Water which comes into our various uses is collected from either ground or surface water sources usually carries various type of dissolved salts, suspended particles, organics and gases. Due to various reasons and impurities present in water, it indicates different taste, smell, colour and odour which makes available water unfit for various applications. Common complaint of the “rotten egg” smell in water is caused by H2S gas produced by sulfate reducing bacteria. The rapid industrial revolution also resulted increased air and water pollution due to the extensive use of various inorganic and organic chemicals, herbicides, pesticides & insecticides, petroleum products and its derivatives, volatile organic chemicals (VOCs). Chlorine which is normally used to disinfect potable water also leave a noticeable smell and odour in water. Further, the residual chlorine also reacts with the organics present in the water and forms trihalomethanes (THMs). Activated carbon products especially in granular, lead shape or powder forms are found suitable for the reduction of taste, colour smell and odour related issues in water. Activated Carbon filters are very commonly used to reduce chlorine, organics, color, tannin, objectionable tastes and odors, and other dissolved organic chemicals from municipal and industrial water supplies to produce crystal clear and odourless water.
During water filtration, the feed water is distributed in the top of the carbon filter which slowly sink through the filter bed. This water flows downward through the filter media. After certain time and depending upon the organics, chlorine and other impurities load, backwash in the upward direction is initiated which expand and loosen the bed and releases all of the adsorbed impurities which flow out of the filter from the top. Sufficient space is provided above the filter bed for expansion during backwash.
Most of the Qarshin carbon filters use normal backwash to re-activate carbon media, to help remove trapped silt, prevent packing and head loss, and to remove carbon fines produced by friction between granules. However, special customized systems are also available which uses steam to activate the carbon media (Ask Water 2000 Customer Support for additional details).
