Activated carbon filters are particularly effective at removing pollutants which create unpleasant taste, colour, and odour in water. These fast-acting filters can eliminate or reduce the levels of chlorine by-products, pesticides, herbicides, and other organic and industrial chemicals.
Activated carbon is made from a variety of organic materials such as coal, coconut, lignite, and wood.
When these are activated by exposure to high temperatures in the absence of oxygen, the result is a substance with millions of microscopic pores and a vast surface area; half a kilo of activated carbon provides more than 50 hectares of surface with the capacity to cling to or absorb smaller organic molecules.
There are two forms of carbon in general use: granular and block. Carbon granules are about the size of coarse sand while carbon block is finely powdered carbon compressed into a solid mass.
To get the most of a carbon filter, it should be kept free of sediment and heavy organic impurities by the incorporation of a sediment filter as an integral part of the system design. It is imperative that filter cartridges be replaced regularly before they reach their expiry date, rather than after.