Newly expanded and upgraded Shelton Wastewater Treatment Plant will improve water quality for community and shellfish

The City of Shelton celebrated its newly expanded and upgraded wastewater treatment plant on September 25 with a ribbon-cutting ceremony, attended by a number of area dignitaries, including Rep. Norm Dicks (6th District).

Most of us don’t spend much time thinking about wastewater. But when an aging treatment plant threatens the health of our aquatic environment, we all pay the price. In Shelton, the treatment plant discharges wastewater into Oakland Bay, a sensitive ecosystem and prime shellfish-producing area for U.S. and worldwide consumption.

Crews get ready to drop a new outfall extension into place for Shelton's new wastewater treatment plant. Photo: City of Shelton
Crews get ready to drop a new outfall extension into place for Shelton’s new wastewater treatment plant. Photo: City of Shelton

Discharge from the treatment plant, which was built in 1979, was nearing the maximum-allowable limit by the Washington Department of Ecology. The $37-million upgrade—a decade in the planning—improves effluent quality through state-of-the art, energy-efficient technology.

As manager of state-owned aquatic lands—which includes the submerged lands where the treatment plant discharges waste through its outfall—DNR applauds the city of Shelton for its commitment to improving water quality in Oakland Bay and supporting Puget Sound recovery.

Some key features of the Wastewater Treatment System Rehabilitation Project include:

  • Extending the outfall diffuser to promote better mixing.
  • Energy-efficient aeration, pumps, and control systems.
  • Effluent storage during slack tide, when very little mixing occurs.
  • Ultraviolet disinfection to replace the old chlorination process.
  • Finer screening and improved grit removal, which will produce Class A Biosolids that can be used as a fertilizer by local farmers, the city’s Public Works and Parks departments, and other reuses.
  • Removal of nitrogen that could promote algae growth and reduce oxygen levels.

In May 2012, the project was recognized with the Environmental Project of the Year award for projects ranging from $25 – $75 million by the Washington State Chapter of the American Public Works Association (APWA). The project was designed by Parametrix and built by Stellar J. Construction.

Read an overview of the wastewater treatment plant upgrade.

DNR: Steward of state-owned aquatic lands
DNR is steward of 2.6 million acres of aquatic lands—the bedlands under Puget Sound, the coast, including many beaches, and navigable rivers and natural lakes. These are managed on behalf of all Washington State citizens to protect fish and wildlife, and to facilitate commerce, navigation, and public access.