A portable system for subatmospheric pressure therapy in connection with healing a surgical wound includes a wound dressing dimensioned for positioning relative to a wound bed and a collection canister in fluid communication with the wound dressing. The canister includes a first vacuum chamber for drawing a vacuum and a second fluid chamber for collecting fluids removed from the wound dressing under the vacuum. The canister further includes a hydrophobic membrane separating the first and second chambers. The hydrophobic membrane is dimensioned to span a major portion of the cross-sectional area of the canister. The hydrophobic membrane may be dimensioned to substantially span an internal dimension of the collection canister. The hydrophobic membrane may include one or more outwardly extending lobes. The hydrophobic membrane may be releasably mountable to the canister, and, may be supported within a divider separating the first vacuum chamber and the second fluid chamber.