Operation and modeling of RO desalination process in batch mode

• This paper assesses the performance of a batch reverse osmosis (RO) desalination process.
• Pilot plant experiments and two literature RO models have been used to study plant model mismatch.
• The concentration polarization phenomena is found to influence permeate salinity trends.
• Strong feed salinity dependence of the water permeability constant is observed.
• Strong feed salinity dependence of the salt permeability constant is observed.

The performance of a batch reverse osmosis (RO) desalination process in terms of permeate quantity and salinity as a function of feed pressure and feed salinity is evaluated by using laboratory experiments and process modeling. Special attention is paid to the water and salt permeability constants (Kw, Ks) which affect the permeate and salt flux across the membrane. Kw and Ks are found to be strongly pressure-dependent for the batch system which is in-line with earlier observations for continuous RO systems. However, the most important findings of this work are the dependence of Kw and Ks on feed salinity, something that have never been observed or reported in the literature. In order to better qualify these observations, further experiments with the batch system are conducted with a constant feed salinity so that the operating condition resembles that of a continuous RO process.