Quartz sand filter of quartz sand

Quartz sand filter is common water treatment device, quartz sand filter is filled quartz sand filter material, filter material specifications generally 0. 6 - 1. 1 - 2毫米 。 2 - 2毫米 4 mm size, fine as long as it is filtering effect, and coarse sand in addition to have the certain filtering effect, good water is the most main through sex, coarse sand gap is big, through the good, so why there are several kinds of quartz sand filter material gradation, that is the reason why in the past because of the limitation of technology is not very good cloth water cap, only in the form of punch for cloth under water, so old to cushion layer at the bottom of the filtering equipment many pebbles, run is to prevent fine quartz sand filter layer material and pollution of water after filtering, no filtering effect, instead of suspended solids in water increased. So why do we must quartz sand instead of river sand and sea sand, this should speak of from the filter principle:
quartz sand filter is using quartz sand filter material to intercept pollutants, suspended solids, so when quartz sand intercept a suspension, it must be a back flush and wash, then washing and are in the washing process, will produce friction between sand and sand, river sand and sea sand if the hardness is high enough, it is easy to broken, then affects the water quality of effluent, broken quartz sand not rinse in running process, will be brought down to the process, then the quartz sand filtering effect greatly discount. River sand and sea sand belt color from the senses, and contains a variety of impurities, unfavorable for water purification.
so choose sand filter must choose quartz sand, with river sand and sea sand is wrong, although the sea sand and river sand is cheap.