Water Desalination and Purification
AMY CHILDRESS
University of Southern California
ABHISHEK ROY
The Dow Chemical Company
Securing a reliable supply of water among growing human populations, changing climate, and increasing urbanization is a global challenge. Water-stressed regions are exploring alternative sources to augment their freshwater supplies. This session focuses on membrane separation processes to desalinate and purify a range of source waters. Innovations in materials, developments in new processes, and synthesis of novel systems are emphasized for applications spanning desalination, wastewater reclamation, and treatment of industrial streams with complex solution chemistries.
Reverse osmosis (RO) desalination is currently the most efficient and widely adopted commercial desalination technology; however, it requires a great deal of energy to create the high pressures necessary to overcome the osmotic pressure of saline waters and there are often significant issues with disposal of brine resulting from the process. Technological advances are needed to improve the energy efficiency, contaminant removal, and environmental impacts of the processes. Current focus is on improving sustainability in conventional applications such as sea- and brackish-water desalination and exploring emerging opportunities in municipal and industrial wastewater desalination markets.
Membranes with high flux, high rejection, and low tendency for fouling are most desired for use in emerging and conventional treatment processes that provide consistently high process performance, require few chemicals, and produce little waste. The goal is to develop highly efficient, reliable, and durable treatment systems that can be scaled for use in distributed or centralized applications. Centralized systems capitalize on use of existing infrastructure; smaller-scale, distributed systems may offer better opportunities for coupling treatment with
alternative energy sources. Sustainable system performance is key for efficiency and economics as well as adherence to health and regulatory standards.
The session provided a forum for the audience to discuss and identify collaborative opportunities in four critical areas of water desalination and purification: new materials development, analytical characterization techniques, emerging desalination technologies, and innovative system design and operation. It began with a talk by Manish Kumar (Pennsylvania State University), a high-level overview of RO technology, applications, and recent membrane chemistry innovations.
Chris Stafford (National Institute of Standards and Technology) delved into state-of-the-art polyamide membrane chemistries, emphasizing the importance of advanced membrane characterization techniques to drive breakthrough innovations.
Baoxia Mi (University of California, Berkeley) introduced emerging desalination treatment technologies and highlighted new materials being developed to further advance these technologies.
Kevin Alexander (Hazen and Sawyer) wrapped up the session with a techno-economic assessment of high-recovery treatment from impaired waters, including applications with challenging solution chemistries and efforts to achieve zero liquid discharge.
