Application of solar energy in water treatment processes: A review

The utilization of solar energy to drive water treatment processes is a potential sustainable solution to the world's water scarcity issue. In recent years, significant efforts have been devoted to developing and testing innovative solar based water treatment technologies, which are comprehensively reviewed in this paper. Recent developments and applications of seven major solar desalination technologies, solar photocatalysis process and solar disinfection are investigated. Potential integration of solar technologies and desalination processes are summarized. By collecting and analysing performance data from recent studies, the status of productivity, energy consumption and water production costs of different technologies is critically reviewed. The real world applicability as well as technical and economic feasibility is also evaluated. Presently, most of the solar water treatment processes are still under development with limited real applications. Economic competitiveness is among the major reasons that affect the scaling up and commercialization. It is revealed that the reported water costs of small to medium scale solar desalination plants are in the range of US$0.2-22/m(3), much higher than conventional fossil fuel based plants. However, the estimated low water costs (US$0.9-2.2/m(3)) for large scale solar based plants indicate that solar based alternatives will become potentially viable in the near future.