Newly established process combining partial hydrogenotrophic denitrification and anammox for nitrogen removal
Kenta Shinoda1, Rawintra Eamrat2, Yuya Tsutsumi3
1Integrated Graduate School of Medicine, Engineering and Agricultural Sciences, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-0016, Japan.
Summary
Partial hydrogenotrophic denitrification (PHD) efficiently produces nitrite for the anammox process. This combined approach achieved high nitrogen removal from contaminated water, optimizing wastewater treatment.
Area of Science:
- Environmental microbiology
- Wastewater treatment technologies
- Biogeochemical cycles
Background:
- The anaerobic ammonium oxidation (anammox) process is crucial for nitrogen removal in wastewater.
- Stable production of nitrite-nitrogen (NO2--N) is essential for optimal anammox performance.
- Nitrate-nitrogen (NO3--N) is a common contaminant in nitrogen-rich water.
Purpose of the Study:
- To investigate the use of partial hydrogenotrophic denitrification (PHD) for stable and efficient NO2--N production.
- To evaluate the performance of a combined PHD-anammox process for treating nitrogen-contaminated water.
- To elucidate the microbial community structure and mechanisms involved in the combined nitrogen removal process.
Main Methods:
- Partial hydrogenotrophic denitrification (PHD) was employed for nitrite production.
- The effect of initial pH on PHD efficiency was investigated, with pH 10.5 found to be optimal.
- A combined PHD-anammox system was operated for over three months.
- 16S rRNA gene amplicon sequencing was used to analyze microbial communities.
Main Results:
- An initial pH of 10.5 ensured a high NO2--N production efficiency of 77.9% during PHD.
- The combined PHD-anammox process achieved maximal removal efficiencies of 93.4% for ammonium-nitrogen (NH4+--N), 98.0% for NO3--N, and 86.9% for total dissolved inorganic nitrogen.
- Analysis of N-ratios suggested the involvement of multiple bioprocesses during the anammox stage.
- Microbial community analysis provided insights into the mechanisms of nitrogen removal.
Conclusions:
- Partial hydrogenotrophic denitrification is an effective method for stable nitrite production for anammox processes.
- The combined PHD-anammox process demonstrates high efficiency in removing nitrogen pollutants from wastewater.
- Understanding microbial communities is key to optimizing nitrogen removal through combined bioprocesses.
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