PPCP degradation by UV/chlorine treatment and its impact on DBP formation potential in real waters.
The ultraviolet/chlorine (UV/chlorine) water purification process was evaluated for its ability to degrade the residues of pharmaceuticals and personal care products (PPCPs) commonly found in drinking water sources. The disinfection byproducts (DBPs) formed after post-chlorination were documented. The performance of the UV/chlorine process was compared with that of the UV/hydrogen peroxide (UV/H2O2) process in treating three types of sand-filtered natural water. Except caffeine and carbamazepine residues, the UV/chlorine process was found to be 59-99% effective for feed water with a high level of dissolved organic carbon and alkalinity, and 27-92% effective for water with a high ammonia content. Both chlorine radicals and hydroxyl radicals were found to contribute to the observed PPCP degradation. The removal efficiencies of chlorine- and UV-resistant PPCPs such as carbamazepine and caffeine were 2-3 times greater than in the UV/H2O2 process in waters not enriched with ammonia. UV/chlorine treatment slightly enhanced the formation chloral hydrate (CH), haloketone (HK) and trichloronitromethane (TCNM). It reduced haloacetonitrile (HAN) formation during the post-chlorination in comparison with the UV/H2O2 process. In waters with high concentrations of ammonia, the UV/chlorine process was only 5-7% more effective than the UV/H2O2 process, and it formed slightly more THMs, HKs and TCNM along with reduced formation of CH and HAN. The UV/chlorine process is thus recommended as a good alternative to UV/H2O2 treatment for its superior PPCP removal without significantly enhancing DBP formation.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China. Electronic address: yangx36@mail.sysu.edu.cn.
Xin
X
Yang
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong.
Jianliang
J
Sun
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Wenjie
W
Fu
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong; Hong Kong Branch of China National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Hong Kong. Electronic address: cechii@ust.hk.
Chii
C
Shang
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Yin
Y
Li
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Yiwei
Y
Chen
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Wenhui
W
Gan
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Jingyun
J
Fang
D002713:Chlorine / Q000737:chemistry*; D004203:Disinfection; D054879:Halogenation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D018508:Water Purification
D002713:Chlorine; D006861:Hydrogen Peroxide
Advanced oxidation processes; Disinfection byproducts (DBPs); Pharmaceuticals and personal care products (PPCPs); UV/H(2)O(2); UV/chlorine