两级序批式MBR膜污染特性研究

采用两级SBR与膜法相结合的两级序批式MBR工艺处理生活污水,考察两级序批式运行模式对膜污染特性的影响.对运行111 d后的平板膜污染阻力分布进行了测算,并对两级序批式MBR与连续流单级好氧MBR的平板膜污染速率进行对比试验.结果表明: 两级序批式MBR的平板膜污染阻力以凝胶极化阻力为主,占总阻力的43%,沉积阻力较低,仅占总阻力的10%;与连续流单级好氧MBR相比,两级序批式MBR可以在更高的膜通量下运行,保持更低的膜污染速率,在运行42 d后,过膜流量从100 L/h下降至85 L/h,过膜压差从1.52×10~4 Pa增加至2.22×10~4 Pa;而连续流好氧MBR系统,过膜流量从61 L/h降低至39 L/h,过膜压差却从1.01×10~4 Pa增加至2.63×10~4 Pa.研究表明,两级序批式MBR工艺可以改善膜过滤过程的水力条件,从而有效地减缓浓差极化,降低沉积污染及凝胶层污染,序批式、膜间歇运行与空曝的结合起到了关键性作用.

Research on the membrane fouling characteristics of the two-stage sequencing batch MBR

The given paper hopes to introduce our results of our experimental investigations of the two-stage SBR with the establishment of the two-stage sequencing batch MBR (TSBMBR) treatment of the urban sewage. In addition, the paper has also investigated the influence of the method on the degree of the membrane fouling with the calculation of the resistance distribution of flat-sheet membrane fouling done during and after our 111 days' experimental operation. The results of our investigation and experiments show that, in TSBMBR the gel polarization proves to be the major component of flat-sheet membrane fouling resistance, which may roughly account for 43% of the total resistance, whereas the sedimentation resistance merely accounts for 10% of the total. In addition, TSBMBR tends to work under the higher trans-membrane flux than the continuous-flow one-stage aerobic MBR. Besides, TSBMBR also proves to be able to reduce the membrane fouling rate. Moreover, 42 days' operation reveals the fact that the trans-membrane flux could be reduced from 100 L/h to 85 L/h while the trans-membrane pressure can rise from 1.52×10~4 Pa to 2.22×10~4 Pa. Nevertheless, the trans-membrane flux of the continuous flow aerobic MBR system may reduce from 61 L/h to 39 L/h after 30 days operation, yet the trans-membrane pressure would increase from 1.01×10~4 Pa to 2.63×10~4 Pa. At the same time, TSBMBR proves to be favorable for the hydraulic condition of membrane filtration process and effective mitigation of the concentration polarization, as well as reducing the sedimentation and gel-layer pollution. Thus, it can be generalized that the sequencing batch operation mode and the combined intermittent filtration with idle aeration indeed play an important role in the above said process.