Title : A novel hybrid chemical precipitation - coagulation Method for the treatment of paper and pulp industrial wastewater
Abstract:
Industrial wastewater generates a variety of pollutants that have a negative effect on the environment, human health, natural resources, and public property. The pulp and paper industry is a very water-intensive industry, consumes high amount of freshwater per ton of product, and generate highly toxic wastewater. Therefore, the major goal of this work is to treat an industrial wastewater effluent from paper and pulp plant utilizing a precipitation agent known as ammonium hydroxide (NH4OH), followed by coagulation-flocculation, sedimentation, and filtration. Attempts were made in this study to examine the effectiveness of coagulation and flocculation processes using aluminum sulfate (alum). The optimum conditions for coagulation/flocculation process, such as coagulant dosage and pH of solution, were investigated using jar-test experiment. Alum was found effective in a dosage range of 100 to 500 ppm. This dosage range was investigated further in detail at a stirring time of 3 hours, and a mixing speed of 400 rpm at different pH levels ranging from 8 to 11. The removal of total solids (TS), total dissolved solids (TDS) and total organic carbon (TOC) was assessed. The results revealed that in the range of pH tested, the optimal operating pH was 11. At an optimum initial pH of 11, maximum TS and TOC reductions of 52% and 77% were obtained, respectively, with an alum dosage of 500 ppm., although the maximum TDS reduction was 40% using an alum dose of 100 ppm. To this end, this research shows that chemical precipitation can serve as an efficient technique in industrial wastewater treatment for TS, TDS, and TOC reduction.
