Abstract
One of the critical issues for the successful application of seawater reverse osmosis (SWRO) in the desalination processes is membrane fouling. However, it is difficult to evaluate fouling by the flux decline since recently commercialized SWRO membranes have better permeability than the initial membranes and the two-way coupling between salt concentration polarization and fouling influences permeate flux. In this study, we evaluated membrane performance using various factors, namely the permeation coefficient (Lp) and concentration polarization factor (fcp). The values of Lp and fcp were obtained according to the changing conditions of feed water total dissolved solids (TDS) concentration and operating pressure. As a result, Lp and fcp increased with increasing operating pressure at the same feed water TDS, on the other hand, they decreased with increasing feed water TDS at the same operating pressure. The reasons for these results are that concentration polarization is enhanced with increasing operating pressure at the same feed water TDS and concentration polarization is weakened with increasing feed water TDS concentration due to osmotic pressure at the same operating pressure. Based on these factors and the equation combined with osmotic cake filtration theory and thermodynamic model, we could calculate the resistance by NaCl (Rcp), which is constant with time like membrane resistance (Rm). Thus, we would identify the fouling rate through fouling resistance (Rc) by calculating Lp and fcp according to time after spiking organic foulants.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call