Decontamination slowed

COLUMBUS - Decontamination efforts to reduce chemical levels in a few municipal drinking water wells have been prolonged by equipment problems and uncooperative weather.

The Environmental Protection Agency (EPA) has been working to reduce and eventually eliminate the plume, or contaminated area, created by chemicals from a dry cleaning facility. The site came to the attention of the Nebraska Department of Health in 1983 when trichloroethylene (TCE) was detected in four of the municipal wells and 15 years later the source was identified as One Hour Martinizing Dry Cleaners.

Chuck Thomerson, the Columbus public works and environmental services director, said work is being conducted in the vicinity of 20th Street and 23rd Avenue to reduce the TCE and tetrachloroethylene (PCE) to acceptable levels.

“They are essentially adding a chemical oxidant (sodium permanganate) to oxidize contaminants and release them out of a soluble state in the water,” Thomerson said. “This will reduce the level of contamination and (the TCE and PCE) should dissipate a little faster in the process.”

Joe Arello, environmental engineer for the EPA, said the chemical oxidation remediation began Jan. 22 and was expected to take four weeks to complete, but complications have extended the time frame.

“The project has taken longer than anticipated,” Arello said, because of “the weather and running into things that we didn't anticipate when we drilled holes in the ground” to apply the oxidizing agent.

Nancy Swyres, EPA project manager for the 10th Street Superfund Site, said the maximum levels of TCE and PCE for a public drinking supply is five parts per billion for each, but the contamination created levels significantly higher, a couple hundred parts per billion.

“The city water wells are still in operation ... (but) there is a groundwater pump and treatment system that strips contaminants out of the water,” making it safe to drink, Swyres said. “The water is clean and well below five after it goes through the process.”

The plume has been determined to span from 18th Avenue to 25th Avenue and 23rd Street to slightly south of the railroad tracks, she said. Periodic treatments will be applied in approximately six month cycles to continue to reduce the contamination.

“We are doing a string of injections and will continue to monitor” the area, Swyres said. “We will do it again in another six months after we look at the plume and sampling locations to determine where the most contamination is. That is where the chemical does the best work.”

Thomerson said although they have hit a few snags in the past couple months thus far efforts during the past two years have been successful.

“They are ahead of the anticipated time they are expecting for this whole thing to be completed,” he said. “They anticipated at least 10-15 years to get the entire area cleaned up. We are probably eight to 13 years out but are looking towards the lower end.”