Biological purification tank device for rural domestic sewage treatment

The utility model provides a biological purification tank device for rural domestic sewage treatment, which belongs to the technical field of sewage treatment and comprises a shell component and a treatment component. The shell assembly comprises a support, a purification tank, a sewage tank and a clean water tank, and the treatment assembly comprises a filler partition plate, a driving shaft, a driven shaft, a scraping belt, a driving motor, a spiral conveying shaft, a sludge discharge pipe, a silt pumping piston and an air cylinder. The spiral conveying shaft continuously conveys gathered sludge to the position close to the sludge discharging pipe, the air cylinder controls the sludge pumping piston to pump the sludge in a negative pressure reciprocating mode, the filtering scraping design is adopted, sewage is precipitated and filtered, meanwhile, the filtering effect of the filler is improved by scraping sludge accumulated on the filler, the spiral conveying pumping design is adopted, and spiral conveying