Acid scrubber when processing waste

Waste processing lines often release ammonia (NH₃). Ammonia is a colourless, toxic and flammable gas with a characteristic strong pricking odour and can be harmful to humans, animals and the environment in high concentrations. That is why the government imposes strict emission rules on ammonia emissions. An acidic air scrubber is a good technical solution to remove ammonia from the air.

In addition to ammonia, an acid air scrubber can remove many more alkaline components from an air stream. By adding an acid, the pH of the washing water is lowered and the alkaline components react with the acid to form a salt. The dosing of the acid is done by means of a pH control, in most cases the pH value of the washing water varies between 3 and 6.

Depending on the salt formed, more or less washing water is discharged, this is measured on the basis of density and/or conductivity. The spray can contain up to 15 % of salts and is discharged or evaporated for reuse.

Various acids can be added, sulphuric acid (H₂SO₄) and nitric acid (HNO₃) are most common. For specific applications, e.g. to capture ammonia (NH₃), the acid then forms ammonium sulphate or ammonium nitrate, both salts can be used as fertiliser or soil improver. Because of their alkaline character, amines and esters (odour components) can also be captured in an acid scrubber.