MWH and Slayden Constructors worked with the City of Spokane to achieve major upgrades to their Riverside Park Water Reclamation Facility. The upgrade included a Next Level of Treatment (NLT) - a new membrane filtration system that significantly improved the quality of effluent released into the Spokane River. The primary reason for the NLT was to decrease 99% of the phosphorus from the effluent. The new filtration system also removed more significant amounts of heavy metals, PCBs, and other pollutants associated with the facility. The advanced membrane filtration technology provides pollution reduction benefits and is designed to treat an average wastewater flow of 50MGD. The NLT upgrade is part of a major initiative to improve the health of the Spokane River.

The project included 7 GMP’s to balance early construction with design evolution and procurement of long lead equipment. Phase 1 included upgrades to the existing facility such as: SCADA upgrades, a new primary clarifier, a new chemical storage facility, modifications to 4 aeration basins, and digester gas improvements.

Phase 2 consists of the installation of a 75MGD peak flow tertiary treatment facility that comprised of: a new diversion structure, a new drum screen structure for 18’ diameter drum screens, new flocculation basins, a new membrane pump wet well and a new membrane facility.