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A novel sulfide-driven denitrification methane oxidation (SDMO) system: Operational performance and metabolic
Wei Wang1, Lei Zhao1, Bing-Jie Ni2
1State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Water Research
|August 2, 2022
Summary
This study introduces a novel sulfide-driven denitrification methane oxidation system for cost-effective water treatment. The system efficiently removes nitrogen using biogas without external carbon, enhancing microbial processes.
Area of Science:
- Environmental Microbiology
- Water Treatment Technologies
- Biogeochemical Cycles
Background:
- Traditional denitrification requires external organic carbon, increasing costs.
- Developing cost-effective and sustainable nitrogen removal methods is crucial.
- Biogas utilization in wastewater treatment offers potential for resource recovery.
Purpose of the Study:
- To develop and evaluate a novel sulfide-driven denitrification methane oxidation (SDMO) system.
- To assess the system's performance in sewage denitrification without external carbon sources.
- To investigate the metabolic mechanisms and microbial community dynamics within the SDMO system.
Main Methods:
- Operation of two SDMO systems for 735 days using nitrate and nitrite as electron acceptors.
- Monitoring nitrogen removal efficiency, biogas desulfurization, and hydraulic retention time (HRT).
- Metabolic mechanism characterization using genomic analysis and microbial community profiling.
Main Results:
- Achieved 100% nitrogen removal and biogas desulfurization without external carbon at 10-day HRT.
- Nitrate was a preferable electron acceptor, with a 1.2:1 ratio of autotrophic denitrification (AD) to denitrification anaerobic methane oxidation (DAMO).
- Biogas enhanced DAMO, doubling nitrogen removal via this pathway, and promoted the growth of *Candidatus Methylomirabilis*.
Conclusions:
- The SDMO system offers a cost-effective solution for nitrogen removal and biogas utilization.
- Nitrate as an electron acceptor significantly enhances DAMO activity and microbial growth.
- A novel metabolic pathway involving the upregulated gene *mfnE* in *Candidatus Methylomirabilis* may enable nitrate reduction without archaea.
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