The Success of South-to-North Water Diversion Project (Eastern Route): From the Perspective of the Distribution of Nitrate Reducing Bacteria in Multistage Constructed Wetland
Posted: 23 Jul 2019
Date Written: July 20, 2019
Nitrogen is one of the key environment pollutant threatening the implement of the South-to-North Water Diversion Project (SNWDP). This study revealed that the three microbially mediated nitrate reduction pathways (denitrification, anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA) in multistage constructed wetland (mCW)) contributed significantly to the improvement of water quality in Nansi Lake, guaranteeing the success of SNWDP. DNRA rather than denitrification or anammox occupied a very important position for nitrate reduction in Xinxue River mCW. The quantitative real-time polymerase chain reaction analysis showed that the abundance of DNRA bacteria at all sites was higher than these of denitrifying bacteria and anammox bacteria, ranging from 2.10×1010 to 1.10×1011 copies/g of dry weight sediments. The abundance of DNRA bacteria, denitrifying bacteria and anammox bacteria was significantly negatively correlated with Eh and positively correlated with the NO3--N removal rate by statistical analysis. The total nitrate removal rate reached 85.73% flowing through the mCW. Anaeromyxobacter (belong to Deltaproteobacteria) was the most abundant DNRA bacteria at all sites. Interestingly, Deinococcus-thermus and Actinobacteria were firstly discovered as DNRA bacteria in mCW.
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