Gas-liquid exchange
Water treatment before use. Dissolved substances

Generally placed at the head of treatment, it is necessary for all waters deprived of dissolved oxygen: groundwater, water in the deep layers (hypolimnion) of eutrophic reservoirs, or water subject to very high levels of organic pollution. It has the following effects.

a) Introduce dissolved oxygen (the most economical oxidizing agent available): in further treatment, it thus promotes the oxidation, by physical-chemical or biological means, of iron, manganese, ammonium, H₂S,...