A Systematic Comparison of Two Pharmaceutical Decomposition Treatments for Wastewaters

Abstract

The ever-increasing presence of pharmaceuticals in freshwater poses a dangerous threat to both humans and animals; the leaching of pharmaceuticals from poorly treated or disposed of wastewater into the environment risks contamination of drinking water and irreparable damage to fragile ecosystems of the world. In this paper, the oxidation of pharmaceutical remnants present in wastewaters via both free chlorine and ozone was assessed and the overall efficiency of each of the methods was compared. Treatment of antibiotics in swine wastewater via free chlorine resulted in the oxidation and decomposition of all selected sulfonamides, a common class of antibiotics, following a dose of 25mg/L of free chlorine at a pH of 6.6. Monochloramine, a byproduct of free chlorine and ammonia, was less effective in the oxidation of selected sulfonamides. In contrast, pharmaceutical-rich wastewaters were also treated using ozone. This testing resulted in the determination of second order rate constants for the reactions of a number of different pharmaceuticals with ozone and its derivatives. Upon the assessment of reduction potentials for both free chlorine and ozone, as well as an analysis on the overall efficiency of both methods, those methods in which ozone was incorporated were found to be up to 50% more effective than those using free chlorine.