Mercury emissions too high during incinerator test
Plant turns off one control system for annual monitoring
Spokane’s Waste-to-Energy Plant violated air pollution law during annual air testing in June.
April Westby, an environmental engineer for the Spokane Regional Clean Air Agency, said the agency’s director, Bill Dameworth, will issue the city a notice of violation as a result of tests that showed that one of the plant’s two boilers exceeded standards for mercury.
The notice marks the first time the plant has violated the mercury standard since it was set in the late 1990s by the Environmental Protection Agency, Westby said.
If the violation is sustained, the plant could be required to continuously run a carbon pollution control system that it turns off during annual testing to prove that it can meet standards without it. A fine also is possible.
Because the plant in previous years met mercury limits without the carbon system, use of it was voluntary – though city officials say it is always in operation.
The city will have 30 days to respond to the notice, but it already is disputing the violation.
Even so, Russ Menke, director of the Spokane Regional Solid Waste System, said the plant likely would accept a requirement to always run the carbon system.
“We wanted to maintain the flexibility – if the carbon system jammed – that we didn’t have to shut down the plant,” Menke said. “Whether it’s in our permit or not, we’re going to run it.”
Also as a result of the test, the city likely will install additional monitoring equipment to ensure the carbon system is running correctly, Menke said.
Once a year, three measurements are taken and averaged to determine if the plant meets the rules. In the mercury test, one of the three readings was more than twice the limit. The other two were within the standard, but the average was above the EPA requirement.
In an earlier test, with the carbon system running, mercury readings were well below the EPA standard.
Menke said random errors easily could account for the variation. He also said that the plant repeated the test in July without the carbon system operating and that the boiler did not exceed EPA regulations.
Westby, however, said the possibility of error was “already accounted for when the EPA sets the limits.” Just because the plant met standards in July doesn’t mean the plant is off the hook for the June test, she said.
It’s unclear what caused the spike.
“You have to think that there was something that was going through the system that was high in mercury,” Westby said. “This is just a snapshot.”
The plant is part of the Spokane Regional Solid Waste System and is owned by the city of Spokane. Wheelabrator Technologies, a subsidiary of Waste Management Inc., contracts with the city to operate it.
Spokane County Commissioner Bonnie Mager, a longtime critic of trash incineration, said she hopes the notice will force the plant to always operate the carbon pollution control system.
“There’s no safe level of mercury,” said Mager, a member of the Spokane County Solid Waste Advisory Committee.
The plant’s last notice of violation occurred in 2006 as a result of flawed testing.