Evaluation of the efficiency of water treatment by a solar heating and distillation system

Abstract

Presently, many industries discharge colored wastewater without any treatment to water bodies such as rivers and lakes affecting flora and fauna. Due to its chemical composition, its self-purification in phreatic bodies is complicated. Although there are chemical, physical and biological treatments dedicated to the degradation of this type of compounds, they present economic and energetic disadvantages. This study reports the use of solar energy for the treatment of water containing carmine red dye at 25 ppm. The system consists of the coupling of two modules; the first heats wastewater using a parabolic heater, while the second separates clean water (distilled) from pollutants. It was observed that when a galvanized ZnO plate is introduced into the distillation unit a photodegradation process takes place improving the characteristic of the concentrate. Optimal conditions allow an efficiency of 87 % in the production of the distilled water obtained. Parameters such as pH, Conductivity, COD, Turbidity and Total Solids, indicate that the distilled water complies with the maximum permissible limits for water quality established in Mexican regulations. A 93 % photodegradation of carmine red dye wastewater was detected within 120 min during the process, which was verified by UV-Vis and IR characterization.