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Zhang J, Wang S, Wang X, Jiao W, Zhang M, Ma F. A review of functions and mechanisms of clay soil conditioners and catalysts in thermal remediation compared to emerging photo-thermal catalysis. J Environ Sci (China) 2025; 147:22-35. [PMID: 39003042 DOI: 10.1016/j.jes.2023.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 07/15/2024]
Abstract
High temperatures and providing sufficient time for the thermal desorption of persistent organic pollutants (POPs) from contaminated clay soils can lead to intensive energy consumption. Therefore, this article provides a critical review of the potential additives which can improve soil texture and increase the volatility of POPs, and then discusses their enhanced mechanisms for contributing to a green economy. Ca-based additives have been used to reduce plasticity of bentonite clay, absorb water and replenish system heat. In contrast, non-Ca-based additives have been used to decrease the plasticity of kaolin clay. The soil structure and soil plasticity can be changed through cation exchange and flocculation processes. The transition metal oxides and alkali metal oxides can be applied to catalyze and oxidize polycyclic aromatic hydrocarbons, petroleum and emerging contaminants. In this system, reactive oxygen species (•O2- and •OH) are generated from thermal excitation without strong chemical oxidants. Moreover, multiple active ingredients in recycled solid wastes can be controlled to reduce soil plasticity and enhance thermal catalysis. Alternatively, the alkali, nano zero-valent iron and nano-TiN can catalyze hydrodechlorination of POPs under reductive conditions. Especially, photo and photo-thermal catalysis are discussed to accelerate replacement of fossil fuels by renewable energy in thermal remediation.
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Affiliation(s)
- Juan Zhang
- State Key Laboratory of Advanced Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Shuo Wang
- State Key Laboratory of Advanced Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xin Wang
- State Key Laboratory of Advanced Metallurgy, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wentao Jiao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Minghua Zhang
- College of Agricultural and Environmental Sciences, University of California, Davis, CA 95616, USA
| | - Fujun Ma
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
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2
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Ashkanani Z, Mohtar R, Al-Enezi S, Smith PK, Calabrese S, Ma X, Abdullah M. AI-assisted systematic review on remediation of contaminated soils with PAHs and heavy metals. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133813. [PMID: 38402679 DOI: 10.1016/j.jhazmat.2024.133813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/05/2024] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
This systematic review addresses soil contamination by crude oil, a pressing global environmental issue, by exploring effective treatment strategies for sites co-contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs). Our study aims to answer pivotal research questions: (1) What are the interaction mechanisms between heavy metals and PAHs in contaminated soils, and how do these affect the efficacy of different remediation methods? (2) What are the challenges and limitations of combined remediation techniques for co-contaminated soils compared to single-treatment methods in terms of efficiency, stability, and specificity? (3) How do various factors influence the effectiveness of biological, chemical, and physical remediation methods, both individually and combined, in co-contaminated soils, and what role do specific agents play in the degradation, immobilization, or removal of heavy metals and PAHs under diverse environmental conditions? (4) Do AI-powered search tools offer a superior alternative to conventional search methodologies for executing an exhaustive systematic review? Utilizing big-data analytics and AI tools such as Litmaps.co, ResearchRabbit, and MAXQDA, this study conducts a thorough analysis of remediation techniques for soils co-contaminated with heavy metals and PAHs. It emphasizes the significance of cation-π interactions and soil composition in dictating the solubility and behavior of these pollutants. The study pays particular attention to the interplay between heavy metals and PAH solubility, as well as the impact of soil properties like clay type and organic matter on heavy metal adsorption, which results in nonlinear sorption patterns. The research identifies a growing trend towards employing combined remediation techniques, especially biological strategies like biostimulation-bioaugmentation, noting their effectiveness in laboratory settings, albeit with potentially higher costs in field applications. Plants such as Medicago sativa L. and Solanum nigrum L. are highlighted for their effectiveness in phytoremediation, working synergistically with beneficial microbes to decompose contaminants. Furthermore, the study illustrates that the incorporation of biochar and surfactants, along with chelating agents like EDTA, can significantly enhance treatment efficiency. However, the research acknowledges that varying environmental conditions necessitate site-specific adaptations in remediation strategies. Life Cycle Assessment (LCA) findings indicate that while high-energy methods like Steam Enhanced Extraction and Thermal Resistivity - ERH are effective, they also entail substantial environmental and financial costs. Conversely, Natural Attenuation, despite being a low-impact and cost-effective option, may require prolonged monitoring. The study advocates for an integrative approach to soil remediation, one that harmoniously balances environmental sustainability, cost-effectiveness, and the specific requirements of contaminated sites. It underscores the necessity of a holistic strategy that combines various remediation methods, tailored to meet both regulatory compliance and the long-term sustainability of decontamination efforts.
