Effects of dissolved organic phase composition and salinity on the engineered sulfate application in a flow-through system

Shafieiyoun, Saeid; Al-Raoush, Riyadh I.; Ismail, Reem Elfatih; Ngueleu, Stéphane K.; Rezanezhad, Fereidoun; Cappellen, Philippe Van

doi:10.1007/s11356-020-07696-6

Cited by 3 publications

(1 citation statement)

References 51 publications

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“…However, to the best of our knowledge, there is no study that explores the effects of salinity on the engineered sulfate injection as a remediation method in the organic contaminated subsurface systems. Shafieiyoun et al (2020) in a series of flow-through experiments showed that the overall effects of salinity on organic compounds degradation under sulfatereducing conditions are affected by substrate interactions and NAPL composition. The goal of this study was to delineate the net influence of salinity on the remediation of a hydrocarbon plume by a sequential sulfate injection scenario in a (semi)-arid brackish coastal soil environment, and hence, a single organic contaminant was chosen for the purpose of this evaluation.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Naphthalene Degradation by a Sequential Sulfate Injection Scenario in a (Semi)-Arid Coastal Soil: a Flow-Through Reactor Experiment

Shafieiyoun

Al-Raoush

Ngueleu

et al. 2020

Water Air Soil Pollut

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Engineered sulfate injection has been introduced as an effective technology to enhance the remediation of soil and groundwater contaminated by petroleum hydrocarbons. While some studies indicate that sulfate injection is a promising method for the treatment of hydrocarbon-contaminated subsurface systems, its application in the brackish soil environments is unknown. In this study, we explored related geochemical indicators along with soil adsorption and dissolved phase concentrations to provide an improved understanding of the hydrocarbon-contaminated subsurface responses to the sulfate injection in brackish environments. A series of flow-through experiments representing in situ groundwater anaerobic bioremediation were conducted and two sulfate injection episodes were applied to examine the degradation of dissolved naphthalene under low salinity and brackish conditions. As opposed to the substantial body of previous studies that salinity restricts biodegradation, the results from this study showed that naphthalene anaerobic degradation was more stable once the salinity was as high as that at the sampling location in the coastal brackish environment. While increasing naphthalene concentration from 4 to 12 mg L −1 did not limit biodegradation efficiency under brackish condition similar to the sampling location, it adversely restricted the developed reducing conditions and biodegradation process under low salinity conditions. This highlights the adaption of the microbial communities within the soil to the brackish environment at the sampling location suggesting that changing the salinity during engineered sulfate application can make the remediation process more susceptible against the environmental stresses and substrate toxicity. The results of this study provide insight into the engineered sulfate application as a remediation strategy for potential removal of dissolved naphthalene from the contaminated brackish groundwater.

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Section: Introductionmentioning

confidence: 99%

Enhancement of Naphthalene Degradation by a Sequential Sulfate Injection Scenario in a (Semi)-Arid Coastal Soil: a Flow-Through Reactor Experiment

Shafieiyoun

Al-Raoush

Ngueleu

et al. 2020

Water Air Soil Pollut

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The impact of water table fluctuation and salinity on LNAPL distribution and geochemical properties in the smear zone under completely anaerobic conditions

2023

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Climate and groundwater are always in a state of dynamic equilibrium. Subsurface systems contaminated by light non-aqueous phase liquid (LNAPL) present a challenge to understand the overall impact of water table dynamics, due to various interacting mechanisms, including volatilization, and LNAPL mobilization/dissolution along the groundwater flow direction and oscillating redox conditions. We investigated the impact of water table fluctuations on LNAPL natural attenuation and soil geochemical characteristics in semi-arid coastal areas under saline conditions. Four soil columns operated for 151 days under anoxic conditions where a layer of benzene and toluene were subjected to a stable and fluctuating water table associated with low and high salinity conditions. The bottom of stable and fluctuating columns reached an anaerobic state after 40 days, while the middle of stable column took 60 days. pH values of the fluctuating columns covered a wide range, and at the end shifted towards alkaline conditions, unlike the stable columns. In fluctuating columns, pore water sulfate decreased in the middle, but in stable columns, it decreased in the first 40 days, which suggested that sulfate was the primary electron donor and sulfate-reducing bacteria were present. At the source zone, benzene and toluene reached their maximum concentration after 30 and 10 days for the stable and the fluctuating columns, respectively. Significant decrease in benzene and toluene concentrations occurred under the fluctuating water table. Salinity did not affect benzene and toluene concentrations in the aqueous phase, although water table fluctuations have the most effect. Soil solid-phase analysis shows fluctuating columns have less toluene than stable columns. Solid-phase analysis showed the fluctuating columns have less benzene and toluene concentrations as compared to the stable columns.

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Anaerobic-petroleum degrading bacteria: Diversity and biotechnological applications for improving coastal soil

Wang

Kuang

Shao

et al. 2021

Ecotoxicology and Environmental Safety

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Effects of dissolved organic phase composition and salinity on the engineered sulfate application in a flow-through system

Cited by 3 publications

References 51 publications

Enhancement of Naphthalene Degradation by a Sequential Sulfate Injection Scenario in a (Semi)-Arid Coastal Soil: a Flow-Through Reactor Experiment

Enhancement of Naphthalene Degradation by a Sequential Sulfate Injection Scenario in a (Semi)-Arid Coastal Soil: a Flow-Through Reactor Experiment

The impact of water table fluctuation and salinity on LNAPL distribution and geochemical properties in the smear zone under completely anaerobic conditions

Anaerobic-petroleum degrading bacteria: Diversity and biotechnological applications for improving coastal soil

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