BIOLOGICAL NITROGEN REMOVAL IN A SINGLE AEROBIC REACTOR BY ASSOCIATION OF A NITRIFYING ECOSYSTEM TO AN AEROBIC DENITRIFIER, MICROVIRGULA AERODENITRIFICANS

Aerobic nitrification and anoxic denitrification are the two main step s of the biological nitrogen removal processes. However, studies have shown the ability of pure strains to consume simultaneously oxygen and nitrate. These properties of co-respiration were used to combine nitr ifiers and aerobic denitrifier (Microvirgula aerodenitrificans) in a s ingle aerated reactor under continuous and Sequencing Batch Reactor (S BR) cultures. The aerobic denitrifier was maintained by discontinuous addition of carbon. Under these conditions, nitrifying and denitrifyin g activities were observed with aerobic reduction of the N-oxides prod uced by autotrophs into nitrous oxide and nitrogen. (C) 1998 Elsevier Science B.V. All rights reserved.