Deep Treatment of Tailwater by Aerobic Denitrifying Bacteria Enhanced Biofilter

Abstract

The high concentration of total nitrogen in the tailwater discharged from some wastewater treatment plants is relatively high, which is easy to cause eutrophication in the receiving water bodies. In this study, the aerobic denitrifying bacteria were combined with denitrifying biofilter through bioreinforcement technology. The aerobic denitrifying bacteria strains W30 and Z66 isolated from activated sludge were used to construct a complex bacterial agent to strengthen the denitrifying biofilter, and the enhanced nitrogen removal effect of the complex bacterial agent was investigated, and the microbial community structure in the system after bioreinforcement was analyzed by high-throughput sequencing technology. The results showed that strain W30 was identified as Pannonibacter and strain Z66 as Pseudomonas by 16S rDNA sequencing analysis. The bioreinforced denitrification biofilter had a fast start-up rate of membrane hanging, and the removal rate of total nitrogen (TN) increased by 9. 36% under natural oxygenation compared with that under aeration; the single-factor test of carbon/nitrogen ratio (C/N) and hydraulic retention time (HRT) determined C/N=4. 27 and HRT=1. 0 h as the optimal working conditions of the filter cell; the highthroughput sequencing results further showed that the percentages of Pannonibacter and Pseudomonas in the denitrifying biofilter decreased from 0. 49% and 2. 56% at the beginning of operation to 0. 073% and 0. 18% after 130 days of operation. A stable denitrification system was formed with Thauera, Dechlorobacter, Exiguobacterium and other genera.