Bioretention cell incorporating Fe-biochar and saturated zones for enhanced stormwater runoff treatment

Jiaqing Xiong; Sihui Ren; Yifan He; Xiaochang C Wang; Xuechen Bai; Jiaxuan Wang; Mawuli Dzakpasu

doi:10.1016/j.chemosphere.2019.124424

Bioretention cell incorporating Fe-biochar and saturated zones for enhanced stormwater runoff treatment

Chemosphere. 2019 Dec:237:124424. doi: 10.1016/j.chemosphere.2019.124424. Epub 2019 Jul 22.

Authors

Jiaqing Xiong¹, Sihui Ren², Yifan He², Xiaochang C Wang³, Xuechen Bai⁴, Jiaxuan Wang⁵, Mawuli Dzakpasu⁶

Affiliations

¹ Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China. Electronic address: xiongjiaqing@xauat.edu.cn.
² School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China.
³ Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China.
⁴ China United Northwest Institute for Engineering Design & Research Co., Ltd (CUCED), Zhang Ba Si Road. No.16, Xi'an, 710077, China.
⁵ School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Yan Ta Road, No. 58, Xi'an, 710054, China.
⁶ Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an, 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Yan Ta Road. No.13, Xi'an, 710055, China.

PMID: 31377594
DOI: 10.1016/j.chemosphere.2019.124424

Abstract

Nitrogen (N) and phosphorus (P) removal in conventional bioretention systems is highly variable. Therefore, five novel experimental columns with different media configurations and constituents, and incorporating a saturated zone were developed and assessed to optimize the removal of N, P and other nutrients. Three types of media composed of the conventional mixed sand and soil media (T₁), biochar-amended media (T₂), and iron-coated biochar (ICB)-amended media (T₃) were evaluated. Two of the experimental columns were designed with double-layer configurations, while the other three were of a single-layer structure. Removal efficiencies of nutrients in the experimental columns were evaluated and compared using simulated runoff. Also, the effect of media depth on the retention of P and denitrifying enzyme activity (DEA) in the bioretention columns were evaluated. The experimental column only filled with T₃ showed the best performance for COD, ammonia (NH₄⁺-N) and total phosphorus (TP) removal (94.6%, 98.3% and 93.70%, respectively), whereas columns filled with T₂ performed poorly for TP removal (57.36%). For the removal of nitrate (NO₃^--N) and total nitrogen (TN), the columns using a single-layer and only filled with either T₃ or T₂ exhibited the best performance (93% and 97% TN removal, respectively). Overall, this study demonstrates that our proposed single-layered bioretention cell only filled with T₃ and incorporating a saturated zone effectively improves the runoff quality, and can provide a new bioretention cell configuration for efficient stormwater treatment.

Keywords: Amended media; Bioretention; Iron-modified biochar; Nutrients; Runoff pollution.

MeSH terms

Charcoal / chemistry*
Denitrification
Iron
Nitrates
Nitrogen / isolation & purification*
Phosphorus / isolation & purification*
Rain*
Soil / chemistry
Water Purification / methods*

Substances

Nitrates
Soil
biochar
Charcoal
Phosphorus
Iron
Nitrogen