SOUTH GATE — The city has joined the state Department of Health Services in an experimental project to cleanse well water contaminated by chemicals that have forced the closure of five city wells.
A demonstration of the treatment process was held Tuesday at municipal well No. 18, which was closed in January, 1986. Tests had shown that tetrachloroethylene (also known as perchloroethylene or PCE) exceeded the state health services's recommended "action level." The state calls for action--closure or cleaning of the water--if the chemical's level reaches four parts per billion. Levels in No. 18 exceeded 7 parts per billion.
The treatment process combines ultraviolet light and ozone gases to oxidize or break down the toxic molecules into nontoxic materials--mostly carbon dioxide, clean water and salt. The process has been shown to destroy other toxic chemicals and pesticides, according to representatives of Ultrox International, the Santa Ana company that manufactures the water treatment system.
The Legislature has appropriated funds the past two years for pilot projects seeking solutions to hazardous waste problems. There are 17 projects being funded statewide through the program. The South Gate project is the only one in Southeast Los Angeles County.
Water From Common Source
Under a state law that went into effect in 1985, cities and other water utilities are required to test periodically for dozens of organic chemicals commonly used in industry. South Gate and other area cities draw their water from the Central Basin, a huge underground body of water.
Downey, Santa Fe Springs, Bell Gardens and Bellflower have also closed some wells during the past two years after testing chemical contamination. The contamination in all of these wells is believed to have come from industrial solvents, but officials say the chemicals have not been linked to specific sources.
"It is extremely difficult to pinpoint. The contamination may have been in the ground water for 10 years. It is moving, it is hard to backtrack and document where it might have come from," said Frank Mele, associate water management engineer for the Department of Health Services. The South Gate wells, which were closed over a period of 13 months beginning in November, 1985, had levels as high as 14 parts per billion. "The chemicals in the water at this level pose a very low health risk. In an emergency you could drink this water, " Mele said.
"The ideal situation would be to have zero contaminants in the water. So the state sets the action level at four parts per billion and says something must be done at that point," said Mele, who is with the state Department of Health Services Toxic Substances Control Division Alternate Technology section.
The division administers the pilot projects with money provided through the state Hazardous Waste Reduction, Recycling and Treatment Research and Demonstration Act of 1985.
More than $2 million has been appropriated statewide through the program, which provides grants to universities, governmental agencies and private organizations for research, development and treatment technologies.
David B. Fletcher, president of Ultrox International, said the South Gate test will run through the end of the year. A report will be ready for the city and state by March.
South Gate is the first city to try this method of removing chemical contamination in a municipal well, according to Alex Cunningham, chief deputy director, Department of Health Services.
Ultrox has received more than $130,000 in state funds to demonstrate the ultraviolet process in a series of tests, according to Fletcher. The city of South Gate was not required to put in money in the project.
In addition to the ultraviolet process, South Gate is considering other methods to restore the five wells that supplied half of the city's water. The city asked residents to voluntarily curtail their use of water during peak usage last summer.
"The program worked quite successfully and we were also lucky that there were no long heat waves," said Rollie D. Berry, director of public works for South Gate.
To augment its wells, the city purchases well water from the Metropolitan Water District--at about twice the cost of pumping its own well water. The city has bought about 16% of its water from Metropolitan this fiscal year, which began in July, Berry said. It has cost the city $280,000 so far this year.