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Mesocosm-Scale Constructed Wetland Design for Wastewater Treatment
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Plants boost pyrrhotite-driven nitrogen removal in constructed wetlands
Cheng Shen1, Liti Su2, Yaqian Zhao3
1Zhejiang Province Key Laboratory of Recycling and Ecological Treatment of Waste Biomass, School of Environment and Natural Resources, Zhejiang University of Science & Technology, Hangzhou, Zhejiang 310023, China; Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Belfield Dublin 4, Ireland.
Bioresource Technology
|November 4, 2022
Summary
Plants significantly boost nitrogen removal in constructed wetlands (CWs) using pyrrhotite. This study reveals plants accelerate pyrrhotite dissolution, enhancing overall treatment efficiency and microbial activity in these crucial wastewater systems.
Area of Science:
- Environmental Science
- Water Treatment Engineering
- Microbiology
Background:
- Pyrrhotite is an effective electron donor for autotrophic denitrification in carbon-limited wastewater.
- Constructed wetlands (CWs) integrating pyrrhotite show potential for enhanced nitrogen removal.
- The role of plants in pyrrhotite-based CWs is debated due to potential oxygen release impacting anoxic conditions.
Purpose of the Study:
- To investigate the impact of plants on nitrogen removal in pyrrhotite-integrated CWs.
- To assess the effects of plant presence on pyrrhotite oxidized dissolution and microbial communities.
- To elucidate the role of plants in accelerating pyrrhotite-based autotrophic denitrification (PAD).
Main Methods:
- Comparison of CWs with and without plants using pyrrhotite as substrate.
- Analysis of total nitrogen (TN) removal efficiency.
- Evaluation of pyrrhotite dissolution rates.
- Characterization of microbial community composition and network structure.
Main Results:
- Plants significantly enhanced TN removal from 41.6 ± 3.9% to 97.1 ± 2.6%.
- Plant presence accelerated pyrrhotite dissolution, indicating enhanced PAD.
- CWs with plants exhibited enriched functional bacteria (Thiobacillus, Acidiferrobacter) and a more complex microbial co-occurrence network.
Conclusions:
- Plants play a crucial role in accelerating pyrrhotite-based autotrophic denitrification in CWs.
- The presence of plants strengthens pyrrhotite dissolution, leading to improved nitrogen removal.
- This study provides a deeper understanding of plant-pyrrhotite interactions in constructed wetland systems for wastewater treatment.
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