The fulfilled promise: a green way for seawater desalination through reverse osmosis

Reverse osmosis (RO) is a widely used technology for producing drinking water from seawater. The energy needed for RO water treatment has decreased, but energy costs remain a challenge, especially in communities where drinking water consumption is far from seawater. This study explores the best RO configuration for energy efficiency in scenarios where solar and gravity energy are available. A case study is presented for the community of La Higuera (Coquimbo, Chile), that includes two small villages, La Higuera and Chungungo. The study evaluated two alternative hydraulic systems for operating the RO plant and delivering drinking water to the main tanks in Chungungo and La Higuera, completely independent of the power grid. The results showed that the most energy-efficient system uses solar energy and filtered seawater accumulated at high altitudes in a coastal mountain range. A 20-y evaluation showed that while the investment may not be fully recovered, the implementation of this RO scheme would have significant economic gains with the addition of public financial incentives and reduction of CO2 emissions.