01:00 AM EDT on Tuesday, October 18, 2005

BY JENNIFER LEVITZ
Journal Staff Writer

Heavy rains caused extraordinary havoc at sewer plants along Rhode Island waterways over the weekend, forcing state officials to take the unusual step of closing both Narragansett Bay and all coastal ponds to shellfishing.

And the worst isn't over. Woonsocket's damaged wastewater treatment plant continues to dump millions of gallons of partially treated sewage into the Blackstone River.

State officials say they can't recall so much storm-related environmental damage in one period in Rhode Island. The Bay and coastal ponds could be closed for at least 10 days; Woonsocket officials yesterday were scrambling to replace equipment at the plant, which has been spewing at least 26 million gallons of storm runoff and half-treated sewage into the river daily since Saturday. The city hoped to have it fixed by tomorrow or Thursday.

Although sunny weather is back, people are advised to avoid contact with the Blackstone River and to be cautious of raw shellfish until the state can test the Bay, starting today, for bacteria levels.

"We had overflows throughout the state," said Angelo Liberti, chief of surface water protection for the state Department of Environmental Management. "It's certainly unprecedented in terms of the number of facilities affected."

Environmentalists warn that more pollution could be flowing downstream, from another sewerage failure in Massachusetts.

Unable to handle the weekend's torrent, the Upper Blackstone plant near Worcester was forced to send 120 million gallons of storm runoff and sewage into the Blackstone River without complete treatment, but is back to full operation, according to Thomas Walsh, director of the plant. He believes much of the storm and sewer water will be diluted from rain.

But John Torgan, baykeeper for Save the Bay, predicts "trouble for all of us who live downstream. The system has failed and sewage is flowing into the river, which is precisely what these things are designed to prevent."

Currently, the Woonsocket treatment plant is only able to strain sewer water for grit and heavy solids, add chlorine, and rush it through the treatment plant and into the Blackstone. What's not being done is the important secondary treatment.

"They lost their biological treatment," said Warren Towne, supervising engineer of the DEM. "It breaks down the biological matter -- human feces and whatever goes down the toilet and sink, and industrial wastewater. They lost the ability to break that down."

Towne said with partially treated sewage, "basically, there is possibility for disease."

In 2002, some 2 million gallons of untreated sewage and an estimated 4 million gallons of partially treated sewage emptied into the Blackstone after a power failure at a Millbury, Mass., treatment plant. Following that spill, officials found elevated levels of fecal coliform bacteria in the waters near the Cumberland-Lincoln line and in Woonsocket.

While sewer plants have been temporarily overwhelmed by storms before, Woonsocket was unusual because the flow of water broke equipment, said Liberti, of the DEM.

Michael Annarummo, the city's public works director, said the plant was designed to handle a 100-year storm, but not the kind of seemingly biblical rains that hit Rhode Island in recent days: the city received 8.3 inches of rain between 10:30 p.m. Friday and 10:30 p.m. on Saturday.

Five years ago, the city spent $22 million to upgrade its plant, which empties into the river just below the Hamlet Street overpass.

On a typical day, wastewater flows from homes down pipes in a volume that can be processed by the sewer plant. On a stormy day, though, those same collection systems fill up.

Over the weekend in Woonsocket, some streets became rivers; the river became rapids; and more and more water found its way into the sewer system. On many flooded streets, manhole covers blew off. "The river was flowing right into the sewer lines," Annarummo said.

The treatment plant is designed to process about 16 million gallons a day, from about 50,000 households in northern Rhode Island and parts of Massachusetts, according to the DEM. But with the storm, some 40 million gallons flowed through.

Equipment shorted out; the plant burned through three pumps and three backups. "At one point, we went to the [Emergency Management Agency] and DEM and said, 'Find us more pumps.' They couldn't," said Annarummo.

Adding to the mess, he said, old floodgates along the river didn't work and the plant flooded. He said the "water was just flowing right in. At one point, we were a couple of feet away from losing the whole administration building."

Annarummo said he switched off the secondary treatment to save the plant. "We would have lost everything."

The Woonsocket plant still needs new pumps to resume full treatment, said Liberti of the DEM. He said the city "has been on top of the situation and has already ordered the equipment they need," but that "it's going to be awhile before they are able to provide a full secondary treatment." No one could say exactly how long that would be.

Elsewhere, two state-run sewer plants struggled to keep up as did a plant in Newport, he said. Many of the state's treatment plants are still unable to do the job they normally do.

"Most facilities are probably still fully treating it," Liberti said. "But given the high flows, [water] is not receiving the level of treatment that it typically would."

Torgan, of Save the Bay, said he was among the weather buffs drawn unknowingly to the banks of the Blackstone over the weekend when the river crested, thundering and misting people and cars like a miniature Niagara Falls.

"It was quite a spectacle," he said. "To add to it that it has sewage in it makes it a pretty horrifying image."

-- With reports by Cynthia Needham.