Study On The Characteristics And The Microbial Community Structure In Atmosphere-Exposed Biofilm

Water is the source of the life and the resource for human alive. With the development of the industrialization and urbanization, the water pollution become a serious problem to all the world, so the wastewater treatment emerges as the time require. The biofilm technology is widely used in the field of wastewater treatment because it has several advantages including a large specific surface area, lake of return sludge, convenient operation and management, and resistance to shock loading.In this study, the synthetic wastewater was treated by Atmosphere-Exposed Biofilm. The characteristics of COD, TN, TP at different OLR and filling height; at the same time, the microbial community structure and succession at different OLR were analyzed by PCR-DGGE to provide a molecular ecology basis for the use of Atmosphere-Exposed Biofilm. The mainly conclusions were as follows:1) The effluent concentrations of COD, TN were in keeping with the B standard of level 1 of’discharge standard of pollutants for municipal wastewater treatment plant’at 0.08-0.33 kg COD/m3/d. The effluent concentrations of TP were in keeping with the B standard of level 1 at 0.08-0.17 kg COD/m3/d.2) The removal rate of COD, TN and TP increased with the increased of the OLR from 0.08-0.42 kg COD/m3/d. The effect of the OLR on the removal rate of COD and TN became more significant with increased in the filling height, however, this effect was the opposite for the removal rate of TP. Besides, there was a linear relationship between the OLR and removal rate of COD, TN and TP.3) The Shannon-Wiener index and the microbial similarity were significant both before and after the operation of the Atmosphere-Exposed Biofilm. The Shannon-Wiener index of most samples became small after the operation and the microbial similarity were less than 50%.4) Microbial communities were significantly correlated with the filling height. The dominant strains were Frateuria terrea, Myoschiston duplication, Thermomonas fusca, and Leifsonia xyli subsp. xyli str.. Frateuria terrea, Thermomonas fusca and Leifsonia xyli subsp. xyli str. were dominant at all filling heights; Thermincola carboxydiphila and Sphingopyxis ummariensis were dominant at low filling heights: and Myoschiston duplicatum, Geothrix fermentans were dominant at high filling heights.