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

Ke Xu , Dan Xu , Hongmin Ji , Hongqiang Ren , Jinju Geng , Kan Li


Received March 11, 2019,Revised , Accepted May 13, 2019, Available online May 21, 2019

Volume 32,2020,Pages 205-212

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.

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