Basic Principles of Simulating Boron Removal in Reverse Osmosis Processes

Removing boron to meet increasingly stringent water quality regulations has been challenging for sea water reverse osmosis (SWRO) membrane plants. The rejection of boron follows a mechanism different from those of other ionic solutes such that it cannot be readily correlated with the rejection of other ionic species. Therein, computer simulations have been proven to be an effective tool to predict and optimize boron removal by full-scale SWRO processes. This chapter summarizes fundamentals of a mechanistic predictive model based on an irreversible thermodynamic model coupled with a film theory. The model takes account of boron speciation as a function of pH which significantly affects the overall boron removal. The finite element analysis approach to simulate spiral wound elements and mass balance approach for pilot- and full-scale RO (reverse osmosis) processes are further discussed. Finally, an example on how the model can be utilized to predict the boron rejection in pilot- and full-scale plants under various design and operation scenarios is presented.