Columbia’s Water disinfection method switched from chlorine to chloramine

Nov 6, 2014

COLUMBIA – The City of Columbia will switch its water disinfection process from chlorine to chloramine this week. Columbia Water and Light used the chlorine disinfection method until August 2009 when the water was tested and exceeded the maximum contaminant level.

Columbia’s Water Production Superintendent Ed Fisher said the city will add ammonia to its chlorinated water to stop the formulation of disinfection by-products like high levels of trihalomethanes (THMs).

“We had a violation on THMs, several years ago, probably about six years ago,” Fisher said. “And when we go to chloramines it keeps the THMs down to an acceptable level. And we go to free chlorine in the summer to prevent any nitrification.”

The Environmental Protection Agency limits THM levels in public water systems to keep water healthy.

The Missouri Department of Natural Resources and the Columbia City Council approved this switch to chloramine disinfection to slow the formation of total trihalomethanes.

Gena Terlizzi works for the Missouri Department of Natural Resources and said the city looked for alternatives to make sure the public water system has the highest water quality, while meeting regulations and requirements that are in place to protect people on a public water supply.

“The purpose of the chloramines is to protect the water quality,” Terlizzi said. “As it moves through pipes the chlorine provides long lasting protection and that’s very important when we’re talking about drinking water and we don’t want bacteria in the drinking water because it’s coming into our homes and we’re using it a multitude of things including of course drinking.”

She said Columbia chose chloramine because it would clean the water with little impact.

The city worked with the Department of Natural Resources and the University of Missouri to determine chloramine as the solution to balance THM levels.  

Columbia’s water quality report and the water testing results can be found on the city’s website.