Membrane-based zero liquid discharge: Myth or reality?

The environmental impacts of brine disposal from seawater desalination plants and wastewater treatment plants represent a subject of growing concern; thus, determining the potential applicability of zero liquid discharge (ZLD) for water treatment is crucial. Membrane-based technologies are a potentially attractive strategy that can be used to reach this goal. Recent studies have highlighted that integrating a series of membrane processes is a viable approach to achieving ZLD for industrial use. However, a relatively limited number of reports have been published on the challenging problems encountered with ZLD approaches. Here, we provide a review of membrane processes that may be used in ZLD approaches and describe their problems as well as potential solutions and innovative technologies for improving their performance. Furthermore, the energy consumption of the different approaches is calculated and analyzed because it represents a major contributor to the total cost, and investments in innovative technologies are discussed. Finally, the prospects for membrane-based ZLD and further research are highlighted.