Filters Restore Tainted Well as Water Source

The carbon filters stand like giant kidneys in an industrial area of South Gate, ready to remove dangerous chemicals from the tainted water that will be drawn from 500 feet below the ground and sent to homes and businesses.

The 25-foot-tall gray tanks are part of a new water treatment system--local water officials’ latest effort to deal with contaminated ground water that has forced well closures in several area cities, including South Gate, Bellflower and Downey.

When the $220,000 system at Nevill Avenue and Mason Street is switched on this week, the tainted well will provide about 10% of the water that runs through the municipal water system to homes and businesses in South Gate, said water Supt. Tom Watson.

The state Department of Health Services issued a permit for the system last week, and local water agencies plan to expand the program.

“We would expect over the next five years maybe you’ll see a dozen or so of these in the (Southeast) area,” said Richard W. Atwater, general manager of the Central Basin Municipal Water District, which is co-owner of the equipment with the Central and West Basin Water Replenishment District.

The Central Basin Municipal Water District is a wholesaler that sells water supplied by the Metropolitan Water District to cities and independent water companies throughout the Southeast area. The Water Replenishment District manages the area’s ground-water supply.

The districts are hoping the well treatment program will increase the amount of ground water the area can depend on during the drought.

In addition, the program will help clean up local aquifers, the underground geological formations that the wells tap, by removing the tainted water.

Water from South Gate’s Well No. 7, which is polluted by the industrial solvent trichloroethylene (TCE), will pass through carbon in the twin tanks. The water is then run through a nearby chlorine tank, which kills bacteria, before it is pumped to residents and businesses in South Gate. Initial samples of the filtered water showed no trace of TCE, Watson said. The material, suspected of causing cancer, has been used to remove grease from tools and machinery.

South Gate has leased the system from the districts at $3,000 a month for a year. After that, the lease could be renewed or the system could be disassembled, loaded onto trucks and hauled to another tainted well in the area.

Other cities, including Downey, are considering participating in the districts’ well-head treatment program. Downey has two inactive wells because of contamination, said water Supt. Greg Mayfield.

Ground water is vital to the Southeast area, accounting for a little more than half of the water consumed. Municipal water departments and independent water companies buy the rest from the MWD, which imports water from Northern California and the Colorado River.

More than 50 wells in the Southeast area have been contaminated by industrial solvents such as TCE. The water from most of those wells does not need to be treated because contamination levels are low. In other instances, tainted water is mixed with clean water to bring contamination levels within state guidelines before it is delivered to homes and business.

But 13 wells in the area are no longer pumped for drinking water because of chemical contamination.

South Gate has seven of those wells, which made the city a perfect candidate for the new treatment program, said Atwater, the Municipal Water District’s general manager.

The city had lost about half of its capacity to draw water from the ground because of the closed wells. That wasn’t much of a problem in the fall, winter and spring, when demand for water was relatively low. South Gate simply pumped its seven clean wells more often.

“So far we’ve been able to make it up,” Watson said.

But the city has more of a problem in the summer, when water usage among the 75,000 residents and businesses jumps and the city needs more wells to meet peak demands.

Without Well No. 7, South Gate would be forced to buy water from the MWD at more than three times the cost of pumping and treating the contaminated water, Watson said.

South Gate usually buys about 5% of its water from the MWD. But because of the drought and increased fees, the city hasn’t purchased any MWD water this year.

“It’s cost-effective and it makes sense to get (the contaminated water) out and use it rather than letting it spread somewhere else,” said James A. Biery, South Gate’s director of public works.