PLANT: Sewage-to-Energy Plan Hits Snags : Sewage-Power Plant Turns Into ‘Disaster’

On a windy coastal bluff, a complex of plain-looking buildings where Los Angeles is trying to convert sewage into cheap electric power serves as a $350-million warning to other cities about gambling on high technology.

Two years after it was supposed to be ready, the Hyperion Energy Recovery System has yet to burn even a day’s worth of sewage.

After more than 2,000 design changes and a yearlong string of fires and other snarls, the system’s designers concede that they don’t know when the labyrinth of pipes and boilers will begin to work. Further, they admit now that the system cannot be counted on ever to burn all the Los Angeles sewage, a major retreat from promises that were made to sell the system to city officials.

Since work began in 1980, costs have tripled, and the share to be borne by Los Angeles taxpayers, once a mere $12 million, has soared to $155 million, city records show.

Yaroslavsky a Critic

“It has been a disaster,” said Councilman Zev Yaroslavsky, a frequent critic. “If anything could go wrong, it did.”

This was not the scenario envisioned when Mayor Tom Bradley and the Los Angeles City Council decided to gamble on a vaunted but untested new technology for processing sludge, the vilest portion of the waste flushed through sewers.

The HERS system, as it is known to engineers throughout the country, was supposed to be the state-of-the-art alternative to piping the sludge out to sea, a practice Los Angeles was under a federal court order to halt. The system would burn every bit of the sludge and also reduce the city’s reliance on foreign oil.

Physically, the system is nearly complete. But in the last year, several fires have erupted as the engineers try to coax the machinery into handling the volatile sludge, including a stubborn blaze last February that took a week to douse and caused a costly five-month delay. Engineers also found that major parts were poorly designed and needed to be junked. A key contractor, fired in 1986 for allegedly slowing the project down, filed a $30-million lawsuit against the city.

Even the most loyal engineers on the project have grown discouraged. “We’ve been trying to bring this up on line for about a year,” said William Hartnett, a top engineer with Foster Wheeler Corp., who is known around the HERS complex as Captain Sludge. “It’s been one battle after another.”

When conceived in the late 1970s, the HERS system was hailed by city officials as the most ambitious public works project ever undertaken by Los Angeles.

It uses a process first conceived as a way to extract vitamins from fish livers, but never tried on urban sewage. The process was designed to dry the sludge and use it as the fuel to generate enough electricity to power 40,000 typical homes. The latest pollution controls would prevent the creation of smog, and only a harmless ash would be left behind.

Built Without Controversy

Best of all, city officials figured, the whole system could be built without controversy on a corner of the city’s sprawling Hyperion sewage treatment plant on the coast near El Segundo.

Hyperion is where sludge is extracted from the sewage and--until last November--was piped out to sea. Engineers thought that it would be a simple matter to divert the sludge into the new HERS system.

The alternative, building a sludge pipeline across Los Angeles County to the desert, would bring a political wrath down on City Hall. With HERS, the obstacle was technical, not social, and the city was stocked with skilled engineers.

“If it had worked, we would be trotted out as a big success,” said Bradley Smith, the top city engineer involved in HERS from the beginning, as 1987 ended.

Engineers first promised to have HERS working by July, 1985. That was the deadline agreed on to settle a lawsuit against the city by the EPA and state of California. Last year, in a revised settlement, the city said HERS would be working by no later than 1989. In October, the city told federal Appeals Court Judge Harry Pregerson, who is overseeing the EPA suit, that the system would be done by early this year.

No More Predictions

City engineers refuse now to make any more predictions about completion. Ralph Kennedy, the veteran engineer brought in three years ago to finish the job, said it would only be “guesswork.” But he said that once full testing has started, “I expect we’ll have five more years to really get it polished off.”

In recent months, the recurring problems forced city officials to switch their thinking on HERS. Instead of burning all the sludge, the system would only be counted on to burn a portion. “I think it’s still a viable concept,” Smith said. “But today we might have a different version of what ‘operating’ means.”

To avoid being pressured into placing sludge back in the ocean, which would incur fines, the city has begun to sign contracts with companies to take the sludge and process it for use in soil enrichment products. The city has also expanded its sludge storage at Hyperion and even resorted to paving a vacant piece of ground at Hyperion so sludge can be dumped there if the storage tanks fill up.

Landfills Not Reliable

Since Nov. 2, all the sludge has all been trucked to landfills. The city stopped dumping in the ocean that day after 30 years, beating a federal deadline by nearly two months. But the privately owned landfills are not considered reliable. They stop accepting the sludge in bad weather, and could stop altogether if there is more money to be made elsewhere.

The progress on HERS is being closely monitored by the Los Angeles County Sanitation Districts, which also decided in 1980 to build a similar system, and two New Jersey sewer authorities. All of the projects are under construction, but they are moving slowly to see what happens here.

Snarls in the HERS system can be traced to the hurried 1980 decision to have the process working in time to stop putting sludge in the ocean by July, 1985.

The engineers expressed confidence they could do it. “There never was a second when anybody said, ‘Let’s sit back and tell the world we can’t do it,’ ” Smith said. But “if we were honest with ourselves, there probably weren’t very many of us who thought we could do it.”

