Douglas County Public Works plans to resume sending leachate from the Douglas County Landfill to the Winston-Green Sanitary Treatment Plant by the end of this week or beginning of next, Public Works Director Scott Adams said Thursday.
The treatment plant had stopped accepting the leachate on April 26, after a highly potent batch nearly wiped out the good bacteria, or “bugs,” Winston-Green uses to treat its wastewater.
The leachate had unusually high levels of ammonia and a substance called biochemical oxygen demand, or BOD. The county attributed the problem to new well drilling by Woodland, Washington-based Stellar J sister company Roseburg Energy, which collects methane at the landfill for electricity production.
After the incident, the county began shipping its leachate, first to a facility in Eastern Oregon and then to PPV in Portland.
Adams said the ammonia and BOD concentrations are coming down as additional leachate pumping out of the landfill dilutes the problem substances.
The county pumps its leachate into a 350,000-gallon holding tank at the landfill. It then puts the leachate onto trucks. Prior to the April incident, the county then pumped that leachate into a manhole which led to the Winston-Green plant.
Now the county is installing two large tanks, called Baker tanks, at the Winston-Green plant. Instead of pumping into a manhole, the county will put the leachate into those tanks so that workers there can meter the flow into their system.
The Baker tanks are 12 feet tall, 50 feet long and 8 feet wide. Each will hold about 21,000 gallons of leachate. The county purchased the tanks used and filled them up with water earlier this week to test for leaks, Adams said.
A long-range fix for handling the leachate is in the design stage. It would involve the creation of a county-owned leachate treatment plant and possible piping so the county would have more control over the condition of the leachate before it’s sent to Winston-Green. Adams said he hopes the design and construction for that project will be completed by the end of 2020.
Adams said in the short run, the county has put additional safeguards in place, including an ammonia metering system. Already the leachate’s ammonia levels are low enough they wouldn’t pose a threat to Winston-Green’s “bugs,” but the county also intends to ensure the levels are low enough that they don’t cause Winston-Green any problems meeting state regulatory requirements.
The leachate emergency hauling and treatment cost the county more than $400,000 and was not budgeted. Adams said the solid waste department will have to squeeze its program to stay within budget.
“I feel good that it’s almost done,” Adams said of the short-term fix. “But it’s a kick in a gut what happened. To have something like that happen and take a $400,000 hit on a budget that can’t handle a $400,000 hit, that’s a tough one.”
The Baker tanks cost the county about $50,000 but had already been part of the county's budget.
Adams said the county and Winston-Green are working on a new intergovernmental agreement, and he’s glad the partnership continues. He said the county is committed to rebuilding trust.
“We want to make sure they’re happy with what we’re doing,” he said.