MORGAN HILL
– South Valley’s perchlorate issue will be tackled again this
week when the agency in charge of minding the cleanup meets
Thursday and Friday.
MORGAN HILL – South Valley’s perchlorate issue will be tackled again this week when the agency in charge of minding the cleanup meets Thursday and Friday.
The Central Coast Regional Water Quality Control Board will gather at its headquarters in San Luis Obispo to discuss, among other things, Olin Corp’s. perchlorate contamination of South Valley groundwater. The board will hear a status report from David Athey, project manager for the Olin cleanup progress in Morgan Hill.
Athey will bring the board up to date and reply to a board question from Dec. 5 about the U.S. Environmental Protection Agency (USEPA) Region IX staff’s position on biological treatment of perchlorate contaminated groundwater. Athey’s written report said that, in the opinion of Wayne Praskins of the USEPA’s Superfund Cleanup Division, biological treatment is a good place to start.
“He (Praskins) mentioned that biological treatment of perchlorate is a proven technology, is cost effective and has been used at the Aerojet facility in Sacramento since 1998,” Athey quoted in his report.
Biological treatment is a cheaper and less work-intensive method of soil cleanup done by mixing ethanol and bacteria into the factory site’s soil.
The bacteria digests the ethanol and perchlorate to produce harmless chlorite.
“Overall, USEPA is pleased with the results that biological treatment of perchlorate provides,” Athey said.
The board will also discuss a waiver of waste discharge requirements for the Olin site on Tennant Avenue in Morgan Hill.
Olin has installed a groundwater containment system – three extraction wells – at the Tennant Avenue site. Water drawn from the wells – up to 260 gallons per minute – will be treated by ion exchange and sent to the city’s storm drain leading to the Butterfield retention pond. The purpose of the extraction, Athey’s report said, is to reduce perchlorate presence to below 4 parts per billion, the federal mandated level at which the city must notify water users of the chemical’s presence.
“On Dec. 8, 2003, the (RWQCB) executive officer enrolled Olin in the general waiver for low threat discharges to land,” the report said. “This enrollment is subject to Olin’s compliance with conditions contained in Resolution No. R3-2002-0115.”
Athey said the regional board’s staff will have a teleconference with Olin Wednesday.
“We have reviewed comments from Morgan Hill, Gilroy, the water district (Santa Clara Valley Water District) and the public,” Athey said, “and will be discussing them with Olin.”
One item on the agenda will be Olin’s study of perchlorate appearing in groundwater northeast of the original site, an occurrence that caused the city to temporarily shut down several municipal wells, install its own treatment plants and will cause a boost in water rates to pay for having to tackle the problem by itself.
Olin has not taken responsibility for any pollution north of Tennant Avenue.
Jim Ashcraft, public works director for Morgan Hill, said he was aware that the regional board and Olin would be talking next week but hadn’t yet seen the report on the northeast wells.
“We are the ones most directly affected,” Ashcraft said. “I had hoped the new staff would be more aggressive with Olin but it looks as if they are less aggressive.”
Details: www.swrcb.ca.gov/rwqcb3 or (805) 549-3147.
