Trihalomethane (THM) formation from synergic disinfection of biologically treated municipal wastewater: Effect of ultraviolet (UV) irradiation and titanium dioxide photocatalysis on dissolve organic matter fractions

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 303; pp. 252 - 260
• Main Authors: Meng, Yingjie, Wang, Yan, Han, Qi, Xue, Nan, Sun, Yangyang, Gao, Baoyu, Li, Qilin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2016
• Subjects: Biological effects; Chlorination; Degradation; Disinfection by-production; Formations; Irradiation; Organic matter characteristics; Photocatalysis; Synergic disinfection; TiO2 photocatalysis; Titanium dioxide; UV irradiation; Wastewater treatment; TiO2 photocatalysis; UV irradiation; Organic matter characteristics; Disinfection by-production; Synergic disinfection
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.05.141

•THM formation affected by UV/chlorination and UV/TiO2/chlorination was reported.•UV irradiation degraded high MW THM precursors into small MW fractions.•TiO2 photocatalysis reduced more aromatic functional groups.•UV/TiO2 photocatalysis degraded more THM precursors than UV irradiation. The trihalomethane (THM) formation of two synergic disinfection methods, UV/chlorination and TiO2 photocatalysis/chlorination, was evaluated to assess the health and ecological risks of biologically treated municipal wastewater. The effect of molecular characteristics of dissolved organic matter (DOM) from membrane bioreactor (MBR) and A2/O process treated municipal wastewaters was investigated. Results showed that THM formation was elevated in both UV/chlorination and TiO2/chlorination synergic disinfection processes compared to chlorination alone. The UV/chlorination process formed the most THMs. Both UV irradiation and UV/TiO2 photocatalysis were found to (i) degrade high molecular weight (MW) THM precursors to small fractions, and (ii) increase the amount of humic acid-like and fulvic acid-like components. Compared with UV irradiation, UV/TiO2 photocatalysis preferably degraded aromatic protein I, aromatic protein II and soluble microbial byproduct-like. Content of CO band and CO band in DOM after UV/TiO2 photocatalysis was lower than that after UV irradiation. In addition, specific THM formation potential of the precursors in the MBR-treated municipal water was higher than that in the A2/O-treated municipal water.