Avaliação da desinfecção de esgoto doméstico oriundo de tratamento secundário por meio da ionização de cobre e prata

Abstract

The objective of this work was to use an electrochemical reactor to promote the disinfection of treated sewage and to evaluate the inactivation of total coliforms and Escherichia coli. The collection and physical-chemical-biological characterization of the secondary sewage of a compact wastewater treatment plant (WWTP), composed of septic tank, submerged aerated filter and secondary decanter, was carried out in a commercial building in the city of Santarém PA. The experimental planning was based on the DCCR2 statistical model of the factors studied were the currents applied to the copper and silver electrodes. The copper and silver ionization process of the sewage treated by the WWTP was carried out on a bench scale at the premises of the Environmental Biology Laboratory of Water Sciences and Technology Institute/Federal University of Western Pará. The result for total coliforms in the first three experiments reached an efficiency of 70, 81.66 and 95%, respectively and in the other samples, 100% inactivation was obtained. For Escherichia coli the result was 100% inactivation in all experiments performed. The minimum and maximum copper concentration was 5.86 and 39.52 mg/L, respectively. The minimum and maximum silver concentration was <0.01 and 8.75 mg/L. These values are not in line with the maximum values allowed by National Environment Council (CONAMA) Resolution 430/2011