Working Principle of Multi-Media Filter
Multi-media filter uses one type or several types of filter media to effectively remove suspended impurities from high turbidity water which flows through granular or non-granular materials with certain thickness under certain pressure. Commonly used filter materials are quartz sand, anthracite coal, and manganese sand, etc., which are mainly used for turbidity removal in water treatment, and pretreatment of softened water and pure water. Outlet water turbidity is below 3 NTUs.
Composition of Multi-Media Filter
A multi-media filter is mainly composed of a filter body, assorted pipe fittings and valves.
The filter body mainly consists of: a cylinder, a water distribution assembly, a supporting component, a backwash air pipe, filter materials, and an exhaust valve (externally installed).
Filter Material Selection Criteria
(1) Sufficient mechanical strength, to avoid abrasion or damage during backwashing;
(2) High chemical stability;
(3) Not containing substances harmful to human body and toxic substances; not containing substances disadvantageous to production or matters affecting production;
(4) With high adsorption capacity, high sewage interception capability, high water production, and high outlet water quality
Among filter materials, pebbles are used for support. During filtration, forward flush process becomes simple, and the after filtration water flows through the filter material smoothly, due to their high strength, stable distance and space in between, and high porosity; similarly, during the backwash process, backwash water and backwash air may pass through smoothly.
In conventional configuration, there are four specifications of peddles, which are laid from bottom to top, from the large to the small. The relationship between particle diameter of filter material and packing height
The ratio of the filter bed height to the average particle diameter of filter material is 8001000 (design specification). Particle diameter of filter material is related to filtration precision.
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