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Affiliation(s)
- Zainab Ashkanani
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA.
| | - Rabi Mohtar
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Salah Al-Enezi
- Petroleum Research Center, Kuwait Institute for Scientific Research, Al-Ahmadi, Kuwait
| | - Patricia K Smith
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Salvatore Calabrese
- Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Xingmao Ma
- Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77840, USA
| | - Meshal Abdullah
- Sultan Qaboos University, College of Arts & Social Sciences. Al-Khoud, Sultanate of Oman
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3
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Duan G, Wei G, Li Q, Zhu Y, Zhang L, Liang L, Huang Z, He S, Li B. Insight into catalytic activation of bisulfite for lomefloxacin degradation by simple composite of calcinated red mud. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:29125-29142. [PMID: 36409411 DOI: 10.1007/s11356-022-23706-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Antibiotic was detected in many environments, and it had posed a serious threat to human health. The advanced oxidation process has been considered an effective way to treat antibiotics. In this work, using industrial waste red mud (RM) as raw material, a series of modified RM (MRM-T; T donates the calcination temperature) was obtained via a facile calcination method and applied to activate sodium bisulfite (NaHSO3) for the lomefloxacin (LOM) degradation. Among all MRM-T, MRM-700 exhibited superior catalytic activity, and approximately 89% of LOM (10 mg/L) was degraded at 30 min through the activation of NaHSO3 ([NaHSO3] = 0.5 g/L) by MRM-700 ([MRM-700] = 0.9 g/L). Moreover, the kinetic constant of LOM removal in the MRM-700/NaHSO3 system (0.082 min-1) was 16.4 times higher than that of the RM-raw/NaHSO3 system (0.005 min-1). The as-synthesized product of MRM-700 was characterized by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectra. The result indicated that the catalyst possessed excellent pore structure, high specific area, and abundant Fe3+ sites, and the lattice of Fe2O3 was doped after calcination, both of which were favorable for the activation of NaHSO3. The quenching experiment proved that •SO4- and •OH- active species were produced in MRM-700/NaHSO3 system, and •SO4- played a dominant role in LOM removal. In addition, the potential LOM degradation pathway was analyzed via UPLC-MS technology and density functional theory (DFT) calculation, and the toxicity of the treated LOM solution was tested by the culture of mung bean sprouts. This study not only provided a feasible strategy for the valuable use of RM to activate NaHSO3 but also offered a cost-effective catalyst for the efficient removal of pollutants in wastewater.
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Affiliation(s)
- Guangxiang Duan
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Guangtao Wei
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China.
- Guangxi Key Laboratory of Processing for Non-Ferrous Metallic and Featured Materials, Guangxi Zhuang Autonomous Region, Nanning, 530004, People's Republic of China.
| | - Qingyong Li
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Youlian Zhu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Linye Zhang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
- Guangxi Key Laboratory of Bio-Refinery, Guangxi Zhuang Autonomous Region, Nanning, 530007, People's Republic of China
| | - Lulu Liang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Zhenjing Huang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Shuo He
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
| | - Baiying Li
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning, 530004, People's Republic of China
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4
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Wacławek S, Lutze HV, Sharma VK, Xiao R, Dionysiou DD. Revisit the alkaline activation of peroxydisulfate and peroxymonosulfate. Curr Opin Chem Eng 2022. [DOI: 10.1016/j.coche.2022.100854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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5
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Analysis of the Remediation of Coal Tar-Contaminated Groundwater Using Ex Situ Remediation. WATER 2022. [DOI: 10.3390/w14142182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The article describes the remediation of contaminated groundwater during the ex situ remediation of coal tar contamination following the closure of a coking plant in the Moravian–Silesian Region (Czech Republic). The aim of the article is to point out the advantages of ex situ soil remediation via the excavation of the contaminated geological environment combined with thermal desorption, a method of removing contaminants both from soil and groundwater. Its advantage is the absolute qualitative and quantitative control over the contaminated soil with the possibility of precise segmentation into contaminated and non-contaminated soils. Next, all contaminated groundwater may be pumped off upon the construction of sealing walls to control groundwater flows. To excavate the soil, it is necessary to reduce the contaminated groundwater level inside the sealing walls and thus create conditions for the extraction of contaminated soils using standard machinery. In detail, the article describes the removal of the contaminated groundwater and compares the quality of the pumped and inflowing water before and after the remediation. The locality is characteristic of a high horizontal and vertical grain-size heterogeneity of gravel-sand, which led to a varying filtration coefficient affecting the capacities of pumped groundwater quantity during the remediation. At the start of the remediation process, the contaminant levels exceeded the limits by the Czech Environmental Inspectorate several times. The post-remediation monitoring showed that all the contaminant levels were below the limit. Surprisingly, the overall groundwater contamination amounted to 232.86 t of contaminants as non-aqueous phase liquids, and 6872.9 kg of dissolved contaminants. As much as 12,200 t of contaminants were removed from the soil.
