IRVINE — Gray-brown water enters the treatment plant, carrying everything from coffee grounds to cigarette butts.
Half a day later, after being strained, treated by waste-munching bacteria, filtered through charcoal and bubbled with chlorine gas, the sparkling clear water leaves the sewage treatment plant to be used again on front lawns, ball fields and crops.
This scenario of recycling water for nondrinking purposes, which is becoming more common in Southern California as fresh water becomes increasingly difficult to import, is old hat to the Irvine Ranch Water District. The district has been recycling water for 24 years and is considered a statewide leader in supplying recycled water.
"They are the pioneers, I'd say," said Lynn Johnson, chief of the state's Office of Water Recycling. "If you think of leadership in using reclaimed water in the state, L. A. County, the Orange County Sanitation District and Irvine Ranch Water District come to my mind."
The reclamation system allows Irvine Ranch, the seventh-largest supplier of reclaimed water in California, to import about 10,330 acre-feet less water a year. That's enough water to supply more than 10,000 large families for a year.
The district supplies 10 million gallons a day for use in irrigating residential and commercial landscaping, parks, school grounds, farms and orchards, and to fill the lake at William R. Mason Regional Park in Irvine. Health authorities prohibit the use of recycled water for drinking.
Last month, the water district hooked a 20-story office building to the recycled water system--a first in the nation for a municipal water district. Highly treated waste water is used to flush the toilets and urinals in the building.
A handful of office buildings elsewhere in the nation already use reclaimed water to flush their toilets, but their water is recycled by mini-plants in the buildings' basements, not by a city water district, said Art Masse, an expert on technology for the American Waterworks Assn.'s research foundation.
"Irvine Ranch is the first to reclaim water on a municipal scale and pump it into an office building," Masse said.
Los Angeles County is actually California's leader in the amount of water being reclaimed. But officials said Irvine's district has put its recycled supplies to broader use over a longer period of time.
The Sanitation Districts of Los Angeles County, a cooperative of 27 sanitation districts, supplies more than 60 million gallons of reclaimed water every day to users ranging from golf courses to two paper mills in Pomona.
About 75% of the water reclaimed from sewage is simply fed into the ground to recharge the county's ground water supply, said Earle Hartling, Los Angeles County's water reuse coordinator.
Expansion plans call for Los Angeles County to be using about 110 million gallons of reclaimed water a day in about five years. "As the cost of imported water goes up--and it's going to go up dramatically in the future--it's going to be more economical and we're going to be more competitive to areas farther away from the treatment plants," Hartling said.
Meanwhile, the city of Los Angeles pumps 450 million gallons of usable water daily through four sewage-treatment plants in Los Angeles, but more than 99% of that water flows out to the ocean, said Bahman Sheikh, the city of Los Angeles' reclaimed-water chief.
Getting the reclaimed water to customers is the key to expanding its use, Sheikh said. The cost of digging up streets to install pipelines for reclaimed water has been a major impediment in the city of Los Angeles, he said.
Although about 200 water agencies in California recycle water to some extent, none compare to Irvine for its many uses or the sophisticated system in place, Sheikh said.
"What sets apart the Irvine Ranch Water District is their dedication to the (recycled water) concept," Sheikh said. "They took some risks when people weren't so sure it was a good idea. In fact, it was a fantastic idea."
Last month, after 3 1/2 years of planning and working with regulators, engineers connected the 20-story office building in Jamboree Center to the water district's reclaimed water system, said Ronald E. Young, general manager of the water district.
Using treated water to flush toilets is expected to cut down the building's use of fresh drinking water by 70% and save enough water to supply about 35 homes in Irvine for a year, Young said.
"This represents a novel use of reclaimed water and breaks away from traditional uses, like irrigating a park or growing alfalfa," said Mark Adelson, chief of surveillance and enforcement for the Santa Ana region of the California Regional Water Quality Control Board.
State regulations did not cover using recycled water in rest rooms, he said, so the water district had to spend years working with local and state regulatory agencies to set standards for the public's safety.