采用聚合氯化铝-聚二甲基二烯丙基氯化铵(PAC-PDMDAAC)复合混凝剂处理腐殖酸-高岭土模拟水样,对混凝出水进行超滤处理,研究了混凝剂投药量及进水pH值对处理效果的影响;出水用NaClO溶液进行了氯消毒实验,用一级模型进行了氯衰减数据拟合,计算得出了快速反应物与慢速反应物的初始浓度.结果表明,在要求出水中消毒副产物前驱物浓度最小的前提下,混凝与混凝-超滤所要求的投药量及进水pH值有所不同.混凝过程中残余絮体的粒径分布显示,残余絮体的粒径较小且分布集中时,混凝出水中消毒副产物前驱物浓度最低;残余絮体的粒径在粒径较小的区域有一定的分布,在粒径较大的区域有较高体积百分数时,混凝-超滤出水中消毒副产物前驱物浓度最低.
The synthetic water containing humic acid and kaolin was treated using composite coagulant polyaluminum chloride and polydimethyldiallylammonium chloride(PAC-PDMDAAC) firstly.Then, the water treated by coagulation was filtrated using ultrafiltration membrane.The effect of coagulant dosage and pH on the water treatment efficiency was investigated.Disinfection was carried out for the water treated by coagulation or by combined coagulation-ultrafiltration processes using NaClO solution as disinfectant.The residual chlorine data was fitted using first-order chlorine decay model and the initial concentrations of fast reacting agents and slow reacting agents were obtained by calculating the residual chlorine data using the software AQUASIM.For the purpose of lowest concentration of precursors of disinfection by-products, there existed different coagulant dosages and pH for coagulation and coagulation-ultrafiltration processes.For the water treated by coagulation, the concentration of precursors of disinfection by-products was the lowest when the flocs size was small and the flocs size behaved a concentrated distribution.While for the water treated by coagulation-ultrafiltration, the concentration of precursors of disinfection by-products was the lowest when the flocs size distribution curve had two peaks and the volume percentage of flocs with larger particle size was higher.