Sewage treatment getting better, says plant supervisor

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, common to industrial cleaners, insecticides, and other manufacturing products, were dumped into the sewer system.

Barton said city and Maryland Department of the Environment officials don't know where the chemicals came from. Anyone who saw suspicious activity or dumping into the sewer system has been asked to call MDE at 301-739-8068.

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.

On Monday, the plant switched back to using ozone to disinfect the waste water, which will do a better and more consistent job of killing bacteria because the plant is designed to use ozone, Barton said.

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