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6
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Wang Q, Guo S, Ali M, Song X, Tang Z, Zhang Z, Zhang M, Luo Y. Thermally enhanced bioremediation: A review of the fundamentals and applications in soil and groundwater remediation. JOURNAL OF HAZARDOUS MATERIALS 2022; 433:128749. [PMID: 35364527 DOI: 10.1016/j.jhazmat.2022.128749] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/11/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Thermally enhanced bioremediation (TEB), a new concept proposed in recent years, explores the combination of thermal treatment and bioremediation to address the challenges of the low efficiency and long duration of bioremediation. This study presented a comprehensive review regarding the fundamentals of TEB and its applications in soil and groundwater remediation. The temperature effects on the bioremediation of contaminants were systematically reviewed. The thermal effects on the physical, chemical and biological characteristics of soil, and the corresponding changes of contaminants bioavailability and microbial metabolic activities were summarized. Specifically, the increase in temperature within a suitable range can proliferate enzymes enrichment, extracellular polysaccharides and biosurfactants production, and further enhancing bioremediation. Furthermore, a systematic evaluation of TEB applications by utilizing traditional in situ heating technologies, as well as renewable energy (e.g., stored aquifer thermal energy and solar energy), was provided. Additionally, TEB has been applied as a biological polishing technology post thermal treatment, which can be a cost-effective method to address the contaminants rebounds in groundwater remediation. However, there are still various challenges to be addressed in TEB, and future research perspectives to further improve the basic understanding and applications of TEB for the remediation of contaminated soil and groundwater are presented.
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Affiliation(s)
- Qing Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Siwei Guo
- Zhejiang University, Hangzhou, China
| | - Mukhtiar Ali
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Song
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Zhiwen Tang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuanxia Zhang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meng Zhang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yongming Luo
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Makri C, Aspray TJ. Use of an automated respirometer for in situ chemical oxidation (ISCO) activator type and concentration selection. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:3141-3146. [PMID: 34792776 DOI: 10.1007/s11356-021-17394-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
In situ chemical oxidation (ISCO) is a popular remediation technique for hydrocarbon-contaminated soil and groundwater. A range of oxidising agents and activators are available for ISCO; however, selection is usually based on contaminant destruction which is time-consuming and impacted by sample heterogeneity based on 1-10 g sample contaminant analysis. In this paper, we demonstrate the use of an automated respirometer, measuring CO2 production, as a rapid and reliable approach for activator type and concentration selection. The approach is demonstrated based on tests in matrices of different types (loam soil and sand). In both matrices, CO2 production was significantly increased following sodium persulphate (SPS) oxidation with iron activation in a concentration-dependant manner. Alkaline activation led to no increased CO2 production compared to SPS addition without activation. The approach will provide greater confidence in treatability testing and reagent efficiency in ISCO projects.
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Affiliation(s)
- Christina Makri
- Environmental Reclamation Services Ltd, Westerhill Road, Bishopbriggs, Glasgow, G64 2QH, Scotland, UK
| | - Thomas J Aspray
- Environmental Reclamation Services Ltd, Westerhill Road, Bishopbriggs, Glasgow, G64 2QH, Scotland, UK.
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8
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Bioremediation of Toxic Pesticides in Soil Using Microbial Products. Fungal Biol 2021. [DOI: 10.1007/978-3-030-54422-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Guo Y, Wen Z, Zhang C, Jakada H. Contamination and natural attenuation characteristics of petroleum hydrocarbons in a fractured karst aquifer, North China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:22780-22794. [PMID: 32323239 DOI: 10.1007/s11356-020-08723-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
A rare super-large fractured karst aquifer located in Zibo city, Shandong Province of Northern China was polluted by petroleum hydrocarbons from a petrochemical company. Over the last 30 years, it has been the focus of several remediation efforts. In this study, the contamination and natural attenuation characteristics of the petroleum hydrocarbons were elucidated using hydrogeochemical indicators (DO, DOC, Cl-, HCO3-, pH, NO3-, and SO42-), petroleum hydrocarbons elements and environmental isotopes (δ15NNO3, δ18ONO3, δ13CDIC, and δ13CDOC). With the aid of GIS, statistical analyses, as well as first-order decay model and electron-acceptor-limited kinetic model, the spatio-temporal evolution characteristics of the petroleum hydrocarbons were modeled. Results showed a positive natural attenuation trend over the last 3 decades where intrinsic biodegradation mechanism was found to be the most important factor driving the degradation of hydrocarbons in the aquifer system. The hydrogeochemical association between the indicators and petroleum hydrocarbons provided the evidences of biodegradation and also served as markers, highlighting the occurrence of anaerobic respiration without methanogenic activities within the heterogenous karst media. Furthermore, the mean natural attenuation rate of petroleum hydrocarbons was calculated to be 3.76 × 10-3/day whereby the current highest petroleum hydrocarbons concentration (361.13 μg/L) is estimated to be degraded completely in 6 years under the present hydrogeological and environmental conditions.
