Regresar

Fenton processes as a complementary treatment for the removal of surfactants and coliforms from municipal wastewater

Abstract:

The inefficiency of conventional methods for removal surfactants and pathogens from wastewater has led to developing alternative treatments, such as the Fenton process and its variants. In this study, the conventional Fenton process and modified Fenton process with ethylenediaminetetraacetic acid (EDTA) were applied to reduce surfactants and fecal coliforms as a complementary treatment for wastewater in Quito, Ecuador. Initially, the conditions for hydrogen peroxide (H2O2) concentration, molar ratio Fe2+:H2O2, and stirring were established for a conventional Fenton process; these conditions were after applied in a modified Fenton process with EDTA in which the conditions for the molar ratio Fe2+:EDTA and pH were defined. The best experimental conditions were: H2O2 concentration of 124.4 mM, a continuous stirring of 130 rpm, molar ratio EDTA:Fe2+:H2O2 of 1:1:20, and pH of 6.41. With these conditions, from a sample with an initial concentration of surfactants, fecal coliforms, and COD of 6.12 mg/L, 71000 CFU/mL, and 980 mg/L, respectively, total inactivation of fecal coliforms was achieved, and it was obtained a reduction of 97% for surfactants and 93% for chemical oxygen demand after 15 min of treatment. The final concentration of these pollutants met water quality standards, according to the Environmental Protection Agency (EPA). This treatment could be potentially applied to treat wastewater dealing with the same problem.