The seventh sewage treatment plant in Wuqing District, designed by our company, has a design scale of 10 thousand m3/d for a period. At present, the civil engineering and equipment installation project has been fully completed, and has officially entered the operation and commissioning stage. The new biological doubling technology is adopted in the project. Compared with the conventional domestic sewage treatment process, the project has the advantages of small footprint and low operation cost, and saves two sedimentation tanks and sludge reflux pump house.