SLUDGE: A Growing Headache : Trying to Tame the Wild, Wild Waste : Agencies Grapple With Growing Problem of Where to Put Sludge

It was not the Encina sewage plant’s finest hour.

In December, 1986, a series of glitches forced operators of the plant in Carlsbad to begin piling huge mounds of sludge, the oozy byproduct of sewage treatment, on the facility’s lush green lawns.

The unsightly stuff was normally hauled to a local farm and tilled into the soil, but a contract dispute eliminated that outlet. As officials scrambled to find a new disposal site, the sludge piled higher.

Finally, after more than two weeks, a South Bay landfill agreed to take the sludge. The crisis was over, but it left its mark on Encina officials.

Problem Has Escalated

Along with several other North County sewage agencies, Encina began searching for a permanent cure for the sludge-disposal headache, a problem that has escalated as the region’s population has boomed and as space in landfills, the traditional dumping ground for sludge, has dwindled.

North County is not alone. San Diego city officials are seeking ways to get rid of the thousands of tons of sludge that sit at Fiesta Island in the middle of scenic Mission Bay.

San Diego officials--who were caught several years ago illegally dumping sludge near the border--have already missed a 1987 state deadline to move the sludge hills from Fiesta Island to a more acceptable location.

Their hopes to open a new $28-million sludge operation at Miramar Naval Air Station next year have hit several snags, not the least of which is the Navy’s fear that sludge will attract the kind of large birds that interfere with military jets.

It will take $1.3 million and at least three more years to check out that and other environmental questions, the officials say. And other engineering costs have pushed the anticipated price tag for the new sludge farm to at least $48 million--nearly double the original estimate two years ago.

Meanwhile, the sludge keeps piling up as the average household produces 350 pounds a year. As landfill space dwindles, county sanitation officials hope more creative techniques will enable them to convert sludge into something other than a dirty word.

North County agencies feel they have found the solution--a high-tech composting operation that would turn the spongy byproduct of countless flushed toilets into a marketable soil amendment for green houses and back-yard gardeners.

But several obstacles remain, the biggest being the struggle to find a site for the composting plant. Though the agencies have narrowed the search to six finalists, every one of the areas is ringed by residents upset at the prospect of a sludge-composting facility rising nearby.

“There isn’t one of these sites that doesn’t have someone around it saying, ‘No, don’t put it by me,’ ” said Richard Graff, general manager of the Encina

Water Pollution Control Facility. “Wherever we go, that’s a given.”

In San Diego, city officials have been peddling their sludge as a fertilizer to the American Sod Farm. The farm in the Tijuana River Valley tills the sludge into the ground before planting a fresh patch of sod, destined to cover the lawns and grounds of the area’s burgeoning residential and business neighborhoods.

Richard Potter, an associate civil engineer in the San Diego Water Utilities Department, said the city’s sludge rates as a good fertilizer because it is relatively “clean.”

“We don’t have the heavy metals (in the sludge) compared to the rest of the folks in the country,” he said.

Exploring Other Avenues

The sod farm began taking San Diego’s sludge in September, 1987, and the contract called for it to buy 38,000 cubic yards in the first year--an amount that equals the yearly production of sludge from the city’s sewage-treatment plant at Point Loma.

However, that amount will be cut to 27,000 cubic yards by 1992; thus, city officials are exploring other avenues for getting rid of their sludge.

One proposal is to spread it over the farmlands of Imperial Valley, but that plan has run into considerable opposition from Imperial County officials, who are fearful the sludge could contaminate their crops and soil. The issue is on appeal before the state Water Resources Control Board.

The city is also gearing up to start a small trial program of composting at Fiesta Island next spring. “It’s not going to be a very big deal,” Potter said. “We want to get some dirt under our fingernails and see.”

And last week, city officials unsealed bids for yet another sludge-elimination project: deep-well oxidation. The idea is to pump the sludge underground, subject it to heat under pressure and reduce it into a fine ash.

For all their plans, however, city officials still face an immediate crisis about what to do with the sludge pits at Fiesta Island, which was designated a temporary sewage drying site in 1963.

Ordered Site Moved

In 1981, the California Coastal Commission determined that sludge operations there were inappropriate, and it ordered the city to move its sewage-drying beds within six years.

Between June, 1982, and May, 1985, city sewage officials tried to reduce the embarrassing stockpile at Fiesta Island by secretly dumping 171,135 cubic feet of the material into a canyon near Brown Field, at a savings of $643,700. But the state Regional Water Quality Control Board, which monitors sludge dumping, found out and recently ordered a $1.5 million cleanup of the illegal dump site.

Since then, the city has resorted to the traditional method of burying its sludge at landfills. The current dump spot is in Imperial County, to which the city has made periodic monthly shipments of between 9,000 and 14,000 tons each, recent records show.

Trucking those quantities of sludge has helped reduce the Fiesta Island stockpile to about 100 tons--about a third of what it was a couple of years ago, said Yvonne Rehg, a spokeswoman for the Water Utilities Department. By the end of 1989, the city expects to remove all of the sludge from the island except the amount used by the sod farm.

Meanwhile, city officials are trying to find a new home for their sludge beds. They first proposed building a new sludge pipe from the Point Loma treatment plant to a spot at Miramar, where the sludge would be left in open pits to dry.

But preliminary environmental studies have indicated the city would not be able to build its open-air pits without damaging vernal pools and rare mesa mint that dot the air station. Instead, it will have to resort to smaller parcels of land and a more expensive, mechanical drying process--changes that will drive the price of the project up from $28 million to $48 million.

