The scope of the project is i) To determine the effect of normal (compressive) stresses on the effective thickness of spacer and of the respective spacer-filled membrane channel. ii) To determine the pressure drop in the spacer-filled retentate channel as a function of cross-flow velocity. iii) To determine the average mass transfer coefficient at the membrane surface as a function of cross-flow velocity for the specific spacer geometry. iv) To assess the overall spacer performance in two types of applications, i.e. brackish and sea-water desalination.