The project is phase II for expansion of the Sichuan Lezhi County Sewage Treatment Station. Phase I adopts the Carrousel oxidation ditch process with a capacity of 10,000m³/d. Phase II is to provide an additional capacity of 15,000m³/d on the reserved land. The effluent after treatment is required to meet the requirement for class 1A in GB18918-2002. Adopting the BioDopp biochemical process, the project was commenced in 2012, and put into operation in 2013. The actual effluent fully meets the design requirements.