A water-scrubber consists of a gas flow and a biological engine. In the water-scrubber the components to remove from the gas flow are absorbed in the water. In the biological engine the absorbed pollution in the water is further decomposed biologically. The purified water is recycled to the scrubber where it absorbs pollution. Biologically degradable hydrocarbons are converted into the water-scrubber into H2O and CO2. The non degradable hydrocarbons remain in the water. Components such as H2S and NH3 are converted into respectively sulfate and nitrate. To keep the salinity and the non-degradable KWS low enough, regular ventilation is needed. This can happen on the basis of conduction or by means of a fixed ventilation. The degree of ventilation depends on the finished gas composition. There has been determined that even salinities that correspond to a conduction of 5 mS/cm still can obtain a stable biological degradation.

A hydraulic stay time of the water for 20 - 40 (maximum) days gives good results.The scrubber must be devised as such that the stay time of the gases in the scrubber is approximately 1 second. Depending on of the solubility of the components this can be more or less. The scrubber must have a special open packing and special spray heads to avoiding constipation of the biosilt. The biological system needs beside a carbon source (KWS) also nutrients to survive. For that purpose a nutrient mix is added to water-scrubber.This nutrient mix contains nitrogen, phosphorus and track elements.The biological engine contains ventilation to provide the bacteria with sufficient oxygen to break down the components. In the case of a bad soluble and a difficult degradable components the danger for stripping of the components to air is real. To prevent that stripping pollution becomes emitted into the air of the ventilation in these cases can best be recycled back to the water-scrubber. The biological engine can be carried out as an active silt system or biofilmsysteem on carrier. The systems with carrier generally know a lower silt production. At starts up of scrubber biology is grafted with silt from a biological water purification installation or another scrubber. This silt must adapt to the specific component proposition of the degassing. Especially the adaptation to degradable more with difficulty components can some weeks up to a month last before the postulated.