Due to multiple factors, trihalomethanes (THMs) can be challenging for municipalities. After being treated with chlorine, potable water will have a fair amount of disinfection byproducts (DBPs) that can impact the health of the community that the water department serves. Long-term exposure to high levels of THMs has been associated with health risks, making their removal from drinking water crucial. The following will explore practical methods for removing THMs from your water, ensuring it remains safe and healthy for consumption, one of which may surprise you.
Methods to Remove Trihalomethanes from Water
1. Activated Carbon Filtration
Activated carbon filters are highly effective at removing THMs from water. The carbon’s porous nature allows it to adsorb organic compounds, including THMs, as water passes through the filter. This method is widely used in both residential and municipal water treatment systems.
How it works: Activated carbon filters can be installed at municipal water facilities, the point of entry (whole-house systems), or the point of use (under-sink or countertop filters). Regular replacement of the carbon media is essential to maintain their effectiveness.
2. Aeration
Aeration involves exposing water to air, allowing volatile compounds like THMs to evaporate. This method is particularly effective for removing chloroform and other volatile THMs.
How it works: Aeration can be achieved through various means, such as air stripping towers, diffused aeration systems, or simply allowing water to stand in an open container for several hours. NOTE: An exceptionally effective and new method, though not technically aeration and relatively new for municipalities, is placing a large blower at the top of a ground reservoir, allowing the moist air containing THMs found in the headspace to be exchanged with fresh air, carrying away unwanted DBPs
3. Reverse Osmosis
Reverse osmosis (RO) is a filtration process that uses a semi-permeable membrane to remove contaminants, including THMs, from water. RO systems are highly effective at producing clean, THM-free water.
How it works: Water is forced through the RO membrane, which blocks contaminants while allowing clean water to pass through.
4. Granular Activated Carbon (GAC) Adsorption
Granular activated carbon (GAC) adsorption is another effective method for removing THMs from water. GAC systems are often combined with other filtration systems for enhanced effectiveness.
How it works: Water passes through a bed of granular activated carbon, which adsorbs THMs and other organic compounds. Regular maintenance and replacement of the GAC media are necessary to ensure continuous removal of contaminants.
5. Ultraviolet (UV) Treatment
While UV treatment alone does not remove THMs, it does enhance overall water quality. UV treatment effectively disinfects water, reducing the need for chlorine and lowering the formation of THMs.
How it works: Water is exposed to UV light, which inactivates harmful microorganisms. UV treatment can help maintain safe and clean water when combined with activated carbon filtration or RO. Still, ultimately, it leaves the water susceptible to breeding contaminants further along the distribution line. So, adding a small amount of chlorine to the water after UV treatment is often recommended.
Preventing THM Formation
In addition to removing THMs from water, minimizing their formation is essential. Here are some preventive measures:
– Optimize Chlorination: Adjusting the timing and amount of chlorine added to the water can help reduce THM formation. This can be a fully automated process by adding a water tank mixer and a chlorine boosting system that automatically adds chlorine to the water and maintains proper residual.
– Remove Organic Matter: Pre-treatment processes, such as coagulation and sedimentation, can remove organic matter before chlorination, reducing the precursors for THM formation.
– Use Alternative Disinfectants: Consider using alternative disinfectants, such as ozone or chloramine, which produce fewer THMs than chlorine. Equipment, such as a chloramine boosting system, will help maintain a safe chloramine residual, reducing the overall consumption of chemicals and enhancing the safety and taste of the product.
Removing THMs From Drinking Water in Summary
Removing trihalomethanes from potable water is essential for ensuring its safety and quality. Methods like activated carbon filtration, aeration, reverse osmosis, granular activated carbon adsorption, and UV treatment eliminate THMs from your water supply. Adopting preventive measures to reduce THM formation can further enhance water safety. By implementing these strategies, you can enjoy clean, healthy, and THM-free drinking water, safeguarding the health and well-being of our communities.