微曝气生态浮床的净化效果与生物膜特性研究

Purification Effect and Biofilm Characteristics of Micro-aerated Ecological Floating Bed

大清河是滇池的主要支流之一，其水质污染严重，长期处于黑臭状态，针对这种情况开展了微曝气生态浮床净化其水质的研究。在进水量为6000～10000m^3／d、曝气总量为50m^3／h时，对TN、NH4^＋-N、TP、SS和COD的平均去除率分别为77．4％、84．7％、75．1％、86．2％和72．5％。沿水流方向布设若干观测点，进一步对YDT弹性立体填料上生物膜的发育过程和特性进行了研究。系统水体流速为0．0353～0．1288m／s，弹性填料上的生物膜厚度在14—17d达到最大，生物膜量则在21d达到最大；生物膜的形态、厚度、数量、脱氢酶活性和细菌数量具有沿水流方向渐变的特点。进水端的生物膜较厚、成分复杂，生物膜量沿水流方向则呈逐步递减的趋势，脱氢酶活性呈现先上升再平稳下降的趋势，而异养菌和硝化菌群的数量逐渐增高。对于进水端而言，上层生物膜的脱氢酶活性和异养菌数量明显高于下层，而出水端的则变化不大。系统中硝化菌群的数量较高，与异养菌处在同一个数量级，其总量占异养菌数量的52．2％-138．1％。

The Daqing River is a major tributary of Dianchi Lake. Its water was heavily polluted, and it was a black-odor river. Based on this, a research on the purification of the water by micro-aerated ecological floating bed was conducted. When the inflow rate is 6 000 to 10 000 m^3/d and the total aeration rate is 50 m^3/h, the average removal rates of TN, NH4^＋ - N, TP, SS and COD are 77.4%, 84.7%, 75.1%, 86.2% and 72.5% respectively. The development process and the characteristics of biofilm on the YDT elastic space packing were also studied at many sampling spots along the water flow direction. The flow rate is from 0. 035 3 m/s to 0. 128 8 m/s, the maximum thickness of the biofilm is achieved between 14 and 17 d, and the biomass is reached on the 21 d. The biofilm pattern, thickness, biomass, dehydrogenase activity and bacteria number are characterized by gradual change along the water flow direction. The biofilm thickness is thicker and the composition is more complex at the inlet. The bio-mass is gradually decreased along the water flow direction, and the dehydrogenase activity is first ascended and then is slowly descended, while the numbers of heterotrophic bacteria and nitrifying bacteria are gradually increased. The dehydrogenase activity and heterotrophic bacteria content of the upper layer are significantly higher than those of the lower layer at the inlet. However, the difference is not significant at the outlet. The amount of nitrifying bacteria is higher and accounts for 52.2% to 138.1% of the amount of heterotrophic bacteria.