A liquid filtration system comprising a syringe pump comprising a gas chamber and a movable plunger, wherein the gas chamber has an aperture at a first end and the plunger forms a seal within the internal walls of the chamber; a liquid chamber having two openings, the openings positioned at opposite ends of the chamber and the first opening connected to the aperture of the gas chamber; a bioreactor in fluidic communication with the second opening of the liquid chamber; a filter arranged to filter liquid passing between the bioreactor and the liquid chamber, the filter comprising a permeate outlet for removing filtered liquid; wherein, in use, the plunger may be moved in a reciprocating motion causing a corresponding movement of gas which drives liquid alternately between the liquid chamber and the bioreactor such that liquid passes through the filter and filtered liquid may be removed via the permeate outlet.