Adsorption and Coagulation Tertiary Treatment of Pulp & Paper Mills Wastewater

The pulp & paper industry generates a considerable amount of wastewater in its manufacturing processes. Currently, the pulp and paper industry is facing more stringent standards for discharges of wastewater and associated permits. Biological processes such as activated sludge and aerated lagoons are conventionally used to treat pulp mill effluents. However, these processes have limited ability to provide effluents of high-quality conforming to stringent regulations, since large amounts of lignin and lignin-derived compounds remain in the wastewater. These compounds cannot be metabolized biologically because of their size and complex structure. The objective of this work was to improve the treatment performance of pulp & paper mill effluents, and hence the quality of treated wastewater. For this purpose, a combination of adsorption and coagulation treatment has been proposed. In this study, bentonite was used as adsorbent while PASiC (Polyaluminum Silicate Chloride) was used as coagulant. Respectively, 60.87% of COD removal and 41.38% of color removal can be obtained at the optimum conditions for coagulant dosage and adsorbent are 400 mg/L and 450 mg/L, and adsorption reaction temperature is 30°C, while stirring at the speed of 300rpm for 30min, and the pH value is nature.