Filter method

Overview of various procedures

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Updated on: 03/24/2020

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Mechanical

A mechanical filter effect works according to the principle of a sieve. All solids that are larger than the pores of the sieve, the filter bed or the membrane are retained or filtered out. The group of mechanical filters includes e.g. sand, gravel, stone, plastic or metal filters as well as micro-, ultra- and nanofiltration with corresponding filter membranes.

- Depending on the pore size, solids such as sand, suspended particles, rust particles, asbestos fibres, microplastics or pathogens such as bacteria and viruses are filtered out.

-Not filtered out are all dissolved substances like nitrate or lime

Catalytic table

A catalytic filter effect is achieved by converting the contents of the water by activated carbon or ion exchangers. In this way, the hardness builders magnesium or calcium (both form lime) can be converted by catalytic treatment into larger crystalline lime clusters, the water is softened. Lime and magnesium remain in the water, but they no longer form lime deposits and scale. This prevents stubborn lime incrustations on sanitary surfaces.
Chlorine and various chlorine compounds such as CKWs and CFCs as well as other harmful substances such as heavy metals, pesticides or iron can also be removed in this way. No addition of chemicals is necessary and the balance of the water is not changed. The group of catalytic filters includes activated carbon and ion exchange resin.

- Chlorine and various chlorine compounds, nitrate, sulphate and arsenic, but also magnesium or calcium ions are filtered out or converted

Adsorptive

Adsorption is a physical process in which substances (usually molecules) adhere to the surface of another substance and accumulate there. In water filters, an adsorptive filtering effect is achieved by certain substances in the water being adhered to or sucked in by the surface of the activated carbon, as in the case of a magnet. Since this adsorptive effect works independently of the pore size, inorganic and organic substances that are smaller than the actual pores and channels are also retained. Substances removed by adsorption are heavy metals such as lead or copper as well as herbicides, pesticides, fungicides, hormone and drug residues and odour and taste disturbing substances.

- Heavy metals such as lead or copper as well as herbicides, pesticides, fungicides, hormone and drug residues and odour and taste disturbing substances are filtered out.