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Affiliation(s)
- Yongli Guo
- School of Environmental Studies, China University of Geosciences, NO. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, 430074, People's Republic of China
- Institute of Karst Geology, Chinese Academy of Geological Sciences / Key Laboratory of Karst Dynamics, MNR and GZAR, Guilin, 541004, People's Republic of China
| | - Zhang Wen
- School of Environmental Studies, China University of Geosciences, NO. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan, 430074, People's Republic of China.
| | - Cheng Zhang
- Institute of Karst Geology, Chinese Academy of Geological Sciences / Key Laboratory of Karst Dynamics, MNR and GZAR, Guilin, 541004, People's Republic of China
- International Research Center on Karst under the Auspices of UNESCO, Guilin, 541004, People's Republic of China
| | - Hamza Jakada
- Department of Civil Engineering, Baze University Abuja, Abuja, Nigeria
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10
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Shafieiyoun S, Al-Raoush RI, Ismail RE, Ngueleu SK, Rezanezhad F, Van Cappellen P. Effects of dissolved organic phase composition and salinity on the engineered sulfate application in a flow-through system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:11842-11854. [PMID: 31981033 PMCID: PMC7136190 DOI: 10.1007/s11356-020-07696-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 01/09/2020] [Indexed: 06/10/2023]
Abstract
Engineered sulfate application has been proposed as an effective remedy to enhance the rate-limited biodegradation of petroleum-hydrocarbon-contaminated subsurface environments, but the effects of dissolved organic phase composition and salinity on the efficiency of this method are unknown. A series of flow-through experiments were conducted for 150 days and dissolved benzene, toluene, naphthalene, and 1-methylnaphthalene were injected under sulfate-reducing and three different salinity conditions for 80 pore volumes. Then, polycyclic aromatic hydrocarbons (PAHs) were omitted from the influent solution and just dissolved benzene and toluene were injected to investigate the influence of dissolved phase composition on treatment efficiency. A stronger sorption capacity for PAHs was observed and the retardation of the injected organic compounds followed the order of benzene < toluene < naphthalene < 1-methylnaphthalene. Mass balance analyses indicated that 50 and 15% of toluene and 1-methlynaphtalene were degraded, respectively. Around 5% of the injected naphthalene degraded after injecting > 60 PVs influent solution, and benzene slightly degraded following the removal of PAH compounds. The results showed substrate interactions and composition can result in rate-limited and insufficient biodegradation. Similar reducing conditions and organic utilization were observed for different salinity conditions in the presence of the multi-component dissolved organic phase. This was attributed to the dominant microbial community involved in toluene degradation that exerted catabolic repression on the simultaneous utilization of other organic compounds and were not susceptible to changes in salinity.
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Affiliation(s)
- Saeid Shafieiyoun
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar
| | - Riyadh I Al-Raoush
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar.
| | - Reem Elfatih Ismail
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar
| | - Stephane K Ngueleu
- Department of Civil and Architectural Engineering, College of Engineering, Qatar University, PO Box 2713, Doha, Qatar
- Ecohydrology Research Group and Water Institute, Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Fereidoun Rezanezhad
- Ecohydrology Research Group and Water Institute, Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Philippe Van Cappellen
- Ecohydrology Research Group and Water Institute, Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
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Gou Y, Zhao Q, Yang S, Wang H, Qiao P, Song Y, Cheng Y, Li P. Removal of polycyclic aromatic hydrocarbons (PAHs) and the response of indigenous bacteria in highly contaminated aged soil after persulfate oxidation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 190:110092. [PMID: 31874406 DOI: 10.1016/j.ecoenv.2019.110092] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Integrated chemical-biological treatment is a promising alternative to remove PAHs from contaminated soil, wherein indigenous bacteria is the key factor for the biodegradation of residual PAHs after the application of chemical oxidation. However, systematical study on the impact of persulfate (PS) oxidation on indigenous bacteria as well as PAHs removal is still scarce. In this study, the influences of different PS dosages (1%, 3%, 6%, and 10% [w/w]), as well as various activation methods (native iron, H2O2, alkaline, ferrous iron, and heat) on PAHs removal and indigenous bacteria in highly contaminated aged soil were investigated. Apparent degradation of PAHs in the soil treated with PS oxidation was observed, and the removal efficiency of total PAHs in the soil ranged from 38.28% to 79.97%. The removal efficiency of total PAHs in the soil increased with increasing consumption of PS. However, the bacterial abundance in soil was negatively affected following oxidation for all of the treatments added with PS, with bacterial abundance in the soil decreased by 0.89-2.93 orders of magnitude compared to the untreated soil. Moreover, the number of total bacteria in the soil decreased as PS consumption increased. Different PS activation methods and PS dosages exhibited different influences on the bacterial community composition. Bacteria capable of degrading PAHs under anoxic conditions were composed predominantly by Proteobacteria and Firmicutes. The total amount of Proteobacteria and Firmicutes also decreased with increasing consumption of PS. The results of this study provide important insight for the design of PAHs contaminated soil remediation projects.
