COLUMBIA — Ammonia could change the taste of Columbia’s water and make it safer to drink.
Local officials were notified in April that levels of carcinogens called trihalomethanes, or THMs, in Columbia’s drinking water were above federal standards. This spurred the city to spend more than $90,000 on a contract with the MU Water Resources Research Center to identify the cause of the problem.
Researchers concluded that about 70 percent of THMs are introduced before water is pumped through distribution pipes. Pending City Council and state approval, Columbia Water and Light wants tackle the issue with a mixture of chlorine and ammonia.
It’s called a chloramine treatment process, and Water and Light thinks it’s the first step toward lowering levels of the carcinogen.
Matter of taste
In addition to lowering levels of THMs, the chloramine treatment process could change how tap water tastes.
“All sorts of people swear it tastes better, and then there are those who don’t like it. Most say there’s no difference,” said Everett Baker, an environmental engineer for the Missouri Department of Natural Resources.
“Sort of like when Coke changed its formula. It wasn’t bad, it just wasn’t the same.”
Kirksville switched to a chloramine treatment process two years ago to comply with EPA standards for THMs, and the number of complaints about taste and odor did not go up, said John Buckwalter, director of Kirksville Public Works.
“We anticipated some taste and odor problems, but there really weren’t many complaints,” Buckwalter said. “There aren’t any more complaints now than there were before we started using chloramine.
“Our change was pretty much a non-event,” Buckwalter said.
He said an aggressive public information campaign to dispel concerns could be the reason for the smooth transition to a chloramine treatment process.
The city of Columbia plans to send out a public notification to residents before any change in the water treatment process is made, Connie Kacprowicz of Water and Light said.
How it Works
When chlorine is used to kill harmful bacteria in drinking water, as it is in Columbia, the chemical interacts with organic material and forms THMs. But removing chlorine from the treatment process is not considered to be a viable solution.
“The good thing about chlorine is that it continues to fight harmful bacteria as it moves through the distribution system,” Kacprowicz said of Water and Light's plan to use chloramine.
A common fix is adding ammonia – which, when it interacts with chlorine creates a chemical compound called chloramine.
Chloramine does not interact with organic material the same way that chlorine does, and fewer THMs are produced when it is used as a disinfectant.
Columbia's drinking water comes from ground wells, which generally provide cleaner water than surface water sources like lakes and rivers. Because the water is cleaner and there are less bacteria for chlorine to interact with, it was not believed that adding ammonia to limit the formation of THMs was necessary. But once the city was notified that it had a problem with THMs in its drinking water, it began to consider adding ammonia and creating a chloramine treatment process, Kacprowicz said.
History of chloramine treatment
The chloramine treatment process was first used in the U.S. at a Denver water treatment plant in 1917 and is in place in major cities such as Los Angeles, Dallas and Philadelphia.
St. Louis started a chloramine treatment process in 1938, and Kansas City has been using it since 1964, according to the American Water Works Association, a nonprofit group that specializes in water treatment.
As an environmental engineer for the DNR, Baker works with water distribution systems across the state and said using chloramine to control levels of THMs is standard practice.
“St. Louis and Kansas City have used it for a long time," Baker said. "We’re not getting complaints from anyone.”
Though the chloramine treatment process is a common solution for elevated levels of THMs, the state requires extensive testing before any changes in water treatment can be made.
To comply with state regulations, the city hired water scientists at MU to gather data on where THMs are forming in the treatment process.
Preliminary results have been confirmed showing that most of the problem occurs before water travels through city pipes. Researchers are now determining where the ammonia can be added to effectively reduce levels of THMs, said Enos Inniss of MU’s Water Resources Research Center.
A chloramine treatment process could be in place as early as this spring, according to a Jan. 8 press release from the city.
Lead and copper problem
Despite its safe use across the country and throughout the state, the proposed water treatment method was linked to increased levels of lead and copper in Washington, D.C.’s, drinking water, causing a major public health scare.
Levels of lead and copper spiked at an alarming rate after Washington, D.C., began using a chloramine treatment process in 2001. The Environmental Protection Agency concluded that chloramines interacted with the chemistry of the city's water supply in a way that corroded lead and copper pipes.
The anti-corrosion treatment chemical orthophosphate was added to the treatment process in 2004, and it prevented the harmful elements from leaching into the city’s tap water. Washington, D.C.’s, water now complies with EPA standards.
Baker didn’t think Columbia would experience similar troubles because its water chemistry differs significantly from that of Washington, D.C.
“Columbia’s water (chemistry) is much more stable, and lead and copper issues should not be a problem,” Baker said.
The city tests drinking water for lead and copper on a regular basis, and any spike in levels would be corrected, Kacprowicz said. Levels of copper and lead in drinking water are well within EPA standards, according to numbers published by Water and Light.
In Kirksville, levels of lead and copper in drinking water did not go up after switching to a chloramine treatment system.
“We test for lead and copper at service taps, and we have not seen any significant change,” Buckwalter said. But he added that if chloramine is corroding lead and copper pipes, it would take longer than two years to become a major problem.
A chloramine treatment process could be just part of the solution.
“There isn’t a silver bullet or one answer," Baker said. "I wish there were. You have to do multiple things.”
Additional treatment methods, such as membranes to filter out bacteria and structural changes at the treatment plant, also are being considered. Using ultraviolet light to kill bacteria is not likely to be part of a long-term solution, partially because it does not fight bacteria as water works its way through the distribution system, Kacprowicz said.
Though a chloramine treatment process might only be one method used for reducing levels of THMs, Kacprowicz said it would represent progress.
“I think that it is a step in the right direction.” Kacprowicz said. “Adding ammonia is a good interim solution, and we should see the level of (THMs) drop significantly.”
Moberly and Macon could also begin using a chloramine treatment system to ensure they remain in compliance with EPA standards for THMs, Baker said.
If the City Council approves the switch to a chloramine treatment system, kidney dialysis patients that use home dialysis machines should take special precautions to prevent chloramines from entering their bloodstream. Chloraminated water is safe for kidney dialysis patents to drink and bathe in, and only poses a problem during dialysis.
Kirksville officials worked with the local hospital and health care professionals to ensure dialysis patients were not at risk before the switch was made, Buckwalter said.
Columbia plans to send out a public notice, but additional details of a public information campaign have not been decided, Kacprowicz said.
A chloramine treatment process would also pose a problem for Columbia residents with fish tanks. Ammonia, which is in chloramine, is toxic for fish, and pre-treatment systems should be set to filter out the chemical.