May 2016 completed the sewage treatment project of sanli real estate development co., LTD. The project is located in yishui lake scenic area, yixian county. The sewage treatment capacity is 132m /D, and the original water quality COD is less than 400mg/L and BOD is less than 200mg/L. After treatment, the water quality meets the maximum allowable discharge standard of pollutants stipulated in class A of urban sewage treatment plant gb18918-2002. In September 2017, due to the expansion of the scenic spot, the sewage treatment scale was expanded from 132m3/d to 300m /d.