CLAREMONT, Calif. -- Water agencies and private businesses have joined together to initiate a new pilot project that could soon revive a massive groundwater cleanup project in the San Gabriel Valley. The project has been stalled for more than a year because of uncertainty about how to deal with a troublesome contaminant, perchlorate.
Three Valleys Municipal Water District, the La Puente Valley County Water District, and the Baldwin Park Operable Unit Steering Committee (composed of 14 businesses) are cooperating in the pilot project, which will use a biological treatment system to remove perchlorate from groundwater.
In addition to perchlorate, the pilot project also is expected to remove nitrate, another contaminant that is sometimes found in groundwater in the basin, and will include a treatment process for a compound discovered earlier this year called N-nitrosodimethylamine (NDMA).
Neither perchlorate nor nitrate would have been removed under the treatment project as originally proposed under the Baldwin Park Operable Unit (BPOU) Consensus Plan. The plan represents the largest groundwater cleanup effort in the San Gabriel Valley and is one of the largest groundwater projects ever proposed under the U. S. Environmental Protection Agency Superfund program. The project was developed to remove volatile organic compounds from groundwater underlying Azusa, Irwindale, and Baldwin Park. But the treatment system for volatile organic compounds is not effective for removal of perchlorate. The project has been essentially placed on hold for more than a year because of the absence of a proven, effective treatment system for perchlorate.
The pilot project will be built early next year at a well in Baldwin Park owned by La Puente Valley County Water District. Once constructed, the plant will be operated for several months while authorities determine whether its output can meet state drinking water standards. None of the water will he delivered to customers until it is proven safe.
Construction, operation and evaluation of the treatment system will be at a cost exceeding $ I million, with 75 per cent coming from the Baldwin Park Steering Committee and 25 per cent from the U. S. Bureau of Reclamation through a grant obtained by Three Valleys Municipal Water District.
Perchlorate, a component in solid rocket Fuel, was detected in wells in the San Gabriel Valley in June, 1997. The BPOU Steering Committee had tested wells in the area for several years for perchlorate, which went undetected until new analytical techniques lowered detection levels from 300 parts per billion to just 4 parts per billion.
Perchlorate has previously been used as a prescribed medicine for hyperthyroidism because large doses reduce the production of the thyroid gland. Since high concentrations of perchlorate can affect the function of the thyroid gland, the California State Department of Health Services has established 18 parts per billion as its provisional action level, the untested threshold at which it may have health concerns with perchlorate in water.
Despite the difficulties with perchlorate, Three Valleys Municipal Water District, a public agency and wholesaler of water for the eastern San Gabriel, Pomona and Walnut valleys, remains committed to the cleanup project.
"We've had some big hurdles thrown at us this year, but they are challenges that all of us, working together, will overcome," said Richard W. Hansen, General Manager/Chief Engineer at Three Valleys. "We have to clean the basin. It is a valuable resource that has to be fully utilized."
Up to 90 percent of the water delivered to homes and businesses in the San Gabriel Valley is pumped from the ground.
The BPOU pilot project could have strong national implications since there is no established and effective treatment system at this time, and perchlorate is also found in other parts of the country. Hansen said other technologies for perchlorate removal are also being explored in local efforts organized by the Main San Gabriel Basin Watermaster and in projects nationally funded by the American Water Works Association Research Foundation.
"This is a national problem," Hansen said, "but Southern California is way out ahead of everybody else in finding treatment technologies. This pilot project is unique and very significant."
In the San Gabriel Valley, perchlorate was found in seven wells, including all three of those owned by La Puente Valley County Water District. Forced to shut down all of its wells, the district has been able to continue serving its 2,400 customers in La Puente and the City of Industry by buying water from other agencies, but it had to raise water rates by 60 percent to cover its added costs.
Michael Berlien, general manager of La Puente Valley County Water District, said, "The district needs to find a solution that not only removes perchlorate and other contaminants, but also is economically viable. If we can't operate our own wells with treatment systems at less cost than we are now paying for water, it doesn't make sense to do it."
Besides participating in the pilot project, the La Puente Valley district has separately issued a request for proposals inviting companies to submit other perchlorate and NDMA treatment options for the district's evaluation.
A much smaller version of the perchlorate treatment system has already been tested successfully by Aerojet-General Corp. at Rancho Cordova, near Sacramento. Aerojet is one of 13 participants in the Baldwin Park Steering Committee, which was formed by companies that have been alleged by the U. S. Environmental Protection Agency to be potentially responsible for cleaning up groundwater contamination in the BPOU Superfund area.
Hansen, at Three Valleys Municipal Water District, said that two principal approaches are initially viewed as having the best potential for perchlorate treatment -- biological reduction and ion exchange -- and each system has advantages and disadvantages.
The biological system destroys perchlorate in a process using microorganisms. The ion exchange process traps and removes perchlorate. Hansen said the disadvantage of ion exchange is that it concentrates the perchlorate in a waste stream that must ultimately be eliminated. The biological process eliminates the waste disposal problem, but it must be proven that the interaction does not introduce any other contaminant into the water, he explained.
The Department of Health Services will closely monitor the pilot project to determine whether the treatment produces water that meets all state drinking water standards. The pilot project includes disinfection and a filtration system as part of the process. Meeting drinking water standards is necessary because the cleanup plan for the Baldwin Park Operable Unit is economically viable only if the water produced can be sold to customers.
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