(230322) -- TIANJIN, March 22, 2023 (Xinhua) -- A researcher displays industrial wastewater and processed recycled water at the National Research Center of Industrial Water Treatment Engineering and Technology in north China's Tianjin, March 22, 2023. The National Research Center of Industrial Water Treatment Engineering and Technology at China National Offshore Oil Corporation Tianjin Chemical Research and Design Institute Co., Ltd. in Tianjin endeavors to promote scientific research and tackle key problems in industrial water treatment technology. Since 1993, the United Nations has declared March 22 of every year as World Water Day. The re-utilization of industrial water is an important issue in our modern life. (Xinhua/Sun Fanyue)