Olin Corp. announced Monday that it will install two groundwater
treatment systems to remove perchlorate from water supply system
wells in the west San Martin area.
Olin Corp. announced Monday that it will install two groundwater treatment systems to remove perchlorate from water supply system wells in the west San Martin area.
The ion exchange groundwater treatment systems, at a cost of approximately $500,000, will be installed during August at the West San Martin Water Works, which serves approximately 250 homes and several county office buildings in the area.
“This news is wonderful,” said Sylvia Hamilton, president of the San Martin Neighborhood Alliance and chair of the Citizens Advisory Committee on perchlorate, a group formed as a liaison between water officials and the public. “At least the community can see that there’s some movement. This should ease people’s minds, knowing that something’s happening.”
The treatment systems are the first to be installed by Olin for removal of perchlorate from groundwater. Similar ion exchange systems have been approved by the California Department of Health Services (DHS) for use in potable water systems in other locations.
“The treatment systems we are installing in the west San Martin area will remove perchlorate from these wells to below non-detect levels,” said Rick McClure, Olin project manager for the local site. “This significant event is part of Olin’s continuing effort to resolve perchlorate issues in a positive and proactive way. We are very pleased that this agreement was reached with the West San Martin Water Works and we look forward to continuing this spirit of cooperation in the future.”
The San Martin treatment plants should be similar to ones being installed by the City of Morgan Hill on two of its wells, also closed because of the contamination.
“The biggest boost to the city’s water system occurred on Saturday,” said Jim Ashcraft, city public works director. “The Nordstrom perchlorate treatment plant went on line shortly after noon on Saturday.”
Because the well is north of the source site, and because Olin has not taken responsibility for contamination in that area, the city itself paid for the plant, estimated to be between $200,000 and $300,000, plus installation, maintenance and operating expenses.
The existing Nordstrom well pumps 1,040 gallons per minute into the city system. Since it is one of the highest wells, and since it has tested non-detect – below 4 ppb – for several months, it has been turned on recently during periods of high water use when reserves are low.
A second treatment plant is planned for the Tennant well.
“We just completed an initial round of testing,” Ashcraft said. The tests looked for a particular spot within the well where contamination was higher and could be treated more intensely – a “zone of extraction.”
Ashcraft said he expected the final results back by the end of the week and that the plant would be on line within two or three more weeks.
“U.S. Filters (the manufacturer of the ion exchange plant) only needs 24-hour notice,” he said. The Tennant well will produce less than its 400 gpm full capacity because they intend to zero in on the concentrated area.
Negotiations between the city and Olin Corp. over the Tennant treatment have not been resolved; the water district has loaned the city the funds.
The West San Martin Water Works, Inc. wells produce about 600 gallons per minute. Olin began supplying bottled water to West San Martin customers as a precautionary measure in February when two of the system’s wells exceeded the four parts per billion DHS action level for perchlorate. Though DHS only requires that water providers notify customers that the water tests at or above action levels; it does not require that the wells be shut down. However, most water providers, including the City of Morgan Hill, have done just that.
Mark Lucca, senior project manager for the SCVWD’s imported water unit, said he could not make any comments since he had only just learned of the announcement.
Olin also recently completed the characterization of on-site soil and groundwater conditions at its former Morgan Hill plant site on Tennant and Railroad avenues.
The company plans to begin cleaning up the soil in the fall and also will begin pump tests at the same time as a necessary step to treating on-site groundwater.
Olin continues to investigate the nature and extent of perchlorate in the San Martin area. Under the direction of and orders from the state Regional Water Quality Control Board (RWQCB), the company has proposed an expanded monitoring program that will provide further information regarding the presence and seasonal effects of perchlorate in the local aquifers in the direction of groundwater flow. The monitoring well network includes over 350 wells southeast of the property, an eight-and-a-half mile strip that stretches into north Gilroy.
Since perchlorate was discovered to have leached into the groundwater system from the Tennant Avenue plant that manufactured highway safety flares for 40 years, Olin has expedited a many-phased environmental investigation that include testing of on-site soil and groundwater conditions as well as off-site private water supply wells.
Olin has worked cooperatively with the RWQCB and the Santa Clara Valley Water District to identify affected wells and provided bottled water, along with the water district, to users of affected wells.
ION EXCHANGE METHOD
The ion exchange method is one way of treating water contaminated with perchlorate and other chemical. It draws water into cells containing adsorbent material. Resins are common for this use but silica gels, activated carbon and molecular sieves are also used, according to the Calgon Carbon Corp., a manufacturer of the systems. The perchlorate ions attach themselves to resin units and add chloride molecules; the altered chemical configuration renders the perchlorate harmless.
However, in the past, along with treated water, the process produced a brine solution which must be disposed of. This was dumped, in the ocean or elsewhere or burned. Dumping will become illegal in California by 2006. Ion exchange is frequently used to treat water in Southern California which has a serious perchlorate problem because of the numerous defense facilities.
The San Martin Perchlorate Community Advisory Group has changed its meeting times to 7-9 p.m. the fourth Thursday of every month. The group meets at the San Martin Lions Club, 12415 Murphy Ave., behind the airport. Details: 683-2667.
