Columbia's water to undergo new disinfection process

The new cleaning process will reduce carcinogenic by-products.

By Kyle Daly

Published June 2, 2009

A change is on the horizon for the disinfection process of Columbia's public water.

For more than a year, Columbia Water and Light, the Missouri Water Resources Research Center and the Missouri Department of Natural Resources have been working in conjunction to lower trihalomethane levels in the city's water. THMs are by-products of the city's disinfection process, formed after chlorine breaks down organic material, and some THMs are considered carcinogenic.

According to the MoDNR, if people drink two liters of over-the-limit water each day for 70 years, then three to four cases of cancer would develop out of every 10,000 drinkers.

Because of these health risks, the Environmental Protection Agency has a limit on the amount of THMs that can exist in a public water system.

"The regulations are put in place to be as cautious as possible," said Dr. Enos Inniss, member of the Water Resources Research Center.

In 2007, the city of Columbia's water contained more than the 80 microgram per liter maximum contaminant level and received a notice of violation from the Missouri Department of Natural Resources. Columbia reported an average concentration of 82.3 mcg/l. The city went over this limit twice in 2008 before coming back down to regulation levels.

MoDNR spokeswoman Renee Bungart said Columbia wasn't the only town to have high THM levels.

"There are 14 systems in Missouri violating the EPAs Maximum Contaminant Level," she said. "This is out of 2,800 public water systems in Missouri."

Testing conducted by the Water Resources Research Center has found that THM levels can be reduced by adding ammonia to the already chlorinated water, a method used by many water systems in the United States according to the EPA Web site. Adding ammonia to chlorinated water will form the chemical chloramine, which will help slow the formation of THMs.

Floyd Turner, Columbia's water operations manager, said the city could see as much as a 50 percent reduction in THM formation by adding ammonia to the water after it is treated with chlorine, and he said this would make ammonia a secondary disinfectant for the water. Columbia uses chlorine as its primary disinfectant.

According to Columbia Water and Light reports, one reason for the increased levels of THMs is the growth of the city's water distribution system. Because the water has a greater distance to travel than in previous years, it allows more time for the formation of THMs.

Turner said even if Columbia continues to grow in population, the use of chloramine would prevent the water from going over the EPA's set limit.

Using chloramine as a disinfectant has its own set of risks. According to the EPA's Web site, ingestion of water containing chloramine might cause irritation of the eyes and nose, stomach discomfort and Anemia, which is a deficiency in red blood cells or hemoglobin. But these risks only pertain to people with chemical sensitivities or other health issues. Hospital patients who are undergoing kidney dialysis are also susceptible to chloramine if it is contained in the water used for their dialysis treatment.

University Hospital spokesman Jeff Hoelscher said the change is not something that will affect the hospital's dialysis patients in that the hospital does not use the city's water, but instead utilizes its own water treatment facility. He said the water used for dialysis is pretreated and mirco-sterilized prior to use.

The change in the disinfection process is expected to take place in July or August.