Integration of nitrification and denitrification in airlift bioreactor

This paper presents the preliminary data on nitrogen removal in a novel airlift bioreactor. The aim is to obtain nitrification and denitrification in a single reactor. Several aspects including reactor design, oxygen availability for nitrification and effective utilization of carbon source for denitrification were considered to optimize the performance of the reactor. Continuous trials demonstrated that nitrification and denitrification were accomplished simultaneously in the reactor over distinct periods. Control was achieved by varying aeration rate and wastewater inlet position of the reactor. Total nitrogen (TN) removal efficiency comes up to 82% under optimal conditions. Batch studies, using cultures from different sections of the reactor, indicated that variation of bulk parameters successfully stratified the reactor into zones that predominantly either nitrified or denitrified. Evidence also indicated that simultaneous nitrification and denitrification (SND) occurred throughout the airlift bioreactor.