Fuente: WIPO "circular economy" The utility model discloses a negative pressure type septic tank system which comprises a negative pressure blow-off pipe which is vertically arranged, a plurality of communicating pipes are longitudinally arranged on one side of the negative pressure blow-off pipe at intervals, and the communicating pipes are respectively connected with blow-off pipes of corresponding floors of a building; the septic tank is a buried septic tank, and an inner cavity of the septic tank is communicated with the lower end of the negative pressure blow-off pipe; the negative pressure device assembly comprises an air pressure sensor arranged in the septic tank and a negative pressure vacuum pump positioned on the outer side of the septic tank; when the pressure measured by the air pressure sensor is higher than a set high pressure value, the single-chip microcomputer transmits an electric signal to start the negative pressure vacuum pump until the pressure measured by the air pressure sensor is reduced to a set low pressure value, and the single-chip microcomputer transmits an electric signal to close the negative pressure vacuum pump. Compared with a common closestool and a sewage collection system, the water can be saved by more than 90%, and the sewage carrying amount is greatly reduced. In addition, after the water is saved and the concentration of the liquid dung is improved, the resource utilization degree can be greatly improved.