Study On Municipal Sewage Reclamation By Membrane Bioreactor

A study on municipal sewage reclamation using Dynamic Membrane Bioreactor and A/O Membrane Bioreactor is presented in this paper. Both techniques showed desirable quality effluents. The dynamic membrane made of 0.1mm Dacron mesh was utilized to develop a submerged Dynamic Membrane Bioreactor, instead of static membrane such as microfiltration membrane or ultrafiltration membrane. The result illustrated that, in the condition of 5 hours HRT and at flux of 13.9 L/(m~2·h),16.7 L/(m~2·h),20.8 L/(m~2·h), the removal efficiency of COD and SS in the system was 90% and 100%, respectively. In the course of experiment, we found that the concentration of MLSS was increased steadily and reached 7500 mg/L at last. Under several times of shock loading, all COD concentration of effluent maintained ca. 20mg/L and the concentration of SS was measured to be zero. It was showed that the reactor had strong anti-shock loading capability similar to traditional MBRs, and the removal efficiency of SS was immune to the shock loading. On the other hand, the high initial flow rate resulted in the lentamente formation of dynamic membrane. After 2 hours, the effluent was still feculent. Once formed, the dynamic membrane would be so firm that it was hardly affected by the shock loading of flux. When the flux was 112.5 L/(m~2·h), no SS was found in the effluent at all. In the process of A/O Membrane Bioreactor applied in the sewage reuse on pilot scale test, its high disposal efficiency was verified by experiment subsequently. In the case of HRT=5h, it concluded that the turbidity of effluence was less than 1.2NTU, and the removal efficiencies of COD and NH3-N could reach 90% and 95% respectively. In addition, the removal efficiency of TP in the system could get to 70%. The system had run a long time with the gas/liquid ratio of 8, without the problem of the decline of flux. Recognized from the results, it was made clear that the A/O Membrane Bioreactor had advantage of lower total energy consumption than the common MBRs. It has promising application foreground.