ABSTRACT
Two emerging pressure-retarded osmosis (PRO) hybrid processes have been presented in this chapter. By integrating PRO and membrane distillation (MD), the resultant PRO–MD has the unique advantages of (1) lower operation costs for desalination, (2) higher water recovery, (3) less membrane fouling, and (4) minimal negative environmental impacts. To tackle the PRO membrane fouling from the process perspective, a new PRO hybrid using forward osmosis (FO) as the pretreatment step aims for sustainable osmotic power generation with (1) low fouling propensity, (2) easy membrane cleaning, and (3) minimal external energy requirements. For both PRO hybrids, their processes have been evaluated in detail covering mathematical modeling, membrane/module design and operation, as well as some economic analyses. Specific considerations on the challenges encountered and future prospects are also highlighted in this chapter.
