August 26, 2009

Seattle pledges more pollution control to help Puget Sound

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The city of Seattle and King County will step up efforts to prevent raw sewage from flowing into Puget Sound and its tributaries, the U.S. Environmental Protection Agency announced today.

But the steps are small compared to those called for by environmentalists who want to see Puget Sound and the Duwamish River cleaned up. The current schedule gives Seattle until 2020 and King County until 2030 to almost completely end pollution from so-called “combined sewer overflows.” (PDF)

These sometimes-smelly oopsies result from a piping system that mixes untreated sewage with rainwater runoff. Most of the time it’s a good system because the rainwater — aka stormwater, the largest remaining water pollution source in the country — goes to a wastewater treatment plant.

But when a lot of rain hits overloaded systems like the one King County and Seattle operate, the whole mess comes shooting out into waterways. Sometimes the stuff backs up into streets or even basements.

Major pollution discharges into the Duwamish River are scheduled to continue for decades, despite today’s order and despite what’s supposed to be a  major EPA effort to clean up the Duwamish.

Such discharges happened 336 times in the Seattle-King County system in 2007, the most recent figures available.

A surprising number of these overflows happen during relatively dry periods after little or no rain. Twenty such incidents occurred between December 2004 and November 2007, ranging from a low of 60 gallons to a high of 125,000 gallons.

Under the compliance agreement announced today, Seattle will be taking a number of steps, including doing more systematic maintenance of the system and making adjustments to allow the system to hold additional water before letting it overflow.

King County agreed to more thoroughly monitor the discharges that do occur, and to improve performance of its Elliott West wastewater facility. Built as part of a $140 million upgrade of the sewage system, the facility has at times failed to meet treatment goals. 

Environmentalists have called for faster cleanup of all the sewage overflows to help support the Puget Sound restoration efforts being undertaken by the state and federal governments and other entities.

Rob Grandinetti, an EPA engineer, said even the overriding 2020 and 2030 dates for ending the overflows aren’t technically mandated yet — just scheduled. As for the steps ordered today, he said:

These are more short-term issues.

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