Fig 1.
Schematic representation of the experimental setup.
Table 1.
The packing parameters.
Fig 2.
Performance of the biofilters for the removal of NB: effect of the EBRT (a) and the elimination capacity vs. the inlet loading rate (b).
Fig 3.
Outlet concentrations of NB and REs in different layers with an EBRT of 55.4 s.
Fig 4.
Rarefaction curves based on 16S rRNA gene sequencing of the samples (from top, middle and bottom layers) and the initial inoculum.
The Chao1 index is also shown. The OTUs were defined by a 97% cutoff.
Fig 5.
Principal component analysis (PCA) of bacterial communities from the initial inoculum and samples of the top, middle and bottom layers based on the classified OTUs (a). Heat map illustrating the abundances of all the major genera (with a relative abundance of more than 1% in at least one sample). The color intensity (log scale) in each panel indicates the relative abundance of the genus in each sample (b).
Fig 6.
Concentrations of nitrite released.
Fig 7.
Venn diagram illustrating the overlap of the four bacterial communities from the initial inoculum and the samples of the top, middle and bottom layers.
The shared OTUs (69) were analysed at the phylum level.
Fig 8.
Abundances and distributions of the different phyla in the four biofilm samples.
Table 2.
Genera (relative abundance>1% at genus levels) in the initial inoculum and the samples of the top, middle and bottom layers.
The dominant genera in the different layers are shown in bold.