SAN MARTIN
– Olin Corp. delivered two lengthy reports covering potential
groundwater treatment and soil remediation alternatives to the
state Central Coast Regional Water Quality Control Board in San
Luis Obispo Monday, meeting a deadline company officials said they
wouldn’t meet last week.
Mike DiMarco, public information officer for the Santa Clara
County Water District, confirmed the delivery of the documents.
However, while the company presented its preference for soil
treatment, it was not able to select a method for treating water
because it did not yet have enough information.
SAN MARTIN – Olin Corp. delivered two lengthy reports covering potential groundwater treatment and soil remediation alternatives to the state Central Coast Regional Water Quality Control Board in San Luis Obispo Monday, meeting a deadline company officials said they wouldn’t meet last week.
Mike DiMarco, public information officer for the Santa Clara County Water District, confirmed the delivery of the documents.
However, while the company presented its preference for soil treatment, it was not able to select a method for treating water because it did not yet have enough information. Olin said it will present that report by June 30. Failure to meet the deadline could have resulted in penalties of up to $1,000 a day, according to John Mijares of the RWQCB.
The Olin plan does not discuss the cost of cleanup except in relative terms.
Olin Project Manager Rich McClure had said last week that he did not believe the plan could be ready by March 31 until the many methods of perchlorate removal have been evaluated.
“Once we understand the geology, the groundwater flow, where it is and which technology can work, then we can combine those things and commit to a plan,” McClure said. “It may be that a multitude of remedial technologies can be applied.”
Olin has proposed a combination of “capping” the area and on-site bioremediation to degrade the perchlorate in soil at the company’s former highway flare plant at Tennant and Railroad avenues in Morgan Hill.
The company has until the end of the year to offer a plan for alleviating the contamination of San Martin-area wells to which the perchlorate “plume” has spread, according to the water board.
The flares and related products were manufactured on the site between 1955 and 1996 when the plant closed and the buildings were razed. Perchlorate interferes with iodide absorption and is known to cause thyroid malfunctions, some cancers and other serious health problems.
Since the water district announced in mid-January that the chemical had been found in nearby wells, tests have since shown water in 304 of 850 wells surveyed to have levels above the 4 parts per billion “action level.”
The chemical has been found as far south as Leavesley Road in Gilroy, 7 miles south of the source site, and recently showed up in three Morgan Hill municipal wells north of the site. The Morgan Hill wells were closed.
The RWQCB sent a letter on March 4 to McClure informing him that, under State Water Resources Control Board Resolution No. 92-49, the company may be required to investigate, cleanup and abate the discharge of a hazardous substance either in a “progressive sequence” or “concurrently.”
The letter states that “the San Martin contamination fits the description … where the Regional Board may require concurrent investigation and cleanup actions.” The actions cover three areas:
• Soil: Olin must evaluate ways to “remove the threat of ongoing discharge of perchlorate” from the source soil down to the groundwater, and must be able to do so by fall.
• Groundwater: Olin must evaluate the number of additional treatment wells needed to abate the basin-wide contamination, if any, and to determine where they would be most effective. The company must also evaluate alternatives for re-use, disposal or treatment of the extracted groundwater.
• Basinwide groundwater: Olin must “describe alternatives for long-term, basinwide groundwater cleanup.” The company was not required to choose a particular plan at this time.
If Olin had not met Monday’s deadline, or if the water board is not satisfied with the steps the company has taken, it could be hit with significant penalties, Mijares said Thursday.
“If (a company) does not submit a report on time,” he said, “the Board can take administrative civil action up to $1,000 a day.” He said the amount would depend upon the situation and reasons for the delay.
Packard’s letter was amended in a telephone conversation on March 18.
The plan for soil
Olin’s objectives on soils include a description of current technologies effective in removing perchlorate from soils, evaluating these technologies, describing a preferred method to address the contaminated soil at the Olin site and to provide a work schedule.
The report found that the perchlorate intensity is highest nearer the surface and decreases with depth. The company had installed a “cap” and covered the area with tarps at the end of January to reduce the chance of rains leaching more chemical into the aquifer.
The site remains covered and a rig appeared at the scene this week as Olin continues to drill test wells.
The “cap”, in-situ and ex-situ ( “at” or “out of” the site) bioremediation and excavation and off-site disposal were evaluated as effective treatments.
The bioremediation process treats the soil with natural reactants acting as electron donors – usually a carbon source – combining with the perchlorate functioning as an “electron acceptor – in an anaerobic reaction (without oxygen) to degrade the perchlorate.
In-situ remediation occurs at the site by mixing amendments to the contaminated soil. With ex-situ treatment the soil is dug up, hauled away to another – approved – site for disposal. The soil is replaced with clean soil. This is not Olin’s preferred method.
The report states that both types of remediation can eliminate perchlorate in soils.
Plans were considered for cost, “implementability” and short and long-term effectiveness.
Olin recommends
The plan recommends a combination of in-situ bioremediation and a cap as the appropriate method of perchlorate control at the site. The cap will be maintained and bioremediation will tackle the soil on the site down to the water table – to a depth of 15-feet.
The company will perform a “treatability study,” expected to take five months, that will decide the most effective carbon source and the amount to be used. The cap will cover the amended soil to encourage anaerobic conditions.
The report said Olin expects that the soil treatment and cap installation will be in place by the end of March 2004, or one year from the report’s date.
Cost for the two-treatment combination will be higher, the report said, but less than off-site disposal and “equally effective.” The approach, the report said, “will provide a high level of short-term and long-term effectiveness while being implementable and feasible.
Water treatment
The Olin plan describes several widely used methods for treating perchlorate in water but was not able to choose among them because, it said, more “data, information and analyses” are needed. Methods included both in-situ and ex-situ formats. In-situ treats water in the aquifer, generally with filters or harmless (except to the perchlorate) bacteria; ex-situ treats water by pumping it out of the aquifer (or well) and treating it on the surface – known as “pump and treat”.
After the June 30 plan is filed and the preferred method identified, Olin will perform feasibility studies for groundwater remediation and will perform pilot tests to help determine a site groundwater remedy.
For more information, visit the Santa Clara Valley Water District’s Web site at www.valleywater.org or call 888-HEY-NOAH (888-439-6624).
