Comparison of the UV/chlorine and UV/H 2 O 2 processes in the degradation of PPCPs in simulated drinking water and wastewater: Kinetics, radical mechanism and energy requirements

• Published in: Water research (Oxford) 2018-12, Vol.147, p.184
• Main Authors: Guo, Kaiheng, Wu, Zihao, Yan, Shuwen, Yao, Bo, Song, Weihua, Hua, Zhechao, Zhang, Xuewen, Kong, Xiujuan, Li, Xuchun, Fang, Jingyun
• Format: Article
• Language: English
• ISSN: 1879-2448

The degradation of pharmaceuticals and personal care products (PPCPs) by the UV/H O and UV/chlorine processes was compared at practical concentrations in simulated drinking water and wastewater. In pure water, the UV/chlorine process performed better than the UV/H O process for the degradation of 16 PPCPs among the investigated 28 PPCPs under neutral conditions. Interestingly, the UV/chlorine approach was superior to the UV/H O approach for the removal of all PPCPs in simulated drinking water and wastewater at the same molar oxidant dosage. The radical sink by oxidants and/or H O was 2-3 orders of magnitude higher in UV/chlorine than UV/H O in pure water. Thus, the UV/chlorine process was less affected by the water and wastewater matrices than UV/H O . In UV/chlorine, the concentration of ClO was calculated to be ∼3 orders of magnitude greater than that of HO in pure water, and the reactivities of ClO with some PPCPs were as high as > 10  M  s . ClO was mainly scavenged by the effluent organic matter (EfOM) with a rate constant of 1.8 × 10 (mg L ) s in wastewater. Meanwhile, secondary radicals such as Br , Br , ClBr and CO further contributed to PPCP degradation by the UV/chlorine process in wastewater, whose concentrations were at least 2 orders of magnitude higher than that in UV/H O . Compared with the UV/H O process, the UV/chlorine process saved 3.5-93.5% and 19.1%-98.1% electrical energy per order (EE/O) for PPCP degradation in simulated drinking water and wastewater, respectively.