Teng Xia, Johan Alexander Huisman, Chen Chao, Jing Li, Deqiang Mao
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引用次数: 0
Abstract
Dynamic monitoring of in-situ chemical oxidation (ISCO) of LNAPLs in groundwater is the foundation for evaluating remediation effectiveness. In this study, spectral (SIP) and time-domain induced polarization (TDIP) measurements are conducted in laboratory columns and sandboxes to monitor the ISCO of LNAPL for characterizing oxidant transport and quantifying contaminant consumption under different injection strategies. To support the interpretation, this was combined with total petroleum hydrocarbon (TPH), hydrochemistry and computed tomography (CT) measurements. Experiments were performed using two media, and the monitoring results showed similar variations in key parameters. The electrical resistivity, chargeability and TPH decreased significantly during ISCO remediation, while the hydrochemical parameters showed an increasing trend. Specifically, IP variations before and after injection revealed that more oxidant remained in the source area using a multiple-injection strategy compared to a single-injection strategy. The effect of contaminant consumption under well-controlled conditions on electrical resistivity was <3 % and the effect on chargeability was <8 %. In conditions with oxidant migration, the effect of oxidant on the resistivity and chargeability was similar at ∼89 % in the source area, whereas the oxidant had a greater effect on the resistivity (>58 %) than the chargeability (<40 %) outside the source area. Based on the experimental results, a conceptual model for the IP response during ISCO remediation is proposed and we delineate the pore structural characteristics of porous media based on the conceptual model. Oxidant injection develops a high conductivity environment and causes a decrease in LNAPLs content and number of interfaces, leading to the suppression of the IP response. In conclusion, IP measurement in combination with supporting information clearly enables the characterization of the ISCO remediation of LNAPLs in groundwater and facilitates the pore structure characterization of porous media based on the IP conceptual model.
期刊介绍：
The Journal of Contaminant Hydrology is an international journal publishing scientific articles pertaining to the contamination of subsurface water resources. Emphasis is placed on investigations of the physical, chemical, and biological processes influencing the behavior and fate of organic and inorganic contaminants in the unsaturated (vadose) and saturated (groundwater) zones, as well as at groundwater-surface water interfaces. The ecological impacts of contaminants transported both from and to aquifers are of interest. Articles on contamination of surface water only, without a link to groundwater, are out of the scope. Broad latitude is allowed in identifying contaminants of interest, and include legacy and emerging pollutants, nutrients, nanoparticles, pathogenic microorganisms (e.g., bacteria, viruses, protozoa), microplastics, and various constituents associated with energy production (e.g., methane, carbon dioxide, hydrogen sulfide).
The journal''s scope embraces a wide range of topics including: experimental investigations of contaminant sorption, diffusion, transformation, volatilization and transport in the surface and subsurface; characterization of soil and aquifer properties only as they influence contaminant behavior; development and testing of mathematical models of contaminant behaviour; innovative techniques for restoration of contaminated sites; development of new tools or techniques for monitoring the extent of soil and groundwater contamination; transformation of contaminants in the hyporheic zone; effects of contaminants traversing the hyporheic zone on surface water and groundwater ecosystems; subsurface carbon sequestration and/or turnover; and migration of fluids associated with energy production into groundwater.
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