Journal of East China Normal University(Natural Science) ›› 2021, Vol. 2021 ›› Issue (4): 46-54.doi: 10.3969/j.issn.1000-5641.2021.04.006

• Water Pollution Control and Treatment • Previous Articles     Next Articles

Characteristics of dissolved organic matter and its effects on denitrification in urban river sediments

Rui WENG1,2,3,4, Zheng WEI1,2,3,4, Yanmei YANG1,2,3,4, Jing HAN1,2,3,4, Yan HE1,2,3,4,*(), Minsheng HUANG1,2,3,4   

  1. 1. Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
    2. Institute of Eco-Chongming, Shanghai 202162, China
    3. Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, China
    4. Technology Innovation Center for Land Spatial Eco-Restoration in Metropolitan Area (Ministry of Natural Resources), Shanghai 200062, China
  • Received:2020-11-16 Online:2021-07-25 Published:2021-07-23
  • Contact: Yan HE


Understanding the impact of dissolved organic matter (DOM) on the denitrification process is critical to addressing the challenges associated with nitrogen removal in urban river treatment. In this paper, we show that DOM in urban rivers are mainly comprised of small-molecule fulvic acids. The humic acid content and aromaticity of the DOM, moreover, were found to be low. Compared with the control case, DOM can promote the denitrification process; specifically, the removal efficiency of TN and NO3-N in the DOM-added group increased by 7.24% ± 0.36% and 23.52% ± 1.17%, respectively. DOM with an acetate group had an even better effect on the removal of TN and NO3-N, reaching 74.48% ± 1.29% and 98.62% ± 0.07%, respectively. Microbiological analysis showed that the DOM-added group can significantly increase the diversity and richness of the bacteria community compared with the control case. However, the relative abundance of the heterotrophic denitrifiers Pseudomonas and Brevundimonas as well as the nirK-type denitrifier Paracoccus in the DOM-added group was less than that of the DOM with an acetate group. Additionally, a relatively high concentration of NH4+-N (> 3.7 mg/L) was observed in the DOM-added group. The addition of DOM can significantly increase the relative abundance of Anaeromyxobacter related to dissimilatory nitrate reduction to ammonium (DNRA) functional genes. It is speculated that DOM promotes the denitrification process and induces the DNRA process simultaneously.

Key words: urban river, dissolved organic matter, denitrification, fulvic acid, dissimilatory nitrate reduction to ammonium

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