Abstract: Pervaporation or vapor permeation apparatus and method having a separator module located in an unpressurized tank. The module has a plurality of stacked, disk-like separator elements mounted on a central, axial permeate removal tube. The separator elements have a central permeate transport plate, a pervaporation membrane enveloping the permeate transport plate and annular sealing rings located between adjacent membranes, so that fluid has to pass through the membranes to enter the permeate removal tube. A vacuum applied to the permeate removal tube draws permeate through the pervaporation membranes and permeate transport plates into the permeate removal tube. The permeate can be condensed right in the permeate removal tube by direct contact condensation using chilled liquid permeate, however an external condenser can be used. Jets of solution or bubbles of permeate vapor passing between the separator elements reduce or prevent concentration polarization.