N-nitrosamines concern has been increasing in China since some water sources are under threat of domestic and industrial waste discharge. This investigation was conducted to focus a lake in Yantze Delta which was used as the water source. The characteristics of dissolved organic matter (DOM), formation potential of N-nitrosamines and the treatability of conventional and advanced treatment process were included in this paper.  The sourcewater had fairly high concentration of DOM, 4-7 mg/L, which was regarded to be mainly originated from the phytoplankton secretion. The organic fraction with molecular weight lower than 3000 Dalton took the majority of DOM, over 95%, by high performance size exclusion chromatography (HPSEC). Aromatic protein and soluble microbial products (SMPs) present the dominant peaks in the three-dimensional excitation-emission matrix (EEM) fluorescence spectra.  Five kinds of N-nitrosamines, including NDMA, NDEA, NMOR, NPYR, and NPIP, were detected by SPE-UPLC-MS-MS when the raw water was disinfected with sufficient monochloramine. NDMA and NDEA were found to be the dominant nitrosamine species which formation potentials were as high as 30 ng/mg-C and 10 ng/mg-C individually.  The conventional and ozone-GAC process could effectively remove the organic matters. The average decreases of DOC, SUVA254, COD, and ammonia were about 67.4%, 46.8%, 64.0%, and 65.5%, respectively. More than 70% and 67% of molecular weight < 500 Da and molecular weight between 500 and 1000 Da could be removed respectively by this advanced process. The ozone-GAC process also showed higher efficiency in removal of aromatic protein and soluble microbial products as well as the N-nitrosamines precursors. Therefore, the conventional and ozone-GAC process could be used as the best available technology to treat the similar source water and solve the N-nitrosamine concern.

N-nitrosamines concern in the sourcewater of one lake in Yangtze Delta, China: Precursor and treatability

243rd National Meeting (2012)

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