Water Quality

Although Michael S. Balter provided some facts in his article (Editorial Pages, April 6), “The Wrong Way to Remove Toxics in Our Tap Water,” he unfortunately chose the “wrong way” to interpret them.

Because the San Fernando Valley Groundwater Basin provides 15% of the city’s water, steps are being taken by the Los Angeles Department of Water and Power to stop the contamination from spreading and affecting more and more wells. We plan to extract the contaminated water close to its source, remove it and treat it. This can be done for a cost of $500,000 per year.

Rather than remove the contamination at its source so it doesn’t continue to spread, Balter proposes we treat each well. This could mean treating 50 times as much water and costing our customers from $10 to $15 million a year.

There are two methods available today to treat the contaminated water--granular activated carbon filtration and aeration. Both are technologies that have been approved by the U.S. Environmental Protection Agency.

After weighing the advantages and costs of both technologies, we are convinced that an aeration facility is the most appropriate. Based on scientific evidence, which indicates that the risk from these extremely low levels of trichloroethylene (TCE) are insignificant, this aeration facility does not present a health hazard. In fact, the allowable levels of TCE in the workplace, set by the federal Occupational Health and Safety Administration, is 1 million times higher than the maximum level of emissions produced by the proposed aeration facility.

The DWP recognizes activated carbon filtration is effective in removing contaminants from groundwater. However, after activated carbon has absorbed the contaminants, it must be disposed of in a hazardous waste landfill. Few of these landfills are available. In addition, granular activated carbon filtration is significantly more costly.

Good common sense dictates that ratepayer funds should be used on a technology that would provide the greatest benefit for the dollars spent. Aeration is both a safe and cost-effective approach.

LAURENT McREYNOLDS

Assistant Chief Engineer-Water

Los Angeles Department

of Water and Power