INFORMATION PRESENTED TO THE TROUP CITY COUNCIL ON DECEMBER 16, 2024 CONCERNING TROUP'S FREE CHLORINE CONVERSION
The Temporary Conversion to Free Chlorine that began in November was completed in early December.
As was quickly apparent, the use of free chlorine significantly oxidized the color in Troup’s water. Since the appearance of the water changed relatively quickly throughout the distribution system, it would indicate that the source of the tint in the water is the source water and not the distribution system.
Our water was submitted for laboratory analysis before the conversion and during the conversion. While utilizing free chlorine, unfortunately, the Disinfectant by Product (DBP), Total Trihalomethanes (TTHMs), greater than Texas Commission on Environmental Quality (TCEQ) and US Environmental Protection Agency (EPA) standards, were created. This is identical to what occurred in 2004 when the TCEQ required Troup to convert to chloramines, the combination of chlorine and ammonia, to disinfect Troup’s water to reduce TTHM levels in Troup’s water. Since the use of chloramine began, Troup has never been out of compliance for TTHM levels in the water supply.
TTHMs pose health risks when individuals are exposed to them in significant quantities over long periods of time. TTHMs are possibly carcinogenic to humans based on evidence of carcinogenicity in laboratory animals and limited evidence in people. Some of the individual chemicals that comprise TTHMs have also caused other effects in laboratory animals following high levels of exposure, including toxicity to the liver, kidneys, and to neurological and reproductive systems.
Friday, December 13, 2024, the TCEQ met with the city and proposed some experimental changes which might help keep Troup in compliance with TTHM levels and perhaps reduce the color in the water. At Well Number 1, we are studying making some plumbing changes so that the Liquid Ammonia Sulfate (LAS) is added to the water as the water enters the distribution system rather than before it enters the storage tank as it is now. Troup’s Well Number 2, which produces less color in its distributed water than Well Number 1, already utilizes this process. In theory, this will give the chlorine additional time to perhaps oxidize the color in the water before ammonia is added.
The TCEQ agrees that the color in the water is a cosmetic issue and is not caused by harmful chemicals in the water. When there are not TTHMs in the water, Troup water meets all TCEQ and EPA guidelines for water safety.
All treatment processes that could perhaps help mitigate the color in the water require significant investment in upfront infrastructure and in ongoing annual cost. Both of these costs would directly and significantly impact customers’ water rates.
Notice of Temporary Disinfectant Conversion from Chloramine to Free Chlorine
(This notice is being mailed to each City of Troup water customer)
The City of Troup public water system, (PWS) ID 2120003, will temporarily convert the disinfectant used in the distribution system from chloramine to free chlorine. The conversion will begin on November 4, 2024 and continue through December 2, 2024. During this period, you may experience taste and odor changes associated with this type of temporary disinfectant conversion.
Public water systems are required to properly disinfect their water and maintain an adequate disinfectant residual in the distribution system. Chloramine, free chlorine combined with ammonia, is widely used as a disinfectant because it persists for long periods while also limiting the formation of disinfection by-product contaminants. Prolonged use of chloramine coupled with other factors that can affect water quality, such as high temperatures or stagnation of water, may result in the growth and/or persistence of organic matter within the pipes of the distribution system, which may hinder the ability to maintain an adequate disinfectant residual. A temporary conversion to free chlorine, partnered with flushing activities, helps to rid distribution pipes of this organic matter and improve the quality of your water overall.
Flushing during this time may cause temporary drops in pressure in areas being flushed and may result in short-term cloudiness or discoloration. If you encounter this condition, flush faucets, tubs and toilets until the water clears.
The City of Troup Public Water System has chosen to implement a temporary disinfectant conversion to free chlorine based on the following:
TO CLEAN DISTRIBUTION SYSTEM PIPING AND IMPROVE WATER QUALITY. TROUP WILL ALSO COLLECT ADDITIONAL SAMPLES DURING THIS TIME TO FURTHER EVALUATE TREATMENT TECHNIQUES THAT MY FURTHER IMPROVE WATER QUALITY.
Please share this information with all people who drink this water, especially those who may not have received this notice directly (i.e., people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.
If you have questions regarding this matter, you may contact John Odom, Public Works Director at 903.842.3128, extension 14.
For additional information follow this link on TCEQ’s website: https://www.tceq.texas.gov/downloads/drinking-water/chemicals/gi-466.pdf
You may also access the EPA’s information on Chloramines in Drinking Water here:
https://www.epa.gov/dwreginfo/chloramines-drinking-water
You may also access information on the City of Sugarland's 2024 Free Chlorine Conversion on their website:
https://www.sugarlandtx.gov/2104/Free-Chlorine-Conversion-2024
This is Kilgore’s explanation of their current Free Chlorine Conversion beginning October 21:
https://www.cityofkilgore.com/513/Free-Chlorine-Conversion
The City of Lake Jackson, Texas also does Free Chlorine Conversion:
https://www.lakejackson-tx.gov/797/Free-Chlorine-Conversion
Fort Bend County Texas Free Chlorine Conversion 2024:
https://www.fbmud47.org/latest-news/temporary-free-chlorine-conversion/
Facts about Drinking Water Disinfection and the Free Chlorine Conversion Process
Why is drinking water disinfected?
