Water purification uses activated carbon filtration which allows to retain a number of pollutants such as COD, BOD, surfactants, residual chlorine, oils, solvents, organic substances, hydrocarbons, etc…
The activated carbon filters work according to an absorption process, the granular activated carbon used in water purification processes is activated with a steam process, this physical reaction creates a great porosity and exchange surface, the granular carbon has a high reactive degree of the surface, with an absorption capacity and a total area ranging from 700 to 2,500 square meters per gram of weight.
The carbon used for pressure filtration of water must have specific characteristics based on the type of wastewater and pollutant to be treated, the porosity of activated carbon is characterized by micropores, mesopores and macropores, for proper filtration of water with activated carbon is also important to define the absorption capacity and density of the carbon.
The water treatment uses active carbon filtration also to eliminate any suspended solids present in the water, in case of discrete and continuous presence of solids it is, however, preferable to include in the carbon filtration a mechanical quartzite filter, this ensures to fully use the active carbon and its absorption capacity in the purification plants.
The process of pressure filtration with activated carbon in a purification plant is so composed: an electric pump sends the water that has to be treated inside a column containing granular activated carbon that continues to absorb pollutants, cyclically the carbon placed inside the filtration must be backwashed, in this case water is pumped from the bottom to the top of the filter, the carbon subjected to this reverse pressure increases its expansion and is free from pollutants.
