Zhang Jin, Sun Yu-xin, Huang Zhi-feng, Liu Xing-qin, Meng Guang-yao
Department of Materials of Science and Engineering, University of Science and Technology of China, Hefei, China.
J Environ Sci (China). 2006;18(4):629-33.
The oily wastewater generated from pretreatment unit of electrocoating industry contains oils, phosphate, organic solvents, and surfactants. In order to improve the removal efficiencies of phosphate and oils, to mitigate the membrane fouling, coagulation for ceramic membrane microfiltration of oily wastewater was performed. The results of filtration tests show that the membrane fouling decreased and the permeate flux and quality increased with coagulation as pretreatment. At the coagulant Ca (OH)2 dosage of 900 mg/L, the removal efficiency of phosphate was increased from 46.4% without coagulation to 99.6%; the removal of COD and oils were 97.0% and 99.8%, respectively. And the permeate flux was about 70% greater than that when Ca(OH)2 was not used. The permeate obtained from coagulation and microfiltration can be reused as make-up water, and the recommended operation conditions for pilot and industrial application are transmembrane pressure of 0.10 MPa and cross-flow velocity of 5 m/s. The comparison results show that 0.2 microm ZrO2 microfilter with coagulation could be used to perform the filtration rather than conventional ultrafilter, with very substantial gain in flux and removal efficiency of phosphate.
电泳涂装工业预处理单元产生的含油废水含有油类、磷酸盐、有机溶剂和表面活性剂。为提高磷酸盐和油类的去除效率，减轻膜污染，对含油废水进行了陶瓷膜微滤的混凝预处理。过滤试验结果表明，采用混凝预处理可减少膜污染，提高渗透通量和水质。在混凝剂Ca(OH)₂投加量为900mg/L时，磷酸盐去除率从未混凝时的46.4%提高到99.6%；COD和油类的去除率分别为97.0%和99.8%。且渗透通量比未使用Ca(OH)₂时提高约70%。混凝和微滤得到的渗透液可作为补充水回用，中试和工业应用的推荐操作条件为跨膜压力0.10MPa、错流速度5m/s。比较结果表明，采用混凝的0.2μm ZrO₂微滤器可用于过滤，而不是传统超滤，通量和磷酸盐去除效率有显著提高。
