Abstract:Fluorescence spectrum of dissolved organic matter (DOM) in domestic wastewater and membrane foulants during membrane bioreactor (MBR) treatment process was analysed and the comparison of DOM between MBR and traditional anaerobic/anoxic/aerobic process was also carried out. The fluorescent components in domestic wastewater DOM were mainly protein-like (Peak A and Peak B) and humic-like fluorophores (Peak C). The fluorescent intensity reduced by 16%~35% and the structure of protein-like fluorophores changed during the MBR treatment process. Decrease of the number of conjugated bonds and the molecule size in the protein-like structure had been observed in dissolved membrane foulants. And the membrane foulants contained less humic-like matter than the filtrate from aerobic zone. Compared with MBR process, the anaerobic zone increased the reduction of fluorescence intensity of Peak A and Peak C and the change of protein-like structure was different in the AAO process.