Photodegradation of pharmaceuticals and personal care products during UV and UV/H 2O 2 treatments

Abstract

Photodegradation characteristics of pharmaceuticals and personal care products (PPCPs) and the effectiveness of H 2O 2 addition for PPCPs photodegradation during UV treatment were examined in this study. Average k (1st order rate constant) value for all the PPCPs investigated increased by a factor of 1.3 by H 2O 2 addition during UV treatment using biologically treated water (TW) spiked with the 30 PPCPs. Therefore, the effectiveness of H 2O 2 addition for PPCPs removal during UV treatment in real wastewater treatment process was expected. It could be also known that H 2O 2 addition would improve photodegradation rates of PPCPs highly resistant for UV treatment such as DEET, ethenzamide and theophylline. UV dose required for 90% degradation of each PPCP was calculated from k values obtained in UV and UV/H 2O 2 treatment experiments using TW spiked with 30 PPCPs. For UV treatment, UV dose required for degrading each PPCP by 90% of initial concentration ranged from 38 mJ cm −2 to 5644 mJ cm −2, indicating that most of PPCPs will not be removed sufficiently in UV disinfection process in wastewater treatment plant. For UV/H 2O 2 treatment, all the PPCPs except seven PPCPs including cyclophosphamide and 2-QCA were degraded by more than 90% by UV irradiation for 30 min (UV dose: 691 mJ cm −2), indicating that H 2O 2 addition during UV treatment will be highly effective for improving the degradation of PPCPs by UV, even though much higher UV dose is still necessary comparing to for UV disinfection.