Study On Flocculent Purification Of Waste Water From Soybean Protein Isolated

Recently, waste water from production of soybean isolated proteins has become a serious environmental problem. This waste water was highly organic water, because it contained plenty of hydrocarbon, protein, amino acid and other nutritious substances containing nitrogen and phosphorus.Flocculation was preponderant method of treating this wastewater. In this article several flocculants were choosed as the objects of the experiment, such as aluminum chloride, calcium chloride, sodium phosphate, polyaluminium chloride (PAC), ferric sulphate polymer flocculant (PFS) and polyacrylamide (PAM). A comparative study of application of the flocculants was made, and confirming the optimum amount of usage and operational conditions are the experimental purposes. The best scheme was obtained by the comparison of effection and economic analysis.Using PFS is the optimum choice. In the conditions of room temperature and adjusting pH to 7, the optimum amount of usage is 2.5g/L, and the rate of removal for protein is up to 61.9%. The operation conditions of flocculation reaction are solution quickly stired about one minute (at a speed of 150rpm) and slowly stired for 5 minutes afterwards (at a speed of 50rpm).