Bacteria Aids Lake Cleanup

February 01, 2004

By Mark Weiner

The 466 trillion foam beads, each coated with untold numbers of friendly bacteria, are loaded in the tanks and ready to go to work.

Their mission: Clean Onondaga County's sewage by consuming ammonia and converting it to less harmful forms of nitrogen. If all goes as planned, the result will be dramatic improvements to Onondaga Lake's water quality starting this spring.

The beads and bacteria are two of the key elements in a $125 million expansion near completion at the Metropolitan Sewage Treatment Plant on Hiawatha Boulevard in Syracuse.

Metro's expansion is the single largest project in the county's $380 million, 15-year program to clean the lake by eliminating sewage overflows and related pollution.

County officials say they reached a major milestone in that effort this month as testing started on a new ammonia-removal facility, the first half of the Metro expansion project.

Contractors turned on all of the systems in the new plant, which will process up to 126 million gallons of sewage per day.

Last week, those contractors were in the middle of a 14-day performance test to make sure everything works properly, said Michael Cunningham, director of the county's Onondaga Lake Improvement Project.

Cunningham said he doesn't expect to see any difference at the end of the pipe until later this spring.

"From an ammonia standpoint, the lake should improve dramatically," he said. "The quality of the water in terms of toxicity to fish or other aquatic organisms should be greatly improved."

The second half of the project, a new phosphorus removal facility, is to be completed by July.

State regulators say ammonia and phosphorus are the two contaminants of greatest concern when it comes to Onondaga Lake's sewage pollution.

High levels of ammonia from the treated sewage makes the lake inhospitable to smaller fish and aquatic organisms.

Phosphorus is a natural element found in human sewage and fertilizer. In lakes, it promotes the growth of algae, the microscopic plants that give the water a cloudy, green appearance and deplete oxygen crucial to fish.

Under a federal court order, the county must make improvements to its sewage system that will allow Onondaga Lake to meet standards for swimming and fishing by the end of the cleanup in 2012.

The lake is one of the most polluted in the nation and is among only three lakes listed on the federal Superfund list of toxic waste sites.

Steve Eidt, regional water quality engineer for the state Department of Environmental Conservation, said officials are pleased with the county's progress on the Metro plant.

"From a regulator's standpoint, it's really good what's happening out there," Eidt said. "They're years ahead of schedule on the ammonia project."

Cunningham said the recent winter weather, marked by temperatures substantially colder than normal, has been one of the obstacles slowing the progress.

"The biggest thing that we're fighting is the cold air and cold water temperature," he said. "Bacteria are living things that don't like cold. So they're not going to multiply as fast in this weather."

The bacteria convert ammonia in the sewage to other, less harmful forms of nitrogen, such as nitrite or nitrate.

The tiny foam beads, which provide a surface for the bacteria to cling to, are loaded in 18 concrete treatment tanks. Each tank is filled with 273,000 gallons of bubbling sewage water. But the bacteria won't begin to multiply in larger numbers until the warm weather, Cunningham said.

Over the coming weeks, contractors will continue to conduct tests and add more bacteria to the tanks.

Once testing is successfully completed, then the county will take over operation from the construction contractors, USFilter Kruger Products. A two-year warranty starts once the county accepts the plant.

As part of the Metro expansion, the county will no longer rely on chlorine-based chemicals, which also can harm fish, to disinfect the treated sewage water discharged to the lake.

The new plant will use 300 submerged high-energy lamps to produce ultraviolet light that disinfects the discharge.

At its peak, the expansion project employed 120 construction workers who had to drive 1,200 piles to an average depth of 275 feet to support the new buildings.

Cunningham said the remaining work includes a new building that will house the Metro plant's operations center and control room.

A formal ribbon-cutting ceremony will likely take place with county officials this summer, he said.

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