Corrugated fluid treatment packs and methods of making corrugated fluid treatment packs are disclosed. The fluid treatment packs may comprise a non-woven fibrous structure and/or porous membrane having a tubular configuration and a longitudinal axis, the fibrous structure and/or porous membrane being corrugated to define at least one crest, at least one trough, and at least one corrugation, each corrugation including first and second webs, the first and second webs extending into one another along a crest or a trough. The crests, troughs, and corrugations may include webs may which extend circumferentially or helically.