Comparison of soluble microbial products released from activated sludge and aerobic granular sludge systems in the presence of toxic 2,4-dichlorophenol.

The objective of this study was to compare the release of soluble microbial products (SMP) from activated sludge (AS) and aerobic granular sludge (AGS) in the absence and presence of 2,4-dichlorophenol (2,4-DCP). Data implied that NH4+-N removal efficiencies remarkably decreased to 53.8% and 36.4% after the addition of 2,4-DCP, respectively. Three-dimensional excitation-emission matrix (3D-EEM) implied that three major components (tryptophan protein-like, humic-like and fulvic-like substances) were identified in SMP without the addition of 2,4-DCP. And aromatic protein-like substances appeared after the addition of 2,4-DCP in both systems. Synchronous fluorescence spectra demonstrated that the behavior of released protein-like fraction and fulvic-like fraction was different in both systems. Two-dimensional correlation spectroscopy (2D-COS) suggested that protein-like fraction and fulvic-like fraction preferred to be released in both systems. The results could reveal the characterization of SMP and be better to improve the effluent quality from wastewater treatment system in the presence of toxic compound.