Estudo comparativo entre sistemas de tratamento unifamiliar de esgoto com pós-tratamento ou disposição final no solo.

Abstract

This work deals with the results of experimental investigation comparing the performance of septic tank and UASB rector in a single family domestic sewage. It was possible to evaluate the viability of UASB instead of septic tank concerning the organic matter (COD) and solids in suspension. Both reactors were applicated in real scale while the septic tank and UASB were operated with the hydraulic detention time (HDT) of 2 days and 13 hours respectively. The reactors were operated simultaneously and the time for the UASB to became steady was also analyzed. Concerning the reactor's effluents the following possibilities were studied: post-treatment of anaerobic ascendant flux filters (pilot scale) operated in different HDT; direct soil application through cesspool (pilot scale). The UASB collected data have shown that the reactor starting was of 14 weeks, and that during this time the reactor was less efficient in the COD removal, but after reaching its steady state, the UASB exhibited better efficiency than the septic tank in the removal of both COD and solids in suspension. The anaerobic filters were satisfactorily efficient in the removal of solids in suspension in both types of effluents, and in the case of COD the post-treatment removal, was more significant when this was applied to the septic tank effluent. The rate monitoring of cesspool infiltration indicated that both outfall types with effluents presented the same rates, and not different from the previous pointed out, discarding therefore the possibility of soil clogging. In this way, the main conclusions of this work are that UASB presented a better applicability than the septic tank, also in the single family treatment, and for having minor volume, and for not demanding periodic cleaning is economically viable.