Performance evaluation of a solar still for industrial wastewater treatment

Abstract

Wastewater from industries are generally highly polluted but, unfortunately in some developing countries, are discharged into the environment without proper treatment. Wastewater treatment is a process, where contaminants are removed from wastewater in order to make it suitable for discharge or reuse. In this study, a single sloped basin solar still was employed for the treatment of wastewater obtained from a paint industry. The efficiency of solar distillation in the treatment of the wastewater over a period of 8 consecutive days was examined. 20 Litres of wastewater was placed inside the solar still under outdoor conditions. Approximately 5 Litres of distillate water was obtained at the end of the experiment. The quality of the untreated wastewater and its distillate were determined. In addition, solar radiation and volume of distillate obtained for each day was measured. The distillate produced was 80% less in terms of Total Dissolved Solid (TDS), 99.3% less in terms of Total Suspended Solids (TSS), 96% less in terms of turbidity, 64.6% less in terms of Biochemical Oxygen Demand (BOD), 87.5% less in term of Chemical Oxygen Demand (COD), completely removed of phosphate, 83.8% less in terms of Calcium Carbonate, 68.6% less in terms of Nitrate, 93.7% less in terms of Chloride and 40% less in terms of Total Coliform Count. The physio-chemical characteristics of the treated wastewater fell within drinking water standards set by World Health Organization (WHO) but the bacteriological quality of the distillate did not meet WHO recommended standard for potable water .