SEPARATION MEMBRANE ELEMENT

摘要

A separation membrane element includes a perforated water collection tube; and an envelope-shaped membrane formed of a separation membrane and wound around a periphery of the perforated water collection tube, in which the separation membrane has a difference in surface level of 100 to 2,000 mum on at least one surface thereof and has a strip-form region in each of both ends of the separation membrane in terms of the longitudinal direction of the perforated water collection tube, the strip-form region having an average difference in surface level of 50 mum or less.