LAKEPORT — A proposal from the US Environmental Protection Agency (EPA) to inject mercury mine wastewater from the Sulphur Bank Mercury Mine Superfund site cleanup will be discussed by the Lake County Board of Supervisors this Tuesday.
For several years the EPA has been investigating disposal alternatives for discharging mercury mine water as part of the Superfund site cleanup, according to a memo from Mark Dellinger, special districts administrator for Lake County. Recently, however, the EPA expressed interest in discharging the water into the effluent pipe and injecting it into The Geysers steamfield.
“We are looking at alternatives to keep the mercury out of the lake,” said Rick Sugarek, remedial project manager with the EPA in a telephone interview.
The Southeast Geysers effluent pipeline”s Joint Oversight Committee (JOC), composed of Lake County Sanitation (LACOSAN), the Northern California Power Agency (NCPA) and Calpine, shares this concern with the EPA, according to a draft letter composed by them to Sugarek.
But the JOC differs with the EPA on injecting the mercury and sulphate-laden water into The Geysers and will ask the Board of Supervisors to consider and evaluate other alternatives because the pipeline “was not intended for this type of discharge,” according to the JOC letter.
The JOC states in the letter that during the environmental impact review (EIR) process, when the pipeline was being proposed it was to be used to “transport only Clear Lake water and secondarily treated municipal wastewater,” to mitigate “groundwater contamination caused by slow leaks from the pipeline”. Such leaks will occur due to the materials used to construct the pipeline, as well as the air release valves throughout the entire pipeline, which allow the release of small amounts of pipeline fluid.
In their letter to Sugarek, the JOC suggests a potential alternative to injecting the water into The Geysers ? to inject the water into the Sulphur Bank Geothermal Area instead.
“The Sulphur Bank Geothermal area is not proven,” Sugarek said. “You have to get hot water out of it. All of the people who put wells into that site in the 1970s walked away because there is no permeability.”
Sugarek explained that the EPA intends to treat the water before it goes into the pipeline ? they just haven”t decided on the level of treatment, which varies from “less costly to exorbitant.”
First level treatment, the less costly option, would remove mercury from the water, but will not remove sulphate, a derivative of mining waste. Nor does it remove the naturally-occurring boron, which would require tertiary treatment.
“Basically,” Sugarek said, “you”d have to distill the water to get it out of there.”
If the water received tertiary treatment ? the exorbitant option ? it would make the water of a high enough quality to discharge to Clear Lake, Sugarek said.
But when the City of Lakeport recently asked the Board of Supervisors to explore the same thing ? discharging tertiary treated wastewater into Clear Lake ? Dellinger reminded the board that the current Basin Plan states that no treated wastewater can be discharged into the lake. Additionally, Dellinger noted, for such a proposal to even be considered, a full EIR would have to be prepared, with supporting analysis, and that could cost millions of dollars.
“We”re combating being a Superfund site, mercury and algae in the lake, and they want to put the county”s image at risk,” Board Chair Anthony Farrington said in April about Lakeport”s proposal.
Considering the board”s stance then, it seems unlikely board members would consider this option from the EPA.
“After talking to agencies,” Sugarek said, “they would rather us not discharge it back to Clear Lake. The only other place we could discharge it would be back to the center of the earth. But first we have to be sure it won”t adversely affect The Geysers.”
Sugarek said the EPA will, “sit down with JOC and make sure we can solve every problem ? engineer to engineer, then lawyer to lawyer.”
The item will come before the board on Tuesday, but has not been given a specific time.
The board meeting begins at 9 a.m.
Contact Terre Logsdon at tlogsdon@record-bee.com.
