ABSTRACTReverse osmosis experiments were performed to concentrate the green tea juice, and the experimental data was analyzed by using a set of transport equations together with osmotic pressure and density data of the green tea juice. the transport parameters obtained numerically by the above analytical procedure were then used to calculate several dimensionless quantities that can characterize a reverse osmosis module. an example of module design calculation was attempted using the dimensionless parameters so obtained. It has been found that an increase in operating pressure reduces the module length significantly when the feed tea juice concentration is high. an increase of the mass transfer coefficient on the high pressure side of the membrane has the same effect.