Metodologia para avaliação do uso de traçador em um sistema descentralizado

Abstract

Access to adequate sanitary sewage services is a fundamental right and essential to ensure decent housing conditions, health care and maintenance, and environmental preservation. Thus, the decentralization strategy is increasingly complementary and not opposed to the centralization of sewage treatment in the search for the universalization of sanitary sewage services. In this work we will deal with a decentralized system composed of a septic tank, anaerobic filter and sand filter, focusing on the application of a tracer to later verify the hydrodynamic behavior of this system. In this context, the application of the hydrodynamic study in reactors is given to evaluate the flow regime inside the reactors, enabling the identification of dead zones, preferential paths and hydraulic short circuits, which are anomalies that can directly affect the useful volume of the reactor and cause operational failures. Thus, the use of tracers after application can translate the flow regime of the effluent within the reactor. Thus, this work aimed to propose a methodology for the application of the tracer for the proposed system. For this purpose, the systems were sized following the specifications of the Brazilian Standards 7229/1993 and 13969/1997, which establish the general and specific conditions for the construction of septic tanks and complementary treatment units, based on data survey and bibliographic research. The results of the tests with tracers will be presented graphically by means of response curves (Concentration x Time). Through them it will be possible to determine the hydraulic detention time, the hydraulic and volumetric efficiency, Morril's Dispersion Index, the dispersion number, the mass of recovered tracer, the void volume and the short circuit index of the analyzed system. With the study developed it was possible to verify that the methodology is viable due to its implementation aspects being easy to understand. However, it is suggested that full-scale tests be carried out first in a bench system, for better definition of the parameters, the amount of tracer mass to be used, among others.