溶解氧对动态膜生物反应器的处理效果及膜污染特性

采用孔径为37 μm涤纶滤布作为分离介质构成一体式动态膜生物反应器（DMBR）处理模拟生活污水，考察溶解氧（DO）对反应器处理效果和胞外聚合物（EPS）的影响，并研究了膜污染的特性。结果表明，当DO＞0.5 mg/L时，溶解氧对COD的去除效果影响不大，出水COD浓度为16.67 mg/L；氨氮、硝氮和总氮的浓度受DO影响较大，DO浓度在3.0～3.5 mg/L时，出水氨氮浓度最低，总氮的去除效果最好。当DO＞2.0 mg/L时，EPS浓度不受DO的影响，反应器中EPS浓度在20 mg/gMLSS，并且多糖浓度大于蛋白质浓度。在DMBR工艺中，滤布本身的阻力为2×10⁶ m^－1，动态膜形成的阻力为4.32×10⁷ m^－1，后者是总膜阻力的主要决定因素。在进水流量为3.0 L/h时，反应器膜通量为25 L/(m²·h)，反冲洗周期为33 d，反冲洗后膜通量恢复率为100%。

Effect of dissolved oxygen on DMBR treatment efficiency and characteristics of membrane fouling

Polyester filter cloth with mean pore size of 37 μm was used as the separation medium to develop a submerged dynamic membrane bioreactor（DMBR）for treating model household wastewater. The treatment efficiency and extracellular polymeric substances（EPS）were investigated at different dissolved oxygen（DO）concentrations，the characteristics of membrane fouling were dicussed. The results showed that when the concentration of DO was more than 0.5 mg/L，the concentration of effluent COD was stable at 16.67 mg/L. The concentration of DO had a significant effect on the effluent of ammonia nitrogen，nitrate and total nitrogen. When the concentration of DO was 3.0～3.5 mg/L，the effluent concentration of ammonia nitrogen was the lowest，and the removal of total nitrogen was the maximum. When the concentration of DO was more than 2.0 mg/L，the concentration of EPS was almost unchanged. Under such circumstances，the concentration of EPS was 20 mg/g MLSS，and the polysaccharide concentration was more than the protein concentration in the DMBR. The resistance values of cloth and dynamic membrane was 2×10⁶ m^－1 and 4.32×10⁷ m^－1，respectively. The latter was the main resistance in the DMBR. At a constant influent flow of 3.0 L/h，the flux of the dynamic membrane could reach 25 L/(m²·h)，with its backwashing period of about 33d and 100% recovery of the membrane flux.