DO 对两级 AO 型 MBR 工艺处理填埋污泥脱水液的影响

Two stage anaerobic-oxic membrane bioreactors（AO-MBR）were established to investigate the effect of DO concentration on nitrogen removal from landfill sludge dewatering effluent. Three-dimensional fluorescence excitation-emission matrix-parallel factor analysis（EEM-PARAFAC）and synchronous fluorescence spectroscopy were used to explore the transfer and transformation of dissolved organic matter in the systems. Results showed that the high DO（5~6 mg∙L^-1）system had higher nitrogen removal rate and more stable partial nitrification compared with the low DO（2~3 mg ∙ L^-1）system. The removal rates of ammonia nitrogen and total nitrogen were 98.1%±0.2% and 97.3%±0.2%，respectively. Three fluorescent components were identified by EEM-PARAFAC，namely humic acid-like component C1，tryptophan-like component C2 and fulvic acid-like component C3. The fluorescence intensity of humic acid-like and fulvic acid-like fluorescence decreased more significantly and the fluorescence intensity of tryptophan-like fluorescence increased more significantly in the high DO system than that in the low DO system. Further analysis by two-dimensional correlation spectroscopy showed that fulvic acid-like species were preferentially degraded in both DO conditions. However，microbes in the high DO system had higher degradation efficiency for humus-like and protein-like substances.