Temporary Disinfection Change in the Water System

On Friday, January 15, 2015 and continuing through Monday, February 15, 2015, the water treatment plant will undergo a temporary system disinfection change. In order to maintain good water quality, the Water Department will be performing a process called de-nitrification, commonly known as a free chlorine burn that will increase the free chlorine residual throughout the water distribution system.

You may experience higher than normal chlorine residuals over the next 30-days, but the process is safe and has no known health risks associated with it. The process is designed to remove the bio-film from the mains due to chloramine disinfection and once completed will help to improve water quality.

Chloramine disinfection aids in Trihalomethane reduction and for that reason, the district had to
change to chloramine disinfection several years back rather than the conventional free chlorine
disinfection that has been used in the past. Chloramine disinfection does reduce Trihalomethanes (TTHM) but its by-products are more difficult to remove than with using free chlorine.

The process De-Nitrification is where free chlorine is temporarily injected from the water plant at 4 mg/L of free chlorine until the residual is constant throughout the system. Once that preferred residual level is achieved, the free chlorine is flushed from the system and we will then go back to normal chloramine disinfection. The process can take up to 30-days to complete. The process is a temporary chemical change approved by TCEQ.

Should you have any further questions, please do not hesitate to contact Ramon Sepulveda at
512-263-2707.

Thank you for your cooperation in this matter.