絮凝沉降法处理含油废水的絮凝优化复配研究

气浮法是含油废水处理的常用方法,但该法工艺复杂,操作要求高.乌鲁木齐铁路局哈密机务段用气浮法处理含油废水,使用的聚合氯化铝-聚丙烯酰胺絮凝剂配方的效率及安全性欠佳,为此提出了用聚乙烯亚胺-活化硅酸-可溶性淀粉3种絮凝剂复配投加的絮凝沉降法.研究表明,本法可使废水中油的去除率达到93.9%,COD去除率达82.2%,浊度去除率达92.3%,具有去除效率高、无毒安全和处理成本低的优点,有望取代原有方法及药剂配方,具有推广应用价值.

Improvement on optimum composition of composite flocculant for oil wastewater treatment by flocculation- sedimentation

The present paper aims at introducing the authors' improvement on the composite flocculant for oil wastewater treatment. As a common practice, flotation is often used for the treatment of oil wastewater. However, it is far from being desirable for its being too complex and too much involved for its operation. In order to improve this situation, we have compared the flocculation efficiency of polyethyleneimine with that of polyaluminum chloride and polyacrylamide. The experiment has shown that the polyethyleneimine is more efficient than others. Therefore we suggest that the flocculation-sedimentation technique be adopted by the flocculants composed of polyethyleneimine-active silicic acid. The optimum composition of this composite flocculant and the optimum operation conditions were determined by the orthogonal experiment. Furthermore, in order to reduce the cost of treatment of oil wastewater, the above composite fulocculant was used along with the soluble starch as flocculation assistant. The experiment results show that the removal efficiencies for oil, COD and turbidity can reach 94%, 82% and 93% respectively by the new method and only 61%, 52% and 58% respectively by old method. The cost of the new method is only 0.66 yuan RMB for a ton of wastewater while with the old method, the cost is 1.7 yuan RMB for a ton of wastewater. Therefore it can be concluded that new method enjoys higher removal rate, and new composite fulocculant has lower cost as compared with the original method and composite fluocculant which was used in the wastewater treatment workshop with Wulumuqi railway. In addition, the new method is innocuous, but the old one is harmful for human body because of the toxicities of aluminum and residual acrylamide to people.