'GOOD BUGS' CLEANING UP TAINTED WATER MICROSCOPIC CRITTERS GOBBLING MTBE FROM MILLIONS OF GALLONS.

Byline: Kerry Cavanaugh Staff Writer

NORTH HOLLYWOOD - To clean up a massive plume of MTBE in Los Angeles' drinking water supply, scientists have produced trillions of tiny ``bugs'' that feed on the toxic gasoline additive and leave the water pure enough to return to the aquifer.

The project is the first of its kind in Los Angeles, and officials rave that the superefficient microbes will restore millions of gallons of precious San Fernando Valley groundwater, which provides 10 percent of the city's drinking supply.

``This is exciting because we're saving the water, and water is precious in the region,'' said Yue Rong, a senior environmental scientist with the Los Angeles Regional Water Quality Control Board.

Scientists expect MTBE-gobbling bacteria will become a cheaper, safer way to clean up groundwater contamination.

MTBE - methyl tertiary butyl ether - was added to gasoline beginning in 1979 to cut air pollution. Extremely water-soluble, MTBE tainted water supplies with its distinct turpentine taste and odor when underground gasoline storage tanks leaked into groundwater.

An estimated 2,300 water systems in 36 states have been contaminated by MTBE, according to a June report from the Association of Metropolitan Water Agencies. California stopped using the chemical in 2004.

In North Hollywood, the former Fast Fuel Service Station at Victory and Vineland boulevards leaked thousands of gallons of gasoline into the groundwater before going out of business, leaving oil company Tesoro with the cleanup.

Tesoro found a thick layer of gasoline floating on the groundwater and MTBE levels up to 100,000 parts per billion. The acceptable limit for drinking is 5 ppb.

More troubling, the massive plume of MTBE was migrating toward Los Angeles Department of Water and Power wells. The utility shut down two of the wells for fear of pulling the chemical even closer.

The contamination was so severe that Tesoro probably would have had to buy property in the residential neighborhood and build a water-treatment plant if a better cleanup method had not been found, said Jeffrey Baker, environmental remediation supervisor for Tesoro.

Instead, Baker and the company's consultant, Haley & Aldrich, sought the help of Kate Scow, a soil-science professor at the University of California, Davis, and graduate student Kristin Hicks. Scientists in their lab had discovered a microbes strain called PM1 that feeds on MTBE, destroying the molecule and leaving carbon dioxide behind.

PM1 is found naturally in the groundwater. To accelerate the bug's natural hunger for MTBE, experts cultivate the bacteria inside carbon filters - similar to the filters found in household water purifiers - and add oxygen. The bacteria multiply and quickly chomp through MTBE.

``This is an efficient organism that breaks it down to natural elements and creates no byproducts,'' Baker said.

Tesoro has been using bacteria to remove MTBE in North Hollywood for two years, piping tainted water to two small units at a self-storage facility on Victory Boulevard, where the water runs through several chambers that house the carbon filters and bacteria.

After several trips through the filters, the MTBE is below the detection level of 0.5 ppb.

Until recently, Tesoro released the clean water into the storm-drain system and it eventually washed out to the ocean - a waste of 7 million gallons of water that frustrated local officials.

Just this week, however, Tesoro flipped the switch on the second phase that reinjects the treated water into the aquifer. It's the first time Los Angeles water officials have allowed someone to put treated water back into the San Fernando Valley aquifer.

``We had to prove beyond a shadow of a doubt that it was safe,'' Baker said.

The new process will save 10 million gallons of water, or enough to serve 60 families for a year.

Now that the scientists have shown that tiny bugs can do the work of high-tech water-treatment devices, Scow hopes other companies will embrace a cheaper, less-destructive and more natural way to clean up contamination.

``This work is an excellent example of how working with nature, supporting the cleanup activities of organisms already present, rather than creating artificial systems, was successful.''

Kerry Cavanaugh, [phone]

kerry.cavanaugh(at)dailynews.com