Avaliação da remoção de microorganismos termotolerantes utilizando radiação solar

Abstract

Solar disinfection is a simple option for the water treatment in rural communities. The sun's rays are very efficient for the removal of pathogens and can also be used for the treatment of wastewater, mainly for regions that favor this type of treatment. The objective of the present study is to evaluate the efficiency of solar disinfection for the treatment of wastewater through three solar reactors: transparent PET bottle, clear glass container, PET bottle with half painted black. The affluent of the disinfection system comes from a septic tank and the experiment was conducted in two stages. In the first stage of the work 3 repetitions were performed. The reactors were exposed to solar radiation for three consecutive days and sample collections were performed every 5 hours, at 8:00 am, 1:00 p.m. and 6:00 p.m. In the second stage, 3 replicates were also carried out, where the solar reactors were exposed for 8 hours and samples were collected every 2 hours, at 8:00 a.m., 10:00 a.m., 12:00 a.m., 2:00 p.m. and 4:00 p.m. The efficiency of the treatment was evaluated for the parameters of fecal coliform concentration, effluent temperature, chemical oxygen demand (COD) and pH. During the treatment it was possible to observe that in addition to the concentrations of coliforms, there were decreases in COD concentrations. In addition, the highest values of temperature were reached by the reactors, respectively, PET bottle with half painted black (PP reactor), transparent glass vessel (VI reactor), transparent PET bottle (PT reactor). The PP reactor achieved the best efficiency in the inactivation of coliforms, probably because it reached the highest temperature values. The VI reactor, on the other hand, achieved the worst results, probably due to its type of material.