Before you can get the right chemical water filter for your home, you need to know exactly what’s in your water. At US Water Systems, we offer a variety of water test kits to help you find out what you need to treat. Once we have the results, our water specialists can help you choose the right system for your family.
Chemicals that may be found in your water include the following:
- Trihalomethanes (THMs) – a byproduct of chlorine disinfection
- Industrial solvents
- Polychlorinated biphenyls (PCBs)
- Halogenated hydrocarbons
- Polycyclic aromatic hydrocarbons (PAHs)
All water is treated at the municipal level to ensure that it’s pure enough to drink, but that doesn’t mean that all of the chemicals have been removed. Chlorine, for example, is often added as a disinfecting agent, since it kills many biological contaminants. The water is also filtered by various methods, and fluoride is often added in an attempt to reduce tooth decay. While the resulting water is considered safe to drink, many people are still concerned about the number of chemicals that remain. People who get their water from wells or other private sources need to test that water regularly and treat it for any chemical contaminants.
Types of Chemical Water Filters
Activated carbon is one of the most effective chemical filter methods available. It’s especially beneficial because it adds nothing to the water, only removes certain types of chemicals. There are two main types of carbon water filters for chemical removal: granular activated carbon (GAC) and catalytic carbon.
Granular Activated Carbon Filters
One of the most common and useful types of chemical water filter systems, GAC is known to be effective at removing chlorine, pesticides, and a range of organic contaminants. Granular activated carbon is simply carbon that has been specially treated to make it extremely porous and to give it a very high surface area. These characteristics make the carbon high adsorptive, which means that the chemicals dissolved in the water will be attracted to the carbon and stick to it.
Backwashing carbon chemical water filters are a good choice for whole house systems because they offer good flow rates (up to 20 gallons per minute) and a relatively low price. The GAF filtering media is stored in a large tank and, because it’s backwashed and cleaned automatically by the system, it can be used again and again. In most cases, the media can last for years before it needs to be replaced.
Catalytic Carbon Filters
While regular GAC removes a wide range of organic chemicals and chlorine, there are contaminants that it is less effective at removing. One of these, chloramine, is a derivative of ammonia and is increasingly being used as an alternative to chlorine disinfection in water treatment plants. This chemical can kill fish and damage plants, and it must be removed from water used by dialysis patients.
Because a standard GAC chemical filter cannot remove chloramines very effectively, you need a catalytic carbon filter to remove these chemicals from your water. Catalytic carbon is similar to GAC, and can remove all of the same contaminants. However, because this type of carbon – typically made from coconut shells – has had the electronic structure of its surface modified, it attracts chloramines much more effectively.
Like regular granular activated carbon, a catalytic carbon chemical water filter needs to be backwashed regularly to clean the media and rinse away all of the accumulated chemicals. The media will typically last for several years before it needs to be replaced, although this will vary by how much water the system treats and the concentration of chemical contamination.
Additional Filtering Options
Carbon is one of the most effective chemical filtration media available, but it cannot remove all contaminants. Often, carbon filters are combined with additional water treatment methods to get the best water quality possible. Reverse osmosis (RO), for example, is very effective at removing cryptosporidium cysts and a range of bacteria, but exposure to chlorine will effectively ruin the membrane. It’s extremely common, therefore, to find an RO system that includes several carbon filters before the membrane. Catalytic carbon can be combined in a system with a bone char filter to also remove fluoride from the water.