Remoção de coliformes totais e e. coli em lagoas de polimento: produção de efluentes adequados à utilização em irrigação e piscicultura

Abstract

The World Health Organization (WHO) has recently changed his criteria for the utilization of sanitary wastewater in irrigation and fish farming. The criteria previously expressed as control of thermotolerant (fecal) coliforms, became described as control of E.coli. However, recognizing situations in which analytical or financial constraints can impose restrictions on the determination of E.coli, it remains valid to evaluate the possibility of, alternatively, monitor the pond effluent as total coliforms. This study confirms the high capacity of a polishing pond in producing an effluent with excellent microbiological quality, in a system of ponds in series/maturation pond. According to a planned monitoring program, during almost four years, an experimental system of ponds was controlled. As a result, a much similar trend between the decay of total coliforms and E.coli was found, and a difference, perceptibly consistent, of one logarithmic order (1 log10) between them. It is suggested, therefore, that the recommendation of WHO, expressing the limit of E.coli/ 100 mL, would be equally satisfied if Total Coliforms/ 100 mL were used, one logarithmic order (1 log10) being considered as a difference.