Air stripping of ammonia from pig slurry: characterisation and feasibility as a pre- or post-treatment to mesophilic anaerobic digestion

The study tested how to remove ammonia from pig slurry using air stripping at high temperature. Fresh slurry needs a very high pH to remove all the ammonia, but digested slurry can be cleaned without changing the pH. Digested slurry also gives cleaner recovered ammonia. The tests also showed that air stripping should not be used before anaerobic digestion, because it makes the digestion process less effective.