聚合铝基复合絮凝剂用于城市纳污河道废水处理

以城市纳污河道废水为处理对象,聚合氯化铝-二甲基二烯丙基氯化铵（PAC-PDMDAAC,代号JYF-1）复合絮凝剂为处理药剂,在室内模拟化学强化一级处理（CEPT）现场工艺,进行了烧杯絮凝实验,主要考察废水中颗粒物、有机物和氮磷的去除效果,以及pH和表面负荷率（SOR）对絮凝效果的影响,分析了投药前后废水中颗粒物粒径分布和电荷特性的变化,讨论了JYF-1药剂的作用机理及其在CEPT工艺中的应用. 结果表明,聚合铝基复合絮凝剂JYF-1比传统的PAC拥有更好的絮凝效果,对pH和SOR的适应能力更强. JYF-1对非溶解性污染物的去除要好于溶解性污染物的去除,8 mg·L^-1的JYF-1对COD和溶解性COD（SCOD）的去除率分别为76.72%和64.31%,处理后出水的可生化性大幅提高,BOD/COD从处理前的0.23增加到处理后的0.53. JYF-1具有良好的除磷效果和一定的脱氮效果,当JYF-1投量为12 mg·L^-1时,溶解性总磷（STP）的去除率可达到90%以上,总磷（TP）的去除率可达到80%左右,总氮（TN）去除率为20%左右. 将JYF-1应用于CEPT工艺,可以无需改变现有的设备和工艺,以更少的投药量获得更好的出水水质,产生更少的污泥,是值得推广应用的高效低价絮凝剂.

Municipal Wastewater Treatment Using a Composite Flocculant Made of Polyaluminum Chloride and Polydimethyldiallyammonium Chloride

A composite flocculant (denoted JYF-1), made of polyaluminum chloride (PAC) and polydimethyldiallyammonium chloride (PDMDAAC), was used in jar-tests to simulate the chemically enhanced primary treatment (CEPT) for municipal wastewater. Removal of particles, organic compounds, nitrogen and phosphorus in wastewater was investigated, and the effects of pH and surface overflow rate (SOR) on flocculation were also examined. Electrical charge and distribution of particles in wastewater were analyzed before and after flocculation. Furthermore, the flocculation mechanism and application of JYF-1 in CEPT were discussed. The results demonstrate that JYF-1 performs better than PAC under a wide pH and SOR range. When 8 mg·L^-1 JYF-1 is added, 76.72% COD and 64.31% soluble COD (SCOD) can be removed. About 90% soluble TP (STP), 80% TP and 20% TN can be removed by addition of 12 mg·L^-1 JYF-1. After flocculation, the BOD/COD ratio increases from 0.23 to 0.53, which indicates the biodegradation ability of wastewater is improved. It can be concluded that JYF-1 is a high-efficiency low-cost flocculant, which can improve outlet water quality and produce less sludge without changing the existing equipments and treating process in sewage plants.