The multi-process reaction model and underlying mechanisms of 2,4,6-trichlorophenol removal in lab-scale biochar-microorganism augmented ZVI PRBs and field-scale PRBs performance

Wenbing Wang; Tiantian Gong; Hui Li; Yiming Liu; Qianling Dong; Rixia Zan; Yulin Wu

doi:10.1016/j.watres.2022.118422

The multi-process reaction model and underlying mechanisms of 2,4,6-trichlorophenol removal in lab-scale biochar-microorganism augmented ZVI PRBs and field-scale PRBs performance

Water Res. 2022 Jun 15:217:118422. doi: 10.1016/j.watres.2022.118422. Epub 2022 Apr 7.

Authors

Wenbing Wang¹, Tiantian Gong¹, Hui Li², Yiming Liu³, Qianling Dong¹, Rixia Zan⁴, Yulin Wu⁵

Affiliations

¹ School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
² School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China. Electronic address: huili2018@shu.edu.cn.
³ Department of Geography, McGill University, Montreal, QC H3A 0G4, Canada.
⁴ School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
⁵ Shanghai Geotechnical Investigations and Design Institute (SGIDI) Engineering Consulting (Group) Co. Ltd., China.

PMID: 35413559
DOI: 10.1016/j.watres.2022.118422

Abstract

This work developed calcium alginate (CA) embedded zero-valent iron (ZVI@CA) and CA embedded biochar (BC) immobilized microorganism (BC&Cell@CA) gel beads as alternative to conventional Fe⁰ permeable reactive barriers for treating groundwater contaminated with 2,4,6-trichlorophenol (2,4,6-TCP). Lab-scale and field-scale biochar-microorganism augmented PRBs (Bio-PRBs) were constructed and tested. The underlying mechanisms were revealed by a multi-source data calibrated multi-process reaction model, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and high-throughput sequencing. Moreover, calibrated advection-dispersion (a) coupled with the two-site sorption (K_d) and chemical-biological multi-process reaction (λ) model were used for revealing 2,4,6-TCP transport behavior and optimizing Bio-PRBs. Compared to that in the ZVI@CA (0.004 h^-1) system, the reaction rate (0.011 h^-1) of 2,4,6-TCP increased by 175% in the combined chemical-biological batch system. Moreover, chemical-biological augmentation significantly improved the retardation effect of Bio-PRBs for 2,4,6-TCP. It came from that chemical-biological augmentation significantly decreased the dispersivity a (0.53 to 0.20 cm), and increased the distribution coefficient K_d (2.20 to 19.00 cm³ mg^-1), the reaction rate λ (2.40 to 3.60 day^-1), and the fraction (30% to 80%) of first-order kinetic sorption of 2,4,6-TCP in the lab-scale one-dimensional Bio-PRBs. Moreover, versatile functional bacteria Desulfitobacterium was crucial in the transformation of Fe (III) iron oxides. The diversity and richness of archaea in the reaction solution were improved by ZVI@CA gel beads addition. Furthermore, the field-scale reaction system was designed to remediate the chlorinated organic compounds and Benzene Toluene Ethylbenzene & Xylene contaminated groundwater in a pesticide factory site. The field test results demonstrated it is a promising technology to construct vertical reaction columns or horizontal Bio-PRBs for the efficient remediation of actually contaminated groundwater.

Keywords: 2,4,6-trichlorophenol; Biochar; Groundwater remediation; Immobilized microorganism; Permeable reactive barriers.

MeSH terms

Charcoal
Chlorophenols
Environmental Restoration and Remediation*
Groundwater* / chemistry
Iron / chemistry
Water Pollutants, Chemical* / chemistry

Substances

Chlorophenols
Water Pollutants, Chemical
biochar
Charcoal
Iron
2,4,6-trichlorophenol