Renewable energy-driven membrane distillation in the context of life cycle assessment

Desalination and water treatment processes have seen a worldwide increase due to increasingly limited access to drinking water sources. In this context, the article focuses on membrane distillation (MD), an affordable and promising separation process that can use low-grade waste and alternative energy sources. Therefore, the use of alternative energy sources, especially renewable energy (RE), whose global production has consistently increased, plays an important role in MD development. Any comprehensive procedure to be developed has to document the environmental impact of the process at every stage of its life-cycle following standardized ISO procedures. The review describes the main aspects that have to be analyzed in relation to the connection between the different configurations of MD and the use of RE-PV systems, wind energy, hydropower, solar thermal, geothermal systems, and the Organic Rankine Cycle. Life cycle assessment (LCA), life cycle cost (LCC), and social life cycle assessment (SLCA) are discussed as current trends. The analysis concludes that the use of RE to support MD is a promising development, particularly with geothermal energy. Additionally, MD is a potential process for resource recovery from brine, and a rethink is needed to treat brine as a raw material rather than a waste. LCA, LCC, or SLCA are considered harmonious and complementary methods which can be combined in the evaluation of MD-RE systems. The study findings offer the potential for sustainable water treatment through RE with the use of combined LCA ensuring a comprehensive and environmentally responsible approach to MD-RE systems.