Construction of a treatment system in Burbank may be the next phase in the attempted cleanup of contaminated San Fernando Valley ground-water supplies under the federal Superfund program, water officials said Tuesday.
The U.S. Environmental Protection Agency has authorized local water officials to begin planning the treatment system, which would restore use of Burbank's polluted drinking water wells and slow the seepage of toxic contaminants toward Los Angeles and Glendale wells.
The system could be operating in about two years, said Ron McCoy, assistant chief engineer with the Los Angeles Department of Water and Power, which is coordinating the cleanup study under contract with the EPA.
Water from seven of Burbank's 10 municipal wells contains excessive levels of perchloroethylene (PCE) or trichloroethylene (TCE), industrial solvents that are suspected to cause cancer under conditions of chronic exposure. Recently, Burbank stopped pumping water from the remaining three wells to avoid drawing in polluted ground water from areas of Burbank and North Hollywood that are upgradient, or at higher elevations.
The shutdown leaves the city wholly dependent on surface water from the Metropolitan Water District. Well water is less expensive and could furnish 15% to 20% of the city supply. The shutdown also gives tainted ground water--moving generally northwest to southeast toward the Los Angeles River narrows--a quicker path to the cleaner wells of Los Angeles and Glendale, which draw 15% to 20% of their water from the ground.
Using Superfund money, the DWP is building an aeration tower in North Hollywood to cleanse part of the tainted water and slow its spread toward Burbank. The $2.5-million aeration tower, which is scheduled to begin operating in May, will remove PCE and TCE from 2,000 gallons of water per minute. The water will be pumped to the top of the tower and allowed to cascade down against an upward blast of air, which will convert the volatile chemicals to vapor.
It is uncertain whether the proposed Burbank system will involve aeration, a proven method, or one of several alternatives that will be considered in the planning study, according to McCoy. He said the cost would probably be higher than the $2.5 million needed to build the North Hollywood tower.
Whatever the choice, the system probably will be put next to the Burbank water reservoir near Victory Boulevard and Ontario Street, according to Fred Lantz, water system manager for the Burbank Public Service Department.
By the time the Burbank plant is built, it probably will be the third ground-water cleanup system in the immediate area. Along with the DWP aeration tower in North Hollywood, Lockheed Aeronautical Systems Co. is expected by September to begin treating highly contaminated ground water from beneath its Burbank plant. At a cost to the company of nearly $3 million, Lockheed is building a system that will use aeration and carbon filters to treat up to 1,000 gallons per minute of solvent-tainted water.
An investigation ordered by the state Regional Water Quality Control Board three years ago concluded that leaky storage tanks and piping at the massive Lockheed plant over the years had polluted the ground water. The plant is a short distance upgradient from several Burbank wells and was assumed to be the chief culprit after ground water from beneath the plant showed PCE levels of up to 12,000 parts per billion and TCE concentrations of up to 1,600 parts per billion. Under health guidelines, PCE and TCE in drinking water are not to exceed 4 ppb and 5 ppb, respectively.
But last fall, water from a test well upgradient of most of the Lockheed complex showed even higher PCE and TCE levels of 19,000 ppb and 3,600 ppb. This means "there's obviously substantial contamination coming upgradient of Lockheed from some other source," according to Ross Hopkins, public affairs manager for Lockheed Aeronautical Systems.
Since then, the Regional Water Quality Control Board has ordered about 20 small to mid-size companies near the upgradient Lockheed well to investigate possible soil and water contamination. And the EPA has tentatively agreed to finance the Burbank cleanup system, while serving notice on Lockheed that the company will have to pay if it is eventually found responsible.
Besides the North Hollywood aeration tower, the DWP hopes to complete a pilot plant later this year that will use concentrated ozone and hydrogen peroxide to break TCE and PCE into harmless byproducts. The 1,000- to 2,000-gallons-per-minute demonstration plant will be attached to an one of Los Angeles' North Hollywood wells, McCoy said.
Waste Disposal Avoided
According to McCoy, the ozone-peroxide process--recently studied by UCLA scientists under contract with the city and EPA--has the advantage of avoiding waste disposal headaches. With aeration, carbon filters used to trap solvent vapors must be handled as hazardous waste.
If the ozone-peroxide demonstration is successful, that method could be chosen over aeration for the Burbank treatment system, according to Lantz and McCoy.
Well fields serving Los Angeles, Burbank, Glendale and La Crescenta were designated Superfund sites in 1986--six years after TCE, PCE and lesser amounts of other chemicals were found in dozens of the wells.
Of about 120 wells in the area, roughly half have been found to contain excessive PCE or TCE, which have been widely used as dry-cleaning compounds and metal degreasers.
This has led to the shutdown of at least 25 of the most polluted wells and has required water utilities to blend moderately tainted water with clean supplies.
Since the area was designated as a recipient under the $8.5-billion Superfund program, the EPA has committed about $12 million for DWP use. About $4.4 million of that is for construction and operation of the North Hollywood aeration tower, and the rest is for a comprehensive study of ground-water pollution and cleanup methods for all the affected well fields.