The Tri-City Service District (TCSD) provides wastewater treatment services at the Tri-City Water Pollution Control Plant, located in Oregon City, Oregon, to the cities of Gladstone, Oregon City and West Linn.
Daily operations are managed by Water Environment Services (WES), a department of Clackamas County. Because WES provides only wholesale wastewater treatment services to the TCSD, each partner city is responsible for its own collection and conveyance system as well as billing customers for services.
The District was formed in 1980 to carry out a sewage improvement program for the Willamette and Clackamas Rivers. The Tri-City Service District is governed by the Clackamas County Board of Commissioners. The Tri-City Advisory Committee, comprised of representatives from each city, provides feedback and direction to the governing board regarding District policies and budget decisions.
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The Tri-City Water Pollution Control Plant
The Water Pollution Control Plant was built between 1983 and 1986, replacing 21 raw sewage overflow points to the Clackamas and Willamette Rivers, to respond to a potential building moratorium and to replace obsolete treatment plants in Oregon City and West Linn.
The cost of original construction was $66 million, which included pipelines. The federal government’s Environmental Protection Agency funded approximately $36 million through a Clean Water Act Construction Grant.
In 1996, a new laboratory was constructed and jointly funded by the TCSD and Clackamas County Service District No. 1 (CCSD #1) to centralize and meet water quality testing needs for both districts. One year later, a de-chlorination system was added to comply with new permit limits on chlorine discharge. Aeration basin modifications were added in 2002 to handle waste increases coming from industrial customers in the District. Then, in 2006, an odor control project was completed to replace aging ventilation equipment and ductwork.
An expansion of the treatment plant, completed in 2011, provided much-needed capacity to the plant. The additions were built in cooperation between the Tri-City Service District and Clackamas County Service District No.1 to relieve the over-capacity Kellogg Creek Water Pollution Control Plant, ultimately protecting public health and the Willamette River. The expansion was a result of a lengthy public process to determine the most cost-effective way to increase treatment capacity while employing sustainable development practices. The plant expansion, which took three years to complete, includes a state-of-the-art membrane bioreactor treatment system that produces effluent that meets Oregon’s highest reclaimed water standards. It is the largest MBR treatment system in the Northwest to run in parallel with a conventional treatment system.