梯级混凝技术在造纸废水处理中的应用

选取聚合氯化铝(PAC)和聚丙烯酰胺(PAM)作混凝剂对速生材造纸中段废水进行了梯级混凝(即混凝及其污泥回流)处理,考查了pH值、PAC投加量、污泥回流量等因素对处理效果的影响。结果表明,当废水pH值为6.5～8.2、PAC用量3 mL/L、污泥回流量为40%～60%时,实验效果明显优于传统混凝方式,COD由400 mg/L降至100 mg/L左右,去除率达75%。出水pH值为7.5～8.2,符合国家排放标准,并满足造纸回用水要求。

The Technique of Step Coagulation for Paper Making Wastewater

Liquid Polyaluminum chloride(PAC) is chosen as flocculation,while the step flocculation technic is used to deal with paper making wastewater.The influence of pH value of wastewater,and the adding amount of flocculant and return sludge flow and other factors on treatment effect are investigated in treating paper making wastewater.The results show that,the appropriate pH value is from 6.5 to 8.2,the adding amount of PAC is 3ml/L,the appropriate return sludge flow is from 40% to 60%.Experimental results is clearly better than the traditional way of coagulation,The COD of the wastewater fall from 400 mg/L to about 100 mg/L,the remove of COD is 75%,meanwhile,the pH value is about 7.5 to 8.2,the water can reach the discharge standard.