Membrane transport parameters from a running plant data were studied to und
erstand their changes with time, as well as the causes of membrane fouling
under various running conditions. First, the mass-transfer coefficient of a
spiral-type reverse osmosis (RO) element was measured using a polyamicle m
embrane, designated UTC-80, and an appropriate correlation equation was obt
ained. Then, a computer program was developed to obtain membrane transport
parameters from flux and rejection data of an actual RO plant. When it beca
me apparent that the temperature corrections should be applied, laboratory
experiments were used to determine them. Thus, the time course change of bo
th solution and salt permeabilities and the relation between them could be
followed The permeability of each ion or solute can be obtained by the same
method when their analytical data are available.