外循环三相生物流化床载体挂膜的研究

Study on formation of Biofilm and Biofilm Thickness in a Three-phase Bio-fluidized Bed with external loop

实验研究了外循环三相好氧生物流化床处理生活废水时活性炭载体表面生物膜的形成条件以及空气流量、水力停留时间等因素对生物膜厚度的影响.由于外循环流化床包含好氧区和缺氧区,有利于好氧菌和兼氧菌的生长.实验结果表明,0.09m3/h的空气流量,3～4 h的水力停留时间和较少的接种污泥浓度有利于启动挂膜,在HRT为3～4 h,有机容积负荷3～9.8 kg COD/(m3·d)条件下,能培养出稳定的生物膜,10 d膜厚达100μm以上;当HRT为3 h,空气流量0.09m3/h,有机容积负荷率为9.8 kg COD/(m3.d)时,生物膜厚度为145μm,此时生物膜活性最好,COD去除率最高,均在90%以上.

The experiments were conducted in a three- phase biological fluidized bed with external loop to investigate the effects of operation condition（airflow rate, hydraulic retention time） on the formation of biofilm on a carrier surface, This equipment include aerobic zone and anoxic zone. It was beneficial for the growth of aerobiosis bacterium and anoxic bacterium. The best condition of the rapid biofilm format are 0.09 m^3/h of airflow rate ,HRT 3 ～ 4 h and smaller inoculation concentration. It was beneficial to the rapid biofilm formation. Under the condition of the HRT of 3 ～ 4 h and the organic volume load rate of 3 ～ 9.8 kgCOD/（m^3·d）, the biofilm can form steadily on the carrier surface and reaches more than 100 it m in thickness after 10 days. When HRT is 4 h, airflow rate is 0.09 m^3/h, the organic volume load rate is 9.8 kgCOD/（m^3·d）,the biofilm of 145μm thick has the best activation and the highest removal rate of COD. The COD removal rate reach more than 90 %.