SIMPLE STRATEGIES TO CONTROL THE OXYGEN BUDGET OF AN OLAND ROTATING BIOLOGICAL CONTACTOR

摘要

Oxygen-limited autotrophic nitrification/denitrification (OLAND) is a one stage process that removes ammonium from wastewaters with a low C/N ratio through a combination of partial nitritation and anammox. This process is based on the cooperation between aerobic ammonium oxidizing bacteria (AerAOB), which oxidize about half of the ammonium to nitrite in the outer aerobic zones of the biofilm (partial nitritation), and anoxic ammonium oxidizing bacteria (AnAOB), who subsequently convert nitrite and the residual ammonium to 89% nitrogen gas and 11% nitrate (anammox) (Vlaeminck et al., in press). Oxygen plays a crucial role by providing sufficient oxygen for nitritation and by suppressing aerobic nitrate formation (nitratation) allowing for sufficientanammox activity. A rotating biological contactor (RBC) is a simple and robust technology, in which the oxygen supply can be indirectly controlled by the immersion level and the rotation speed of the discs. In this study, the exact effects of both factors on oxygen loads and bulk dissolved oxygen (DO) levels were investigated on short and long term in both a biotic OLAND RBC and in a parallel, abiotic RBC.