Water quality regulators are threatening to fine Sonoma County $10,000 per day if it doesn't figure out a way to eliminate runoff from the composting operations at the county's central landfill site west of Cotati.
The 25-acre compost facility run by the Sonoma County Waste Management Agency has been under orders since last year to prevent runoff from reaching nearby creeks.
In a March 18 letter, the North Coast Water Quality Control Board officials said they were "concerned by the lack of progress" in resolving the problem before next winter's rainy season.
Regulators ordered the facility to cease all discharges of wastewater from composting operations by Oct. 1 or face fines of up to $10,000 per day and $10 per gallon over 1,000 gallons.
The waste agency has had a license to operate the composting facility at the county-owned landfill for the past 20 years. But it is the county that is ultimately responsible for ensuring all operations at the landfill comply with environmental regulations.
"We're taking this letter extremely seriously," said Susan Klassen, the county's transportation and public works director.
The waste agency, the county and its landfill operator, Republic Services, have been in discussions about how to comply with the wastewater restriction on compost, which was added to the landfill's new permit for the first time in March last year, Klassen said.
The water board considers runoff from compost to be different and potentially more harmful to aquatic environments than the storm water allowed to run off the landfill site, said David Leland, assistant executive officer for the water board.
When rain hits the long rows of compost it soaks into the piles and picks up nutrients and organic matter which, after mixing with landfill storm water, during heavy rains can be carried into nearby Stemple Creek, he said. That drains into San Antonio Estero and empties in the Pacific north of Dillon Beach.
Klassen said the inclusion of additional restrictions on the runoff was a surprise, but Leland said they shouldn't have been.