碱减量-印染混合废水的预处理研究

针对碱度大、COD高、组成复杂的碱减量-印染混合废水,采用高碱度下直接混凝再酸析相结合的方法进行预处理,取得理想效果.试验结果表明,在高碱度条件下先加入镁盐及少量高分子絮凝剂,可去除大部分可溶性及不溶性污染物;再通过降低pH的酸析法,能有效去除废水中的色度、浊度,大大降低COD.在MgSO4用量为800～1 500 mg/L,阴离子聚丙烯酰胺用量为2 mg/L,酸析pH小于3.0时,色度去除率达97%,COD去除率达92%,浊度去除率近100%.

Pretreatment of a textile wastewater from alkali reduction,printing and dyeing operations

Textile wastewaters from alkali reduction, printing and dyeing operations are usually highly basic, turbid and have many COD and color constituents present in high concentrations; therefore, effective pretreatment is required to make them biotreatable. Direct acidification of one such wastewater failed because it resulted in heavy production of colloidal products. Coagulation and flocculation, using 800~1 500 mg/L of MgSO_ 4 and 2 mg/L of a high molecular weight organic flocculant HPAM, and followed by acidification to a pH of <3.0, achieved excellent pretreatment performance; COD, color intensity and turbidity of the wastewater sample were reduced by 92%, 97%, and nearly 100%, respectively.