Over the past half century, reverse osmosis (RO) has grown from a nascent niche technology into the most versatile and effective desalination and advanced water treatment technology available. However, there remain certain challenges for improving the cost-effectiveness and sustainability of RO desalination plants in various applications. In low-pressure RO applications, both capital (CAPEX) and operating (OPEX) costs are largely influenced by product water recovery, which is typically limited by mineral scale formation. In seawater applications, recovery tends to be limited by the salinity limits on brine discharge and cost is dominated by energy demand. The combination of water scarcity and sustainability imperatives, in many locations, is driving system designs towards minimal and zero liquid discharge (M/ZLD) for inland brackish water, municipal and industrial wastewaters, and even seawater desalination. Herein, we review the basic principles of RO processes, the state-of-the-art for RO membranes, modules and system designs as well as methods for concentrating and treating brines to achieve MLD/ZLD, resource recovery and renewable energy powered desalination systems. Throughout, we provide examples of installations employing conventional and some novel approaches towards high recovery RO in a range of applications from brackish groundwater desalination to oil and gas produced water treatment and seawater desalination.
About the Author
Dr. Eric M.V. Hoek is a professor in UCLA's Department of Civil & Environmental Engineering, Institute of the Environment & Sustainability and the California NanoSystems Institute. He is also the Director of the UCLA Sustainable LA Grand Challenge. His research explores the union of membrane technologies, nanomaterials and electrochemistry for water, energy and environmental applications. He has over 200 technical publications including over 70 patents filed globally. He has also co-founded several technology startups and has advised a wide array of state, federal and international government agencies, local water utilities, technology companies, investment funds, law firms and research funding agencies.