Environmental Science Program, Faculty of Science, Burapha University, Chonburi 20131, Thailand.
J Environ Sci (China). 2011;23(4):587-94. doi: 10.1016/s1001-0742(10)60451-2.
A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate (alum) sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal efficiency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids (TSS), total chemical oxygen demand (TCOD), total anionic surfactants, and turbidity removal efficiencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal efficiencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal efficiency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.
混凝-絮凝工艺通常用于处理日用化学品行业生产洗涤剂、肥皂等产生的工业废水。处理这种废水需要耗费大量的化学药品，包括混凝剂和 pH 值调节剂。本研究旨在评估重复使用硫酸铝（明矾）污泥作为混凝剂或助凝剂的可行性，以减少新鲜明矾的用量或提高去除效率。实验在模拟混凝-絮凝过程的搅拌试验装置中进行，同时去除有机物、阴离子表面活性剂、悬浮物和浊度。在初始 pH 值为 10 和新鲜明矾浓度为 400mg/L 的最佳条件下，总悬浮固体（TSS）、总化学需氧量（TCOD）、总阴离子表面活性剂和浊度的去除效率分别为 71.5%、76.4%、95.4%和 98.2%。单独添加明矾污泥而不添加新鲜明矾，即可显著去除浊度、TCOD 和阴离子表面活性剂。沉降后上清液中仍留有 TSS，但添加新鲜明矾后可将其去除。同时添加明矾污泥和新鲜明矾也可提高 TSS、TCOD 和浊度的去除效率。COD 的去除效率超过 80%，这是单独使用新鲜明矾从未达到的。结论是，明矾污泥可重复用于处理日用化学品行业产生的工业废水。
