Dovletoglou Olga, Philippopoulos Constantine, Grigoropoulou Helen
National Technical University of Athens, Department of Chemical Engineering, 9 Heroon Polytechniou Str., GR-15780 Athens, Greece.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2002 Aug;37(7):1361-77. doi: 10.1081/ese-120005992.
In the present study, the coagulation of paint industry wastewater was examined. Ferrous and aluminum sulphate and polyaluminum chloride (PACl) were used as coagulation agents and the influence of the coagulant dose and effective pH on the quality of treated wastewater was investigated. Optimum pH for FeSO4 addition was near 9.7, the required coagulant dose was about 2 g/L and average process efficiency varied between 30 and 80% in COD and between 70 and 99% in turbidity terms, for a wide spectrum of wastewater batches. In the case of Al2(SO4)3, no pH adjustment was needed and process efficiency varied between 70 and 95% in COD and between 90 and 99% in turbidity terms, for an effective dose of 2.5 g/L. Further improvement of process efficiency was possible by raising the pH of the supernatant liquid after alum-sludge sedimentation to 10. In the case of PACl optimum pH was around 7 and process efficiency was about 98% based on both quality parameters, for an effective dose of 4 g/L. Cationic polyelectrolytes were proved to have a higher potential vs. coagulation than anionic ones when acting as primary coagulants. Combination of Al2(SO4)3 or PACl with polyelectrolytes resulted in high process efficiencies, while maintaining liquid pH values at acceptable limits.
在本研究中，对涂料工业废水的混凝处理进行了考察。使用硫酸亚铁、硫酸铝和聚合氯化铝（PACl）作为混凝剂，并研究了混凝剂投加量和有效pH值对处理后废水水质的影响。投加硫酸亚铁的最佳pH值接近9.7，所需混凝剂投加量约为2 g/L，对于多种废水批次，平均处理效率在COD去除率方面为30%至80%，在浊度去除率方面为70%至99%。对于硫酸铝，无需调节pH值，在有效投加量为2.5 g/L时，处理效率在COD去除率方面为70%至95%，在浊度去除率方面为90%至99%。通过将明矾污泥沉淀后的上清液pH值提高到10，可以进一步提高处理效率。对于PACl，最佳pH值约为7，在有效投加量为4 g/L时，基于这两个质量参数的处理效率约为98%。当用作主要混凝剂时，阳离子型聚电解质被证明比阴离子型聚电解质具有更高的混凝潜力。硫酸铝或PACl与聚电解质的组合可实现较高的处理效率，同时将液体pH值保持在可接受的范围内。
