Solar energy is energy derived from the sun’s radiation. The sun’s energy can be exploited using a variety of technologies, including (a) photovoltaic (PV)/concentrator photovoltaics (CPV) systems that convert photons to electricity; and (b) solar thermal technologies that capture thermal energy from the sun’s radiation using solar collectors or concentrated solar power systems (CSP). Due to the quest for power supply from renewable, cheap, and non-gaseous emission sources coupled with the attempts to combat the shortage of potable water in rural areas, much research on the interface of solar energy power systems with water treatment plants has been reported. However, the greater part of the existing reports are based on theoretical modelling, with only minimal experimental, cost analysis, pilot projects and strategic studies. Also, even though solar-powered water treatment technologies are still in the early stages of research, and very rare studies based on real plants have been conducted, existing publications are mostly focused on single principles, making it impossible to assess and compare several technologies. Globally, this review has particularly highlighted the recent advances in the application of solar energy technologies in desalination and wastewater treatments. It likewise highlighted the key research findings and the critical gaps in the existing achievements. It further highlighted the attempts made on hybrid techniques with other renewable energy sources such as wind and geothermal energies which are paramount for scaling up and commercialization uses. However, the findings revealed that most of these studies were restricted to particular parts of the globe without candid evidence from the African perspective, especially Sub-Saharan Africa. Thus, due to the paucity of information concerning this topic within the region, there is a need for further studies on the application of solar energy for water treatment, especially on a pilot scale level for sustainable development.
