On the other hand, osmotically-driven membrane processes such as FO and RO are emerging, which have potential application in water recovery and osmotic Ritonavir harvesting, respectively, and biomimetic aquaporin FO membranes have shown excellent rejection properties . In fact a promising strategy would be to take advantage of synergistic effects in combining FO and PRO with RO . As one example biomimetic FO can be seen as a pretreatment for RO allowing for the use of impaired feed streams due to the lower inherent fouling propensity of the FO process besides the good rejection properties (see Fig. 16a). Also, FO can be used to pre-dilute feed seawater to an SWRO process, which reduces the osmotic pressure of the feed and thus the specific energy consumption of SWRO. Meanwhile, the concentrated brine from SWRO provides a high salinity solution whose osmotic energy can be recovered by PRO (see Fig. 16b).
Fig. 15. Pilot-production facility for making flat sheet AQP membranes based on the approach depicted in Fig. 8.Photo courtesy: Aquaporin A/S.Figure optionsDownload full-size imageDownload as PowerPoint slide