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Integrated, in situ gas/steam thermal desorption–chemical oxidation for volatile organic compounds and odorants in deep, contaminated soils

delete2026-08-13
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PRE
AI
H
Hongguang Zheng
Y
Yanfei Wang
Y
Yi Shi
H
Hefeng Lu
J
Jingqi Zhang
W
Weiguang Zhao
T
Tianran Li
J
Jie Hua
R
Riming Lu
W
Wenlu Li
X
Xiaofei Zhang
J
Juejun Yao *
A
Aizhong Ding *
DOI:10.1007/s10653-026-03429-9delete
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Abstract

Abstract

En 中文
Remediation of deeply contaminated legacy pesticide sites must often achieve risk-based contaminant control while also addressing persistent nuisance odors; however, field-scale performance is frequently limited by vertical heterogeneity and mismatch between odor drivers and standard risk indicators. At a deep (0–25 m) pesticide-manufacturing brownfield in Guangdong, China, a zoned and stratified in situ treatment train that coupled gas thermal desorption (GTD), steam thermal desorption (STD), and alkaline-activated persulfate in situ chemical oxidation (ISCO) was evaluated. The GTD was applied to heavily-contaminated shallow layers (0–12.5 m), STD to deeper layers (12.5–25 m), and ISCO to mildly formaldehyde-contaminated soils. Laboratory trials supported the operational settings for GTD/STD and showed marked reductions in volatile organic compounds and odor intensity, whereas ISCO displayed a non-monotonic response with an apparent optimum of approximately 2.5% persulfate at pH ≈ 11. During the pilot operation, the extracted off-gas odor intensity typically increased in the early stages and then declined, consistent with contaminant mobilization followed by source depletion, and post-treatment soils met the risk-based remediation and project-specific odor control targets established for the site. Post-treatment soil formaldehyde met the remediation target, whereas groundwater formate concentrations increased from ≤ 0.023 to 47.7–63.7 mg/L during staged ISCO and remained elevated at the final monitored stage, indicating aqueous-phase accumulation of a mobile transformation product. Secondary-impact monitoring identified fugitive NMHC, odor concentration, wastewater ammonia nitrogen concentrations, and early-stage nighttime noise as the main operational control endpoints. These results demonstrate pilot-scale feasibility under the site conditions examined and provide a field-based framework for similarly stratified pesticide brownfields requiring concurrent control of contaminant exposure and odor impacts.
Keywords:
Soil remediation
In situ remediation
Thermal desorption
Chemical oxidation
Persulfate activation
Odor intensity

Journal

Environmental Geochemistry and Health cover
Environmental Geochemistry and Health
IF:
3.8
Papers:
4.6K
Citations:
1.0W

Organization

T
Technical Centre for Soil
Scholars:
112
Papers: 45
Citations: 0
H
henan geological bureau
Scholars:
9
Papers: 10
Citations: 0
C
College of Water Sciences
Scholars:
35
Papers: 14
Citations: 0
X
xingtai ecological environment bureau
Scholars:
2
Papers: 1
Citations: 0
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