Biodegradation of pharmaceuticals and personal care products under aerobic condition

Abstract

BACKGROUND: Pharmaceuticals and personal care products (PPCPs) have been worldwide distributed, and attracted increasing attention over the past decades. During wastewater treatment, biodegradation under aerobic conditions plays important role in removal of hazard substances, including PPCPs. Most of previous studies focused on the detection method establishment and occurrence of PPCPs. Some combined methods of biodegradation and other removal processes, have been conducted over a wide range of compound categories. However, so far no researches have been conducted to reveal the PPCPs biodegradation in the activated sludge system. Thus, this study aims to investigate biodegradation processes of selected PPCPs under aerobic conditions in the activated sludge process. METHODS: Removal of twelve PPCPs (acyclovir, ranitidine, fluconazole, carbamazepine, fluoxetine, mefenamic acid, benzylparaben, ethylparaben, methylparaben, propylparaben, benzophenone-1 and benzophenone-3) in activated sludge process was investigated using the batch reactors. Solid phase extraction and ultra performance liquid chromatography-tandem mass spectrometry were used to determine the concentrations of the PPCPs. RESULTS: At environmental relevant concentrations, fluconazole and carbamazepine showed no evident reduction by biodegradation, adsorption, volatilization and hydrolysis in activated sludge process for 48 hr, while 99% of benzylparaben, ethylparaben, fluoxetine, methylparaben, and propylparaben were removed by biodegradation and adsorption within 1 hr under the same condition. Activated sludge process removed 99% of acyclovir, benzophenone-1, benzophenone-3, and metronidazole within 15 hr, while mefenaic acid and ranidine were mainly reduced within 24 hr and 48 hr, respectively. CONCLUSIONS: Most PPCPs can be effectively removed by bacteria in acticvated sludge within 48 hr. However, bacteria failed to metabolize fluconazole and carbamazepine under aerobic conditions. Future work should focus on the mechanisms for those PPCPs which are biodegradable.