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Affiliation(s)
- Yaling Gou
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
| | - Qianyun Zhao
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
| | - Sucai Yang
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China.
| | - Hongqi Wang
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China
| | - Pengwei Qiao
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
| | - Yun Song
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
| | - Yanjun Cheng
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
| | - Peizhong Li
- Beijing Key Laboratory of Remediation of Industrial Pollution Sites, Environmental Protection Research Institute of Light Industry, Beijing, 100089, China
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12
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Johansson C, Bataillard P, Biache C, Lorgeoux C, Colombano S, Joubert A, Pigot T, Faure P. Ferrate VI oxidation of polycyclic aromatic compounds (PAHs and polar PACs) on DNAPL-spiked sand: degradation efficiency and oxygenated by-product formation compared to conventional oxidants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:704-716. [PMID: 31808080 DOI: 10.1007/s11356-019-06841-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/21/2019] [Indexed: 06/10/2023]
Abstract
In situ chemical oxidations are known to remediate PAH contaminations in groundwater and soils. In this study, batch-scale oxidations aim to compare the PAC (polycyclic aromatic compound) degradation of three oxidation processes traditionally applied for soil treatment: permanganate, heat-activated persulfate (60 °C) and Fenton-like activated by magnetite, to results obtained with ferrates (FeVI). Widely studied for water treatments, ferrates are efficient on a wide range of pollutants with the advantage of producing nontoxic ferric sludge after reaction. However, fewer works focus on their action on soil, especially on semi-industrial grade ferrates (compatible with field application). Oxidations were carried out on sand spiked with dense non-aqueous phase liquid (DNAPL) sampled in the groundwater of a former coking plant. Conventional 16 US-EPA PAHs and polar PACs were monitored, especially potential oxygenated by-products that can be more harmful than parent-PAHs. After seven reaction days, only the Fenton-like showed limited degradation. Highest efficiencies were obtained for heat-activated persulfate with no O-PAC ketones formed. Permanganate gave important degradation, but ketones were generated in large amount. The tested ferrates not only gave slightly lower yields due to their auto-decomposition but also induced O-PAC ketone production, suggesting a reactional pathway dominated by oxidoreductive electron transfer, rather than a radical one.
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Affiliation(s)
- Clotilde Johansson
- CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine, 54506, Vandœuvre-lès-Nancy, France
- Bureau de Recherches Géologiques et Minières (BRGM), 45060, Orléans, France
- CNRS, CREGU, GeoRessources, Université de Lorraine, 54506, Vandœuvre-lès-Nancy, France
- SERPOL, 2 chemin du Génie, BP 80, 69633, Vénissieux, France
| | | | - Coralie Biache
- CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine, 54506, Vandœuvre-lès-Nancy, France
| | - Catherine Lorgeoux
- CNRS, CREGU, GeoRessources, Université de Lorraine, 54506, Vandœuvre-lès-Nancy, France
| | - Stéfan Colombano
- Bureau de Recherches Géologiques et Minières (BRGM), 45060, Orléans, France
| | | | - Thierry Pigot
- CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM UMR CNRS 5254), Université de Pau & Pays Adour, 64000, Pau, France
| | - Pierre Faure
- CNRS, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine, 54506, Vandœuvre-lès-Nancy, France.
