Novel anammox-enhanced A-B wastewater treatment process based on carbon capture concept

Abstract

The high energy consumption and high carbon footprint of sewage treatment are technical shortcomings of the conventional activated sludge process. To address the emergency issue, this research demonstrated the viability of a pre-anammox enhanced A-B process to treat municipal wastewater while achieving an energy-efficient operation. In the proposed A-B process, an anaerobic moving bed biofilm reactor (A-MBBR) functions as the A-stage for COD capture, while a nitrification MBBR functions as the B-stage. The results show that during the 210-days of operation, 83.3 % of the influent COD was converted in the A-stage, and 93.1 % NH₄⁺-N removal was achieved, resulting in an effluent NH₄⁺-N concentration of 0.9 mg/L. The metagenomic sequencing results show that, in the B-stage MBBR, Nitrosomonas was the main ammonia-oxidizing bacterium (4.9 % relative abundance) and Nitrospira was the main nitrite-oxidizing bacterium (18.0 % relative abundance). In the A-stage MBBR, Thauera was the dominant denitrification bacterium (9.2 % relative abundance) and Candidatus Brocadia was the dominant anammox bacterium. Finally, hdh and hzs were key anammox genes detected in this system. This study clearly demonstrates a novel pre-anammox enhanced A-B process with an energy-efficient operation.