Research On Operation Performance And Microbial Community Structure Analysis Of The Denitrifying Biological Filter Filled With Limonite

Currently the effluent from the effluents of urban sewage treatment plants contains some nitrogen and phosphorus which will cause a secondary pollution of the eutrophication of water bodies. A further treatment of secondary effluents is being paid more and more attention. Denitrifying biological filter is one of the popular processes and has the advantages of small occupied area, low energy consumption, easy operation maintenance and stable treatment efficiency. In this paper, two denitrifying biological filters filled with limonite and quartz was set up and the start-up, operation performance and microbial community analysis were performed. The experimental results were listed as follows:(1) In the start-up stage results showed that the biological filter using limonite was easier to achieve the stable stage within 8d, which was much shorter compared to the reactor filled with quartz. This showed that using limonite as the filter medium could accelerate the star-up of denitrification filters.(2) When the reactors were stable, removal efficiency of N03-N in the reactor filled with limonite was 98%, which was 15% higher than that in the reactor filled with silicon. Furthermore nitrite in the effluent was significantly lower. With the different initial C/N ratios the removal efficiency of NO3--N was kept above 90%, which was higher compared to the reactor filled with silicone. After backwash, the capacity of reactor filled with limonite can restore shortly and reach the stable state in a shorter period of time.(3) Microbial analysis results showed that four types of bacterial species of Proteobacteria, Bacteroidetes, Chlorobi and Spirochaetes were available in the trwo reacotrs. Proteobacteria mostly has a denitrification ability. Results showed that the microbial abundance in the reactor filled with limonite was higher which meant a greater stability of the microbial community structure. It was also found that more bacteria with the capacities of decomposing aromatic compounds exited in the filter with limonite.