Combined aerobic heterotrophic oxidation, nitrification and denitrification in a permeable-support biofilm

A biofilm reactor, termed the permeable-support biofilm (PSB), was developed in which oxygen was supplied to the interior of the biofilm through a permeable membrane. The reactor was tested on filtered sewage supplemented with nutrient broth; the bulk solution was anoxic and the interior of the biofilm was supplied with pure oxygen. All tests were performed on a non-steady state biofilm with a depth of 1 mm. Mass balances on total organic carbon, ammonia, organic nitrogen and nitrate showed that combined heterotrophic oxidation of organics, denitrification and nitrification occurred simultaneously within the biofilm. The advantages of such a reactor are discussed.