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13
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Luo T, Wan J, Ma Y, Wang Y, Wan Y. Sulfamethoxazole degradation by an Fe(ii)-activated persulfate process: insight into the reactive sites, product identification and degradation pathways. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1560-1569. [PMID: 31364657 DOI: 10.1039/c9em00254e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, the effects of key parameters on the degradation kinetics of sulfamethoxazole (SMX) in an Fe(ii)-activated persulfate (PS) process were elucidated. SMX could be completely degraded within 240 min at an initial pH of 3.3. It was found that 1 : 10 is the optimum molar ratio of Fe(ii) : PS. Typical water quality parameters, including solution pH, SMX concentration, inorganic ions and humic acid, are discussed for the degradation process. Although the SMX degradation kinetics varied for different water quality parameters, relatively high SMX removal could always be achieved. The Fe(ii)-activated persulfate process could maintain excellent SMX degradation under optimum reaction conditions. In addition, the reaction sites and intermediates of SMX were predicted by density functional theory (DFT) calculations and wave function analysis. The results of different calculations consistently indicate that N7 is the site with the highest electrophilic reactivity of SMX. The main intermediates formed were characterized through accurate mass measurement using UHPLC-HRMS/MS. Combined with the theoretical computations, the SMX degradation pathways in the Fe(ii)-activated persulfate process are proposed. This research could provide theoretical guidance for the degradation mechanism of sulfonamides and provide technical support for the design of efficient degradation reactions in the future.
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Affiliation(s)
- Ting Luo
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
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14
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Bartlett CK, Slawson RM, Thomson NR. Response of sulfate-reducing bacteria and supporting microbial community to persulfate exposure in a continuous flow system. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1193-1203. [PMID: 31204424 DOI: 10.1039/c9em00094a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Coupling of chemical oxidation using persulfate with bioremediation has been proposed as a method to increase remedial efficacy at petroleum hydrocarbon contaminated sites. To support this integrated treatment approach, an understanding of persulfate impact on the indigenous microbial community is necessary for system design. As sulfate-reducing bacteria (SRB) are active in most aquifer systems and can utilize the sulfate generated from the degradation of persulfate, this study assessed the impact on SRB and the supporting anaerobic microbial community when exposed to persulfate in a continuous flow system. A series of bioreactors (1000 L) packed with anaerobic aquifer material were operated for an 8 month acclimatization period before being continuously subjected to benzene, toluene, ethylbenzene and xylenes (total BTEX 3 mg L-1). After 2 months, the bioreactors were then exposed to an unactivated persulfate solution (20 g L-1), or an alkaline-activated persulfate solution (20 g L-1, pH 12) then effluent-sampled for 60 days following. A combination of culture and molecular-based techniques were used to monitor SRB presence and structural profiles in the anaerobic SRB-specific and broader microbial community. Post-exposure, the rate of BTEX mass removal remained below pre-exposure values; however, trends suggest that full recovery would be expected. Rebound of SRB-specific and the associated microbial community to pre-exposure levels were observed in all exposed bioreactors. Structural community profiles identified recovery in both microbial species and diversity indices. Findings from this investigation demonstrate robustness of SRB in the presence of a supporting microbial community and, thus, are suitable organisms for target use during bioremediation in an integrated system with persulfate.
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Affiliation(s)
- Christopher K Bartlett
- Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario N2L 3C5, Canada.
| | - Robin M Slawson
- Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario N2L 3C5, Canada.
| | - Neil R Thomson
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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15
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Shafieiyoun S, Thomson NR, Brey AP, Gasinski CM, Pence W, Marley M. Realistic expectations for the treatment of FMGP residuals by chemical oxidants. JOURNAL OF CONTAMINANT HYDROLOGY 2018; 219:1-17. [PMID: 30314848 DOI: 10.1016/j.jconhyd.2018.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 06/29/2018] [Accepted: 08/29/2018] [Indexed: 06/08/2023]
Abstract
Methods to remediate soil and groundwater contamination at former manufactured gas plant (FMGP) sites are scarce. The objective of this study was to investigate the ability of two chemical oxidants (persulfate and permanganate) to degrade FMGP residuals in a dynamic system representative of in situ conditions. A series of physical model trials supported by aqueous and slurry batch experiments using impacted sediments collected from a FMGP site were conducted. To explore treatment expectations a screening model constrained by the experimental data was employed. The results from the aqueous experiments showed that dissolved components (except for benzene) were readily degraded by persulfate or permanganate. In the well-mixed slurry systems, when contact with the oxidant was achieved, 95%, 45% and 30% of the initial mass quantified was degraded by permanganate, unactivated persulfate, and alkaline activated persulfate, respectively. In stark contrast, the total mass removed in the physical model trials was negligible for both permanganate and persulfate irrespective of the bleb or lense architecture used. Hence the net benefit of flushing 6 pore volumes of permanganate or persulfate at a concentration of 30 g/L under the physical model operating conditions was minimal. To achieve a substantial degradation of mass within the treatment system (>40%), results from the screening model indicated that the hydraulic resident time would need to be >10 days and the average lumped mass transfer coefficient increased by two orders-of-magnitude. Results from long-term (5 years) simulations showed that the dissolved concentrations of organic compounds are reduced temporarily as a result of the presence of permanganate but then rebound to a profile that is essentially coincident with a no-treatment scenario following exposure to permanganate. Neither a lower velocity nor higher permanganate dosing affected the long-term behavior of the dissolved phase concentrations; however, increasing the mass transfer rate coefficient had an impact. The findings from this investigation indicate that the efficiency of permanganate or persulfate to treat for FMGP residuals is mass transfer limited.
