Simulated reactive zone with emulsified vegetable oil for the long-term remediation of Cr(VI)-contaminated aquifer: dynamic evolution of geological parameters and groundwater microbial community

Dong, Jun; Yu, Jun; Bao, Qiburi

doi:10.1007/s11356-018-3386-z

Cited by 13 publications

(7 citation statements)

References 44 publications

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“…In contrast, in the amendments where EVO was added, the results indicate that although, during the first 30 days of the experiment, the differences between the k ANAER-M and k ANAER-E are negligible, during the next time period (30-40 days), the k ANAER-E removal rate increases by 78% and then decreases rapidly. This finding is in agreement with the expected effect of EVO on the microbes as a slowly depleted electron donor [74]. It is worth noting that all amendments were able to reduce Cr(VI) to levels below 50 µg/L.…”

Section: Evaluation Of Cr(vi) Reduction Under Complete Anaerobic Cond...supporting

confidence: 91%

Reductive Cr(VI) Removal under Different Reducing and Electron Donor Conditions—A Soil Microcosm Study

Galani

Noutsopoulos

Anastopoulou

et al. 2022

Water

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Increased groundwater and soil contamination by hexavalent chromium have led to the employment of a variety of detoxification methods. Biological remediation of Cr(VI) polluted aquifers is an eco-friendly method that can be performed in situ by stimulating the indigenous microbial population with organic and inorganic electron donors. In order to study the effect of different redox conditions on microbial remediated Cr(VI) reduction to Cr(III), microcosm experiments were conducted under anaerobic, anoxic, and sulfate-reducing conditions and at hexavalent chromium groundwater concentrations in the 0–3000 μg/L range, with groundwater and soil collected from an industrial area (Inofyta region). As electron donors, molasses, emulsified vegetable oil (EVO), and FeSO4 were employed. To quantitatively describe the degradation kinetics of Cr(VI), pseudo-first-order kinetics were adopted. The results indicate that an anaerobic system dosed with simple or complex external organic carbon sources can lead to practically complete Cr(VI) reduction to Cr(III), while the addition of Fe2+ can further increase Cr(VI) removal rate significantly. Furthermore, Cr(VI) microbial reduction is possible in the presence of NO3− at rates comparable to anaerobic Cr(VI) microbial reduction, while high sulfate concentrations have a negative effect on Cr(VI) bioreduction rates in comparison to lower sulfate concentrations.

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Section: Evaluation Of Cr(vi) Reduction Under Complete Anaerobic Cond...supporting

confidence: 91%

Reductive Cr(VI) Removal under Different Reducing and Electron Donor Conditions—A Soil Microcosm Study

Galani

Noutsopoulos

Anastopoulou

et al. 2022

Water

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“…Comparing these results with the results from the Control experiment, biostimulation was achieved and removal rates increased up to 20 times. Addition of single organic electron donors such as molasses or EVO has been evaluated in several laboratory scale studies [40,44,45,[49][50][51]73]. Results from previous studies are in agreement with the findings of this work and indicate that both carbon sources are able to support complete Cr(VI) reduction even at high initial Cr(VI) concentrations, that far exceed pollution levels in the environment.…”

Section: Influence Of Organic Electron Donors In Cr(vi) Bio-reductionsupporting

confidence: 80%

“…In contrast, EVO are slowly soluble substrates, that ferment to acetate and hydrogen [47], thus providing longevity to the remediation process. However, their colloidal nature affects their mobility in porous materials [48,49] and thus their effective distribution. Moreover, laboratory studies have shown that the presence of EVO decreases microbial richness and diversity [50].…”

Section: Introductionmentioning

confidence: 99%

Biotic and Abiotic Biostimulation for the Reduction of Hexavalent Chromium in Contaminated Aquifers

