1 research outputs found
Nitrogen Removal and N<sub>2</sub>O Accumulation during Hydrogenotrophic Denitrification: Influence of Environmental Factors and Microbial Community Characteristics
Hydrogenotrophic
denitrification is regarded as an efficient alternative
technology of removing nitrogen from nitrate-polluted water that has
insufficient organics material. However, the biochemical process underlying
this method has not been completely characterized, particularly with
regard to the generation and reduction of nitrous oxide (N<sub>2</sub>O). In this study, the effects of key environmental factors on hydrogenotrophic
denitrification and N<sub>2</sub>O accumulation were investigated
in a series of batch tests. The results show that nitrogen removal
was efficient with a specific denitrification rate of 0.66 kg N/(kg
MLSS·d), and almost no N<sub>2</sub>O accumulation was observed
when the dissolved hydrogen (DH) concentration was approximately 0.40
mg/L, the temperature was 30 °C, and the pH was 7.0. The reduction
of nitrate was significantly affected by the pH, temperature, inorganic
carbon (IC) content, and DH concentration. A considerable accumulation
of N<sub>2</sub>O was only observed when the pH decreased to 6.0 and
the temperature decreased to 15 °C, where little N<sub>2</sub>O accumulated under various IC and DH concentrations. To determine
the microbial community structure, the hydrogenotrophic denitrifying
enrichment culture was analyzed by Illumina high-throughput sequencing,
and the dominant species were found to belong to the genera <i>Paracoccus</i> (26.1%), <i>Azoarcus</i> (24.8%), <i>Acetoanaerobium</i> (11.4%), <i>Labrenzia</i> (7.4%),
and <i>Dysgonomonas</i> (6.0%)