Why Chloramines?

by Hardly Waite

One of the more puzzling issues to the public is the change from chlorine to chloramines as the disinfectant in public water supplies. When a city changes to chloramines, there is usually significant controversy.  A switch to chloramine is seldom met with approval.  What is lost in the discussion, often, is the reason for the change.  The most frequent cause is the city’s effort to meet federal standards for trihalomethane (THM).

The following town board meeting was reprinted in Water Efficiency.  It illustrates well the dilemma that small cities face when their THM levels get out of control. It is a write-up of a town board meeting that took place in March 2014 in Ulysses, NY, in New York’s Finger Lakes region.  It does a good job of explaining how THM is created, while looking at what makes this small town water system vulnerable. It also underlines the challenges of coordinating among different water districts and residents.  What is really interesting is that the most frequent THM solution–the switch from chlorine to chloramine as the disinfectant–was not mentioned.

At the Ulysses regular town board meeting on Tuesday, Town Supervisor Liz Thomas reported on options to eliminate a buildup of trihalomethane, found in the town’s water source three times. “When the system went in it never had any problem, until 2012 in August there was one reading of 80 parts per million,” Thomas said. Bolton Point tests the water quarterly for contaminants.

Trihalomethane, THM, is a chemical compound usually found in industry refrigerants or solvents. THM forms in water systems when chlorine reacts to organic matter, which had settled on the bottom of water pipes, Thomas said. The Environmental Protection Agency’s maximum allowable level of THM in water is 80 parts per million. Bolton Point reported three readings equal or higher than the maximum allowable level. One of these readings was in 2012; in August and October 2013 the elevated THM levels showed up again.

The four water districts in the Town of Ulysses service 203  residents [let’s assume this is a misprint–Ed.] within the town’s borders. According to the EPA, “Some people who drink water containing total trihalomethanes in excess of the limit over many years could experience liver, kidney, or central nervous system problems and increased risk of cancer.”

“When water gets warmer, organic matter and chlorine react and create a byproduct (THM). We found this happened at Van Dorn Corners Road. The highest traces were found while testing in August and October of last year,” Thomas said. “Of course the first course of action we took was to warn all residents because this byproduct is volatile.”

THM found in the town’s water supply is a result of low water usage. In attempt to clear up the low water usage problem, in October 2013 the town flushed the water pipes to clear out the organic matter. Hunt Engineers reported the flushing did not fix the problem and may have further agitated the organic matter and chlorine. The next reading, in December, found the THM levels at allowable limits.

“I said ‘let’s pretend we have an eraser and could erase all of the municipality lines.’ This way we could figure out what’s best for all of the people here. I really want to emphasize looking at this from a bigger picture,” Thomas said.

Thomas sat down with Bolton Point Municipal Water System, the Town of Ithaca, the Village of Trumansburg, and the Tompkins County Department of Health Department to discuss the possibility of distributing the cost of a $100,000 for a water aerator. A water aerator increases the oxygen saturation in water, which in turn releases volatile elements from the water into the air.

“I brought up splitting the cost of the mixer with Ithaca, the department of health, the village, town and Bolton Point looking for solutions as a unified group instead of us alone. Ithaca didn’t seem very interested in the idea though,” Thomas said.

Thomas also suggested a plan to connect the village and town’s water sources at Cold Springs Road and Podunk Road. Thomas also suggested connecting the town’s water source in with the village’s second source.

“We may need a water tank to connect the village with Jacksonville, which would be an additional cost but I’m not totally sure that’s necessary,” Thomas said.

The board agreed further consideration and discussion of all options is necessary before any plans are made.


Source of town meeting notes: Water Efficiency.

Pure Water Gazette Fair Use Statement