Ground water tainted by decades of septic tank use is being reclaimed in La Crescenta, where a $2.1-million nitrate treatment plant--the first of its kind in Southern California--was dedicated last week.
The Crescenta Valley County Water District's Glenwood Treatment Facility is expected to pay for itself in 10 years, reduce the cost of supplying water to the district's 8,000 customers and eventually help clean the local ground-water supply, said Robert K. Argenio, district manager.
The plant is particularly important in view of the long drought that has diminished supplies of imported water and forced reductions in water usage statewide. The district can instead use the local water supply, which is more economical, officials said.
"It means the ratepayer does not have to pay the increase for importing water, which costs two-thirds more than ground water," said Robert E. Martin, a district director. "Ultimately, bills could decrease."
The plant is set unobtrusively in a rustic, residential neighborhood of Glenwood Canyon. Virtually hidden behind adobe brick walls and lush landscaping at 3730 Glenwood Ave., it produces no noise, no odor and no toxins.
Yet, it allows the district to pump from the ground up to 3 million gallons of water a day that previously could not be used because it was contaminated by high levels of nitrates.
Before use of the treatment plant, the district had to blend local water with large quantities of imported nitrate-free water to meet drinking water quality standards. The district purchased as much as 55% of its water from the Metropolitan Water District, a practice that has grown increasingly expensive as regional demands and the costs of pumping power have risen.
With the new plant, the district is able to meet 75% of its water needs from its own wells. It can purify much of its own water, which can be blended with untreated water and supplemented with imported water to meet quality standards, Argenio said. The plant is controlled and monitored by computer, which continuously checks water quality.
The district expects to reclaim up to 456 million gallons of ground water a year. The increased pumping eventually will remove most of the nitrates from the basin and clean the local water supply in about 25 years, when the plant will no longer be needed, Argenio said.
Argenio said the plant is the short-term solution to the district's water pollution problem. He said the long-term solution was put in place in 1982 when the district installed a sewer system and banned septic tanks.
Crescenta Valley's reclamation plant operates much like a home water softener unit. Nitrates are removed by treating water with a chemical resin that exchanges the nitrate ions for chloride ions. The district uses almost three tons of salt a day in the conversion process.
Nitrate-laden waste water is pumped into a 40,000-gallon storage tank, which is emptied nightly between 2 and 4 a.m. into a sewer that takes it to Los Angeles' Hyperion Treatment Facility in El Segundo.
Boyle Engineering Corp. of Bakersfield, which designed and built the Glenwood plant, began developing the technology in the 1970s through a federal grant. "The problem of nitrates in drinking water is nationwide," said David L. Hardan, Boyle regional vice president, during the dedication ceremony on Friday. He said the Crescenta Valley district "is a leader in utilizing the new technology."
Planning for the Glenwood plant began more than three years ago. The facility has been operating on a test basis since February.