Disinfection of drinking water is critical to protecting consumers from disease-causing
microorganisms, called pathogens, including bacteria or viruses. Disinfectants are very effective at inactivating (or killing) pathogens and have enormously benefited public health.
Public water systems are required to disinfect water prior to it entering the distribution system that carries it through pipes for delivery to consumers. Public water systems in Louisiana are also required to maintain a minimum amount of residual disinfectant throughout the distribution system to make sure levels of harmful microorganisms remain low (Title 51, Part XII, Section 355). Treatment prior to distribution may utilize a number of different disinfectants, but a public water system is required to use either chlorine or chloramine in the distribution system.
Chloramine is a long-lasting disinfectant added to public drinking water for disinfection. It is formed when chlorinated water reacts with added or naturally occurring ammonia present in the source water. It is commonly used for disinfection in many public water systems throughout Louisiana, the United States, and countries around the world.
Chloramine is an effective disinfectant and persists over a long period of time, particularly in areas with high temperatures and PH. The groundwater supplying the Cross Gates system has a moderate amount of naturally occurring ammonia which makes chloramine disinfection more effective in maintaining the required residual while minimizing the negative effects of large amounts of chlorine that would be needed in a free chlorine system. In addition, chloramine typically produces lower levels of regulated disinfection by-products (such as total trihalomethanes (TTHMs) or haloacetic acids (HAA5)) compared to free chlorine because it is less reactive with naturally occurring organic matter that may be in the water.
Disinfection by-products (DBPs) are formed when disinfectants such as chlorine and
chloramines react with natural organic matter in drinking water. The EPA regulates some DBPs, such as total trihalomethanes (TTHMs) and haloacetic acids (HAA5) to minimize their health risks. A challenge faced in drinking water disinfection is to protect the public from waterborne diseases while reducing public exposure to DBPs.
Yes, water disinfected with chloramine is safe for drinking, cooking, bathing, and everyday use. The U.S. Environmental Protection Agency (USEPA), the Centers for Disease Control, and the World Health Organization have determined that chloramine is a safe disinfectant and that water disinfected with chloramine within regulatory standards has no known or expected adverse health effects. Chloramine, like chlorine, must be removed from the water prior to use in dialysis machines and can be harmful to fish and amphibians. However, proper filters and dechloramination products are able to address these concerns.
A free chlorine conversion (also referred to as a “chlorine burn”) occurs when a water system that typically uses chloramines for disinfection temporarily switches the disinfection method to free chlorine. This is accomplished by increasing the amount of chlorine added to the water in order to overcome the naturally occurring ammonia in to produce a free chlorine residual.
The Department of Utilities has in place a Nitrification Plan which calls for routine testing to monitor levels of bacteriological activity and levels of ammonia and ammonia by-products in the system. The plan calls for a chlorine burn to be implemented when certain parameters are exceeded. At this time, none of the parameters as set forth in the Nitrification Plan have been exceeded which would indicate the need for a chlorine burn. However, a chlorine burn is being performed strictly as a precautionary measure and to increase public trust in the water quality as recommended in the Final Report prepared by Owen & White Consulting Engineers, Inc. There is no evidence or indication of bacteriological contaminants in the Cross Gates water distribution system. The Cross Gates water distribution system is in full compliance with all Louisiana Department of Health (LDH) and U.S. Environmental Protection Agency (EPA) regulations.
The temporary change will likely cause some discoloration or cloudiness in the water, minor pressure fluctuations, small air pockets, and a strong chlorine odor and taste. If this is experienced, running water may help minimize the effects. Fire hydrant and valve flushing should remove a majority of the color and odor, but some will reach customer lines during the process.
The significant increase in the chlorine concentration in the water system may cause customers to experience eye or skin irritations and other possible effects similar to swimming pools with a high dose of chlorine. Customers who use tap water for kidney dialysis at home should contact their doctor to determine if any changes are necessary in their residual disinfectant neutralization procedures. Customers utilizing the water for aquariums should monitor the chlorine residuals.
Yes, the water will remain safe to drink (except during precautionary Boil Water Advisories that will be issued during the disinfection transition periods of this process). However, be advised that by significantly increasing the Chlorine concentration, an increase in the production of disinfection by-products (DBP’s) is expected. DBP’s are classified by EPA as human carcinogens that are created during the disinfection process. The DBP’s level will be monitored throughout the Chlorine conversion to ensure levels do not increase beyond the maximum contaminant levels set by the EPA.
St. Tammany Parish Government remains committed to providing customers safe and quality drinking water.
Additional information regarding the reason for the temporary conversion to Free Chlorine can be found in the Final Report by Owen & White Engineering Consultants, Inc. on the www.stpgov.org.