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Visualizing Methane-Cycling Microbial Dynamics in Coastal Wetlands
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Optimization of methane-dependent oxygenic denitrification in sequencing batch reactors by insights into the
Zhanfei He1, Jieni Feng1, Zhen Wei1
1Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, China.
The Science of the Total Environment
|June 30, 2018
Summary
Methane-dependent oxygenic denitrification (O2DN) enhances wastewater treatment by reducing nitrous oxide. Organic matter in influent surprisingly boosts O2DN bacteria growth via cross-feeding, improving reactor efficiency.
Area of Science:
- Environmental microbiology
- Biotechnology
- Wastewater treatment
Background:
- Methane-dependent oxygenic denitrification (O2DN) is a key technology for mitigating nitrous oxide (N2O) emissions in wastewater treatment.
- Metabolic cross-feeding between methane-dependent O2DN bacteria and associated heterotrophic bacteria is proposed but not fully understood.
Purpose of the Study:
- To develop a mathematical model simulating microbial interactions in O2DN systems within a sequencing batch reactor (SBR).
- To investigate the impact of influent substrates, operating parameters, and initial biomass on microbial communities and reactor performance.
- To optimize O2DN reactor operation using the developed model.
Main Methods:
- Development of a mathematical model incorporating growth factor-dependent decoupling of metabolism and growth for O2DN bacteria.
- Simulation of microbial processes and interactions between methane-dependent O2DN bacteria and heterotrophic bacteria in an SBR.
- Optimization of influent substrates and operating parameters using the model.
Main Results:
- Influent organic matter significantly stimulated methane-dependent O2DN bacteria growth while only slightly limiting heterotrophic bacteria.
- This stimulation is attributed to increased growth factor excretion by heterotrophic bacteria and heightened nitrite competition.
- The model successfully predicted and explained these microbial dynamics.
Conclusions:
- Organic matter influences microbial interactions in O2DN systems in a complex, beneficial manner for O2DN bacteria.
- The findings provide a deeper understanding of microbial cross-feeding in O2DN processes.
- This study offers novel strategies for optimizing the operation of O2DN reactors for enhanced greenhouse gas reduction.
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