EAST WENATCHEE — A faulty float and alarm system is responsible for a massive sewage spill from the Douglas County Sewer District plant into the Columbia River Sunday night and Monday morning.
The sewer district estimates about 500,000 gallons of partially treated sewage was dumped into the Columbia before overflow pumps were manually turned on Monday morning, said Jim Robins, district manager. The problem was caused by a faulty pump switch and an alarm system that should have warned district employees of the problem, he said. Records show the overflow began at 6:30 p.m. Sunday and was stopped when the pump was manually turned back on a little after 7 a.m. Monday.
Robins said the sewage had gone through a preliminary cleaning and was free of most organic material and solid matter.
The plant is now back to normal operation.
The Washington Department of Ecology is working with the district to identify the cause of the spill and prevent further spills, said Joye Redfield-Wilder, an Ecology spokeswoman.
Meanwhile, more sewage spilled from a broken sewer line in Trail, British Columbia, about 10 miles north of the Washington border. That spill also flowed into the Columbia River and into Washington state. Canadian officials estimate the broken line spilled 1.15 million gallons of sewage into the river before repairs were completed at 1 p.m. Tuesday
Redfield-Wilder said either spill would be the largest on the Columbia in recent memory. About 370,000 gallons of sewage from a wastewater treatment plant spilled into the Yakima River in April 2010. A Spokane treatment plant spilled 200,000 gallons of sewage into the Spokane River in 2004. Both of those rivers flow into the Columbia.
Redfield-Wilder said the spills are probably not a serious health concern, “but it is a big deal. We don’t like raw sewage flowing in our rivers.”
The U.S. Geological Service station at the Washington-Canada border showed the Columbia flowing at 104,000 cubic feet per second or nearly 47 million gallons of water per minute Tuesday.
The Chelan-Douglas Health Department was not planning to issue a health alert regarding the spills because the sewage would have moved quickly down river and was greatly diluted by the vast volume of the river, said Barry Kling, health department administrator. An alert probably would have been made had the spill occurred during warmer weather when people would be swimming in the river, he said.
The Northeast Tri-County Health District in Colville warned citizens to stay away from the river until sewage from the British Columbia spill has finished running downriver. That alert has since been rescinded.
The state Department of Ecology will investigate the cause of the spills. A penalty is possible, but not likely if the causes were an accidental breakdown of equipment, Redfield-Wilder said.
Rick Steigmeyer: 664-7151