusters; the WWTP currently uses it in its process thus representing ‘free’ chemical by dosing it upstream for odor control.

Renewable Water Resources (ReWa) in Greenville, SC, initiated a dewatering evaluation in 2021 to explore alternatives for dewatering anaerobically digested biosolids from three of their Water Resource Recovery Facilities, Mauldin Road, Pelham and Lower Reedy. The objective of this project was to provide engineering services for evaluation of the remaining useful life or replacement of existing belt filter press (BFP) sludge dewatering equipment with new BFP, centrifuge, or screw press dewatering equipment. Bench Scale testing was conducted considering several technologies and onsite pilot testing of a centrifuge was conducted and compared to the existing BFP. A unique part of the study included comparing the fecal coliform regrowth and odor potential from both the centrifuge cake and BFP biosolids. All facilities showed fecal coliform regrowth and increased total volatile organic sulfur compounds with centrifuge dewatering, as expected, but one facility also showed regrowth with belt filter press dewatering.

DC Water’s Potomac Interceptor system has suffered from corrosion for many years. According to recent CCTV inspection, approximately 95% of the Potomac Interceptor has shown signs of corrosion. Inputting field data to sewer process models that integrate ventilation resulted in recommendations focusing on the operation of existing forced ventilation odor control systems to support reduction in corrosion. These recommendations have been adopted in the PI operation protocol. In addition, DC Water developed a long-term corrosion prevention program implementing various corrosion mitigation measures identified in the case study.

Ammonia is known to be acutely toxic to fish and other aquatic organisms at low concentrations. In effort to predict regulatory non-compliance due to ammonia discharged from two of Metro Vancouver’s wastewater treatment plants, regression models were developed to project final effluent ammonia concentrations at each facility over a 25-year period. These ammonia projections were compared with regulatory requirements, and the risk of non-compliance was quantified over the period under various operational scenarios, such as increased centrifuge operation and per capita flow reduction. The risk assessment concluded that some degree of noncompliance was observed in most scenarios evaluated; to target full compliance with the regulations it is estimated that a 13% reduction in effluent ammonia at LIWWTP and a 22% reduction at AIWWTP under baseline conditions is required. At both facilities, implementing side stream ammonia removal on the dewatering centrate stream would increase compliance to 100% at baseline conditions.

Pima County's unique landscape includes climate temperatures ranging from the low 60's in winter months to the 100's during the spring and summer. Vast coverage areas include urban and suburban populations with numerous mountain ranges resulting in large elevation swings. Due to the warm temperatures, nature of the landscape and the extensive network of sewer lines, Pima County experienced high hydrogen sulfide (H2S) gas levels throughout their collection system. This paper will outline how Pima County leveraged real-time H2S sewer monitoring technology to address odor and corrosion more efficiently in their system. This technology provided actionable real-time information allowing Pima County to optimize chemicals while minimizing gaseous H2S levels at critical locations.

The impacts of climate change are expected to disproportionately affect vulnerable communities and pose an increasing threat to urban infrastructure. It is essential that the City of Los Angeles plan and build climate-resilient, multi-benefit street projects that integrate “grey” (streets/sidewalks), “green” (landscaping/biodiversity), and “blue” (stormwater/water quality) infrastructure strategies to respond to climate change impacts and build resilient infrastructure and communities. StreetsLA is charged with the design, construction, and maintenance of street infrastructure within the public right-of-way to make safe and complete streets for the community. By considering the grey, green, and blue infrastructure as “One Infrastructure,” StreetsLA is engaging in early planning with partner agencies to create streets that are safe, sustainable, and equitable, and prioritize the needs and character of each community.

The coastline of southeastern Massachusetts is comprised of multiple estuarine systems. Nutrient enrichment, primarily associated with population growth and watershed land use changes, has exceeded these watersheds’ nitrogen assimilative capacities resulting in severe water quality degradation. Eutrophication is affecting environmental health, property values, and recreational opportunities. As communities evaluate options for nitrogen Total Maximum Daily Load (TMDL) compliance, they must also navigate issues related to returning treated effluent nitrogen load to impaired watersheds, groundwater mounding impacts on surface water systems, phosphorus load impacts to freshwater systems, and contaminants of emerging concern issues to public water supplies.

Restoration of migratory fish populations to maintain a sustainable fishery often is a function of the effectiveness of fish passage systems at manmade river obstructions. This paper presents a novel design of a fish passage structure for low head dams where conventional type fishways are undesirable or impractical. The hydraulic physical modeling yielded a unique design of a notch in the dam crest combined with three labyrinth (W-shaped) weirs. The notch provides adequate water depth, and the weirs dissipate the flow energy to provide fish with low velocities for passage. For American shad (Alosa sapidissima), the water depth is adequate at minimum river flows, and water velocities are less than the fish burst speeds. The structure complies with the maximum allowable withdrawal at no flow condition over the dam. Weirs provide side openings and center attraction flow. This design is suitable for other low head dams with similar characteristics.

The Milwaukee Metropolitan Sewerage District (MMSD) owns and maintains the Metropolitan Interceptor System (MIS). The MIS is comprised of over 400 miles of interceptor ranging in diameter between 8-inch to 150-inch. MMSD implements an asset management program to assess pipes and manholes. MMSD must identify cost-effective approaches for sewers that cannot be assessed using conventional closed-circuit television (CCTV) equipment. MMSD evaluates the cost and benefit of using different technologies to support data-driven decision making. This paper presents MMSD’s approach to deploying technologies to assess interceptor assets, including lessons learned when using technologies for three challenging applications. The first application is using multiple sensor inspection (MSI) tools to assess a deep interceptor. The second is using sonar and a focused electrode leak location (FELL) sensor to assess difficult access siphons. The third is to deploy divers into the Kinnickinnic River to conduct tactile assessment of outfall pipes.

The City of Alexandria (the City) has experienced repeated and increasingly frequent flooding. The City initiated a study to update stormwater management modeling and evaluate alternatives to mitigate flooding in the entire Four Mile Run (FMR) East watershed within the City. The effort consisted of a pilot area optimization, the results of which were progressed to preliminary design, as well as the wider Four Mile Run East service area analysis used to update the City of Alexandria’s stormwater masterplan. The findings of the study resulted in the City of Alexandria selecting a flood mitigation strategy that addresses the projected 2070 climate scenario. Described are the results of the climate resilience study, including the alternative analysis optimization, and lessons learned from the pilot that were applied to the wider FMR watershed and are applicable to other planning/optimization projects.

Across the United States as well as globally, larger regional projects with multi-disciplinary naturebased components are gaining acceptance and popularity in lieu of traditional project by project stormwater management or as a compliment to green infrastructure programs. Rather than focus on one aspect of water, such as just flood hazard mitigation, these types of projects can incorporate benefits across a wide spectrum of improving habitat, water quality, eco-tourism, recreation, carbon sequestration water supply and recharge and climate change resiliency. In this paper, regional projects in Tampa Bay that focus on water quality and seagrass improvement in lieu of traditional stormwater approaches will be highlighted. Specifically, Atkins and FDOT established a new tidal connection through the SR 60/Courtney Campbell Causeway to improve water quality north of the causeway and significantly improved water quality and ecological conditions that are conducive to seagrass recovery.