Gilroy – The final version of the order to Olin Corp. to clean
the perchlorate plume that stretches from Morgan Hill to the
northern border of Gilroy was released Thursday.
Gilroy – The final version of the order to Olin Corp. to clean the perchlorate plume that stretches from Morgan Hill to the northern border of Gilroy was released Thursday. It contains no significant changes to the scope and time frame of the draft order published last month by the Central Coast Regional Water Control Board.
“This is a significant milestone in the case,” Tracy Hemmeter, senior project manager with the Santa Clara Valley Water District, said. “We’re pleased that the regional board, outside of the normal order, allowed the public to see the draft, and we hope that allowing the public to comment will give us an order that is satisfactory to all parties.”
The order requires Olin to map the exact width and length of the perchlorate plume, determine to what extent the plume is expanding or shrinking, measure the concentration of perchlorate at various depths within the basin, evaluate alternate cleanup systems and propose a final cleanup plan by June 2006.
Olin, along with the Perchlorate Community Advisory Group, the Perchlorate Medical Advisory Group, the Perchlorate Working Group, the City of Morgan Hill, and retired chemist Richard Peekema, of San Jose, commented on the draft order after it was issued.
Peekema was most critical, saying that cleaning the groundwater to background levels is impractical because it’s impossible to know to what level it was polluted before Olin began operating its now closed road flare factory and that the cleanup process could bankrupt Olin.
Cleanup is already under way at the Railroad Avenue sight of the former factory, and the process by which the soil and groundwater there are being treated has been recognized by the Georgia Chapter of the American Council of Engineering Companies.
GeoSyntec Consultants, based in Atlanta and the company hired by Olin to clean the site, received the 2005 State Engineering Excellence Award last month.
“I think Olin’s decision to hire one of the leading candidates in perchlorate remediation has borne fruit,” Olin Project Manager Rick McClure said Thursday. “This was a rather innovative design and obviously the state of Georgia thought so as well.”
There are two stages to the on-site cleanup. The worst of the contaminated soil has been removed from the ground and fed with calcium magnesium acetate and gypsum to spur growth of anaerobic bacteria that eats the perchlorate.
This spring, the soil will be replaced and treated in conjunction with the groundwater, which is pumped out of the ground, treated and allowed to seep back into the subbasin. Reached in Denmark, GeoSyntec’s Evan Cox said the project should be completed in two years.
Tom Mohr, a geologist with the water district, said Thursday that the process has so far lowered the perchlorate levels at the site from thousands of parts per billion to less than 100.
“We commend Olin for hiring the best help they can get,” Mohr said. “There are a number of aspects of Olin’s work on this project that are going very well and are deserving of some acknowledgment and recognition.”