Department of Environmental, Water & Agricultural Engineering, Technion-Israel Institute of Technology, Haifa 3200, Israel.
Water Sci Technol. 2010;62(10):2357-63. doi: 10.2166/wst.2010.499.
The current study analyses the performance of deep sand filtration of greywater from an office building and the performance of a combined physicochemical process comprising of coagulation, sedimentation and filtration. Raw greywater quality exhibited very high variability with average turbidity of 35 NTU, and TSS, COD(t), and BOD of 45, 240, 75 mg/l respectively. The stand-alone filter removed 50 and 70% of the turbidity and TSS, but failed to remove COD and BOD. Quality of the produced effluent was too low to allow any reuse. Clogging rate of the filter was high and under hydraulic loading of 3-4 m(3)/(m(2) h) the filtration cycle had to be terminated after 5-8 h. Clogging occurred mainly on the upper layer, indicating the dominance of "cake" filtration mechanism. Addition of coagulation and sedimentation prior to sedimentation dramatically improved effluent quality, reaching overall removal efficiencies of 92, 94, 65 and 57% of turbidity, TSS COD(t) and BOD respectively. The filtration cycle could be prolonged to 20 h. The effluent produced was of much better quality, yet, it has to be further treated (either biological treatment or membrane filtration). Most of the removal occurred in the coagulation-sedimentation step, while the filter acted as a polishing unit.
本研究分析了办公楼灰水的深层砂滤处理性能，以及包括混凝、沉淀和过滤的组合物理化学工艺的处理性能。原灰水水质表现出非常大的变异性，平均浊度为 35 NTU，TSS、COD(t)和 BOD 分别为 45、240 和 75 mg/L。独立的过滤器去除了 50%和 70%的浊度和 TSS，但未能去除 COD 和 BOD。产生的出水水质太低，无法进行任何再利用。过滤器的堵塞速率很高，在水力负荷为 3-4 m³/(m² h) 时，过滤周期必须在 5-8 小时后终止。堵塞主要发生在上层，表明“滤饼”过滤机制占主导地位。在沉淀前添加混凝和沉淀可显著改善出水水质，总去除率分别达到浊度、TSS COD(t)和 BOD 的 92%、94%、65%和 57%。过滤周期可延长至 20 小时。产生的出水水质要好得多，但仍需进一步处理（生物处理或膜过滤）。大部分去除发生在混凝-沉淀步骤中，而过滤器则起到抛光单元的作用。
