ABSTRACT
Changes in water quality and brominated disinfection by-products (Br-DBPs) during a low temperature multi-effect distillation (LT-MED) process for seawater desalination were investigated. The concentrations of bromide ion and specific ultraviolet absorbance (SUVA) in the seawater (i.e. the influent of LT-MED) were 54.6 mg·L-1 and 1.7 L·(mg·m)-1, respectively. The tryptophan-like aromatic protein, fulvic acid-like and soluble microbial by-product-like organics dominated the fluorescent dissolved organic matter (DOM) in the seawater. After the NaClO pre-chlorination in the LT-MED process, the concentrations of DBPs in the seawater were significantly increased, especially Br-DBPs, and Bromoform(CHBr3) accounted for 100% of total trihalomethanes (THMs), Bromoacetic acid (C2H3BrO2) and dibromoacetic acid (C2H2Br2O2) accounted for 31.9% and 68.1%, respectively of total haloacetic acids (HAAs), while 4-Bromophenol (C6H5BrO) accounted for 100% of total halogenated phenols (HPs). The formation of THMs, HAAs and HPs was not detected in the finishing water produced by the LT-MED desalination process, but these substances were retained in the concentrated brine, of which THMs, HAAs and HPs were 56.9, 35.0 and 0.1 µg·L-1.