Activated carbon units are commonly used to remove organics, such as odors, micropollutants, from drinking water at centralized and decentralized level. At centralized level, they are generally part of one of the last steps, before the water is fed into the water distribution network. At decentralized level, activated carbon filtration units can either be point-of-use (POU) or point-of-entry (POE) treatment. A POE device is recommended for the treatment of radon and volatile organic compounds because these contaminants can easily vaporise from water in showers or washing machines and expose users to health hazards. POU devices are useful for the removal of lead and chlorine. The structure of POU devices can either be in-line, line-bypass faucet mounted (see also advanced filters) or pour-through (similar to the design of ceramic candles, colloidal silver or biosand filters).
Activated carbon filters can also be used as a tertiary treatment in wastewater treatment plants to remove micropollutants from municipal effluents or recalcitrant contaminants from industrial effluents.
Combination of Activated Carbon With Other Processes
Activated carbon is often used as pre-treatment to protect other water treatment units such as reverse osmosis membranes and ion exchange resins from possible damage due to oxidation or organic fouling. The combination of ozonation with activated carbon is a very efficient technique for eliminating organic matter including micropollutants. Moreover, the lifetime of activated carbon filters is prolonged significantly when used in combination with ozone, while decreasing operation costs noticeably.