In addition, Navy officials became concerned that the sludge would attract sea gulls and hawks.

“I don’t want to create an air safety problem with the birds,” said Capt. Gary M. Hughes, Miramar’s commanding officer. “A sea gull-size bird hitting an airplane that is flying along at 150 to 200 knots, there is an awful lot of kinetic force that hits the airplane.

“If they hit the windscreen . . . it shatters, and pilots have been blinded,” Hughes said. “Military aircraft have hit birds and have been lost.”

Potter said city officials are confident the sludge would not attract birds, but they will comply with a Navy request to perform an exhaustive environmental impact study that will cost $1.3 million and take up to three years, further delaying the project.

The environmental study will also examine any potential problem caused by odors from the sludge, Hughes said.

While San Diego wrestles with solutions, sewer officials in North County are pressing ahead with their efforts. If all goes according to plan, a $26-million regional sludge-composting plant should be fully operational by mid-1992, according to Graff.

The plant would sit on 100 acres, with the actual composting facility covering about 30 acres. The rest of the land would act as a buffer zone between the plant and existing landowners.

The six sites under consideration are in rural inland areas. They are a site owned by San Diego Gas & Electric just north of California 76 and another to the south of that highway, a plot next to the Rincon Indian Reservation, an SDG&E-owned; parcel next to the San Marcos landfill, a site in Bonsall and an egg ranch in the Harmony Grove area west of Escondido.

Plans call for the agencies to narrow their search to between three and five sites early next year, then conduct environmental reviews and hammer out purchase options on them, Graff said. A final site would be selected in mid-1990.

Officials are considering technology known as in-vessel composting for the North County plant. Like a back-yard compost pile, the in-vessel technology uses basic biological processes to break down the sludge into a soil amendment similar to peat moss.

The high-tech system, however, uses several techniques to speed up the decomposition process and ensure that unpleasant odors do not become a problem, officials say.

When a load of sludge arrives, it is mixed with sawdust, wood chips and other material, which help fuel the natural biological reaction. The entire process is conducted in an enclosed structure. All emissions are drawn off to scrubbers, which eliminate unpleasant odors, Graff said.

Inside the containment structure, oxygen is injected into the mix and mechanical augers stir it to speed up the decomposition process. As the material breaks down, heat of up to 140 degrees kills off pathogens and other germs.

What is left is a compost that can be bagged and sold. Several sewage agencies across the country are doing just that. As of 1985, nearly 150 sludge-processing plants were planned or in operation in 37 states.

Graff acknowledged, however, that the compost will not be a moneymaker. Authorities estimate that sales would help defray only about 12% of the facility’s annual operating costs and purchase payments.

While the search for a site inches forward, many of the agencies are continuing to dump their sludge in the Otay Mesa landfill, the only facility within an economical hauling distance that accepts the material.

Encina is also paying a Tucson-based firm to haul about 70% of its sludge--the plant currently produces about 22,000 tons annually--to farms in Blythe, Calif., and Yuma, Ariz., where it is tilled into the ground.

Keeping Several Options

Even when a composting facility is in operation, Graff said, the agencies will likely continue to dump a percentage of their sludge into available landfills or onto farmland if economical.

Likewise, with federal regulations on sludge disposal continually shifting, officials remain reluctant to rely on one solution, for fear a crisis could unfold much as it did for Encina in 1986, he said.

Nonetheless, the composting plant is considered the best possibility for North County agencies. The greatest impediment remains homeowners upset by the prospect of a sludge-processing plant next door.

“We would strongly protest it,” said Robert Gaines, a homeowner just across Interstate 15 from the Bonsall site. “We’re trying to get the whole area in line against it.”

Gaines and other residents near the various sites talk of numerous potential problems. They worry about increased truck traffic and the possibility of nasty odors wafting toward their homes.

They also are concerned about tainted runoff polluting the ground water, and they fear the plant could hurt property values.

Moreover, these residents question why the composting plant is being proposed for areas far from the population centers that produce the bulk of the sludge.

“I don’t see anybody volunteering for this in the heavily populated areas,” Gaines said.

Graff said sewer officials expected complaints and are confident that any potential problems can be adequately addressed.

Coastal areas have not been selected as plant sites primarily because of the high cost of land and a dearth of large parcels that could hold the composting operation, he said.

Graff said the search has focused on areas where a plant could be built away from any flood plain, virtually eliminating the risk of ground-water contamination. In addition, the plant’s containment structure will help prevent any potential runoff, he said.

The containment structure will also play a role in adequately controlling odors, authorities say. Agency officials contend that in visits to other composting facilities around the United States, they have been unable to detect odors immediately outside the plants.

“There may be times when odors are released, but that will be a rare occurrence,” said William Hunter, Encina’s resource reclamation manager. “We just don’t envision that happening very often.”

By the year 2010, about 60 daily truck trips would be made to the plant, but most of the sites are near major roads that already handle heavy truck traffic, Graff said. Problems with truck traffic to more rural sites could be addressed by making road improvements or taking other measures to curtail truck noise or visual impacts, he said.

“One more truck is a significant impact to some people,” Graff said. “It’s a matter of perception.”

He admitted that a composting plant “certainly is not going to raise property values” around any of the sites, but he argued that mitigation measures such as trees and other greenery will help screen the facility.

Hunter agreed, saying the intent is to “blend in as much as possible and make the plant as attractive as possible.”