Geochemical stability of zero-valent iron modified raw wheat straw innovatively applicated to in situ permeable reactive barrier: N2 selectivity and long-term denitrification

Ecotoxicology and Environmental Safety

卷:224

Ying Bai¹  Ling Li²  Lin Yin³  Wen Zhang³  Liang Qi⁴  Chengchen Guo⁴ 

[1] Key Laboratory of Coastal Environment and Resources Research of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, Zhejiang Province, China;

[2] Key Laboratory of Surficial Geochemistry, Ministry of Education, 210023 Nanjing, China;

[3] School of Earth Science and Engineering, Nanjing University, 210023 Nanjing, China;

[4] School of Engineering, Westlake University, Hangzhou 310024, Zhejiang Province, China;

关键词: ZVI modified raw wheat straw;    Microbiological and chemical denitrification;    in-situ permeable reactive barrier (PRB);    Nitrate removal;    Groundwater remediation;   

DOI  :  

来源: DOAJ

【 摘 要 】

The zero-valent iron (ZVI) modified wheat straw materials are widely used for treating groundwater by permeable reactive barrier (PRB). We report the performance of a field-scale PRB filled with ZVI modified wheat straw materials for nitrate (NO3-)-contaminated groundwater. In lab-scale PRB filled with ZVI modified wheat straw material, NO3- concentration entering the PRB was varied (27.80–59.86 mg L–1) according to the in situ NO3– contamination. A stable NO3− removal rate of 90% was achieved at a controlled hydraulic retention time of 22 days, together with a proportion of denitrifying bacteria up to 34.37%. The field-scale PRB filled with ZVI modified wheat straw material was successful at removing NO3– from groundwater (removal percentages ≥60%) at a groundwater flow rate of 0.01 m3 d–1. Monitoring of groundwater within this PRB provided evidences that the nitrogen gas (N2) selectivity increased with lower ammonia (NH4+) generated from ZVI reduction of NO3-, and few emission of NO2- present due to denitrification capacity in this PRB. The results are finally compared with the few others reported existing PRBs for nitrate-contaminated groundwater worldwide, and demonstrated that the ZVI modified wheat straw material would be an effective fillings for field PRB to remediate groundwater.

【 授权许可】

Unknown