Desalination, energy, mining, and semiconductor industries, among others, produce large volumes of brine. To recover water for reuse and reduce the impacts of brine discharge, two approaches are often used: zero liquid discharge (ZLD) and minimal liquid discharge (MLD). ZLD maximizes water recovery and avoids the needs for brine disposal; however, it is expensive and energy intensive. MLD, which reduces the brine volume and recovers some water, has been proposed as a practical and cost-effective alternative to ZLD; however, brine disposal is needed.
Despite the development of novel materials and processes for ZLD during the past decade, several factors hinder the development and adoption of innovative technologies for cost-effective and energy-efficient ZLD and MLD. NAWI researchers Tiezheng Tong, Shihong Lin, Paul Westerhoff, Pei Xu, and others have examined the concepts, technologies, and industrial applications of ZLD and MLD. According to their recently published journal article in Nature Reviews Clean Technology, there is no universally optimal approach for all brine management scenarios—the selection of technologies and engineering design for MLD and ZLD treatment trains can be treated as a constrained optimization problem, with technical and economic parameters and constraints that depend on location and regulations.
Future research will be crucial in reshaping both technical and regulatory constraints, thereby influencing future treatment train designs. Understanding the economic factors and scalability of these technologies is vital for assessing their potential impact on advancing brine management practices. Finally, developing a more comprehensive understanding of how brine disposal impacts surface and subsurface aquatic ecosystems, as well as local geological activity, will be essential for creating regulations that achieve a balance between environmental sustainability and economic feasibility.
To learn more, read the full article in Nature Reviews Clean Technology.
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