Main content area

Inhibition effect of magnetic field on nitrous oxide emission from sequencing batch reactor treating domestic wastewater at low temperature

Xu, Dan, Ji, Hongmin, Ren, Hongqiang, Geng, Jinju, Li, Kan, Xu, Ke
Journal of environmental sciences (China) 2020 v.87 pp. 205-212
Nitrosomonas, Zoogloea, ammonium nitrogen, denitrification, denitrifying microorganisms, enzyme activity, genes, high-throughput nucleotide sequencing, magnetic fields, municipal wastewater, nitrogen, nitrous oxide, nitrous oxide production, sludge, temperature, total nitrogen, wastewater treatment
This study aims to investigate the effect of a magnetic field on nitrous oxide (N2O) emission from a sequencing batch reactor treating low-strength domestic wastewater at low temperature (10°C). After running for 124 days in parallel, results indicated that the conversion rate of N2O for a magnetic field-sequencing batch reactor (MF-SBR) decreased by 34.3% compared to that of a conventional SBR (C-SBR). Meanwhile, the removal efficiencies for total nitrogen (TN) and ammonia nitrogen (NH4-N) of the MF-SBR were 22.4% and 39.5% higher than those of the C-SBR. High-throughput sequencing revealed that the abundances of AOB (Nitrosomonas), NOB (Nitrospira) and denitrifiers (Zoogloea), which could reduce N2O to N2, were promoted significantly in the MF-SBR. Enzyme activities (Nir) and gene abundances (nosZ nirS and nirK) for denitrification in the MF-SBR were also notably higher compared to C-SBR. Our study shows that application of a magnetic field is a useful approach for inhibiting the generation of N2O and promoting the nitrogen removal efficiency by affecting the microbial characteristics of sludge in an SBR treating domestic wastewater at low temperature.