Turning Sludge Into Splendor : Ecology: Calabasas’ high-tech plant will transform solid waste into compost for high-grade vegetable gardens.

When construction is completed, the five-acre maze of holding tanks, mixers and conveyor belts will provide the food chain’s last link, turning sludge from human waste into compost suitable for high-grade vegetable gardens.

And after the high-tech plant in Calabasas opens early next year, the Las Virgenes Municipal Water District will become one of the first agencies in the world to reuse nearly all of the water and solids it collects from sewage.

“It’s crap to roses, is what it really comes out to,” water district board President Hal Helsley said. “We’re taking something disgusting and making something that smells nice. Everybody wants to be part of the recycling team, and now it’s just a matter of flushing your toilet.”

Although many waste treatment experts believe it is cheaper to haul sludge to desolate farming areas, officials of the Las Virgenes Municipal Water District justify spending about $50 million on the cluster of gymnasium-sized buildings in ecological terms. For decades, solid waste from millions of toilets and sinks nationwide has been treated and dumped into the ocean or landfills, compounding an already critical waste disposal problem.

Despite tougher regulations, about one-third of California’s sewer sludge is still separated from effluent water, treated and then shipped to landfills, some of which is put to good use as topsoil, according to the U.S. Environmental Protection Agency.

Some sludge in California is incinerated and about half is composted or mixed with soil, which is the most environmentally correct way to deal with it, said Robert Wills, chief of the EPA’s Pre-treatment and Compliance Program.

“We look at sludge as a good thing, something that should be reused, rather than something that is bad,” Wills said. “Its nutrient value and its soil conditioning value certainly can be useful here in our desert areas, where the soil is sandy.”

The idea of fertilizing crops for human consumption with sludge, composted or not, has unsettled some people, however, and its agricultural use in the United States has been mostly limited to grains and cattle feed, said Eugene Tseng, a UCLA professor and nationally recognized solid waste expert.

“I don’t know how ready the public is to eat food that is grown using the product of human waste,” said Eugene Tseng, a UCLA professor and nationally recognized solid waste expert. “It’s a widely accepted practice in Europe and countries in Asia. But I think maybe we’re much more squeamish about that sort of thing in this country.”

At Las Virgenes, workers have for years plowed most of the treated sludge from about 20,000 homes into a district-owned alfalfa farm in the Calabasas hills. Most environmentalists, growers and companies that sell mulch agree, though, that sludge from sewage untainted by large amounts of industrial waste can be turned into compost ideal for growing food for humans.

At the Rancho Las Virgenes Composting and Solids Treatment Facility, the idea is to process solid waste indoors, filtering any foul odors that could escape. Because there are condominiums and apartments across the street, the composting plant also was set back from the road nearly half a mile.

There are only about a half dozen such facilities in the United States--one in Oregon and the rest on the East Coast, where rain, freezing temperatures and more dense populations discourage outdoor composting or farm application.

The makers of the custom-designed Calabasas plant, which is almost completely automated, say it is pioneering for its use of enclosed conveyor belts to move the sludge. In concept, the system resembles a huge digestive tract.

At the upper end, thick sewage from parts of Westlake Village, Topanga, Malibu and elsewhere will pour through an underground pipe into sealed tanks at the facility.

There the sludge will sit for about a month and a half, while microscopic bugs feed on the harmful bacteria, viruses and other living matter. The methane gas produced will be collected and used to heat the tanks to about 95 degrees and help power the whole facility.

Next, the muck will be pushed through a network of conveyor belts and bins, to be spun dry, mixed with sawdust and dumped into eight 220-foot rows in a massive, air-tight shed for another month of baking.

The product--a dark, loamy fertilizer--will be deposited by machine into a warehouse. From there it will be sold in bags or bulk to farmers, landscapers and nurseries.

Gardeners have found compost from sludge mixed with sawdust or ground yard waste to be one of the best sodding mixes for grass and flowers, and it has been used at such famous sites as the lawns at the White House and West Point, as well as some of the nation’s top golf courses.

Composting dates back to 19th-Century India, when a British agronomist developed the idea to use human waste as fertilizer. But the practice remained mostly a back-yard hobby in this country until recently, when a new environmental awareness began to force a change.

Tighter federal restrictions to take effect in October probably will make landfill disposal more expensive, and alternative methods more appealing, Wills said.

The city of Los Angeles already diverts most of its sludge from landfills to farmland in Arizona and an outdoor compost in the San Joaquin Valley, and some is dried and burned to produce energy. Los Angeles has rejected the idea of building an indoor composting facility.

“If you have the proper sites, there’s no question that it’s less expensive to do composting outside,” said Tim Haug, a division engineer for the Los Angeles Department of Public Works. “We have been blessed with being in an area with a lot of remote areas close by.”

But smaller waste treatment agencies, such as Las Virgenes, can sometimes have a tougher time finding contractors to carry their sludge away, Haug said. Although the finished compost is worth little more than the sawdust often used to make it, some other agencies on the West Coast are considering building facilities like the one in Calabasas.

“We’re not going to have to worry about what to do with our waste, regardless of what the market does or what it costs to dispose of the sludge,” said Las Virgenes board member Glen Peterson. “We may even be able to take sludge from other places, where they would normally ship it to a landfill.”

The Las Virgenes system can handle the thick sewage from 16 million gallons of effluent a day--the capacity of the nearby Tapia Water Reclamation Facility. Right now, Tapia treats only about 7.5 million gallons a day.

Planners have predicted that the population in the greater Agoura area will double by the year 2030, a formula Las Virgenes officials are counting on to help produce $50 million to pay for the composting plant, plus about as much in interest on the loan.

Three-quarters of the cost will be paid for by fees for connecting new customers to the sanitation system, while the other one-fourth of the tab will be picked up by current customers, who had about $30 tacked onto the average bill this year, Finance Officer Grace Mooney said. But the percentage paid by existing customers could rise if development in the area continues at a slower pace than expected, Mooney said.

So far, there has been no significant opposition to the project, partly due to the fact that Las Virgenes’ water and sanitation rates are still lower than in many surrounding areas and partly because of the measures taken to ensure the facility would not bother neighbors, Peterson said.