... , which include sand filter, carbon filter, softener, micron filter and RO system. 1.1 First stage pretreatment.(Sand filter)The use of ... head, filter, into the water pipes, drains and flushing water mains, as well as access to water, such as the composition of ... the Ca2 +, Mg2 + was exchanged resin adsorption, and other objects at the same time the quality of the release of sodium Na ...