Recently, China’s first large-scale wet air oxidation unit (WAO) for sulfur-containing waste lye, jointly developed by East China University of Science and Technology and China Petroleum & Chemical Corporation, was successfully put into operation in Zhenhai Refining & Chemical Company of Sinopec, with a treatment capacity of 19.5t/h, meeting all the treatment requirements of sulfur-containing waste lye produced by the integrated unit of 10 million tons of oil refining and 1 million tons of ethylene refining & chemical company, and its performance was better than the design index. The successful commissioning of the plant indicates that the clean production of large-scale refining and chemical plants in China and the technology of domestic high-end environmental protection equipment have reached a new level.