Desalination of brackish groundwater to improve water quality and water supply

Abstract

Brackish groundwater desalination has and will continue to play a critical role in improving water quality and water supply in many parts of the world. While numerous methods exist for desalination, membrane-based desalination technologies are used without exception in treating brackish groundwater. The two most widely adopted processes are reverse osmosis (pressure- driven desalination) and electrodialysis (electric potential-driven desalination). Selection of the appropriate technology is made based on feedwater and target product water composition for a particular application, as well as environmental and cost considerations. This chap- ter outlines the key components of a typical brackish groundwater desalination facility that uses reverse osmosis or electrodialysis, including required pretreatment of source water and post-treatment of product water. Desalination plant energy consumption and economics are discussed. Brine disposal is highlighted as a critical cost driver for inland brackish ground- water desalination. Environmentally-friendly alternatives to current brine disposal methods and conventional energy sources are considered. Because geography is a key consideration in desalination decision-making, regional and national trends in desalination capacity, spending, technology, and source water type are also investigated. The national trends focus on the following desalination players: U.S., Saudi Arabia, China, Australia, Spain, and India.