Chemical Engineering Department, National Institute of Technology, Raipur, India.
Environ Technol. 2010 Apr 1;31(4):357-63. doi: 10.1080/09593330903486665.
Pulp and paper mill effluent is highly polluting and is a subject of great environmental concern. In the present research we studied the removal of chemical oxygen demand (COD) and colour from paper mill effluent, using the coagulation process. A batch coagulation study was conducted using various coagulants such as aluminium chloride (AlCl3), polyaluminium chloride (PAC) and copper sulphate (CuSO4 x 5H20). The initial pH of the effluent had a tremendous effect on the COD and colour removal. The PAC reduced COD by 83% and reduced colour by 92% at an optimum pH of 5.0 and a coagulant dose of 8 mL L(-1). With AlCl3, at an optimum pH of 4.0 and a coagulant dose of 5 g L(-1), 72% COD removal and 84% colour removal were observed. At an optimum pH of 6.0 and a mass loading of 5 g L(-1), 76% COD reduction and 78% colour reduction were obtained with copper sulphate. It was also observed that, after addition of coagulant, the pH of the effluent decreased. The decrease in the pH was highest with AlCl3, followed by PAC and then CuSO4 x 5H20.
制浆造纸厂废水污染严重，是人们非常关注的环境问题。本研究采用混凝法处理造纸厂废水，考察了化学需氧量（COD）和色度的去除效果。通过批次实验，研究了不同混凝剂（如三氯化铝（AlCl3）、聚合氯化铝（PAC）和五水硫酸铜（CuSO4 x 5H20））对 COD 和色度的去除效果。废水的初始 pH 对 COD 和色度的去除有很大影响。在 pH 值为 5.0，投加量为 8 mL/L 时，PAC 对 COD 的去除率为 83%，对色度的去除率为 92%；在 pH 值为 4.0，投加量为 5 g/L 时，AlCl3 对 COD 的去除率为 72%，对色度的去除率为 84%；在 pH 值为 6.0，投加量为 5 g/L 时，五水硫酸铜对 COD 的去除率为 76%，对色度的去除率为 78%。此外，加入混凝剂后废水的 pH 值会降低，其中 AlCl3 降低的幅度最大，其次是 PAC，然后是五水硫酸铜。
