New findings on the occurrence, removal, and risk assessment of nonylphenol and octylphenol in industrial wastewater treatment plants in Korea

Abstract

Nonylphenol (NP) and octylphenol (OP), extensively used in industries, can disrupt the human endocrine system and cause significant ecological toxicity. Therefore, in this study, we aimed to reveal the occurrence and removal characteristics of NP and OP in 30 industrial wastewater treatment plants (IWWTPs). Specifically, this study focused on 13 NP isomers that have not been previously reported. Additionally, the potential environmental risk of NP and OP discharged from IWWTPs was assessed using a minimum dilution factor (MDF), proposed for the first time in this study. We showed that the concentration and proportion of the isomer NP11 were higher than those of the other isomers in the IWWTP influents and effluents. We also identified an activated sludge-activated carbon adsorption process suitable for removing NP and OP. Finally, we proposed the MDF value of 11 for the potential environmental risk assessment of NP and OP, revealing that OP poses a higher risk than NP when discharged into surface water. These findings underscore the importance of focusing on the isomer NP11 and OP in IWWTPs.