Proposal on Water Filtration Draws Fire

Amid growing concern about the purity of the Los Angeles area’s drinking water supply, the Southland’s two biggest water agencies are resisting a filtration treatment method that they say would raise water rates and cost more than $500 million without substantially improving water safety.

At issue is a proposal by Rep. Henry A. Waxman (D-Los Angeles) to strengthen the federal Safe Drinking Water Act by requiring the Environmental Protection Agency to take a major step toward encouraging America’s water supply agencies to adopt granular-activated carbon as a water purifier, a filtration method used by many bottled water companies.

Waxman is opposed by the Los Angeles Department of Water and Power, which serves the city, and by the Metropolitan Water District, which supplies water to Los Angeles, Ventura, Orange, Riverside, San Diego and San Bernardino counties.

Chemical Pollution

The proposal, which has passed the Senate and House and is scheduled to be discussed at a two-house conference committee Thursday, comes after continued disclosures of chemical pollution of the water supply in this and other parts of the country.

Industrial solvents, including trichloroethylene, or TCE, and perchloroethylene, or PCE, have been found in the Department of Water and Power’s underground water supply in the San Fernando Valley, as well as in underground supplies controlled by public and private agencies in other parts of the San Fernando and San Gabriel valleys.

The Metropolitan Water District faces a pollution problem of another kind. Water imported from Northern California picks up dirt, leaves and minerals in the Sacramento-San Joaquin Delta. Before the problem was addressed, the water was treated with chlorine in Southern California, and it formed trihalomethanes or THMs, a chemical containing chloroform. The U.S. Public Health Service has reported that “there is sufficient evidence” that chloroform causes cancer in animals.

After that and similar findings were made, the MWD began treating water with chloramine, which does not produce chloroform.

Called Ineffective

Waxman, chairman of the House subcommittee on the health and environment, said that chloramine and other traditional methods of water treatment used by the MWD, the DWP and the overwhelming majority of American water agencies are not effective against toxic chemicals that are polluting the nation’s rivers and underground water supplies.

“We have a public health problem and we have to deal with it,” Waxman said. A report on his proposal said that “there is mounting evidence that our water supplies are contaminated by dangerous chemicals. Our nation’s ground water, which supplies half the U.S. population with tap water, is becoming increasingly contaminated.”

In the granular-activated carbon method, carbon--in a form that looks like crushed charcoal briquettes--is exposed to gas at high temperatures. Thousands of tiny holes are made in each carbon particle. The particles are put in tall tanks and water is forced through them. As the water moves downward, the toxic chemicals adhere to the particles’ surface and to the tiny holes so that by the time the water leaves the tank, it has been purified.

The Metropolitan Water District purifies water by adding chemicals, by filtering--although not by carbon filtration--and by having the water settle in basins.

The Los Angeles Department of Water and Power also uses chemicals to purify its water. The department is building a $100-million water treatment plant, which will use non-carbon filtration and ozone, a purifying substance added to the water.

Waxman won approval of an amendment to the drinking water act requiring the EPA to specifically list granular-activated charcoal as one of the best available technologies for removing toxic chemicals from water.

Myron B. Holburt, MWD assistant general manager, objected to the language, saying that there is no evidence that granular-activated carbon is the best way to control THMs, although he conceded its superiority in removing many other chemicals.

“GAC (granular-activated carbon) can be effective in removing THMs, but only at a very high cost,” he said. “If Metropolitan were forced to change to a GAC program, it would require a capital investment of at least $500 million,” he said. “The annual costs, including the payment of capital (interest on construction costs) would be about $90 million. By comparison, the chloramine program has a capital investment of $6.5 million and an annual cost of $500,000.”

Officials said water rates would rise, but they had no estimate of the size of the increase.

Michael McGuire, who is in charge of water purity for the MWD and who studied the granular-activated carbon method for his doctoral degree, said the district would be required to build plants triple the size of current filtration facilities at its five filtration plants. And he said it would have to build huge furnaces needed to regenerate the carbon after it has absorbed toxic chemicals. (The used carbon is burned at high temperature and then reinstalled in the filter tanks).

Duane Georgeson, DWP assistant general manager, said granular-activated carbon is not needed to purify water from the valley wells. The department favors aerating the water--removing the chemicals by squirting the water into the air from huge towers.

Georgeson also said that regenerating the carbon would add to air pollution in the South Coast Air Basin.

Opposite Opinion

The air pollution threat was denied by Richard Miller, director of the Cincinnati Water Works Department. Cincinnati has authorized construction of a $48-million plant that would boost that Ohio city’s water rates between 25% and 30%.

“We fitted the burners with an afterburner and what comes out of there is totally harmless,” he said. “It meets any air criteria that exists in this area of the country.”

Miller agrees with MWD officials that granular-activated carbon, while ideally suited to remove the heavy chemicals found in his city’s Ohio River water supply, is too expensive for removing THMs, the MWD’s biggest problem. He said he does not approve of the language in the Waxman proposal.

But many other water experts back granular-activated carbon, as do environmentalists concerned with the safety of drinking water.

They, Waxman and his committee aides have said that current attempts to clean up toxic dumps are failing--that the dumps are too massive and that the chemicals in them are continuing to seep into water supplies. As a result, they have said, the law must be changed to assure that granular-activated carbon will be used.

An article in the Journal of the American Waterworks Assn. by William H. Glaze, head of the graduate program in environmental sciences at the University of Texas, and James L. Wallace of Louisiana Tech University appeared to support the usefulness of granular-activated carbon in removing the organic materials that form THMs (known as THM precursors) in water when they are mixed with chlorine.

“For water that has high THM precursor levels, granular-activated carbon absorption appears to be the most effective of . . . alternative treatment methods,” the authors said.

They noted two objections to using the treatment. One was the cost, cited by the local engineers. The other, they said, is “that relatively few water utilities or consulting engineers have experience with this technology (in the United States).”

Research for this story was contributed by Cecilia Rasmussen, Times City-County administrative aide.