Aplicação de ozônio em esgoto doméstico visando reúso agrícola

Abstract

The increasing scarcity and demand for water in food production according to the need to seek sources of supply. Treated domestic sewage is a way to mitigate this problem; however, it is necessary to adapt it to legislative requirements. The use of ozone in the disinfection of domestic effluents has been used due to its oxidizing solid character, allowing the adjustment of its parameters for agricultural reuse. Thus, the objective of this work was to evaluate the sanitary and agricultural viability of domestic effluent treated with different doses of ozone, through the analysis of physical, chemical and microbiological parameters. The experiment was carried out on a laboratory bench, in which different dosages of ozone were applied: 0; 8; 15; 30; 45; and 60 mg L-1. The application time for each dosage was, respectively: 0 seconds; 14.4 seconds; 27 seconds; 54 seconds; 81 seconds; and 108 seconds. The effluent came from the Sewage Treatment Station in the municipality of Araras. The parameters obtained were: total coliforms, E. coli, pH, turbidity, dissolved oxygen, total organic carbon, total nitrogen, total phosphorus, potassium, magnesium, calcium and sodium. Ozonation did not alter the physical and chemical composition of wastewater, indicating an important advantage in terms of potential agricultural reuse. However, the pathogenic load of E. coli was not reduced enough for the effluent to be used in agriculture. The results obtained further investigate the effects of ozone in relation to the efficiency of domestic treatment, so that we can advance in understanding these interactions in order to identify dosages and ideal exposure time, making the wastewater safe for agricultural reuse.