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. For example, the incidence of typhoid fever was reduced by 1,000-fold in the U.S. in the last century by implementing the disinfection of drinking water.
Even with the advancements in drinking water disinfection practices and decreased incidence of diseases like typhoid fever and cholera in the U.S., disinfection of drinking water remains critical for public health. Failure to adequately disinfect water has led to high-profile illness outbreaks and deaths (for example, the 1991 Peru cholera epidemic and the 2000 Walkerton, Canada bacterial outbreak).
What are the drinking water disinfection requirements in Texas?
Public water systems are required to disinfect water prior to its entering the distribution system that carries it through pipes for delivery to consumers. Public water systems in Texas are also required to maintain a minimum amount of residual disinfectant throughout the distribution system to make sure levels of harmful microorganisms remain low. 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.
What is chloramine?
Chloramine is a long-lasting disinfectant added to public drinking water for disinfection. It is formed by combining chlorinated water with small amounts of ammonia. It is commonly used for disinfection in many public water systems throughout Texas, the United States, and countries around the world.
Why does my public water system use chloramine?
Chloramine is an effective disinfectant and persists over a long period of time, particularly in areas with high temperatures. This makes chloramine useful in Texas’ large distribution systems, such as those of cities with numerous connections and in rural water systems with fewer connections spread out over a large geographic area.
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.
What are disinfection by-products?
Disinfection by-products (DBPs) are formed when disinfectants such as chlorine and chloramines react with natural organic matter in drinking water. The U.S. Environmental Protection Agency (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.
Is chloramine safe?
Yes, water disinfected with chloramine is safe for drinking, cooking, bathing, and everyday use. The EPA, 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 will address these concerns.
What is a free chlorine conversion?
A free chlorine conversion occurs when a water system that typically uses chloramine removes ammonia (needed to form chloramine) from the treatment process, and disinfects the water with only chlorine. Chlorine is more effective than chloramine at inactivating certain types of bacteria. Excess ammonia, which can accumulate in a chloramine-treated distribution system over time, is a source of food for specific types of bacteria that are harmless to people. These bacteria can make it difficult for public water systems to maintain a disinfectant residual, which means that microorganisms that are harmful to people can grow.
The free chlorine conversion is a common practice by many public water systems throughout the country to reduce the number of the bacteria so that a satisfactory disinfectant residual can be maintained throughout the distribution system. Chlorine conversions can be used as a preventative strategy or to stop nitrification (the microbial process that converts ammonia and similar nitrogen compounds into nitrite and nitrate), which can diminish water quality. According to a 2016 EPA survey, 25 to 40 percent of the utilities that use chloramine reported using free chlorine conversion to control nitrification.
Public water systems should notify their customers prior to a chlorine conversion, because changes in taste and odor may briefly occur.
Why is my water system conducting a free chlorine conversion?
A free chlorine conversion is typically conducted for two reasons:
- It is often conducted as a preventative maintenance measure to kill bacteria that can make the maintenance of disinfection residual problematic. A film can form in the distribution system piping that can contain bacteria which use ammonia as a food source. These bacteria in this film are harmless to people. When the water system stops adding ammonia, the bacteria starve. Therefore, a periodic conversion to free chlorine is effective for inactivating these types of bacteria in piping with biofilm by interrupting the supply of ammonia and can help prevent subsequent issues from occurring.
- In rare occasions, if the distribution system receives a moderate to excessive amount of ammonia over long periods of time, bacteria using ammonia as a food source can bloom and cause a loss of disinfectant residual. As a result, the water system may not be able to maintain the minimum required disinfectant residual in the distribution system, and may receive complaints regarding taste/odor.
The conversion to free chlorine, in conjunction with increased flushing activities, assists in removing excess film from the distribution system and also starves these bacteria. The chlorine conversion helps the system return to an environment where the disinfectant residual can be maintained.
Are there any disadvantages to a free chlorine conversion?
Properly conducted free chlorine conversions can often cause the water to have a different taste and/or odor than when using chloramine for disinfection. Customers will likely be able to notice the difference, but there are no health effects associated with the change in taste/odor. Once the water system has returned to using chloramine as the disinfectant, the taste/odor of the water will return to normal.
There may be an increase in the level of disinfection by-products being formed during this short time. Health concerns related to disinfection by-product formation are based on prolonged exposure, and the conversions typically only last two to four weeks at a time. Limited scientific studies following shorter-term exposure to disinfection by¬products have been published that did not find any association between exposure and dermatitis (skin rashes).
There have been a number of other studies that investigated maternal exposure to disinfection by-products and birth outcomes (such as small-for-gestational age infants) following shorter-term exposure to disinfection by-products. Evidence in epidemiological studies looking at exposures to disinfection by-products above 80 ppb and pregnancy outcomes is mixed and limited by study shortcomings. Regulatory agencies worldwide continue to evaluate possible associations between disinfection by- products exposure and pregnancy outcomes. Reduction of disinfection by-products may be desirable, but it should never compromise effective disinfection.