Liquids from incoming wastewater are separated from solids at the plant. After extensive treatment the liquids are discharged to Puget Sound in accordance with strict standards specified in the the county's National Pollutant Discharge Elimination System (NPDES) permit.
Disposal of solids
Nutrient-rich solid byproducts, known as biosolids, are refined into a dry pellet and sold as SoundGRO fertilizer to local and commercial customers. SoundGRO meets Environmental Protection Agency Class A “Exceptional Quality” biosolids standards. Some solids, including grease, are disposed of at a sanitary landfill.
WWTP Service Area
The Sewer Division has two types of service areas: urban and rural.
The Urban Service Area is the Sewer Division’s primary service area consisting of a 117-square mile sewer service basin. This basin is made up of 20 individual sub-basins corresponding with previous urban growth around the City of Tacoma, including the cities of DuPont, Fife, Lakewood, Milton, Puyallup and in and around the Town of Steilacoom. The service area also includes unincorporated areas of the County including Frederickson, Parkland, Spanaway, South Hill, Graham, Browns Point, Dash Point, Fife Heights, the planned community of Tehaleh (Cascadia), and a small area in the City of Edgewood. Covering 36 percent of urban Pierce County, this is the bulk of Pierce County’s urban sewer service area.
The Rural Service Area was established before the adoption of the State Growth Management Act in 1994 and the Pierce County Comprehensive Plan in 1995. These areas were once under the designation of predominately General (G) or Suburban Residential (SR) and other less restrictive zoning designations that at that time allowed sewer connection. Once the Pierce County Comprehensive Plan was adopted in 1995 the Rural Service Area was and has remained restricted to parcels already served, and parcels and projects having vested connection rights.
The Tacoma-Pierce County Health Department has the authority to require parcels in the rural zones and rural service area to connect to the public sewer system in the case of public health and welfare or environmental concerns.
New connections, not vested through past land use decisions or Tacoma-Pierce County Health Department connection requirements are prohibited in any rural area.