Multi media filter is also known as mechanical filter (now some people call quartz sand filter as multi-media filter, because quartz sand particle size is different, divided into 2-3 specifications), mechanical filter, alias many, is actually the same filter, in water treatment process, is the most commonly used mechanical filtering equipment, because the filter material is cheap, environmental protection, filtering effect So quartz sand filter has been fully used in water treatment.
Why should the multi-media filter be backwashed? First of all, we start from the role of multi-media filter, multi-media filter is mainly to filter and intercept suspended solids, sediment, organic matter and other impurities in the water. The filtration principle is mainly intercepted by quartz sand, so after the multi-media filter works for a period of time, there are many fine particles between the sand gaps, such as mud, organic matters and other impurities. If it is not backwashed, the sediment and other impurities intercepted in the filter tank will accumulate more and more, which will affect the trafficability of the source water, reduce the outlet pressure, and reduce the filtration flow, which not only wastes valuable energy (electric energy and pump power), but also the effluent quality is not up to standard. Therefore, the multi-media filter must be backwashed after a period of time.
There are two backwashing methods for multi-media filter, one is air-water backwashing, the other is water backwashing.
Air water backwashing: the air bubble and quartz sand filter material are used to rub each other, and the friction force between the particles of quartz sand filter material is used, that is, the friction force of quartz sand filter material and water is used. The interaction of the four factors increases the backwashing effect to the maximum extent, so that the quartz sand filter material after backwashing can be operated normally Use. The advantages are: shorter backwashing time and less water consumption. Therefore, Gongquan Water Treatment Technology Co., Ltd. recommended backwashing method is: steam water backwashing