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Affiliation(s)
- Saeid Shafieiyoun
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
| | - Neil R Thomson
- Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Andrew P Brey
- Geosyntec Consultants, 12802 Tampa Oaks Boulevard, Tampa, FL 33637, USA
| | - Chris M Gasinski
- TECO Peoples Gas, 702 Franklin Street North, Tampa, FL 33602, USA
| | - William Pence
- Baker & Hostetler LLP, 200 South Orange Avenue, Suite 2300, Orlando, FL 32801-3432, USA
| | - Mike Marley
- XDD Environmental LLC, 22 Marin Way, Unit #3, Stratham, NH 03885, USA
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16
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Ma Y, Liu Z, Xu Y, Zhou S, Wu Y, Wang J, Huang Z, Shi Y. Remediating Potentially Toxic Metal and Organic Co-Contamination of Soil by Combining In Situ Solidification/Stabilization and Chemical Oxidation: Efficacy, Mechanism, and Evaluation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15112595. [PMID: 30463391 PMCID: PMC6266821 DOI: 10.3390/ijerph15112595] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 11/25/2022]
Abstract
Most soil remediation studies investigated single contaminants or multiple contaminants of the same type. However, in field conditions, soils are often contaminated with potentially both toxic metals and organic pollutants, posing a serious technical challenge. Here, batch experiments were conducted to evaluate the performance of combining in situ solidification/stabilization (ISS) and in situ chemical oxidation (ISCO) for the simultaneous removal of aniline (1000 mg/kg) and Cd (10 mg/kg). All four tested ISS amendments, especially quick lime and Portland cement, promoted in situ chemical oxidation with activated persulfate in contaminated soil. Combined ISS/ISCO remediation effectively removed aniline and reduced the bioavailable Cd content at optimal initial persulfate and ISS amendment concentrations of 1.08 mol/kg and 30 wt% with a seven-day curing time, and significantly reduced leaching. Persulfate inhibited the reduction of the bioavailable Cd content, and ISS amendment with persulfate did not synergistically remediate Cd in co-contaminated soil. Strong alkalinity and high temperature were the main mechanisms driving rapid pollutant removal and immobilization. The reaction of CaO with water released heat, and Ca(OH)2 formation increased the pH. The relative contributions of heat vs. alkaline activation, as well as the contaminant removal efficiency, increased with ISS amendment CaO content. Combined treatment altered the soil physicochemical properties, and significantly increased Ca and S contents. Activated persulfate-related reactions did not negatively impact unconfined compressive strength and hydraulic conductivity. This work improves the selection of persulfate activation methods for the treatment of soils co-contaminated with both potentially toxic metals and organic pollutants.
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Affiliation(s)
- Yan Ma
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Zhenhai Liu
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Yanqiu Xu
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Shengkun Zhou
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Yi Wu
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Jin Wang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Zhanbin Huang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
| | - Yi Shi
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
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17
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Lominchar MA, Santos A, de Miguel E, Romero A. Remediation of aged diesel contaminated soil by alkaline activated persulfate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:41-48. [PMID: 29202367 DOI: 10.1016/j.scitotenv.2017.11.263] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/02/2017] [Accepted: 11/23/2017] [Indexed: 06/07/2023]
Abstract
The present work studies the efficiency of alkaline activated persulfate (PS) to remediate an aged diesel fuel contaminated soil from a train maintenance facility. The Total Petroleum Hydrocarbon (TPH) concentration in soil was approximately 5000mgkg-1 with a ratio of aliphatic:aromatic compounds of 70:30. Aromatic compounds were mainly naphtalenes and phenanthrenes. The experiments were performed in batch mode where different initial concentrations of persulfate (105mM, 210mM and 420mM) and activator:persulfate ratios (2 and 4) were evaluated, with NaOH used as activator. Runs were carried out during 56days. Complete TPH conversion was obtained with the highest concentration of PS and activator, whereas in the other runs the elimination of fuel ranged between 60 and 77%. Besides, the abatement of napthalenes and phenantrenes was faster than aliphatic reduction (i. e. after 4days of treatment, the conversions of the aromatic compounds were around 0.8 meanwhile the aliphatic abatements were 0.55) and no aromatic oxidation intermediates from naphtalenes or phenantrenes were detected. These results show that this technology is effective for the remediation of aged diesel in soil with alkaline pH.
