Study On Problems And Solutions In The Operation Of Acrylonitrile Wastewater Treatment By Activated Sludge Process

The acrylonitrile wastewater treatment using activated sludge process were often affected by foam, the bulking, floating, crumbling and losing of sludge and the fluctuation of influent water quality, such as COD and pH etc in the plant, Jilin Petrochemical Company. Since these phenomena led to the reduce of treatment efficacy and the increase of operation cost, it was significant to maintain the normal and stable operation of the system by identifying the cause of problems and finding the corresponding solutionsIn this work, the development of acrylonitrile wastewater treatment technology, including the application of activated sludge process, was reviewed, and the cause of problems and effects of the solutions in the operation were also studied. Results indicated that spraying the water in the aerobic tank and controlling the dosage of nutrients such as potassium dihydrogen phosphate could reduce the foam caused by the low temperature. In addition, adding more industrial-grade methanol could improve the performance of sludge, which was deteriorated by the low concentration of dissolved oxygen and the influent of toxic substance. And adding sodium hydroxide or sodium bicarbonate could neutralize the acid influent by accident and help to control the sludge bulking. Employing a short time backwash and spraying the water on surface of floating sludge in the clarification zone to prevent the blockage of sludge could reduce the floating of sludge. And increasing the the air quantity of return sludge lifter and backwash could reduce the losing of sludge. In short, the problem in the operation of acrylonitrile wastewater treatment could be solved, if the appropriate solution was conducted.