City Water Disinfection Process Reverts Back to Chlormine July 1

As of July 1 the city Water Utilities Department will revert back to chloramine as a means of disinfecting the public water supply. June 1 through June 30 the city has been/ is using free chlorine as part of annual disinfection to the water supply.

Every year the city changes the disinfection process in order to keep the public water supply free of harmful bacteria. As chloramine moves through the distribution system throughout the year normally, it partially decays and releases ammonia. Ammonia can cause side effects over time like nitrification and biofilm.

Nitrification can occur in distribution systems, like San Angelo’s where chloramines are used as the secondary disinfectant. According to the Texas Commission on Environmental Quality (TCEQ) website the key to stopping nitrification is to starve the nitrifying bacteria of nitrogen. The most effective way to do that is to switch disinfectants from chloramine to free chlorine, a common practice by other systems besides San Angelo. Switching back to chloramine on July 1 completes that process.

Biofilm is a group of microorganisms in which cells stick to each other on a surface; it is sometimes compared to slime like consistency, lining the walls of water pipes and other surfaces. Much like the ring in your bathtub biofilm lines water pipes, naturally occurring as mineral deposits build.

Another part of the process is flushing. If disinfectant levels fall when water stands still in the system and usage falls, flushing of the end mains is required to keep new water moving through the system. Click here for an example of flushing.