[Characterization of the change in DOM during wastewater chlorine and chlorine dioxide disinfections by 3DEEM].

The change of DOM (dissolve organic matter) during wastewater chlorine and chlorine dioxide disinfections was characterized by 3DEEM (three-dimensional excitation emission matrix fluorescence spectroscopy) method. The results showed that the DOM in wastewater tested was quite different from drinking water and surface waters. It contained more aromatic proteins and soluble microbial products, and the humus were predominately microbially derived and had less aromatic moieties. After chlorine and chlorine dioxide disinfections, the excitation or emission wavelength of EEM (excitation emission matrix) peaks for aromatic proteins and soluble microbial products shifted to longer wavelength by several nanometers, which was probably caused by the decomposition of aromatic structure; while the excitation or emission wavelength of EEM peaks for humus shifted to shorter wavelength by several to more than twenty nanometers, which was different from surface waters, and this phenomenon was considered to be caused by their different resources. Similar to the change in genotoxicity, ammonia nitrogen significantly influenced the change in EEM during chlorine disinfection, but not during chlorine dioxide disinfection.