Formation of DBPs during chlorination of antibiotics and control with permanganate/bisulfite pretreatment

Antibiotics are widespread in water and wastewater, which could react with chlorine to produce disinfection byproducts (DBPs) during disinfection process. Activation of permanganate by bisulfite generates a permanganate/bisulfite (PM/BS) ultra-fast oxidation system, which exhibits more complete oxidation of refractory organics than conventional advanced oxidation processes. This study explored the formation and speciation of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles, haloketones and trichloronitromethane during chlorination of antibiotics (chloramphenicol, ciprofloxacin and sulfamerazine), as well as the impact of Br - ${\mathit{Br}}^{-}$ . PM/BS pre-oxidation was further applied to control DBP formation from antibiotics. Only THMs and HAAs were quantifiable. Trichloromethane was dominant in THMs. HAAs derived from ciprofloxacin and sulfamerazine were mostly constituted by monochloroacetic acid, while trichloroacetic acid was dominate in chlorinated chloramphenicol. Sulfamerazine exhibited the highest DBP formation potential (DBPFP), of which trihalomethane formation potential (THMFP) was 997.14 ± 13.96 μg L −1 and haloacetic acid formation potential (HAAFP) was 3767.86 ± 325.09 μg L −1 . Chloramphenicol had very low THMFP, but high HAAFP (1560.29 ± 56.55 μg L −1 ), which was six times higher than that of ciprofloxacin. Adding Br - ${\mathit{Br}}^{-}$ increased DBPFP and yields of brominated species. PM/BS pre-oxidation (KMnO 4 /HSO 3 − was 1.0/2.5 mM/mM) significantly reduced the DBPFP and chlorine reactivity, and inhibited the utilization of bromine into DBPs with the presence of Br - ${\mathit{Br}}^{-}$ . After PM/BS treatment, over 50% of the ciprofloxacin in real drug manufacturing wastewater were degraded, and the THMFP decreased by about 50%. Overall. PM/BS process is a promising advanced oxidation technology for antibiotic wastewater treatment and control of DBP formation.