4. Conclusions
A significant loss of nitrogen was observed in a biofilter treating
potable water. The DO consumption and nitrate production results
indicated that both the CANON and the nitrification processes
must have contributed to the removal of NH4 + -N. The CANON process
contributed about 48.5% and 46.6% to the removal of NH4 + -N
when the influent NH4 + -N levels were 1.030 and 1.749 mg/L,
respectively. Remarkably, some of the obtained sequences shared
a high similarity with Candidatus Kuenenia stuttgartiensis and
anaerobic ammonium-oxidizing Planctomycete, and they could be
clustered into a group after the phylogenetic tree analysis.
Table 4
Sequencing results of PCR products and their relatives from GenBank.