| 内容提要: |
Organic pollution of urban rivers is a crucial issue inhibiting the ecological recovery of water bodies. Traditional bioremediation techniques are influenced by the anaerobic environment in the sediment and have low biological effectiveness and organic matter removal efficiency. To solve these issues, we developed a new anaerobic remediation technique for in-situ organic matter removal from river sediments using humic-reducing bacterial agents (HRBs), considering the anaerobic environment and the high humic content in the sediment. The humic-analog, AQS, was used to domesticate the traditional activated sludge to obtain HRBs with a strong humic-reducing ability. The remediation effect of HRBs in different organic matter-contaminated sediments was analyzed, and the effect of HRBs on TOM removal was explored from the perspectives of organic matter structure and composition in sediments. The results showed a positive correlation between TOM removal and TOM, HFOM, ATOM, TN and AVS, and a negative correlation with Fe(III)/Fe(II) and E3/E4. Analysis from molecular biology revealed that after adaptation, HRBs had increased the bacterial population of Anaerolineales and Desulfuromonadales, which was related to the carbon metabolism and electron-transfer ability. The HRBs was more favorable for preferential use of light fraction organic matters (LFOM) and could enhance the removal of heavy fraction organic matters when LFOM was insufficient. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) research revealed that the benefit of decomposing HFOM with HRBs was due to the HFOM carrying redox mediators to enable humic-reducing respiration. These results help to understand humic-reducing mechanisms in sediment during anaerobic bioremediation and provide a novel approach for in-situ anaerobic remediation of urban river sediments. |