An Experimental Study on Choosing Coagulant and Determining Optimum Coagulation Conditions for Treating Wastewater from Regenerate Paper Industries

摘要

Orthogonal experiment was designed to choose coagulant for treatment of regenerate paper industry wastewater. Polyaluminium chloride (PAC) was chosen based on the value of K, K mean, and R of each level of different factors, when taking supernatant liquid COD as an index for evaluating. Furthermore, the optimum coagulation condition was determined when the dosage was 1.24 g / L, and pH value was 7. Under optimum coagulation conditions, the COD removal rate of wastewater was up to 76.78%, pH value was 6.33, turbidity was 10NTU, and the color of the supernatant liquid was slightly yellow. That made preparations for the subsequent land treatment. The Experimental temperature is 14.5 ~ 18.5 °C.