This device provides time programmed sewage treatment, rather than continuous spatial programmed sewage treatment. This system does not require a primary sedimentation tank, a secondary sedimentation tank, or a sludge return system. It is ideal for static sedimentation and has good separation efficiency. The characteristics include simple operation management, low cost, land saving, shock load resistance, reliable operation, flexible operation, and good effluent quality. This biochemical tank is not only suitable for ordinary domestic sewage treatment, but also very suitable for industrial wastewater treatment in food, chemical, light industry, pharmaceutical, printing and dyeing, painting and other industries.