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Sewer threat was minimal

February 25, 2002|By DAN KULIN /Staff Writer

When millions of gallons of largely untreated waste water that flowed from the Hagerstown sewage treatment plant into Antietam Creek this month it wasn't good.

But there was not enough contamination to cause noticeable harm or pose a serious health threat to the creek or those who were on it.

That was thanks to the winter temperatures, the dilution of the waste water by the creek - and later the Potomac River - and the relatively short duration of the contamination, state and local officials say.

The treatment plant off Frederick Street was partially shut down Feb. 9 after high concentrations of chemicals common to industrial cleaners and other industrial products came into the plant and killed the sewage-eating bacteria used to break down complex bacteria and chemicals.

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The chemicals that wreaked havoc in the plant were probably too diluted to cause any harm upon leaving the plant, officials said.

If the chemicals were released in a high enough concentration "we would have seen an impact ... immediately," said Richard McIntire, spokesman for the Maryland Department of the Environment. Fish and insects downstream from the plant would have been killed, he said.

In high concentrations, the chemicals can burn people, said Dr. Thomas Gilbert, chairman of the Washington County Hospital Emergency Medical Department. But Gilbert said the health risk to people who came into contact with the creek the day of the shutdown was "basically nil."

"These chemicals were so diluted when they hit the water," he said.

City Water Pollution Control Department Manager Rick Thomas estimates at least hundreds of gallons of the chemicals were dumped into the sewer system.

The Hagerstown plant empties approximately 5.6 million gallons of waste water into Antietam Creek daily. The creek carries approximately 56 million gallons of water a day past the plant, MDE spokesman John Verrico said.

In addition to the chemicals, the partial plant shutdown allowed contaminants usually removed from the waste water during the treatment process to flow into the creek.

The screening and settling steps of the treatment process, which remove sludge and other solid material, continued operating during the partial shutdown. But the disinfecting and bacteria treatments were stopped.

The levels of fecal coliform bacteria in the waste water skyrocketed when the disinfecting was stopped.

The winter temperatures stopped the influx of bacteria from triggering an algae bloom, McIntire said.

"This is organic material and it needs warmth to reproduce. The bacteria will not reproduce as fast in cold temperatures," McIntire said. "If we were to have seen something we would have seen it already."

The dilution factor lessened the danger to public water supplies, and no measurable effects from the contaminants coming from Hagerstown were detected at down-river water plants.

Gilbert said the threat to people was minimal.

"You would have to drink it. You couldn't get anything just from touching the water," Gilbert said.

Fish could carry some bacteria, but cooking the fish would kill any bacteria and make it safe to eat, Gilbert said.

If the bacteria did make someone sick, the symptoms would include diarrhea and possibly vomiting, Washington County Health Officer William Christoffel said.

Christoffel said the contaminated waste water has "got to make a difference. The extent of it is the question."

"There was probably a very minor impact because (the contamination) was relatively short-lived, and the ability of the stream to absorb it," he said.

On Feb. 12 - three days after the partial plant shutdown - a chlorine disinfecting process was started at the plant, which killed much of the bacteria.

On Feb. 18, the ozone disinfecting process was restarted. It does a better job of killing harmful bacteria because the plant is designed to use an ozone disinfecting process.

Meanwhile, the sewage-eating bacteria has been regrowing at the plant.

The plant should be back to normal operations sometime this week, Thomas said.

If the plant had been down for several weeks or months, the contamination could have built up in the creek and caused problems, he said.

"The difference is between acute and chronic (contamination)," Thomas said. "A treatment plant can go out of whack for a day or two and the stream will be OK."

The public is still being advised not to come into contact with the creek, and MDE continues to monitor wildlife along the creek.

Kimmy Armstrong, acting director of environmental health at the Washington County Health Department, said signs advising people to stay away from the creek will stay up at least 30 more days.

This will give the creek the chance to flush out any contaminants, she said.

"It gives us a buffer."

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