Hastily Designed, Built

The project was hastily designed and built, without the methodical reviews that can slow some government construction projects but that can also prevent hang-ups.

But nothing like HERS had ever been tried, and the complexity of the task cried out for more than the usual deliberation, not less. The city engineers and consultants had experience with conventional sewage plants, but not one of these.

Sludge is a volatile mixture of human waste and decaying food. Besides the solids, about 10% is bacon fat, body fluids and other greasy substances that the engineers refer to euphemistically as “sewage oil.” Sludge is difficult to handle under the best conditions.

Most of the HERS system uses conventional mechanical processes. But the heart of the system--and the location of most of the troubles--is a complex method of drying waste called the Carver-Greenfield process.

The process involves adding a highly flammable, commercial oil to “wet cake,” sludge that has been fermented for 20 days in anaerobic digesters then spun in a centrifuge to remove excess water. The oil keeps the sludge in a fluid state as the remaining water is evaporated.

Dry, Gray Powder

Once the water is out, the mixture is spun again and heated to remove the oil, leaving a dry, gray powder the consistency of flour. The powder smells of oil and is highly combustible, so it is kept in an atmosphere of nitrogen to prevent fires.

“A Carver-Greenfield system, in fact, resembles a petrochemical plant more than a waste-water treatment plant and requires some of the same equipment and skills found in petrochemical plants,” a September EPA report concluded.

HERS was designed to use the powder as the fuel in a brand-new, $61-million electric power generating plant at Hyperion. But the generating turbines have sat idle, largely untested, because the Carver-Greenfield process has been unable to produce more than a trickle of powder.

The EPA report, which evaluated the problems that arose during construction, faulted the city’s practices and concluded that any other locality planning to build a system should study Los Angeles--then go about it differently.

Piping Problems

The hasty design proved to be the first mistake. Designers produced 2,000 pages of drawings and 20,000 pages of specifications. But when construction began, pages were missing from the designs, resulting in piping problems, and careless wording led to other delays, the EPA report said. “Adequate time was not available for sufficient quality control and checking of the design drawings,” the report said.

Bids on the construction jobs were accepted at far below what the project would really cost, in part because work began without the designs being refined. “We decided to go ahead and take care of it all during construction,” Smith said. “We now know that it’s not quite as simple as saying: ‘We’re engineers, we can fix it.’ We may have been a little naive.”

As a result, more than 2,300 major design changes have been ordered, adding $82 million to the cost, city records show. As recently as December, the city Board of Public Works approved eight changes in contracts that increased the cost by $3 million in one day.

Los Angeles also spread the work among too many consulting and engineering firms, the EPA report said. The city should have named a single firm to oversee the entire project, and also should have imposed financial penalties to motivate contractors to finish their work on time, the report said.

‘Essential Need’

“These experiences emphasize the essential need for a single party to have overall control of the design and construction,” the EPA report said.

Erecting the different parts has been relatively easy compared to actually coaxing the machine to dry the sludge into powder. The sludge is far more abrasive than engineers predicted, and has eaten through valves and seals during testing, sometimes in hours. Testing of the Carver-Greenfield process was shut down for four months so new, stronger valves could be designed and installed.

Severe clogging has also occurred when the sludge turned into a paste, an unexpected phenomenon the engineers call the “gummy phase.” Hair and grit carried into the HERS system along with the sludge have also gotten tangled in the intricate machinery, forcing engineers to install “muffin monsters,” powerful steel jaws that pulverize the sludge.

“The powder has turned out to be very difficult to handle,” said Roger T. Haug, a consultant who co-authored a 1980 study that persuaded the city to begin work on HERS. “It does everything opposite what you want it to do.”

Another Major Alteration

Because of the clogging, engineers are considering yet another major alteration that could delay work six months or more--and add several million dollars more to the cost. The change would involve removing a heat exchanger that was installed strictly to improve energy efficiency.

On the morning of Feb. 2, the most damaging of the setbacks began.

A few weeks before, city records show, workers smelled the odor of electrical burning on the third floor of the Carver-Greenfield building, but could find nothing burning. But that morning, an inspector discovered oily sludge powder smoldering inside a pipe that should have been clean.

At 9 p.m., a shocked night operator noticed a weird light and looked up to find a 24-inch thick pipe glowing “cherry red.” Supervisors were alarmed, and not at all sure why the vapor line was overheating--and unable to predict what would happen if it melted. The glowing line was so hot that the fiberglass insulation was melting, and so hot that any attempt to use water on the fire would have exploded the pipe and caused unknown damage.

Powder Caught Fire

Steam helped cool the line while operators threw switches trying to regain control. The line began to cool during the night, but early the next morning the overheating began again. By then engineers knew that somehow the oily sludge powder had blown into the line and caught fire.

“You can’t put this fire out, your only hope is to cool the system until the embers die,” an engineer told his superiors.

Not until Feb. 10, a week later, was the fire fully extinguished and the system cool enough to inspect. A major redesign was needed, delaying the project five months and costing about $3 million.

