Nitrogen removal from municipal wastewater by a bioreactor containing ceramic honeycomb

Abstract

Ceramic honeycombs were used as bio-carriers for removal of nitrogen from municipal wastewater by a bioreactor under aerobic conditions. Firstly, we investigated the removal rates of total nitrogen and ammonium, nitrite and nitrate forms of nitrogen. The experimental results demonstrated that the removal rates of total and ammonium nitrogen averaged 52.61 and 45.71% at a hydraulic retention time of 1 h, and the nitrite and nitrate nitrogen concentrations remained at low levels in influent and effluent throughout the experiment. Then, we investigated whether the nitrification and denitrification processes could occur simultaneously in a reactor using isolation and biological diversity analyses. Finally, the simultaneous nitrification and denitrification mechanisms in the bioreactor containing the ceramic honeycomb were analyzed. The conclusion was that the special structural feature of the ceramic honeycomb served as a bio-carrier, resulting in aerobic and anoxic zones co-existing in the system.