COLIFORM BACTERIA DECAY IN PLANTED AND NON-PLANTED SOIL - DOI: 10.13083/1414-3984.v22n06a08

Abstract

Fertigation is an alternative for the disposal/treatment of wastewater and provides the great advantage of potential application in agricultural use due to its contained nutrients. However, this practice can bring health risks, especially when using domestic sewage that has not undergone tertiary treatment. Factors such as temperature, UV rays, predation and competition can cause a great decay of exogenous microorganisms in the soil. The aim of this work was to monitor the survival and obtain the rate of decay of indicator organisms, total coliforms (TC) and fecal coliforms (FC - E. coli), after 32 days of applying raw sewage to planted and non-planted soil. The vegetation caused greater dispersion of bacteria in the soil, resulting in lower count 0-20 mm. A lower decay coefficient was observed for total coliforms than the E. coli. In the thirty-second day after sewage application, the E. coli count became insignificant in the planted and unplanted areas, estimating that they become negligible after 6.6 and 13.0 days, respectively, after application to the soil. Thus, the fertigation technique showed to be suitable for treatment/disposal of sewage with regard to the inactivation of pathogenic organisms.