Degradation of acetonitrile through a sequence of microbial reactors.

Degradation of nitrogen containing organic compounds often leads to formation of ammonium and some low molecular weight organic compounds. The study is focused on degradation of acetonitrile in a sequence of stirred biofilm reactors, where the degradation of acetonitrile into acetic acid and ammonia takes place in the first two reactors. A large fraction of the acetic acid is also degraded in these reactors. The subsequent two reactors were introduced in order to take care of the ammonia, while a fifth reactor was a polishing step before the water was released to the recipient. From earlier studies it is known that the rate of acetonitrile degradation is approximately 80 g acetonitrile/ (m3 reactor h). In the present study nitrification proceeded with 10 g NH4(+)-N/(m3 reactor h) and the denitrification by 35 g NOx(-)-N/ (m3 reactor h). This means that the reactors involved in removal of the nitrogen component needs to be far larger than those dealing with degradation of the more complex molecules.