Wang Zhiwei, Wu Zhichao, Hua Juan, Wang Xinhua, Du Xingzhi, Hua Hong
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
J Hazard Mater. 2008 Jun 15;154(1-3):535-42. doi: 10.1016/j.jhazmat.2007.10.057. Epub 2007 Oct 22.
The feasibility of using flat-sheet membrane for waste activated sludge (WAS) thickening and digestion was studied in this paper. The characteristics of the processes including the thickening efficiency, effluent water quality and filtration properties of the membrane for sludge thickening process (MST), digestion efficiency, effluent water quality and membrane permeability of the membrane for sludge simultaneous thickening and digestion process (MSTD) were investigated. Test results showed that good sludge thickening efficiency and superior effluent water quality were obtained in the MST process under hydraulic retention time (HRT) 0.26 and 2 d operation of each cycle, and the membrane fouling was mainly due to the increase of apparent viscosity of mixed liquors and the decrease of the cross-flow velocity (CFV) along membrane surfaces during one thickening cycle. Membranes were also selected for the processes and M1 membrane of polyvinylidene fluoride (PVDF) material with pore size 0.2 microm demonstrated better permeability compared with other three membranes. About 80% MLSS destruction rate and 73% MLVSS destruction rate were achieved under HRT 1 d, dissolved oxygen (DO) concentration 0.5-1.5 mg/L, temperature 20-28 degrees C and 15 d operation for one cycle in MSTD process, and membrane fouling of MSTD process was attributed to not only the reason of MST process mentioned above, but also the change of sludge properties such as the increase of soluble COD and microbial polymeric substances including EPS, carbohydrate and nucleic acids, etc. of the mixed liquors.
本文研究了使用平板膜进行剩余活性污泥（WAS）浓缩和消化的可行性。研究了污泥浓缩过程（MST）中包括浓缩效率、出水水质和膜过滤性能等过程特性，以及污泥同步浓缩和消化过程（MSTD）中的消化效率、出水水质和膜渗透率。试验结果表明，在每个周期水力停留时间（HRT）为0.26和2天的运行条件下，MST过程中获得了良好的污泥浓缩效率和优异的出水水质，膜污染主要是由于在一个浓缩周期内混合液表观粘度增加以及沿膜表面的错流速度（CFV）降低。还为这些过程选择了膜，与其他三种膜相比，孔径为0.2微米的聚偏氟乙烯（PVDF）材料的M1膜表现出更好的渗透性。在MSTD过程中，在HRT为1天、溶解氧（DO）浓度为0.5 - 1.5毫克/升、温度为20 - 28摄氏度且一个周期运行15天的条件下，实现了约80%的MLSS破坏率和73%的MLVSS破坏率，MSTD过程的膜污染不仅归因于上述MST过程的原因，还归因于混合液中污泥性质的变化，如可溶性COD以及包括EPS、碳水化合物和核酸等微生物聚合物的增加。
