LD-SA improved AO purification tank is a small buried rural sewage treatment equipment developed based on the existing equipment, based on the existing equipment, drawing on the absorption of advanced technology at home and abroad, with the concept of energy-saving and high-efficiency design for the centralized treatment process of domestic sewage in remote areas with large investment in pipeline networks and difficult construction. Adopting micro-powered energy-saving design and SMC molding process, it has the characteristics of saving electricity cost, simple operation and maintenance, long life, and stable water quality to meet the standard.