Biological filters

In a natural environment, water is cleaned by micro-organism that use pollution as food. This can be done in an environment with or without oxygen. In purification systems that are built by men the same process is being used, only here the living conditions for these micro-organisms are much better. This is because the area for the bacteria is enlarged and the possibility for the bacteria to grow and to increase is strongly improved.  

In biological cleaning, the breaking off organic material and the removal of BZV and nitrogen is  most important. The remains are the same of which pollution is made: water, carbon dioxide, nitrogen gas and some minerals. Multivis uses some techniques by which a solid carrier is used as living environment for the bacteria.

Moving-bed filter with a suspendable carrier and aeration