The Process and Water Quality Specialists

Surface Water
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City of Tacoma Engineering Analysis and Technical Review

MWH/City of Tacoma

MWH Americas, Inc. (MWH) is providing design consultant services to the City of Tacoma, Department of Public Utilities, Water Division (Tacoma Water) for design and construction of a new filtration facility for the Green River supply to meet the requirements of the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). Successful implementation of this project will provide significant benefits to Tacoma Water, its Regional Water Supply System Partners (Partners) and other wholesale customers.

The Green River Filtration Facility (GRFF) will be constructed on the site of the existing Green River Headworks Facilities. It will treat water supplied from the Green River downstream of Howard Hanson Dam and from the North Fork Well Field (NFW). The initial maximum filtration capacity of the new facilities will be 150 mgd with an ultimate filtration capacity of 168 mgd. Planned capacity will be 90 mgd when operating in conventional mode (with pretreatment preceding the filters). Currently, maximum and annual average treatment flows are approximately 110 mgd and 60 mgd, respectively, but are anticipated to increase after construction of the GRFF. Trussell Tech is providing engineering analysis, oversight and technical review services as a subconsultant to MWH.