Illinois-American Water Co. will begin the annual treatment of its water system Sept. 5. Illinois-American Water will be temporarily changing the type of disinfectant used in the water, as they always do this time of year. Instead of combining the chlorine in the water with ammonia, the company will be adding chlorine only.
The city of O’Fallon buys treated water wholesale from Illinois-American, a private company, and then pumps it to all water customers. The water is treated prior to its delivery to the city of O’Fallon’s pumping station in French Village.
This change is needed to remove residues that have been collected due to the normal disinfection practices. Water leaving the plant is usually disinfected with a combination of chlorine and ammonia. Combining the chlorine with ammonia is beneficial in that it prevents bacterial growth by keeping the chlorine in the water longer. It also prevents disinfection by-product formation and taste/odor problems. The use of the ammonia with the chlorine, however, can result in a buildup of amounts of certain chemicals. These chemicals can be removed or prevented from forming by using free chlorine rather than the combined chlorine for a short time each year.
The safety of the water will not be affected by this temporary change. Many water plants use chlorine in the free, uncombined form on a regular basis. Illinois-American Water will continue to supply water that meets the requirements of the Illinois Environmental Protection Agency.
There is no need to boil the water. If an objectionable difference in odor is noticed, residents should allow the water drawn from the tap to sit in a refrigerator for a few hours.
Dialysis patients and renal care facilities should be aware of these changes and adjust their health care practices accordingly.
The city of O’Fallon will be notified when Illinois-American goes back to the normal type of disinfectant in approximately four to five weeks.