Reduction of nitrous oxide emissions from partial nitrification process by using innovative carbon source (mannitol)
Xinwen Zhang1, Xiaoqing Wang1, Jian Zhang1
1Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, 27 Shanda Nanlu, Jinan 250100, Shandong, PR China.
Bioresource Technology
|July 18, 2016
Summary
Mannitol addition to partial nitrification (PN) processes significantly reduced nitrous oxide (N2O) emissions by over 40% without impacting ammonium removal. This carbon source also influenced key microbial and enzymatic activities.
Area of Science:
- Environmental Microbiology
- Wastewater Treatment Engineering
- Biogeochemical Cycles
Background:
- Partial nitrification (PN) is crucial for efficient nitrogen removal in wastewater treatment.
- Nitrous oxide (N2O) emissions are a significant environmental concern during PN.
- Carbon sources influence N2O production and nitrogen removal efficiency.
Purpose of the Study:
- To investigate the impact of mannitol as a carbon source on nitrogen removal and N2O emissions during PN.
- To compare the effects of mannitol versus sodium acetate on PN performance and microbial communities.
Main Methods:
- Laboratory-scale PN sequencing batch reactors (SBRs) were used.
- Reactors were operated with either mannitol or sodium acetate as the sole carbon source.
- Nitrogen removal, N2O emissions, microbial analysis (nosZ gene abundance), and enzyme activities were assessed.
Main Results:
- Mannitol reduced N2O-N emissions by 41.03% without affecting ammonium (NH4(+)-N) removal efficiency.
- Mannitol led to lower nitrite accumulation ratio (NAR) and total nitrogen (TN) removal compared to sodium acetate.
- Mannitol increased nosZ gene abundance and altered enzyme activities (reduced T-SOD, POD, CAT; increased dehydrogenase), alleviating N2O reductase inhibition.
Conclusions:
- Mannitol is a promising carbon source for mitigating N2O emissions in PN processes.
- Mannitol's benefits are linked to increased nosZ abundance and alleviation of N2O reductase inhibition.
- Further optimization is needed to balance N2O reduction with overall nitrogen removal efficiency when using mannitol.
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