China National Petroleum Ordos Energy Chemical Co., Ltd. Tuk project is the largest chemical project in the country and the world. The wastewater in the plant is mainly from phenol ammonia recovery wastewater, methanol wastewater, gasification circulating water and other comprehensive wastewater. sewage treatment process using ozone oxidation and BAF process, further residual organic matter and ammonia nitrogen in the wastewater treatment, combined with high-concentration brine treatment technology, the wastewater reuse rate has reached 98%.