Modeling membrane performance over time.

A diffusion-control solute mass transfer model was developed to describe permeate water quality over time of operation. The changing mass transfer characteristics of four low-pressure reverse osmosis membranes were correlated to feed stream water quality in a 2,000-h pilot study. Solute mass transfer coefficients (MTCs) were correlated to initial solute MTCs, solute charge, feedwater temperature, monochloramine loading, and organic loading (ultraviolet light at 254 nm). Independent data were used to validate the model. The model can be used to predict permeate water quality and sensitivity of permeate water quality to variations in temperature and organic and monochloramine mass loading. [ABSTRACT FROM AUTHOR]