WSP Water Solutions

Wastewater Treatment 

Zambarano Wastewater Treatment Plant Rhode Island Department of Administration Division of Capital Asset Management and Maintenance (DCAMM) | Burrillville, Rhode Island

Clovewood MBR Wastewater Treatment Plant Design Community Planning Consultants LLC | South Blooming Grove, New York ■ Modular MBR system design ■ New York Department of Environment Conservation (NYDEC) discharge standards ■ Odor-controlled structure and community consideration WSP was selected to design on-site wastewater treatment facilities for a 600-home residential development in Orange County, New York. The system was designed to treat an average flow of 260,000 gallons per day using a modular MBR system, with capacity for future expansion via parallel units. The plant met stringent NYDEC discharge standards to a nearby stream, including total suspended solids and biochemical oxygen demand of 10 mg/l, and total phosphorus of 0.5 mg/l. The MBR technology combined activated sludge with hollow-fiber membrane filtration, eliminating the need for large clarifiers and achieving low phosphorus levels. WSP’s design addressed significant site constraints, including proximity to wetlands and residential areas, aesthetic concerns and odor control. Odor-generating processes such as screening, grit removal and sludge handling were fully enclosed with odor-control systems. The MBRs were housed in a prefabricated metal structure with integrated electrical, laboratory and disinfection systems. Additional components included an effluent pump station, force main and full structural, mechanical and electrical design.

SeaTac Industrial Wastewater Treatment Plant Port of Seattle | Seattle, Washington

■ Phased construction plan ■ Tertiary reverse osmosis ■ Contractor outreach

■ Preparation of infrastructure and system designs ■ Airport upgrades and expansion ■ Implementation of Aerated Gravel Beds

The Port of Seattle (Port) is retaining WSP to assist with upgrading the SeaTac Industrial Wastewater Treatment Plant (IWTP) at Seattle Tacoma International Airport. Our work aims to meet stricter discharge limits and support future airport expansion. The project addresses reduced allowable discharges of deicing chemicals, measured as Biochemical Oxygen Demand (BOD), as required by the Port’s Industrial Waste Discharge Permit and National Pollutant Discharge Elimination System conditions. To manage increased runoff and lower BOD mass loadings, the Port will add a high-capacity storage tank and implement Aerated Gravel Beds. This will enhance compliance and operational flexibility for changing weather conditions. Phase I of the project includes validating the Basis of Design, designing infrastructure and systems, supporting general contractor and construction management bidding, and developing operations and maintenance manuals. Future phases may include additional infrastructure and treatment capacity. WSP’s work aims to comply with environmental standards and support sustainable airport operations.

The Rhode Island Department of Administration DCAMM oversees the Zambarano State Hospital wastewater treatment plant, which was out of compliance due to elevated copper and zinc levels. Under a consent agreement with the Department of Environemtal Management, DCAMM initiated a phased upgrade to meet effluent permit limits. WSP conducted a bench scale pilot study evaluating ultrafiltration and reverse osmosis (RO) membranes, confirming their effectiveness in removing targeted contaminants. WSP then designed a prefabricated membrane bioreactor (MBR) system to replace the existing primary and secondary treatment processes. The new system integrates tertiary RO treatment to address copper, zinc, phosphates and other dissolved salts. Due to site constraints and the need to maintain continuous operations, WSP developed a detailed phasing plan, constructing the new MBR over the north aeration basin while keeping the south basin active. WSP also supported DCAMM in contractor outreach and pre-bid coordination, resulting in a successful contract award in early 2025. WSP continues to provide engineering support throughout construction.

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