复合铝铁絮凝剂对印染废水的预处理研究

Study on the pretreatment of printing & dyeing wastewater with composite polyaluminum ferric flocculants

针对某印染工业园废水集中处理厂的印染废水,选择聚合氯化铝铁(PAFC)、聚合硫酸氯化铝铁(PAFCS)进行絮凝预处理,研究了投药量、初始pH及温度对有机物去除效率的影响,结合过程ζ电位变化探讨了絮凝机理,对絮凝剂的污泥产量进行了系统研究,并与聚合硫酸铁(PFS)、聚合氯化铝(PAC)的处理效果进行了比较。结果表明:当温度为25℃,pH=10.0,投药量为620 mg/L时,PAFC、PAFCS的COD去除率分别达到52.6%、43.6%,污泥产率系数分别为1.33、0.80 g/g。与PAC、PFS等常规絮凝剂相比,复合铝铁絮凝剂的处理效率高、投药量低、污泥产量少,可在印染废水处理工程中推广应用。

Aiming at treating the printing ＆ dyeing wastewater in the centralized treatment plant of a printing and dyeing industrial park,polyaluminum ferric chloride （PAFC） and polyaluminum ferric chloride sulfate （PAFCS） have been used for pretreatment by flocculation. The effects of chemical dosage , initial pH and temperature on the organism removing efficiency are studied. Flocculation mechanisms are discussed combining with process ζ potential changes. The sludge output of flocculants is studied systematically, and the treatment efficacies of PFS and PAC are compared. The results show that when the temperature is 25 ℃, pH 10.0, and dosage 620 mg/L,the COD removing rates of PAFC and PAFCS reach 52.6% and 43.6% ,respectively,and sludge output coefficients are 1.33 g/g and 0.88 g/g,respectively. Compared with conventional flocculants PAC,PFS,etc.,polyaluminum ferric flocculant is characterized by high treatment efficacy,low dosage consumption and low sludge output. It can be popularized and applied to printing and dyeing wastewater treatment engineering.