The Los Angeles Department of Water and Power drew praise at a public hearing Tuesday night for its decision to reduce air pollution from the aeration tower that it plans to build in North Hollywood to remove chemical contaminants from water wells in the San Fernando Valley.
But the agency was also urged by some political figures and environmental groups to conduct a full review of environmental impacts and alternative treatment methods before proceeding with the $2.5-million project on city property at 11845 Vose St.
Several speakers at the hearing at DWP headquarters in downtown Los Angeles thanked water officials for agreeing last month to install carbon filters on the tower to prevent solvent vapors from being emitted into the air.
Frank Hughes, a resident of a senior citizens home a quarter of a mile from the proposed site, said he had "been opposed vehemently to the construction of this tower."
The inclusion of filters to trap solvent vapors "could be a compromise that we all could live with," Hughes said.
But aides to City Councilmen Joel Wachs and Ernani Bernardi, who represents the district where the tower would be built, called on the DWP to conduct a full environmental impact review of the project and alternative ways to treat valley ground water, which provides 15% of the Los Angeles water supply. The ground water is contaminated by trace quantities of chemical solvents--particularly the degreasing compounds trichloroethylene and perchloroethylene, both suspected cancer-causing agents.
DWP officials, arguing that the problem should be dealt with immediately, said an environmental impact review would take at least a year and would alter their plans to have the tower in operation by the end of 1987.
Under state law, the Board of Water and Power Commissioners, the policy-making board that oversees the DWP, can order a full environmental impact review or can approve a "negative declaration"--basically a statement that the project can proceed because there are no significant environmental issues to be studied.
Commissioners are scheduled to decide June 26 whether to approve a "negative declaration," as DWP staff recommended.
Despite the agreement to put filters on the tower, which added $170,000 to the estimated construction cost, critics have called for a thorough study of the project's safety and effectiveness contrasted with other treatment methods, such as direct carbon filtering of ground water.
An aeration, or air-stripping, tower is used to cleanse chemicals from water by accelerating the natural process of evaporation. The polluted water is pumped to the top of the tower and blasted with air, which causes most of the solvents to leave the water in vapor form.
The 48-foot metal tower would treat 2,000 gallons of water a minute, or about 1 billion gallons annually, the DWP says.
DWP officials at first opposed inclusion of air-emission controls, arguing that the unfiltered emissions would be minuscule and would pose no significant health risk. They said a person living and working next door to the tower for many years would not increase his risk of getting cancer by more than one chance in a million.
The agency changed its stance after a May 12 hearing in North Hollywood, where speaker after speaker complained that the project merely would transfer pollution from one medium to another.
The next week, Rick Caruso, vice president of the Board of Water and Power Commissioners, said air filtering would be a "worthwhile investment if it makes the public feel more secure."
About a dozen Valley wells, which supply water to people on the other side of the Santa Monica Mountains, have been shut in recent years because concentrations of TCE or PCE are well above state advisory health limits. Water from less-polluted wells has had to be blended with fresh supplies to dilute contaminant levels.