Filtration

Fibre Filters

Irrespective of the type of water treatment system, a first stage filter is used to remove the rust, sand, silt, sediments, and other suspended impurities. A course, medium or fine filter or a combination of these filters may be used depending on the degree of contamination. These filters also help the main treatment system perform optimally. These filters remove the relatively coarse suspended impurities (sizes one micron and over) but they do not filter out bacteria or chemicals like lead. The media of these filters are usually fibrous materials like yarn, rovings, filament or fibres. These filters come in variety of sizes and meshes from fine to coarse, with the lower micron rating being finer. The finer the filter, the more particles are trapped and the more often the filter must be changed.

Ceramic Filters

Microfiltration uses a media with a pore size smaller than 0.2 microns to physically prevent most biological contaminants from passing through. For microfiltration a ceramic filter is commonly used. These filters have the advantage that they can be often cleaned and disinfected and reused a few times. But these filters soon loose their effectiveness and disinfecting them poses a problem. These filters are also more expensive.

Carbon Block Filters

Another more popular type of micro-filter uses the Carbon Block media. This filter is not cleanable and is disposed off when it looses its effectiveness. Carbon Block media, however, provides additional treatment for a variety of other health and aesthetic contaminants (see the Activated Carbon section for more details).

Microfiltration

Microfiltration is effective for treating a wide range of biological contaminants, including hard-shelled cysts like Cryptosporidium.