Abstract:

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.