<p>An aeration diffuser (12) for a pressurized liquid treatment module includes a base having a gas passageway (32) and a liquid passageway (50) fluidically separated from the gas passageway. Liquid is injectable into the liquid passageway of the base of the diffuser. Liquid flows through the base of the diffuser and into the module to be filtered by filtration membrane(s) within the module. Gas is injectable into the gas passageway of the base of the diffuser. Gas flowes through the base of the diffuser separately from the liquid to aerate the filtration membrane(s) within the module. Further a mdule including one or more diffusers and a method of filtration is disclosed.</p>