Removal of selected endocrine disrupting chemicals and personal care products in surface waters and secondary wastewater by ozonation

Abstract

This study investigated the removal of parabens, N,N-diethyl-m-toluamide (DEET), and phthalates by ozonation. The second-order rate constants for the reaction between selected compounds with ozone at pH 7 were of (2.2 ±0.2) × 10 6 to (2.9 ±0.3) × 10 6 M -1/s for parabens, (2.1 ± 0.3) to (3.9 ±0.5) M -1/s for phthalates, and (5.2 ±0.3) M -1/s for DEET. The rate constants for the reaction between selected compounds with hydroxyl radical ranged from (2.49 ±0.06) × 10 9 to (8.5 ±0.2) × 10 9 M -1/s. Ozonation of selected compounds in secondary wastewater and surface waters revealed that ozone dose of 1 and 3 mg/L yielded greater than 99% depletion of parabens and greater than 92% DEET and phthalates, respectively. In addition, parabens were found to transform almost exclusively through the reaction with ozone, while DEET and phthalates were transformed almost entirely by hydroxyl radicals (·OH).