Water Filtration
Different water filter systems use different methods to carry out water filtration including use sieving, adsorption, ion exchanges and other processes. Unlike a sieve or screen, a filter can remove particles much smaller than the holes through which the water passes.
Water treatment plant filters which are large industrial models used normally for the water supply for towns and cities generally use one or more of the following types of water filter:- media filters, screen filters, disk filters, slow sand filter beds, rapid sand filters and cloth filters.
We are more concerned here with point-of-use filters for home use include granular-activated carbon filters (GAC) used for carbon filtering, metallic alloy filters, microporous ceramic filters, carbon block resin (CBR) and ultrafiltration membranes. Some filters use more than one filtration method. An example of this is a multi-barrier system.
Jug filters can be used for small quantities of drinking water. Some kettles have built-in filters, primarily to reduce limescale buildup.
We also like to take a look at Portable water filters, those that can be used by hikers, by aid organizations during humanitarian emergencies, and by the military.
These filters are usually small, portable and light and usually filter water by working a mechanical hand pump, although some use a siphon drip system to force water through while others are built into water bottles.
These filters work to remove bacteria, protozoa and microbial cysts that can cause disease. Filters may have fine meshes that must be replaced or cleaned, and ceramic water filters must have their outside abraded when they have become clogged with impurities.
