Membrane module elements

A layered sheet construction comprising:

• a. at least one gas permeable, liquid water impermeable microporous layer characterized by containing or having on the surface thereof a fluorine-containing material selected from the group consisting of
• i) polymers onto which fluorine-containing groups are grafted;
• and
• ii) macromolecular additives comprising the reaction product of one or more aliphatic polyfunctional compounds having reactive hydroxyl and/or acyl functional groups, one or more fluorochemical monofunctional compounds and optionally one or more aliphatic monofunctional compounds having 12 to 72 carbon atoms;
• and
• a surface energy less than about 17 dynes/cm;
• and
• b. a gas delivery layer bonded to the layer of part a. which gas delivery layer has a plurality of walls integral with and extending substantially perpendicularly from a polymeric base sheet or currugations forming separate flow channels through which gas can be conveyed to the layer of part a.;
• and
• c. a mass of microorganisms proximate the layer of part a.