Carbon Filter

An Activated Carbon Filter (ACF), like the Pressure Sand Filter, is a tertiary treatment unit. It receives the water that is already filtered by the Pressure Sand Filter and improves multiple quality parameters of the water: BOD, COD, Clarity (turbidity), color and odor. 
This filter uses the adsorption action of activated carbon. Activated carbon is typically manufactured from coconut shell or charcoal, the activation process creating a highly porous material with a very large surface area. Organic pollutant molecules are physically adsorbed and held fast within the catacomb-like porous structure of the activated carbon. Granular activated carbon is typically used for this purpose. The water filtered by the Pressure Sand Filter enters the Activated Carbon Filter. Unlike in the case of the sand filter, trapped molecules in the carbon cannot be backwashed and got rid of. Hence, activated carbon in the filter has a finite capacity to adsorb and hold the pollutants, after which the carbon is said to be exhausted. The exhausted material is removed from the filter and disposed off: Fresh activated carbon is charged in the filter. 
How It Works 
This filter uses the adsorption action of activated carbon. Activated carbon is typically manufactured from coconut shell or charcoal, the ?activation? process creating a highly porous material with a very large surface area. Organic pollutant molecules are physically adsorbed and held fast within the catacomb-like porous structure of the activated carbon. Granular activated carbon is typically used for this purpose. The water filtered by the Pressure Sand Filter enters the Activated Carbon Filter. Unlike in the case of the sand filter, trapped molecules in the carbon cannot be backwashed and got rid of. Hence, activated carbon in the filter has a finite capacity to adsorb and hold the pollutants, after which the carbon is said to be exhausted. The exhausted material is removed from the filter and disposed off: Fresh activated carbon is charged in the filter.