Gas-scrubbed hollow fiber membrane module

A membrane module comprising a plurality of porous hollow membrane fibres, each of the fibres having an upper and a lower end, the fibres extending longitudinally between and mounted at the upper end to an upper potting head and at the lower end to a lower potting head, wherein the fibres are sealed at the lower end and open at the upper end to allow removal of filtrate, the fibres being arranged in close proximity to one another and mounted in a bundle in a substantially taut manner between the upper and lower potting heads to prevent excessive movement therebetween, wherein the fibres are surrounded by a perforated cage to further prevent excessive movement of the fibres, the fibres being substantially uniformly mounted in the lower potting head relative to a distributed array of aeration holes in the lower potting head, wherein the aeration holes are sized and located such that bubbles, formed by a pressurized gas passing therethrough when the module is immersed in a liquid, pass substantially uniformly between the fibres, and wherein the lower potting head is connected to a source of the pressurized gas, and wherein the fibres are arranged to be vibrated by means of the gas bubbles, the fibres being mounted relative to one another so as to produce a rubbing effect between the fibres when vibrated by the gas bubbles.