Estimativa de parâmetros cinéticos em ensaio de biodegradação de lodo séptico

Abstract

The biodegradability of the organic matter in water can be verified by BOD test, with estimation of the deoxygenation constant (KD) and BODULTIMATE (Lo). Thus, the kinetics of degradation of pollutants, mainly as regards the representation and mathematical interpretation of the process, continues as a sensitive and extremely important issue with regard to problems of water pollution. The present study analyzes and discuss the limits of these estimates and to evaluate the effect of inhibition of nitrification when estimating the values of KD and BOBULTIMATE (Lo). The study is based on septic tank sludge from wastewater from the city of Juazeiro do Norte, and respirometric data on the biodegradability of organic matter. The methodology applied for the determination of kinetic parameters considered the methods of Thomas and Fujimoto. The results suggested that there is probably more distinction in the analytical procedure than the difference between the estimation methods. Thomas's method, however, is more attractive because it is simpler to apply. The results suggest that even for small samples, but with accurate information, these resources presented great efficiency for the comparison of simulated and observed fields. Regarding the inhibition of nitrification, although the BOD graphs showed a difference between the samples that received the inhibitory reagent for the crude sample, statistically, this difference does not exist, indicating that despite the nitrification, for this Type of wastwater, occur before the seventh day of incubation, as found in the literature, does not cause significant interference in the determination of BOD.