The tailwater treatment project of a sewage treatment plant in Binzhou City covers an area of about 90 acres, including 20 acres of subsurface flow wetlands and 64 acres of effective surface flow wetlands. The incoming water is pre treated domestic sewage, and the water quality meets the Class B standard of the "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (GB 18918-2002). After treatment, the water quality meets the Class IV water standard of the Environmental Quality Standards for Surface Water (GB3838-2002)