Solar still for saline water desalination for low-income coastal areas

Solar still is a simple device that utilizes the evaporation–condensation technique to convert impure saline water into the distilled water by eliminating dissolved salts as well as other dissolved impurities and suspended solids. This study aims to produce fresh drinking water from saline water with solar still in the context of Bangladesh. For this study, a pilot-scale solar still with an effective surface area of 0.214 m2 is fabricated with mild steel sheet. At first, solar still productivity is evaluated by varying basin water amount by 3 L, 3.5 L, 4 L and 4.5 L synthetic water. Experimental investigations show a decrease in water production with an increase in basin water amount. The optimum basin water amount is found to be 3.5 L at which distillate production is maximized. Then, the effect of salt concentration is assessed by synthetic solutions with 2000 ppm, 5000 ppm and 8000 ppm total dissolved solids (TDS). An inverse relation is found between salt concentration and freshwater production. Lastly, real seawater is fed to the basin and an average freshwater production of 2.38 L/m2-day is obtained with a removal efficiency of 99.87%, 99.83%, 99.78% and 99.81% for turbidity, chloride, TDS and electrical conductivity respectively.