Characterizations of dissolved organic matter and bacterial community structures in rice washing drainage (RWD)-based synthetic groundwater denitrification

Qiaochong He; Chuanping Feng; Nan Chen; Dongqing Zhang; Tingting Hou; Jingwen Dai; Chunbo Hao; Bingchun Mao

doi:10.1016/j.chemosphere.2018.10.026

Characterizations of dissolved organic matter and bacterial community structures in rice washing drainage (RWD)-based synthetic groundwater denitrification

Chemosphere. 2019 Jan:215:142-152. doi: 10.1016/j.chemosphere.2018.10.026. Epub 2018 Oct 6.

Authors

Qiaochong He¹, Chuanping Feng², Nan Chen³, Dongqing Zhang⁴, Tingting Hou³, Jingwen Dai³, Chunbo Hao³, Bingchun Mao⁵

Affiliations

¹ School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China; Department of Civil and Environmental Engineering, University of South Florida, 74202 E. Fowler Ave, ENB 118, Tampa, FL 33620, USA.
² School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China. Electronic address: fengcp@cugb.edu.cn.
³ School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China.
⁴ Department of Civil and Environmental Engineering, University of South Florida, 74202 E. Fowler Ave, ENB 118, Tampa, FL 33620, USA.
⁵ China Machinery TDI International Engineering Co., Ltd., Beijing, 100083, China.

PMID: 30316156
DOI: 10.1016/j.chemosphere.2018.10.026

Abstract

In this study, characteristics of dissolved organic matter (DOM) and bacterial community structure in rice washing drainage (RWD)-based groundwater denitrification systems inoculated with and without seeding sludge were investigated. Complete nitrate removal was achieved with a maximum denitrification rate of 64.1 mg NO₃^--N·(gVSS·h)^-1. Analysis of three-dimension fluorescence excitation-emission matrix (FEEM) identified three main compositions of DOM associated with tryptophan protein-like, aromatic protein-like, and polycarboxylate humic acid-like substances in the inoculated system, while one composition associated with tryptophan protein-like substance in the un-inoculated system. Illumina sequencing analysis revealed a distinguished bacterial community structure in two systems over time. Notably, the microbial diversity was significant lower in the un-inoculated system than that in the system inoculated with seeding sludge. The predominant phyla shifted from Proteobacteria (49.2%), Bacteroidetes (20.5%) and Chloroflexi (14.8%) in the seeding sludge to Bacteroidetes (56.3%) and Proteobacteria (37.7%) after the RWD addition in the inoculated system. With RWD as sole microbe source, temporal changes in the bacterial structure from Proteobacteria (99.4%) and Bacteroidetes (5.3%) to Proteobacteria (88.8%) and Bacteroidetes (10.3%) were observed in the un-inoculated system. Specific comparison down to the genus level showed the dominant denitrifying bacteria of Thiobacillus, Anaerolineaceae and Methylophilaceae in the seeding sludge. Ideonella, Cloacibacterium and Enterobacter were dominant after the RWD addition in the inoculated system, while Stenotrophomonas and Enterobacter were dominant genera when RWD as sole bacteria source in the un-inoculated system. This finding indicates that both RWD addition and inoculation had strong impacts on bacterial community structure.

Keywords: Bacterial community structure; Denitrification; Dissolved organic matter; Groundwater; Rice washing drainage.

MeSH terms

Bacteria / classification*
Bacteria / growth & development
Bacteria / metabolism
Bioreactors / microbiology*
Denitrification*
Drainage
Groundwater / chemistry*
Groundwater / microbiology
Microbial Consortia*
Nitrates / chemistry
Oryza / chemistry*
Sewage / microbiology*
Water Purification

Substances

Nitrates
Sewage