Filtering is part of the solid-liquid separation, it used filter medium or a porous membrane retaining of insoluble particles in the liquid. Sometimes uses bed softening by ion exchange water, classified mineral acid, bleaching clay bed filters. In water treatment and in industrial water treatment, has been widely used to filter biological processes, despite the existence of impurities, but it might as well be classified as biological filtration.
Reverse osmosis is the solution-diffusion process, but its membrane separation technology of ultra filtration, microporous filtration are closely related, it is also available as a special case.
First filtering technology is the use of wine clarification. Date filtering technology is still widely associated with beverage industry, aimed at excluding drinks out of the tiny, hard particles, while avoiding a scented protein filtered out.
Water treatment is not only to get rid of various solids from the large amounts of water, and must be very low cost. He relies on gravity sand filtration to meet this need, but it is increasingly being replaced by sand filtration, pool water purification is the modern branch of water purification.
New sewage treatment plants, and contributed greatly to the pressure filter and the development of vacuum drum filter and belt press filter rose to prominence.