Distribution of Microbial Population within a Moving Bed Bio-film Reactor (MBBR) Combining a “Denitrifiltration” Unit

The objective of the research was to identify the different microbial population distributed within a biological reactor system. The system based on several stages including anoxic predenitrification, aerobic reactors and post-denitrification combined with clarification (Denitrifiltration).A pilot set-up was a continuous 4-stage AGAR® (Attached Growth Airlift Reactor), fed by primary effluent from a municipal wastewater treatment plant and operated at conditions that enable substantial nitrification. The last stage was the “denitrifiltration” unit, wherein simultaneous clarification and endogenous post denitrification occurred.The suggested configuration resulted in effluent nitrate levels of 2 mg/L without an addition of an external carbon source at an average hydraulic retention time of 3 hours. Moreover, Anammox activity was detected in the sludge taken from the “denitrifiltration” unit. The heterotrophic population along the AGAR® reactor was directly correlated with the decrease in soluble COD levels. The dominance of heterotrophic bacteria in the first stages suppressed the growth of autotrophs bacteria.