| 研究実績の概要 |
To treat ammonium rich wastewaters in conventional activated sludge systems, conventional nitrification and denitrification is highly cost for aeration and external organic matter. Besides, N2O emission has been an emergent issue for the past few years due to its significant greenhouse effect. N2O emission from wastewater treatment plants is considered as one of major anthropogenic sources, thus reducing N2O emission from WWTPs is important. My current studies focus on investigation the potential of a membrane-aerated biofilm reactor (MABR) for simultaneous nitrification and denitrification as a compact and cost-effective wastewater treatment technology with minimum N2O emission.
In order to understand the impact of C/N ratio in simultaneous nitrification and denitrification process in an MABR and a conventional biofilm reactor (CBR), we operated 2 reactors representative for MABR and CBR. We found that the counter diffusion biofilms in MABR emits 130 times lower N2O than co-diffusion biofilms in a CBR. The MABR for also had 20% higher oxygen utilization efficiency and 12% higher TN removal efficiency than that of CBR at the same operational conditions. The molecular microbiological analysis indicated higher abundance of denitrifying genes, especially nosZ genes, in the MABR versus the CBR, especially the presence of the genera Thauera, Rhizobium, Sphingobacteria, and Brevundimonas as potential N2O-reducing bacteria in the MABR. The works were published in top rank journals including Applied Microbiology and Biotechnology, Water Research, and Bioresource Technology.
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