YOU ARE HERE: LAT HomeCollections

New Plant Revitalizes Bad Water : Pollution: A $4-million facility is treating wells that had been tainted for decades by fertilizers from the region's orange groves.


SAN GABRIEL VALLEY — The heavily fertilized orange groves of yesteryear pose a contamination problem for the water supplies of today's suburbs in the San Gabriel Valley. And so do the wastes left decades ago by dairy cattle and residential septic systems.

But Pomona water officials have found a solution that will reclaim polluted water and help keep utility bills down at the same time. Last month the city opened a $4-million water treatment system designed to combat the nitrate-filled runoff that long ago sullied the area's underground supply.

The new system, billed as the world's largest nitrate-reducing water treatment facility, will allow the water department to pump from nine wells that had been closed for a decade because of the contamination.

By the summer, when demands are heaviest for water use, the Pomona plant on East Third Street will supply as much as a third of the needs of the Pomona water department's 28,000 customers in Pomona, La Verne, Claremont and Chino Hills.

In the past, the water department had relied greatly on the Metropolitan Water District of Southern California, which pipes in water from Northern California and the Colorado River.

"We can produce our own water much cheaper than buying from the MWD," said Anthony J. Skvarek, Pomona water manager.

In recent years, 65% of the water came from local underground sources and the remaining 35% from MWD. Now, the MWD portion will be cut in half.

The financial savings will be significant, Skvarek said. For example, he said, this summer the city would have spent $1.9 million on imported water if the new system had not been installed.

That savings will help pay for the plant, which is financed by a bond issue and will help to keep the costs down on water bills, Skvarek said. Customers pay an average bimonthly bill of $42.

Pomona's treatment system has inspired other water districts to consider building their own, including the city of Glendora, the Southern California Water Co. and suppliers in San Bernardino and Riverside counties, Skvarek said.

"You just can't ignore that there are cheaper alternatives than buying imported water," said Richard W. Hansen, manager of Claremont-based Three Valleys Municipal Water District, which imports MWD water into the eastern San Gabriel Valley.

The long drought--and escalating costs of water--provided the incentive to study and solve the nitrate problem.

Nitrate pollution, Hansen said, "has not been as sexy an issue" as the toxic contamination that made the San Gabriel Basin one of the worst underground-pollution problems of its kind in the nation. "But, in fact, nitrates are the single biggest contaminant in the ground-water basins of Southern California," Hansen said.

Orange groves once stretched across the San Gabriel Valley. The nitrate-rich fertilizers used for decades filtered into the underground water supply, polluting portions of the basin. Likewise, runoff from septic tanks and the dairy farms that once dotted the region contributed to the problem.

Nitrate pollution has forced the closure of 30 of the 400 wells in the San Gabriel Valley. The agency that oversees pumping of water from Alhambra to La Verne, the Main San Gabriel Basin Watermaster, is examining the extent of the nitrate problem.

Although potentially less troublesome than the chemical-cocktail mixture plaguing the San Gabriel Basin, nitrate pollution in high levels in drinking water can pose health problems to infants.

Excessive amounts have been linked to the "blue baby syndrome," an anemic condition caused by high nitrate levels reacting with hemoglobin in the blood of some infants.

But San Gabriel Valley water suppliers meet state and federal standards on nitrate limits. One way to meet the standards is to mix polluted water with purer water, which is what Pomona has done in the past.

As water costs rose, it became more practical to build a treatment facility.

To remove nitrates, water is piped into a series of 10 large tanks that can process up to 15 million gallons daily.

The bottom third of each tank contains a deep layer of granules made of resin. The layer is washed by a saltwater solution that leaves its salty residue.

Then nitrate-filled water is passed into the top of the tank and filtered through the layer. A chemical exchange occurs with the chloride in the saltwater and the nitrates, which are drawn out of the fouled water and into the granules.

The treated water then leaves the tank nitrate-free. To save on water costs, it is then blended with more water, which contains a minimal amount of nitrates. The blended water is substantially under the state and federal nitrate limit.

The waste water is piped to a sewage plant at Whittier Narrows, where it is treated.

Pomona's boon of producing cheaper water may also benefit surrounding water districts, Skvarek said.

He has been talking with the Walnut Valley Water District and the Rowland Water District about selling them some of the Pomona water as a cheaper alternative to MWD water. The two water districts rely completely on imported water. Skvarek said he expects that Pomona can sell the water at 25% lower cost than the MWD water.

Los Angeles Times Articles