Galani

Mamais

Noutsopoulos

et al. 2022

Water

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Hexavalent chromium is a carcinogenic heavy metal that needs to be removed effectively from polluted aquifers in order to protect public health and the environment. This work aims to evaluate the reduction of Cr(VI) to Cr(III) in a contaminated aquifer through the stimulation of indigenous microbial communities with the addition of reductive agents. Soil-column experiments were conducted in the absence of oxygen and at hexavalent chromium (Cr(VI)) groundwater concentrations in the 1000–2000 μg/L range. Two carbon sources (molasses and EVO) and one iron electron donor (FeSO4·7H2O) were used as ways to stimulate the metabolism and proliferation of Cr(VI) reducing bacteria in-situ. The obtained results indicate that microbial anaerobic respiration and electron transfer can be fundamental to alleviate polluted groundwater from hazardous Cr(VI). The addition of organic electron donors increased significantly Cr(VI) reduction rates in comparison to natural soil attenuation rates. Furthermore, a combination of organic carbon and iron electron donors led to a longer life span of the remediation process and thus increased total Cr(VI) removal. This is the first study to investigate biotic and abiotic Cr(VI) removal by conducting experiments with natural soil and by applying biostimulation to modify the natural existing microbial communities.

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“…A large laboratory-scale experiment of a 512-day period identified that injection of EVO in Cr(VI)-contaminated aquifer created an acidic and reducing environment, which facilitated Cr(VI) bioreduction by bacteria. Amendment of EVO also greatly influenced microbial community structure and diversity toward the abundance of EVO biodegradation capabilities, which aided supply of reducing equivalents for Cr(VI) reduction (Dong et al, 2018). Additionally, the utilization of bioelectrochemical systems in the form of microbial electrolysis cell (MEC) and MFC is also an innovative route to sustainable bioremediation of Cr(VI)polluted groundwater He et al, 2021).…”

Section: Role Of Various Chemical Additives In Ex Situ and In Situ Applicationsmentioning

confidence: 99%

Chemical-Assisted Microbially Mediated Chromium (Cr) (VI) Reduction Under the Influence of Various Electron Donors, Redox Mediators, and Other Additives: An Outlook on Enhanced Cr(VI) Removal

Rahman

Thomas

2021

Front. Microbiol.

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Chromium (Cr) (VI) is a well-known toxin to all types of biological organisms. Over the past few decades, many investigators have employed numerous bioprocesses to neutralize the toxic effects of Cr(VI). One of the main process for its treatment is bioreduction into Cr(III). Key to this process is the ability of microbial enzymes, which facilitate the transfer of electrons into the high valence state of the metal that acts as an electron acceptor. Many underlying previous efforts have stressed on the use of different external organic and inorganic substances as electron donors to promote Cr(VI) reduction process by different microorganisms. The use of various redox mediators enabled electron transport facility for extracellular Cr(VI) reduction and accelerated the reaction. Also, many chemicals have employed diverse roles to improve the Cr(VI) reduction process in different microorganisms. The application of aforementioned materials at the contaminated systems has offered a variety of influence on Cr(VI) bioremediation by altering microbial community structures and functions and redox environment. The collective insights suggest that the knowledge of appropriate implementation of suitable nutrients can strongly inspire the Cr(VI) reduction rate and efficiency. However, a comprehensive information on such substances and their roles and biochemical pathways in different microorganisms remains elusive. In this regard, our review sheds light on the contributions of various chemicals as electron donors, redox mediators, cofactors, etc., on microbial Cr(VI) reduction for enhanced treatment practices.

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Simulated reactive zone with emulsified vegetable oil for the long-term remediation of Cr(VI)-contaminated aquifer: dynamic evolution of geological parameters and groundwater microbial community

Cited by 13 publications

References 44 publications

Reductive Cr(VI) Removal under Different Reducing and Electron Donor Conditions—A Soil Microcosm Study

Reductive Cr(VI) Removal under Different Reducing and Electron Donor Conditions—A Soil Microcosm Study

Biotic and Abiotic Biostimulation for the Reduction of Hexavalent Chromium in Contaminated Aquifers

Chemical-Assisted Microbially Mediated Chromium (Cr) (VI) Reduction Under the Influence of Various Electron Donors, Redox Mediators, and Other Additives: An Outlook on Enhanced Cr(VI) Removal

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