Understanding the role of small-scale solar desalination (solar still, humidification-dehumidification) to achieving sustainable development goals (SDGs) in developing nations: a review

In the present critical review, the complex interrelation of small-scale solar desalination systems with various configurations to provide safe drinking water, in relation to achieving the United Nations Sustainable Development Goals (SDGs) by increasing the access to drinking water in developing countries is discussed. Of great importance, this paper deals with four essential and important criteria of drinking water (and their relation for realizing SDGs) that declared in numerous international action plans and instruments of SDGs which are: Affordability, Accessibility, Quality and Quantity. Solar stills and humidification-dehumidification (HDH) were considered in this context as small-scale solar desalination systems from technical and economic point of views since both are practical and currently work in real-world application. Then, regarding to the main international law instruments, including Sustainable Development (2030 Agenda), Agenda-21, General Comment No.15 of the UN, Dublin Statement etc. (with the main focus on 2030 Agenda), it is concluded that using these systems in developing countries would be one step forward to increase access to safe drinking water "Goal 6.1 of SDG 6". Also, it was elucidated that using small-scale desalination systems to provide drinking water regarding the abovementioned criteria (Affordability, Accessibility, Quality and Quantity) could assist for putting steps on the realization of other SDGs including SDG 3, SDG 4 and SDG 11. Indeed, the direct and indirect interrelation between SDG6 (Clean Water) with other goals including SDG 3 (Good Health & Well-Being), SDG 4 (Quality Education), and SDG 11 (Sustainable cities and Communities) were elucidated.