Inativação de microrganismos indicadores de contaminação fecal por radiação ultravioleta e avaliação dos fenômenos de fotorreativação e recuperação no escuro

Abstract

This research aimed to evaluate the performance of ultraviolet radiation (UV) for disinfecting effluents from a municipal wastewater treatment plant, in laboratory bench scale and batch operation. The interference of the operational parameters of exposure time (s) to the radiation and the level of liquid blade (cm) of the effluent in the UV reactor were analyzed. The efficiency of the disinfection process was checked using the indicators microorganisms Clostridium perfringens (C. perfringens), coliphages, Escherichia coli (E. coli) and total coliforms (TC). After disinfection, some tests were carried out to evaluate the phenomena of microbiological recovery: photoreactivation and dark repair, for E. coli and TC. The results indicate effective inactivation of indicator microorganisms by UV radiation during the time of exposure, which was statistically proved by repeated measuresANOVA. C. perfringens was the microorganism that showed the highest resistance against UV inactivation. In microbiological recovery tests, both mechanisms were considered insignificant, which was statistically proven by the Student (t test -parametric data) and the Wilcoxon (nonparametric data) tests. In all analyses, the level of significance was 5%.

Synthesis and Characterization of Boehmite Particles Obtained from Recycling: Water Disinfection Application

“…In addition, it showed the presence of 195.6 MPN of Escherichia coli. These microbes are strong indicators of the presence of feces in the water [40]. The boehmite sample was not able to eliminate the presence of total coliforms and Escherichia coli from the water; however, it reduced their presence by 77.4% (547.6 MPN) and 86.6% (26.2 MPN), respectively.…”

Desinfecção de efluente sanitário biotratado por UV/H2O2 e O3

“…Outros indicadores são propostos, tais como os colifagos, que podem informar sobre a eficiência do tratamento de água na remoção de enterovírus e outros vírus como os das hepatites A e E, que são de veiculação hídrica. Também pode-se citar Clostridium perfringens que, por ser esporulado, informa sobre poluição fecal mais remota que aquelas indicadas pela presença de E. coli (Pedroso et al, 2018). Alguns organismos têm demonstrado, durante tratamentos de águas residuais, a capacidade de entrar em estado de dormência, apresentando níveis de atividade metabólica muito baixos, como se estivessem inativadas (Gupte et al,2003), e, em condições favoráveis, são capazes de se reativar e crescer novamente.…”