Evaluation of LNAPL Behavior in Water Table Inter-Fluctuate Zone under Groundwater Drawdown Condition

Azimi, Reza; Vaezihir, Abdorreza; Lenhard, R. J.; Hassanizadeh, S. Majid

doi:10.3390/w12092337

Cited by 16 publications

(7 citation statements)

References 28 publications

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“…Groundwater contamination by petroleum products is a pervasive issue encountered worldwide, with particular prevalence in urban areas [16]. South Africa, including the city of Cape Town, is no exception to this environmental challenge [17].…”

Section: Introductionmentioning

confidence: 99%

Protecting Cape Town’s Groundwater from Fuel Stations: An In-Depth Analysis of Regulatory Requirements

Nsimba,

Malaza,

Marazula

2023

Sustainability

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In the face of mounting water supply challenges, Cape Town has increasingly turned to alternative sources, like groundwater. However, the utilisation of groundwater carries inherent risks, particularly the contamination stemming from land-based activities, such as fuel stations. Leaks from underground tanks at these stations represent a major global cause of groundwater pollution, and Cape Town is no exception. To safeguard public health and mitigate potential harm, it is imperative to examine the legal regulations governing fuel station development, assess measures for controlling their environmental impacts and evaluate strategies for managing the associated risks. This study aims to provide an exhaustive review of the regulatory framework concerning the environmental impacts of fuel stations, focusing on groundwater protection in Cape Town. A combination of desk research and interviews was employed to gather and analyse data. The findings show a deficiency in precautionary measures for safeguarding groundwater near fuel stations. Consequently, through this study, the existing legal framework’s effectiveness is called into question, with this study suggesting actions to address these identified shortcomings.

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Section: Introductionmentioning

confidence: 99%

Protecting Cape Town’s Groundwater from Fuel Stations: An In-Depth Analysis of Regulatory Requirements

Nsimba,

Malaza,

Marazula

2023

Sustainability

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“…Xin investigated the effect of two types of water level fluctuations (constant water level and water level fluctuation of 20 cm every 10 days) on the nitrate-nitrogen concentration in groundwater. Azimi et al (2020) studied the variation in LNAPL thickness during rises and falls in the water level. Farnsworth et al (2012) studied the effect of transient dissolved oxygen (DO) on manganese oxidation during water level fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Soil column experiment and numerical simulation research of Pb migration process in the groundwater fluctuation zone based on HYDRUS

Jiang²,

Zhang³

et al. 2022

Front. Environ. Sci.

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Groundwater level fluctuation alters hydrodynamic conditions and hydrogeochemical action, thus affecting the migration and transformation of pollutants. This study investigated the effect of groundwater level fluctuations on Pb migration processes. We selected two typical media, coarse sand and medium sand, for the soil column experiments and numerical simulations of the Pb migration process in the groundwater level fluctuation zone. The soil column experiments showed that when the contaminants were distributed at a 30–40 cm depth in the soil column, the Pb migrated into the water in the range of 20–45 cm in coarse sand, while the range of Pb migration in medium sand decreased to 30 cm–40 cm. We constructed a numerical model of Pb migration in the aeration zone–saturation zone coupled with water transport and solute transport by HYDRUS-1D. The model simulated the migration process of Pb in different amplitude and frequency of water level fluctuation and initial concentration of pollutants. The results showed that the coarse sand column and medium sand column showed relatively noticeable changes in Pb concentration in water at 30–40 cm and 30–35 cm, respectively. The migration range and concentration of Pb in water are proportional to the medium particle size and the frequency of water level fluctuation, and inversely proportional to the magnitude of water level fluctuation. The Pb concentration in the water increased or decreased as the initial pollutant concentration of the medium increased or decreased. Its variation is basically the same as the variation of the initial contaminant concentration. The research results can provide a scientific basis for the remediation of heavy metal pollution in groundwater.

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“…Petroleum and its derivatives are the most common LNAPL and its underground contamination represents a recurring problem in industrialized spots and in oil producing factories. In fact, it can affect the environmental matrixes in the form of either vapor phase in soil pore spaces, or liquid residual LNAPL, or free-phase LNAPL in the water-unsaturated zone, or, finally, as entrapped LNAPL globules above and below the water table (ASTM E2531-06 2014; Azimi et al 2020). When the LNAPL contamination state of an area reaches relevant levels, it is common to find a thickness of free-phase supernatant product between groundwater and air.…”

Section: Introductionmentioning

confidence: 99%

Evolution of LNAPL contamination plume in fractured aquifers

Mineo

Dell’Aera²,

Rizzotto³

2022

Bull Eng Geol Environ

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The LNAPL contamination affecting an industrial area of southeastern Sicily (Italy) is reported herein as a case study to analyze some peculiarities on its spatial evolution. The free-phase product of light hydrocarbons, leaked from a tank, deserved investigations due to its anomalous migration trend, which was not consistent with the static groundwater flow direction of the area. The collection of geological and hydrogeological data and their organization into a GIS database allowed reconstructing the evolutionary stage of the plume within the 2014–2020 time interval, providing some explanation to the scientific problem. The supernatant thickness was compared with the groundwater oscillation, leading to consideration on the aquifer typology. The causes of the peculiar migration trend were found in three main factors, among which the geological and geostructural ones gain a key relevance. Achieved results show that the rock mass fracturing and the presence of underground structures, probably of tectonic origin, are responsible in driving the contamination plume through a preferential path under the dynamic condition induced by anthropic activities. This supports the need of underground geological and geostructural knowledge when dealing with similar issues and when designing specific remediation measures; the case study presented herein demonstrates that the correct location of remedial measures is crucial for reclamation purposes. Furthermore, data were statistically analyzed looking for a relation between real and apparent supernatant thickness. Prediction equations, for a quick estimation of the contamination entity in such type of aquifers, are presented providing hints for future studies on other settings worldwide.

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Evaluation of LNAPL Behavior in Water Table Inter-Fluctuate Zone under Groundwater Drawdown Condition

Cited by 16 publications

References 28 publications

Protecting Cape Town’s Groundwater from Fuel Stations: An In-Depth Analysis of Regulatory Requirements

Protecting Cape Town’s Groundwater from Fuel Stations: An In-Depth Analysis of Regulatory Requirements

Soil column experiment and numerical simulation research of Pb migration process in the groundwater fluctuation zone based on HYDRUS

Evolution of LNAPL contamination plume in fractured aquifers

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