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Waste water treatment plant nearly back to normal operation

February 19, 2002

Waste water treatment plant nearly back to normal operation



By DAN KULIN
dank@herald-mail.com


Hagerstown's sewage treatment plant was operating at near pre-shutdown levels after a successful switch back to using ozone to disinfect the waste water on Monday, Plant Superintendent Donald Barton said.

The plant was 80 percent to 85 percent back to normal, and with the use of ozone the waste water flowing from the plant into Antietam Creek was "very close to pre-shutdown levels," Barton said.

Plant operations should be back to normal by Feb. 25, he said.

The city plant was partially shut down Feb. 9 after the bacteria used to help treat sewage were killed when at least hundreds of gallons of chemicals commonly found in industrial cleaners, insecticides, paint and other manufacturing products were dumped into the sewer system.

Barton said city and Maryland Department of the Environment officials are trying to find out where the chemicals came from. The MDE has asked that anyone who saw suspicious activity or dumping into the sewer system call 301-739-8068.

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The screening and settling steps of the treatment process, which remove solid material such as sludge, continued running during the partial shutdown. But the ozone disinfection and bacteria treatments of the waste water were shut down, allowing 5.6 million gallons of largely untreated waste water to flow daily from the plant into Antietam Creek.

The plant began using a chlorine disinfection process on Feb. 12, which killed most bacteria and essentially ended the flow of contaminated waste water into the creek, Maryland Department of the Environment spokesman Richard McIntire has said.

New bacteria used to break down complex bacteria and other chemicals is growing at the plant. Barton said that as the bacteria reproduces it will do a better and better job of treating the sewage.

At about 12:30 p.m. Monday, the plant switched back to using ozone to disinfect the waste water, Barton said.

The ozone will do a better and more consistent job of killing bacteria because the plant is designed to use ozone, he said.

Barton said the plant's biological nutrient removal process, which removes phosphorous and nitrogen from the waste water, was still down, but tests of the waste water taken last week showed that nitrogen and phosphorous levels were within state limits.

The public was still being advised not to come into contact with the creek.

Hagerstown and state officials have said the millions of gallons of untreated or partially treated waste water that has flowed from the city sewer plant over the past week hasn't harmed people or wildlife along the creek.

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