Media Filtration
This involves the separation of suspended solids by a media that is usually retained in a pressure vessel.

The choice of media depends on the application and whether it is a throwaway type, such as a cartridge or bag filter, or a unit where the filtered material can be removed by means of backwashing thus giving a renewed filter ready for further treatment. The principle of all these systems is that water is pumped through a filter media that may consist of a cloth or mesh layer or a depth of a granular media such as sand or activated carbon. The media may act for the physical separation of certain sizes of particles or, in addition, may change the chemistry of the water as it flows through the bed. The following are specific types of Media Filtration:-

Iron/Manganese Removal
The media used consists of a special iron/removal medium but pre-treatment is employed before the filter to ensure effective removal. This type of filter is backwashable.

Suspended Solids Removal
Cartridge or bag filters are used if the amount of suspended solids is low and a backwashable sand filter is used for higher levels of suspended solids. For very high levels of suspended solid, anthracite layers may be added in addition to the sand and an air scour would be added to the backwash system to agitate the solids present on the filter to ensure they are removed.

Chlorine Removal
The media used consists of a special activated carbon medium that reduces the chlorine to chloride and that will also absorb other chlorine species. The filter is backwashable to remove any suspended particles present. Steam sterilization is available to ensure sterility in the carbon bed.

Pesticide/ Organic Removal
The media used consists of a special activated carbon medium that is able to absorb certain pesticides etc and reduces the overall organic level. Generally the carbon will need replacing when saturated. The filter is backwashable to remove any suspended particles present.

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