Water scarcity is now receiving increasing attention worldwide and becoming more challenging in view of expanding population, climate change and socio-economic activities. The growing demand for safe fresh water is driving much effort to explore more sources of water supply such as water reuse and seawater desalination. This undoubtedly calls for more efficient water treatment technologies. On the other hand, the desalination reverse osmosis (RO) brine contains potential “green energy” resulting from the high osmotic pressure bestowed upon it by its high salinity. The osmotic energy-recovering process is known as pressure retarded osmosis (PRO). This presentation will highlight our efforts in developing novel membranes, which include aquaporin-based biomimetic membranes (AMBs) and PRO membranes, in terms of membrane formation and scale –up production for effective water reuse, desalination and energy harvesting.