Waste Water at Hyperion Now Cleaner Than Ever

Los Angeles’ Hyperion sewage treatment plant, which has missed repeated deadlines to comply with federal clean water rules, is discharging the cleanest waste water ever into Santa Monica Bay and has met an important federal pollution standard nine years ahead of schedule, city officials said Tuesday.

In May and most of April, waste water from the plant discharged five miles offshore from El Segundo contained a daily average of 29.7 milligrams of suspended solids per liter, the officials said. Under an agreement reached between the city and the U.S. Environmental Protection Agency, the level of suspended solids must not average more than 30 milligrams per liter by 1998.

The amount of suspended solids in waste water is considered a key measure of its cleanliness. In early 1986, when the city settled a decade-old lawsuit by the EPA over the dumping of sewage into the bay, levels were as high as 110 milligrams per liter. The city is currently required to maintain an average of no more than 95 milligrams per liter, a standard that is scheduled to drop to 70 milligrams in two years.

“They are certainly doing better than we thought they could do,” said Lois Grunwald, a spokeswoman for the EPA. “And we are very happy about it.”

John Crosse, Hyperion’s operations manager, said: “What we have is pretty sparkling clean water. “If you hold it up in the light next to a glass of drinking water, it is pretty hard to tell the difference.”

Although preliminary data for this month shows the daily average edging toward 32 milligrams per liter, Hyperion officials said the increase is not significant, and they predicted that the levels will hover around the 1998 standard indefinitely.

Dorothy Green, president of Heal the Bay, an environmental group that has been monitoring the city’s agreement with the EPA, said the success in cleaning Hyperion’s waste water has astounded even its harshest critics.

“Everybody has been totally amazed, surprised and delighted at what they have been able to accomplish,” Green said. “They have been doing one hell of a job over there.”

The unexpected improvement in the quality of waste water has been traced to three factors: the use of new chemicals during primary treatment of sewage, an improved aeration system during secondary treatment, and a reduced flow of sewage to the plant.

Crosse said the chemicals have helped pull solid waste out of the water by attaching themselves to suspended solids and quickly settling to the bottom of tanks, where the material can be removed. Before the use of the chemicals, he said, the plant was capturing 60% of the suspended solids. With the chemicals, the plant collects about 80%, he said.

In addition, about half of the sewage in the plant now passes through a more efficient aeration system. The process, part of what is known as secondary treatment, provides oxygen for bacteria, which remove suspended solids bypassed during the chemical treatment. Last year, only 35% of the sewage received secondary treatment. The city is required to provide 100% secondary treatment by 1998 under the agreement with the EPA.

The treatment process has also been assisted by a reduction in the amount of sewage passing through Hyperion, which comes from Los Angeles and eight other cities. In 1985, the plant was averaging 420 million gallons per day, about 50 million gallons more than today. City officials attribute the reduction to the diversion of sewage to the the city’s Tillman plant in Van Nuys. Once new construction at the Hyperion plant is finished in 1998, it will be able to handle about 550 million gallons per day.

“The less flow we receive at Hyperion, the better job we can do,” Crosse said. “We have more time to remove the solids. The more time you have, the better chance you have of capturing the solids.”

The state regional Water Quality Control Board, which supported the EPA in its suit and for years hounded the city to improve its waste water treatment, praised the city for its progress in treating suspended solids but cautioned that the city has not solved all of its sewage treatment woes.

David Gildersleeve, chief of the board’s regulatory section, said the city must still complete construction of its secondary treatment facilities at Hyperion, and he said the city is also well above the federal standard for BOD, the biological oxygen demand of waste water. BOD is a measure of how much oxygen bacteria in waste water must steal from seawater in order to oxidize the remaining material in the waste water. The waste water from Hyperion has required an average of 85 to 90 milligrams of oxygen per liter, which is well below the 1991 standard of 195 milligrams per liter set for Hyperion in the EPA agreement but above the 1998 standard of 30 milligrams per liter.

The BOD level is important because oxygen stolen by bacteria in waste water is no longer available for fish and other marine life. City officials said they were pleased to have already met the 1991 standard, but said they did not expect to meet the 1998 standard until the secondary treatment facilities are finished that year. Crosse said he hopes that Hyperion’s improved record in cleaning its waste water will ease public concern about pollution from the plant. For years, the plant has been synonymous with the city’s sewage crisis, in part because it dumped millions of gallons of sludge a day into the bay until it was forced by the EPA to stop in 1987. The city agreed to pay a $625,000 fine for Clean Water Act violations when it settled its dispute with EPA. “We have worked our tails off to achieve this,” Crosse said. “We hope the public gets the message and starts using the beaches more.”

In recent years, public use of beaches in Los Angeles County has been well below record levels of the early 1980s, although there is no evidence that people have been avoiding the beaches because of concerns about Hyperion. Attendance has been gradually increasing since bottoming out in 1986, and county officials say beach-goers probably care more about the weather than pollution from Hyperion.