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Affiliation(s)
- M A Lominchar
- Chemical Engineering Department, Universidad Complutense de Madrid, Spain.
| | - A Santos
- Chemical Engineering Department, Universidad Complutense de Madrid, Spain
| | - E de Miguel
- Environmental Geochemistry Research and Engineering Laboratory, Universidad Politécnica de Madrid, Spain
| | - A Romero
- Chemical Engineering Department, Universidad Complutense de Madrid, Spain
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Chiu H, Verpoort F, Liu J, Chang Y, Kao C. Using intrinsic bioremediation for petroleum–hydrocarbon contaminated groundwater cleanup and migration containment: Effectiveness and mechanism evaluation. J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2017.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Azubuike CC, Chikere CB, Okpokwasili GC. Bioremediation techniques-classification based on site of application: principles, advantages, limitations and prospects. World J Microbiol Biotechnol 2016; 32:180. [PMID: 27638318 PMCID: PMC5026719 DOI: 10.1007/s11274-016-2137-x] [Citation(s) in RCA: 310] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/08/2016] [Indexed: 11/17/2022]
Abstract
Environmental pollution has been on the rise in the past few decades owing to increased human activities on energy reservoirs, unsafe agricultural practices and rapid industrialization. Amongst the pollutants that are of environmental and public health concerns due to their toxicities are: heavy metals, nuclear wastes, pesticides, green house gases, and hydrocarbons. Remediation of polluted sites using microbial process (bioremediation) has proven effective and reliable due to its eco-friendly features. Bioremediation can either be carried out ex situ or in situ, depending on several factors, which include but not limited to cost, site characteristics, type and concentration of pollutants. Generally, ex situ techniques apparently are more expensive compared to in situ techniques as a result of additional cost attributable to excavation. However, cost of on-site installation of equipment, and inability to effectively visualize and control the subsurface of polluted sites are of major concerns when carrying out in situ bioremediation. Therefore, choosing appropriate bioremediation technique, which will effectively reduce pollutant concentrations to an innocuous state, is crucial for a successful bioremediation project. Furthermore, the two major approaches to enhance bioremediation are biostimulation and bioaugmentation provided that environmental factors, which determine the success of bioremediation, are maintained at optimal range. This review provides more insight into the two major bioremediation techniques, their principles, advantages, limitations and prospects.
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Affiliation(s)
- Christopher Chibueze Azubuike
- Department of Microbiology, Faculty of Science, University of Port Harcourt, East-West Road, PMB 5323, Choba, Port Harcourt, 500004, Rivers State, Nigeria.
| | - Chioma Blaise Chikere
- Department of Microbiology, Faculty of Science, University of Port Harcourt, East-West Road, PMB 5323, Choba, Port Harcourt, 500004, Rivers State, Nigeria
| | - Gideon Chijioke Okpokwasili
- Department of Microbiology, Faculty of Science, University of Port Harcourt, East-West Road, PMB 5323, Choba, Port Harcourt, 500004, Rivers State, Nigeria
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Srivastava VJ, Hudson JM, Cassidy DP. Achieving synergy between chemical oxidation and stabilization in a contaminated soil. CHEMOSPHERE 2016; 154:590-598. [PMID: 27088536 DOI: 10.1016/j.chemosphere.2016.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/27/2016] [Accepted: 04/04/2016] [Indexed: 06/05/2023]
Abstract
Eight in situ solidification/stabilization (ISS) amendments were tested to promote in situ chemical oxidation (ISCO) with activated persulfate (PS) in a contaminated soil. A 3% (by weight) dose of all ISS amendments selected for this study completely activated a 1.5% dose of PS within 3 h by raising temperatures above 30 °C (heat activation) and/or increasing pH above 10.5 (alkaline activation). Heat is released by the reaction of CaO with water, and pH increases because this reaction produces Ca(OH)2. Heat activation is preferred because it generates 2 mol of oxidizing radicals per mole of PS, whereas alkaline activation releases only 1. The relative contribution of heat vs. alkaline activation increased with CaO content of the ISS amendment, which was reflected by enhanced contaminant oxidation with increasing CaO content, and was confirmed by comparing to controls promoting purely heat or alkaline (NaOH) activation. The test soil was contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAH), particularly naphthalene (NAP). ISS-activated PS oxidized between 47% and 84% of the BTEX & NAP, and between 13% and 33% of the higher molecular weight PAH. ISS-activated PS reduced the leachability of BTEX & NAP by 76%-91% and of the 17 PAH by 83%-96%. Combined ISCO/ISS reduced contaminant leachability far than ISCO or ISS treatments alone, demonstrating the synergy that is possible with combined remedies.
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Affiliation(s)
| | | | - Daniel P Cassidy
- Department of Geosciences, Western Michigan University, Kalamazoo, MI 49006, USA.
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