A pumping device for pumping waste, comprising a waste chamber, for storing waste, having an inlet for receiving waste and an outlet for transmitting waste; a first valve for controlling received waste from the waste chamber inlet; a second valve for controlling transmitted waste through the waste chamber outlet; a pump; a pressure line; and a pressure chamber, coupled between the pressure line and the waste chamber, the pressure line being coupled to the pump, wherein the pressure chamber is arranged to store pressure generated by the pump, a third valve separating the waste chamber from the pressure chamber; and a fourth valve separating the pressure chamber from the pressure line and pump; wherein the device is characterised in that: the fourth valve is arranged to be opened when the first valve is open and the second and third valves (V22, V23) are closed, such that the pressure chamber receives pressurised fluid generated by the pump; the third valve is arranged to be opened when the first, second and fourth valves (V21, V22, V24) are closed such that stored pressure is released from the pressure chamber into the waste chamber and increases the pressure therein, the third valve being opened and the first and fourth valves being closed (V21, V24) when the waste in the waste chamber reaches a predetermined level or after a predetermined amount of time; and the second valve is arranged to be opened after pressure from the pressure chamber has been released into the waste chamber to thereby force waste from the waste chamber. a waste chamber, for storing waste, having an inlet for receiving waste and an outlet for transmitting waste; a first valve for controlling received waste from the waste chamber inlet; a second valve for controlling transmitted waste through the waste chamber outlet; a pump; a pressure line; and a pressure chamber, coupled between the pressure line and the waste chamber, the pressure line being coupled to the pump, wherein the pressure chamber is arranged to store pressure generated by the pump, a third valve separating the waste chamber from the pressure chamber; and a fourth valve separating the pressure chamber from the pressure line and pump; wherein the device is characterised in that: the fourth valve is arranged to be opened when the first valve is open and the second and third valves (V22, V23) are closed, such that the pressure chamber receives pressurised fluid generated by the pump; the third valve is arranged to be opened when the first, second and fourth valves (V21, V22, V24) are closed such that stored pressure is released from the pressure chamber into the waste chamber and increases the pressure therein, the third valve being opened and the first and fourth valves being closed (V21, V24) when the waste in the waste chamber reaches a predetermined level or after a predetermined amount of time; and the second valve is arranged to be opened after pressure from the pressure chamber has been released into the waste chamber to thereby force waste from the waste chamber. the fourth valve is arranged to be opened when the first valve is open and the second and third valves (V22, V23) are closed, such that the pressure chamber receives pressurised fluid generated by the pump; the third valve is arranged to be opened when the first, second and fourth valves (V21, V22, V24) are closed such that stored pressure is released from the pressure chamber into the waste chamber and increases the pressure therein, the third valve being opened and the first and fourth valves being closed (V21, V24) when the waste in the waste chamber reaches a predetermined level or after a predetermined amount of time; and the second valve is arranged to be opened after pressure from the pressure chamber has been released into the waste chamber to thereby force waste from the waste chamber.