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Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites
Published on: November 28, 2014
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Efficient nitrogen removal through coupling biochar with zero-valent iron by different packing modes in bioretention
Jiajie Chen1, Yu Xie1, Shanshan Sun1
1School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China.
Environmental Research
|January 28, 2023
Summary
Bioretention systems with biochar and zero-valent iron (ZVI) enhance nitrogen removal in stormwater. A design combining biochar in soil and ZVI with biochar in the substrate layer proved most effective for nitrogen management.
Area of Science:
- Environmental Engineering
- Water Quality Management
- Environmental Chemistry
Background:
- Nitrogen pollution from stormwater runoff poses a significant environmental challenge.
- Bioretention systems are effective for stormwater treatment, but nitrogen removal can be further optimized.
- Zero-valent iron (ZVI) and biochar are materials with potential to enhance nitrogen removal in engineered systems.
Purpose of the Study:
- To investigate the impact of zero-valent iron (ZVI) and biochar on nitrogen removal in bioretention systems.
- To compare different packing configurations of ZVI and biochar for optimal nitrogen removal.
- To understand the mechanisms behind enhanced nitrogen removal by ZVI and biochar.
Main Methods:
- Three bioretention designs with varying ZVI and biochar configurations were tested.
- Effluent nitrogen concentrations (nitrate, ammonium, total nitrogen) were monitored during rainfall events.
- Batch experiments were conducted to assess ZVI stability and the role of biochar.
- Microbial community analysis was performed using high-throughput sequencing.
Main Results:
- Bioretention-3, with biochar in the soil layer and a ZVI-biochar mixture in the substrate, achieved high removal rates for nitrate (53.30%), ammonium (98.41%), and total nitrogen (64.03%).
- Biochar protected ZVI from oxidation and promoted denitrification by releasing organic matter.
- Microbial analysis revealed dominant phyla Proteobacteria and Actinobacteriota, with specific genera involved in nitrification and denitrification processes, including aerobic and autotrophic pathways.
Conclusions:
- Combining biochar in the soil layer with a ZVI-biochar mixture in the substrate layer represents a stable and efficient design for improving nitrogen removal in stormwater management.
- This approach offers a novel strategy for enhancing the nitrogen removal capacity of bioretention systems.
- Understanding the interplay between ZVI, biochar, and microbial communities is crucial for optimizing bioretention performance.
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