Treatment of paper and pulp mill effluent by coagulation.
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.
Chaudhari
Parmesh Kumar
PK
Chemical Engineering Department, National Institute of Technology, Raipur, India. pkchaudhari@rediffmail.com
Majumdar
Bidyut
B
Choudhary
Rumi
R
Yadav
Deepak Kumar
DK
Chand
Shri
S
D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry*; D000536:Aluminum Hydroxide / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D003116:Color; D019327:Copper Sulfate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D010209:Paper; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D017607:Aluminum Compounds; D002712:Chlorides; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; C016213:aluminum oxychloride; D000077410:Aluminum Chloride; D000536:Aluminum Hydroxide; D019327:Copper Sulfate