DWP OKs Building of Aeration Tower to Rid Water of Toxics

After lengthy delays, the Los Angeles Department of Water and Power on Thursday cleared the final hurdle for the second part of a program to clean up contaminated San Fernando Valley groundwater.

The DWP approved a contract with the federal Environmental Protection Agency for construction of a $4.4-million aeration tower to evaporate solvents from the water in the ground beneath North Hollywood. Construction of the 40-foot tower will begin within 30 days and be operational next summer, said Duane Georgeson, DWP assistant general manager.

The actual construction costs will be about $2 million, and the remaining $2.4 million will cover the costs of operation and maintenance, Georgeson said.

“Although all water served to DWP customers from the groundwater basin meets state and federal drinking-water regulations, the facility is necessary to stop the spread of contaminants in this vital resource area,” said Rick Caruso, president of the Los Angeles Board of Water and Power Commissioners.

DWP officials estimate that cleanup of the contaminated water will take about 10 years, Georgeson said.

Construction of the tower is the second part of a $12-million groundwater cleanup program in the Valley. The DWP two weeks ago began a $7-million study to determine the sources and extent of groundwater pollution. That study is expected to take about two years, Georgeson said. Both projects are to be financed from the federal Superfund.

An earlier proposal to build the tower near homes led state Sen. Alan Robbins (D-Van Nuys) to introduce legislation requiring residents near treatment facilities to be notified in advance of public hearings. However, DWP officials, citing aesthetic reasons, later chose a new site for the tower at a maintenance yard in an industrial area at 11845 Vose St. in North Hollywood. The treatment facility will process water from two miles of wells near the Lockheed plant.

“There clearly is a massive amount of contamination under Lockheed property,” Georgeson said. “The DWP is not just sitting around doing generic studies, we’re involved in the actual cleanup effort.”

Objections by environmentalists that the tower would simply transfer chemicals removed from the water to the air also led the DWP to redesign the project and plan to install carbon filters in the tower.

The project calls for the contaminated water to be drawn from eight shallow wells and piped to the top of the tower, then dropped into an upward blast of air that will cause any dissolved solvents to evaporate. The solvent vapor will then be caught in a carbon filter before it can escape to pollute the air, according to DWP officials.

About a dozen wells in the North Hollywood area have been shut down because of unacceptable levels of trichloroethylene, or TCE, and perchloroethylene, or PCE. Both are suspected cancer-causing agents and are commonly used in dry-cleaning solvents and in the fabrication of metal plates, Georgeson said.

Water drawn from about a dozen other wells with lower pollution levels is being blended with clean supplies to reduce contamination to acceptable levels.

Water from Valley wells supplies 15% of Los Angeles’ water, primarily to customers in the central, east and southern portions of the city, as well as in Burbank and Glendale. Because of the layout of the DWP’s distribution system, water for Valley customers comes from the eastern Sierra.