Biofilm Properties and Simultaneous Nitrification and Denitrification in Aerobic Rotating Biological Contactors

Abstract

The properties of a blofllm developed on a Rotating Biological Contactor (RBC), such as the spaclal distribution of blofllm density, bacterial population and Intrinsic biochemical reaction rates, were measured. The blofllm density and the number of heterotrophs, nltrlflers and denltrlflers per unit volume of blofllm Increased with the blofllm depth. However, the intrinsic reaction rates per unit blomass did not significantly change with depth. Based on the above evidence, experiments on simultaneous nitrification and denitrificatlon were carried out using a covered RBC in which the oxygen pressure was controlled. The experimental results demonstrated that nitrogen removal efficiency in an aerobic RBC depends on the oxygen partial-pressure in the air phase, water temperature, hydraulic detention time and ratio of the influent concentration of organlcs to ammonia nitrogen.