Biological nitrogen removal using soil columns for the reuse of reclaimed water: Performance and microbial community analysis.

The main aim of this study was to remove nitrogen compounds from reclaimed water and reuse the water in semi-arid riverine lake systems. In order to assess the nitrogen removal efficiencies in different natural environments, laboratory scale column experiments were performed using sterilized soil (SS), silty clay (SC), soil with submerged plant (SSP) and biochar amendment soil (BCS). The initial concentration of NO3 - -N and the flow rate was maintained constant at 15 mg L-1 and 0.6 ± 0.1 m d-1 , respectively. Among the tested columns, both SSP and BCS were able to achieve NO3 - -N levels <0.2 mg L-1 in the treated reclaimed water. The results from bacterial community structure analysis, using 454 pyrosequencing of 16s rRNA genes, showed that the dominant denitrifier was Bacillus at the genera level.