Delineation of hydrocarbon contaminants with multi-frequency complex conductivity imaging

Orozco, Adrián Flores; Ciampi, Paolo; Katona, Timea; Censini, Matteo; Papini, Marco Petrangeli; Deidda, Gian Piero; Cassiani, Giorgio

doi:10.1016/j.scitotenv.2021.144997

Cited by 26 publications

(8 citation statements)

References 56 publications

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“…1–2-m thickness. The whole sequence overlies a thick layer of clays and silty clays (base clays); both the base and the intermediate clays possess hydrogeological characteristics of an aquiclude and aquitard, respectively (Orozco et al 2021 ). The latter reaches its maximum thickness in the western sector while locally disappears to the east, where the mixing groundwaters hosted in the two aquifers (recent and ancient alluvia) occur.…”

Section: Resultsmentioning

confidence: 99%

A field-scale remediation of residual light non-aqueous phase liquid (LNAPL): chemical enhancers for pump and treat

Ciampi

Esposito

Cassiani

et al. 2021

Environ Sci Pollut Res

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The remediation of petroleum-contaminated soil and groundwater is a challenging task. The petroleum hydrocarbons have a long persistence in both the vadose zone and in the aquifer and potentially represent secondary and residual sources of contamination. This is particularly evident in the presence of residual free-phase. Pump-and-treat is the most common hydrocarbon decontamination strategy. Besides, it acts primarily on the water dissolved phase and reduces concentrations of contaminants to an asymptotic trend. This study presents a case of enhanced light non-aqueous phase liquid (LNAPL) remediation monitored using noninvasive techniques. A pilot-scale field experiment was conducted through the injection of reagents into the subsoil to stimulate the desorption and the oxidation of residual hydrocarbons. Geophysical and groundwater monitoring during pilot testing controlled the effectiveness of the intervention, both in terms of product diffusion capacity and in terms of effective reduction of pollutant concentrations. In particular, non-invasive monitoring of the reagent migration and its capability to reach the target areas is a major add-on to the remediation technique. Most of the organic contaminants were decomposed, mobilized, and subsequently removed using physical recovery techniques. A considerable mass of contaminant was recovered resulting in the reduction of concentrations in the intervention areas.

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Section: Resultsmentioning

confidence: 99%

A field-scale remediation of residual light non-aqueous phase liquid (LNAPL): chemical enhancers for pump and treat

Ciampi

Esposito

Cassiani

et al. 2021

Environ Sci Pollut Res

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“…The results show that the measured resistivity generally increases with increasing oil content, which are consistent with existing studies for fresh oil contamination in sandy sediments (Schmutz et al ., 2010; Revil et al ., 2017). However, this observation contradicts with the electrical signatures observed at aged hydrocarbon sites (Aal et al ., 2006; Flores Orozco et al ., 2021; Shao et al ., 2021). Their results showed that organic contaminants generally decrease the resistivity (correspondingly increase the real conductivity).…”

Section: Discussionmentioning

confidence: 99%

Effects of grain size, solution salinity and pH on the electrical response of oil‐bearing carbonate sands

Deng

Qian

Luo

et al. 2022

Near Surface Geophysics

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Researchers around the world have carried out numerous studies on the electrical response of oil‐contaminated silica sands. However, few studies consider the oil contamination in carbonate sands that exhibit quite different characteristics to silica sands. The purpose of this work is to study the influence of grain size (0.5–1.0, 1–3 and 3–5 mm), solution salinity (100, 10 and 1 Ω·m) and pH (4.58, 6.5 and 9.25) on the resistivity and saturation exponent of oil‐bearing carbonate sands. Experimental columns were packed with crushed limestone grains, solution and oil. Electrical resistivity measurements were subsequently performed on the packed columns. Grain size exhibits a complex effect on the electrical response of partially saturated limestone grains. Resistivity decreases slightly with increasing grain size when water saturation is greater than 0.4, while it shows an inconsistent trend when water saturation is lower than 0.4. The resulting saturation exponent n decreases slightly when grain size increases from 0.5–1 mm to 1–3 mm, while it shows a positive change in n values for grain size of 3–5 mm. Changes in solution salinity significantly influence the resistivity and saturation exponent of limestone grains, with higher solution salinity resulting in lower resistivity and higher saturation exponent. However, with solution pH increasing from 4.58 to 9.25, it shows very limited effect on the resistivity and saturation exponent of limestone grains. This can be attributed to the strong buffering ability of limestone. Effects of grain size, solution salinity and pH on the resistivity and saturation exponent of oil‐bearing carbonate sands were investigated. Resistivity is found to show a decreasing trend with increasing grain size from 0.5–1 mm to 3–5 mm above a certain saturation (e.g. Sw > 0.4), while it shows a rapid increase below a certain saturation (e.g., Sw≤$ \le $0.4) for a larger grain size of 3–5 mm. Resistivity decreases and the saturation exponent increases with the increase of solution salinity for oil‐bearing carbonate sands. Resistivity and saturation exponent do not vary significantly with solution pH ranging from 4.58 to 9.25 for oil‐bearing carbonate sands.

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“…It remains challenging to mechanistically relate the SIP signal to biological and physiological processes or simply to the biomass itself. For many applications, the underlying mechanisms of the observed polarization are still the subject of active research and debate (see e.g., Leroy et al, 2017;Eho-sioke et al, 2020), while field applications remain limited (Flores Orozco et al, 2021).…”

Section: Transport Mixing and Reactionmentioning

confidence: 99%

Advancing measurements and representations of subsurface heterogeneity and dynamic processes: towards 4D hydrogeology

Hermans

Goderniaux

Jougnot

et al. 2023

Hydrol. Earth Syst. Sci.

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Abstract. Essentially all hydrogeological processes are strongly influenced by the subsurface spatial heterogeneity and the temporal variation of environmental conditions, hydraulic properties, and solute concentrations. This spatial and temporal variability generally leads to effective behaviors and emerging phenomena that cannot be predicted from conventional approaches based on homogeneous assumptions and models. However, it is not always clear when, why, how, and at what scale the 4D (3D + time) nature of the subsurface needs to be considered in hydrogeological monitoring, modeling, and applications. In this paper, we discuss the interest and potential for the monitoring and characterization of spatial and temporal variability, including 4D imaging, in a series of hydrogeological processes: (1) groundwater fluxes, (2) solute transport and reaction, (3) vadose zone dynamics, and (4) surface–subsurface water interactions. We first identify the main challenges related to the coupling of spatial and temporal fluctuations for these processes. We then highlight recent innovations that have led to significant breakthroughs in high-resolution space–time imaging and modeling the characterization, monitoring, and modeling of these spatial and temporal fluctuations. We finally propose a classification of processes and applications at different scales according to their need and potential for high-resolution space–time imaging. We thus advocate a more systematic characterization of the dynamic and 3D nature of the subsurface for a series of critical processes and emerging applications. This calls for the validation of 4D imaging techniques at highly instrumented observatories and the harmonization of open databases to share hydrogeological data sets in their 4D components.

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Delineation of hydrocarbon contaminants with multi-frequency complex conductivity imaging

Cited by 26 publications

References 56 publications

A field-scale remediation of residual light non-aqueous phase liquid (LNAPL): chemical enhancers for pump and treat

A field-scale remediation of residual light non-aqueous phase liquid (LNAPL): chemical enhancers for pump and treat

Effects of grain size, solution salinity and pH on the electrical response of oil‐bearing carbonate sands

Advancing measurements and representations of subsurface heterogeneity and dynamic processes: towards 4D hydrogeology

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