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About WTD

For questions about the Wastewater Treatment Division website, please send an e-mail message or contact us at:

King Street Center
201 S. Jackson St., Suite 500
Seattle, WA 98104-3855
Phone: 206-684-1280
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Get Directions to our office location in Seattle, Washington.

Staff Contacts
Puget Sound shoreline next to the West Point Treatment Plant, Seattle

Vashon Wastewater Treatment Plant upgrade project

Completed fall 2006

To ensure safe and reliable operations of the Vashon wastewater treatment plant, the state Department of Ecology, King County and Vashon Sewer District decided the plant needed to be upgraded.

The upgraded Vashon Treatment Plant has increased capacity, added backup systems and move the marine outfall farther out in the Puget Sound. These improvements were needed to meet regulatory requirements and will protect human health and the environment.

Dedication ceremony
May 12, 2007

A dedication ceremony was held in May 2007 to celebrate the new treatment facility.
May 2, 2007, News Release --
Dedication ceremony to celebrate new Vashon Island treatment facility

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The Vashon "Experience Clean Water Project"
Read Spring 2007 project update (PDF, 1.3 MB)

Vashon Administration Building
Administration Building
(May 2007)

Vashon Treatment Plant
Vashon Treatment Plant Electrical building (left),
oxidation ditch (center)
and secondary clarifiers (right)
(May 2007)

Secondary Clarifiers
Secondary Clarifiers
(May 2007)

Oxidation Ditches
Oxidation Ditch
(May 2007)

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