Deep Denitrification Performance in Pilot-scale Denitrification Biofilter System and Microbial Community

Abstract:

A pilot-scale denitrification biofilter system was constructed to investigate the deep denitrification performance when the actual secondary effluent was adopted， and the effects of key parameters （i.e. hydraulic load， C/N ratio and temperature） on the operation were carried out. The pilot-scale system mainly used external carbon source for denitrification rather than organic matter existed in the secondary effluent. The recommended hydraulic loading and C/N ratio was 5 m·h^-1 and 4， and under the conditions the average removal efficiencies of COD and TN were 62.8% and 67.3%， respectively. When the temperature was 15~27 ^oC， TN in the effluent was steady below 10.0 mg·L^-1. The relative abundances of conventional denitrifiers such as Hyphomicrobium and Methyloversatilis （accounted for 25.12%） were higher in the pilot-scale denitrification biofilter system， and the relative abundances of simultaneous nitrification-denitrification bacteria such as Methylotenera and Paracoccus were also much higher （accounted for 33.29%）. These bacteria guaranteed the good denitrification performance in the system.

Key words:denitrification;biofilter;pilot-scale system;microbial community;organic compounds utilization