Granular activated carbon (GAC) has a wide range of applications in water treatment and purification. In the water industry it is used to treat surface water to drinking water and improve the organoleptic properties of water, in the food industry for the production of distillates, in the chemical industry to decolorize organic substances and to recover dissolved components from solutions. Other uses can be found in the dechlorination of water and in the removal of other oxidants.
GAC can act as a filter material for the removal of suspended solids, although this is not, with few exceptions, its primary purpose. GAC is mainly used for its sorption capacity, where organic substances of various nature, micropollutants (e.g. pesticides and their metabolites, pharmaceutical residues) or disinfection by-products are adsorbed on its surface. In addition, due to its high specific surface area, GAC serves as an excellent carrier for microorganisms, e.g. for the growth of nitrifying bacteria and the subsequent removal of ammoniacal nitrogen and biodegradation of organic substances.
GAC filters are analogous to sand filters. Unlike sand filters, they are washed with air and water separately or with water only. They can be either open gravity filters or pressure filters. If separation of specific organic pollutants is required, it is advisable to verify the sorption efficiency on GAC using laboratory columns or a semi-operational plant.
Customer benefits
- Sorption of hard decomposed organic compounds, pesticides, pharmaceuticals
- Better organoleptic properties
- Option of reactivation GAC = saving costs
