« Back to News & Notices

Total Trihalomethanes (TTHM)

Trihalomethanes (THMs) are commonly found outside the water system in any environment where chlorine interacts with organic compounds such as in swimming pools, hot tubs, and even chlorine bleach used for household cleaning and washing.

THMs in the water system are a byproduct of the water treatment process. They are formed when natural organic material, such as the decaying vegetation commonly found in lakes and reservoirs, reacts with chlorine used to treat the water. This reaction produces “disinfection by-products,” the most common of which are THMs. The KWSC conducts tests to monitor the levels of total THMs in treated water. The TCEQ also conducts quarterly tests.

Chlorine has been used to disinfect water for almost a century due to its effectiveness at killing bacteria and viruses in water. There is no question that its use has been a huge public health benefit in largely eliminating plagues such as cholera and typhoid and reducing the incidence of intestinal illness and other health problems caused by waterborne germs such as E. Coli and Giardia, in 1974 modified mandated maximum contaminant levels (MCLs) from 100 ppb to the present-day 80 ppb. Drinking water professionals recognized the need to modify the traditional chlorine treatment processes due to advances in knowledge about disinfection byproducts and their health impacts. Kempner Water produces water with the least amount of THMs possible, by doing such things as delaying chlorination (which reduces the formation of byproducts by limiting the time that chlorine is in contact with organic materials), aerating water when levels of organic material are high, enhancing coagulation, which improves the removal of organic materials before the treatment process; and using chloramine instead of chlorine for residual disinfection.

The KWSC has taken action to mitigate THMs by strictly controlling the injection of chlorine into the water purification process at the treatment plant to reduce the level of THMs to a minimum while still maintaining compliance with Federal and State levels during normal purification and free chlorine burn outs especially during periods of high levels of seasonal organic compounds. We have also been actively working with our engineer, State, and Federal authorities to design a prototype aeration system for THM reduction in our ground storage tank which will be the first of its kind in Central Texas. The project is currently awaiting funding approval from the Federal Government to begin construction.

For more information follow us on Facebook at facebook.com/kempnerwsc or please feel free to call Delores Atkinson, General Manager at 254-681-8042.