Later, in August and September, two smaller fires broke out in other areas of the Carver-Greenfield system, and there have been small fires in a sludge storage bin and in a sludge centrifuge.

Although less damaging, the implosion of a storage bin full of sludge powder on Aug. 27 illustrates the complex sensitivity of the HERS process.

Blanket of Nitrogen

The sealed storage bins hold dried powder that is waiting to be burned. Around the Hyperion plant, computers and other sensitive electrical equipment are kept under nitrogen, so the hydrogen sulfide always in the air will not foul contacts. To prevent explosions, the sludge powder is also stored under a blanket of nitrogen.

But that day, a valve was mistakenly left closed so that the compressor pumping nitrogen into the bin began instead to suck the gas out. The pump ran all night and created a vacuum strong enough to crinkle inward a bin several stories high made of 3/8-inch steel. This added another $100,000 in design changes and repairs to the cost.

Engineers agree that the design work was rushed, but they contend that many of the problems encountered are the routine bugs found in testing a new, high-technology process.

“It’s a matter of working out all the problems,” Kennedy said. “You can’t just put one of these in and turn on the switch.”

Unexpected Ammonia

But the engineers admit that even now they do not understand all the complexities. For instance, they have detected unexpected ammonia in the system, enough to disturb the noses of residents in nearby El Segundo.

“We’re still trying to nail down exactly where it comes from. There is a fair amount of ammonia formed out there,” said Hartnett of Foster Wheeler.

The engineers have been cheered by a recent 10-day spurt of operations that saw one section of the Carver-Greenfield system produce 18 tons a day of powder, enough to bank some away so the equipment that burns the powder can be tested.

“A month ago I would have said major modifications will be needed to keep it running,” Haug said. “But they’ve done a good job keeping it going the last month or so. But, if we knew what next month’s problem was, we’d be solving it now.”

‘It Takes a While’

The EPA has also not given up on the project. “We’ve had problems with high-technology projects like this before; it takes a while to get all the bugs out,” said Paul Helliker, who until recently monitored the city’s sewage problems for the EPA regional office in San Francisco. “I think it’s going to work.”

However, another arm of the EPA has refused to pay for much of the HERS project, citing the cost overruns. Bradley and the City Council originally decided to take the HERS gamble because the EPA--aware that the technology was experimental--was willing to absorb most of the costs.

In a 1979 memo, the city’s chief administrative office advised Bradley that the project could be built for $102 million. All but $12 million would come from EPA and state grants. By the time the construction contracts were signed, the cost had risen to $216 million, a recent city report said. But still, the EPA was willing to pay its share.

But in December, a report by the chief administrative office calculated the real cost has topped $330 million--not including $20 million in city salaries and benefits for time spent on HERS by city engineers and work crews. The total includes $49 million for consultants, most of that to a joint venture of the James M. Montgomery Co. and Ralph Parsons Co.

Far Higher Total

That total is far higher than any expense the city has admitted before, and more than $100 million higher than the cost estimate provided last October to Judge Pregerson.

City officials said they began warning in 1983 that the costs were rising sharply because of difficulties with the technology. Nonetheless, the state Water Quality Control Board--which administers the EPA grants--ruled that the city should have been able to build the project within 5% of the original cost.

The board has refused to release money to cover the cost overruns, and city officials have calculated the tab for local taxpayers will top $155 million. City officials have appealed on grounds that the 5% limit applies to conventional sewage treatment plants and does not reflect the problems of trying to devise an entirely new technology. A first appeal to the state was denied, and the EPA office in San Francisco is considering an appeal now.

THE TROUBLED HYPERION ENERGY RECOVERY SYSTEMTHE OPERATION

About 400 million gallons a day of raw sewage, mostly water, flow into the Hyperion treatment plant near El Segundo. It comes through 6,000 miles of sewer pipe beneath Los Angeles and more than 20 other cities. Before entering Hyperion, large objects such as rocks and tree roots are screened out.

In settling and aeration tanks, most of the solids in the sewage are separated from the water. The water, still carrying fine sewage particles, is discharged in the ocean. The solids, a wet mix of home, industrial and body wastes, ferment for 20 days in anaerobic digesters that recover methane gas. For 30 years, this sludge was dumped in the ocean after being digested.

To replace sludge dumping in the ocean, the city has built the Hyperion Energy Recovery System. The idea is to dry and burn the sludge. The first step is to spin the sludge in centrifuges to remove more water. The resulting “wet cake” is then mixed with oil. The wet cake-oil mixture is then heated to evaporate the water left in the sludge. When the water is gone, the oil is vaporized and recovered for reuse. What’s left, in theory, is a dry powder that makes a good fuel for boilers that create steam to drive electrical generating turbines.

THE PROBLEM

The sludge has proven difficult to handle. A February fire took a week to extinguish and set back the project five months. Fires, clogging of the powder and severe abrasion from sand carried in the sludge have stalled efforts to start up the system. Although $350 million has been spent so far, engineers don’t know when or if the system will ever work. Plans are being made to dispose of some sludge permanently in landfills.