Drinking water desalination using low-cost Tubular Solar Still

Abstract

Growing freshwater scarcity in arid and remote areas usually is caused by the growth of population, urbanization and industrialization and the rather limited natural resources of potable water. In coastal belt of southwest region of Bangladesh, groundwater contains high salinity as well as excessive arsenic contamination. Though pond sand filter and rainwater harvesting system are usually used to meet the freshwater demand throughout the year in this area, along with these, household-based solar desalination could be a good source of drinking water in this region. In this study, a low-cost Tubular Solar Still (TSS) was designed using locally available materials to meet such demand. It was consisted of a tubular frame (0.00275 m thick helical GI wire, 1.0 m long and 0.2 m in diameter) and a rectangular tray (1.0 m × 0.16 m × 0.05 m ) covered with black polythene paper. The collection bottle was kept in an insulation box. The field experiment on the constructed TSS was carried out on the rooftop of Civil Engineering Department building from June 25, 2011, to June 20, 2012. Daily distilled output from the TSS was collected approximately 2 h after sunset. The maximum daily production rate was found as 3.83 l/m2 in May 2012. The production cost of distilled water is estimated as 0.39 BDT/L or 0.0046 USD/L. The application of this process can fulfill the demand of freshwater for drinking purpose for single household in coastal areas.