Granular Activated Carbon constitutes an excellent filtration media, having a high density with a balanced pore-structure for more efficient absorption.One of the most common applications for Activated Carbon is the removal of the undesirable taste present in many chlorinated water supplies. This taste is the result of the formation of chlorophenols, often present in raw waters that contain phenols and are subsequently treated with chlorine. These phenols are usually the product of industrial waste. Even 0.1 ppm of chlorophenols can result in an undesirable taste. Activated Carbon has for many years been successful in the absorption of orthochlorophenol and the removal of free chlorine from water supplies. The end product is clean, fresh water with no objectionable taste characteristics.

A filter with granular activated carbon (GAC) is a proven option to remove certain chemicals, particularly organic chemicals, from water.  GAC filters also can be used to remove chemicals that give objectionable odors or tastes to water such as hydrogen sulfide (rotten eggs odor) or chlorine. 

Granular activated carbon is made from raw organic materials (such as coconut shells or coal) that are high in carbon. Heat, in the absence of oxygen, is used to increase (activate) the surface area of the carbon; this is why these filters are sometimes referred to as “charcoal” filters. The activated carbon removes certain chemicals that are dissolved in water passing through a filter containing GAC by trapping (adsorbing) the chemical in the GAC.

It is very important that the type and concentration of contaminants, and average water use, be known in order to determine the correct size and components of the system. All treatment systems require proper installation and periodic maintenance. Eventually, the ability of the GAC to bind and remove chemicals is used up and the GAC needs to be changed. How often the GAC should be changed needs to be based on contaminant levels and water use. While some filters may last for several years if contaminant levels and/or water use are low, higher levels or use may require more frequent change-outs.