(52b) Membrane Separations-100 Years of Achievements and Challenges

Over the past 100 years membrane technology has grown from separations techniques of largely theoretical interest to a multibillion dollar industry covering a vast spectrum of applications. This presentation charts the evolution of the family of membrane processes ranging from dialysis, electrodialysis, liquid phase pressure-driven processes, gas separations, pervaporation and membrane distillation. Key applications will be highlighted. Over the past 50 years, and particularly since the late 1980s/early 90s the application of membranes to water and wastewater has seen dramatic growth. The reasons for this growth will be examined. Key paradigm shifts include the invention of the phase-inversion desalination membrane, followed by the thin-film composite. Module development, particularly the spiral-wound element, has been crucial. Paradigm shifts in the use of low pressure membranes have included the use of deadend flow with backwash for water treatment, the concept of the submerged membrane operated under suction and the use of two-phase bubbly flow in membrane bioreactors. Improved understanding of the nature of membrane fouling in these applications, coupled with insights from modeling and CFD are leading to increasingly efficient processes. However membrane technology in the water (and other) industries faces a major challenge in responding to climate change which requires a reduction in carbon foot print. Some of the strategies available to the membrane industry will be discussed.