Design and Performance Evaluation of a Solar-Powered Water Distillation Unit for Rural Communities in Yobe State

Access to safe drinking water in rural communities of Yobe State, North East Nigeria, is severely limited, with fluoride, nitrate, and total dissolved solids regularly exceeding WHO guidelines in groundwater sources. This study designs, constructs, and evaluates the performance of a passive solar still for producing potable water from brackish groundwater in Damaturu Local Government Area. A basin-type solar still with a glass cover area of 1.5 m2 was fabricated using locally available materials including galvanised iron sheet and float glass, and installed at a tilt of 15 degrees facing south. Performance was evaluated over 30 consecutive days during the dry season by measuring solar irradiation, ambient temperature, basin water temperature, glass temperature, distillate productivity, and condensate quality. Daily distillate output averaged 2.8 litres per square metre under average solar irradiation of 620 W/m2, with peak productivity of 3.6 L/m2/day on cloudless days. Distillate water quality tests showed complete fluoride removal, total dissolved solids reduction from 3,840 mg/L to 18 mg/L, and the absence of detectable pathogens, satisfying WHO and NSDWQ potability criteria. Cost of distillate production was estimated at 3.2 Naira per litre, economically favourable compared to commercial sachet water in remote Yobe communities. The study recommends scaled modular solar still deployment for schools and health clinics in Yobe State. Keywords: solar still, water distillation, brackish water, fluoride removal, Yobe State