Análise do desempenho da estação de tratamento de efluentes do campus I da Universidade de Passo Fundo

Abstract

Higher Education Institutions are providing technical, financial and human resources to deepen studies about sewage treatment, so as to contribute to this service to be extended to all Brazilian households. The University of Passo Fundo-UPF offers several undergraduate courses and Campus I receives about twenty-two thousand people including students, professors and employees, generating approximately 550 m³ / d wastewater, which are treated in the Wastewater Treatment Plant- ETE. The aim of this research was to analyze the performance of each installed equipment and the plant as a whole, to propose alternatives that are able to maximize the efficiency in removing pollutants. For eleven months, efluent sampled had been collecting at the entrance and the exit of the ETE and also of each equipment. The results indicate that the Campus I - UPF, produces an effluent with physicochemical and microbiological properties that are qualified as household sewage with heavy concentration and high concentration of surfactants and phosphorus substances, but low concentration of solids. Approximately 50% of the buildings in the Campus I, that generate wastewater, use septic tank and sink system, although 90% of them are connected to the sewer system installed. The study revealed that the Campus I produces an effluent with high variability in the concentration of the analyzed parameters. In the UASB reactor, 82% of the analysis showed removal of the organic load exceeding 70%. In the activated sludge system the performance did not show good enough in the phosphorus removal. In ETE, the variation of pH was between 6.8 to 7.76 and in three samples, the concentration of oil and grease resulted above 30 mg / L, maximum limit for disposal. The fecal samples resulted in superior values to the allowed limits. In eight samples, at the exit of the ETE, the concentration of surfactants were above the allowed limit. The study showed that in the UASB there is relation between the organic load applied and the efficiency and in the ETE the result was similar, but in the activated sludge system the same results were not observed. The temperature of the effluent inside of the equipment in the ETE ranged from 17 ° C to 27 ° C. The results suggest the alternative process of physico-chemical treatment complemented to the biological, in the phosphorus removal and installation at the exit of the ETE, the injector device of chlorine to disinfect the effluent and a antofoam feeder device to balance the concentration of tensoactive substances as well as deactivate the pre-treatment system with septic tank and sink and more rigor in the maintenance of grease traps installed in some buildings in the Campus