(69a) Water Treatment and Desalination:from High Performance Membranes to Flexible Self-Adaptive Systems

Water scarcity and groundwater and surface water quality impairment are on the rise in various regions of the world. In order to increase and diversify the water portfolio, efforts are growing to upgrade and expand the use of otherwise unutilized water resources and lower the cost of water treatment and desalination. Potable water production from seawater, brackish groundwater, and municipal and industrial water reuse, as well as for management and reuse of agricultural drainage water are now becoming increasingly reliant on membrane-based water treatment and desalination technologies. It is noted that of the various water desalination approaches, reverse osmosis (RO) membrane desalination has become the dominant technology accounting for about 65% of the worldwide desalination capacity, followed by followed by multi-stage flash evaporation (21%), with the remaining 14% capacity provided by other thermal desalination methods (e.g., multiple effect distillation and vapor compression) and electrodialysis (ED)/ED reversal (EDR). It is also noted that other membrane-based desalination technologies which may suitable for small-scale specialized applications have been proposed in recent years including capacitive deionization, membrane distillation and forward osmosis. Admittedly, the market growth of RO water purification/desalination is attributed, in part, to its simplicity and technological maturity. However, despite the rapid progress in RO water purification and desalination and associated pre- and post- feed and product treatment processes, respectively, there are various challenges to overcome that include, for example: membrane fouling and mineral scaling, reducing energy consumption, decreasing plant footprint, improving process efficiency and robustness and of course lowering capital and operational costs. Accordingly, a discussion of the above challenges and solutions will be presented focusing on advances through the progression of a multipronged approach with practical considerations of the following elements and their development from fundamental research to field deployment: (a) high performance membranes for filtration and desalination, (b) real time detection of the onset and evolution of fouling/mineral scaling and membrane integrity monitoring, (c) energy-optimal and flexible desalination via process configuration and model-based control, (d) high recovery desalination, and (d) intelligent (self-adaptive) membrane filtration and fouling control with self-learning, and fault detection and isolation.