Levels of Trihalomethanes in the city's water supply have been drastically lowered in recent months.

At a recent city council meeting, Commerce City Manager Darrek Ferrell announced that huge strides had been made to improve water quality within the city, and the numbers are impressive.

Beginning in January 2016, residents began receiving notices in the mail that the city’s water was routinely tested and found to have exceeded the maximum level of trihalomethanes in the water supply. Trihalomethanes are created when chlorine reacts with certain organic matter in water such as algae. As water “ages,” these chemicals begin to build up. The Maximum Contaminant Level of Trihalomethanes provided by the EPA is .080 milligrams per liter.

The substances can have serious health effects when consumed in very large quantities such as cancer. But the levels that were found in the city’s water were not high enough for serious health problems to occur over a short-term period. Also, if fewer people use the water, the problem is exacerbated as the water ages in the lines.

The situation is a sophisticated balancing act, as more chlorine usage means more trihalomethanes. But if less chlorine is used, bacteria and diseases could potentially spread through the water system as well.

After the first failed test, the city has worked to lower the number of contaminants. To be able to stop sending the letters warning residents, the city would have to pass the test three quarters in a row, which made getting back to acceptable levels not something that could be done in a day.

In March 2018, the city finally eclipsed the three-quarter mark with passed tests.

The city has two water testing sites, one on Washington Street and one on Live Oak Street. The Washington Street site has routinely been at minuscule levels of trihalomethanes, but the Live Oak site has been the problem child. The main issues are not as many customers use water from that line, which makes the water in the lines age more, thus creating more trihalomethanes. In the past few years, more flushing has been done at the Live Oak site, which has helped the issue. In September 2017, Live Oak’s test found .081 milligrams per liter, while it was down to .074 in September 2018.

But now, that figure has been more than cut in half, as the test in September 2019 found just .035 mpl.

This has been credited to new filtration and water treatment processes by the city. Anita Moore, the supervisor at the Commerce Water Plant, said that an employee has been put on monthly flushing duty at the Live Oak site which helps reduce contaminant levels. In addition, new lines, pumps and more were installed at the water plant with the help of Hayter Engineering to facilitate a new treatment process that sees monochloramine, a compound that produces less trihalomethanes, added at the start of the process.

“We started this at the end of July,” Moore said. “Since there was so much construction going on, the levels didn’t drop down as dramatically at first, but now they are down much more,”

Mike Tibbets with Hayter Engineering said that the new “disinfectant scheme” is a big help, but the balancing act required to maintain clean water is still a challenge.

“There is a balance between killing pathogens and creating carcinogens,” Tibbets said.

Ferrell credited the Rural Water Association and the Texas Commission on Environment Quality with help on this project. He also said that for the time being, he doesn’t expect the levels to change much now.

“I don’t expect to see any drastic changes with the contaminant levels,” Ferrell said. “If there is increased usage on the Live Oak line, then we could see the levels drop.”

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