Media filters - Import export

Media filter is used to reduce the level of suspended solids (turbidity) in feed water. Suspended solids consist of small particles such as silt, clay, grit, organic matter, algae and other microorganisms. Feed water that is high in suspended solids can cause a high pressure drop and reduce the effectiveness of downstream equipment such as reverse osmosis membranes and ion exchange beds.

When is used an activated carbon filter? Activated carbon filters are very similar to multi media filters and other pressure filters in construction and operation. The purpose of an activated carbon filter is to remove free chlorine, an oxidizing agent that will damage most resins and/or membranes in a water treatment system. A chemical injection system using sodium bisulfite (a reducing agent) can be used in place of an activated carbon filter to remove chlorine. Granular activated carbon is a particularly good adsorbent medium due to its high surface area to volume ratio. One gram of a typical commercial activated carbon will have a surface area equivalent to 850-1.000 square meters. This high surface area permits the accumulation of a large number of contaminant molecules. Some drinking water may be disinfected with chlorine or chloramines.