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Glaser DR, Henderson RD, Werkema DD, Johnson TJ, Versteeg RJ. Estimating biofuel contaminant concentration from 4D ERT with mixing models. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 248:104027. [PMID: 35640423 PMCID: PMC9383043 DOI: 10.1016/j.jconhyd.2022.104027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/06/2022] [Accepted: 05/10/2022] [Indexed: 06/03/2023]
Abstract
We present the results of a lab-scaled feasibility study to assess the performance of electrical resistivity tomography for detection, characterization, and monitoring of fuel grade ethanol releases to the subsurface. Further, we attempt to determine the concentration distribution of the ethanol from the electrical resistivity tomography data using mixing-models. Ethanol is a renewable fuel source as well as an oxygenate fuel additive currently used to replace the known carcinogen methyl tert-butyl ether; however, ethanol is preferentially biodegraded and a cosolvent. When introduced to areas previously impacted by nonethanol-based fuels, it will facilitate the persistence of carcinogenic fuel compounds like benzene and ethylbenzene, as well as remobilize them to the ground water. These compounds would otherwise be retained in the soil column undergoing active or passive remediation processes such as soil vapor extraction or natural attenuation. Here, we introduce ethanol to a saturated Ottawa sand in a tank instrumented for four-dimensional geoelectrical measurements. Forward model results suggest pure phase ethanol released into a water saturated silica sand should present a detectable target for electrical resistivity tomography relative to a saturated silica sand only. We observe the introduction of ethanol to the closed hydraulic system and subsequent migration over the duration of the experiment. One-dimensional and three-dimensional temporal data are assessed for the detection, characterization, and monitoring of the ethanol release. Results suggest one-dimensional geoelectrical measurements may be useful for monitoring a release, while three-dimensional geoelectrical field imaging would be useful to characterize, monitor, and design effective remediation approaches for an ethanol release, assuming field conditions do not preclude the application of geoelectrical methods. We then attempt to use predictive mixing models to calculate the distribution of ethanol concentration within the measurement domain. For this study we examine four different models: a nested parallel mixing model, a nested cubic mixing model, the complex refractive index model (CRIM), and the Lichtenecker-Rother (L-R) model. The L-R model, modified to include an electrical formation factor geometry term, provided the best agreement with expected EtOH concentrations.
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Affiliation(s)
- D R Glaser
- US Army ERDC Cold Regions Research & Engineering Laboratory, Hanover, NH, United States of America; Earth & Environmental Sciences Department, Rutgers University, Newark, NJ, United States of America.
| | | | - D D Werkema
- US EPA, Center for Public Health & Environmental Assessment, Newport, OR, United States of America
| | - T J Johnson
- Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - R J Versteeg
- Subsurface Insights, LLC, Hanover, NH, United States of America
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Ma J, McHugh T, Beckley L, Lahvis M, DeVaull G, Jiang L. Vapor Intrusion Investigations and Decision-Making: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7050-7069. [PMID: 32384239 DOI: 10.1021/acs.est.0c00225] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
At sites impacted by volatile organic compounds (VOCs), vapor intrusion (VI) is the pathway with the greatest potential to result in actual human exposure. Since sites with VI were first widely publicized in late 1990s, the scientific understanding of VI has evolved considerably. The VI conceptual model has been extended beyond relatively simple scenarios to include nuances, such as biological and hydrogeological factors that may limit the potential for VI and alternative pathways, such as preferential pathways and direct building contact/infiltration that may enhance VI in some cases. Regulatory guidance documents typically recommend initial concentration- or distance-based screening to evaluate whether VI may be a concern, followed by a multiple-lines-of-evidence (MLE) investigation approach for sites that do not screen out. These recommendations for detailed evaluation of VI currently focus on monitoring of VOC concentrations in groundwater, soil gas, and indoor air and can be supplemented by other lines of evidence. In this Critical Review, we summarize key elements important to VI site characterization, provide the status and current understanding, and highlight data interpretation challenges, as well as innovative tools developed to help overcome the challenges. Although there have been significant advances in the understanding of VI in the past 20 years, limitations and knowledge gaps in screening, investigation methods, and modeling approaches still exist. Potential areas for further research include improved initial screening methods that account for the site-specific role of barriers, improved understanding of preferential pathways, and systematic study of buildings and infrastructure other than single-family residences.
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Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing 102249, China
| | - Thomas McHugh
- GSI Environmental, Houston, Texas 77098, United States
| | - Lila Beckley
- GSI Environmental, Houston, Texas 77098, United States
| | - Matthew Lahvis
- Shell Global Solutions (US), Inc., Shell Technology Center, Houston, Texas 77082, United States
| | - George DeVaull
- Shell Global Solutions (US), Inc., Shell Technology Center, Houston, Texas 77082, United States
| | - Lin Jiang
- National Engineering Research Centre of Urban Environmental Pollution Control, Beijing Municipal Research Institute of Environmental Protection, Beijing 100037, China
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Yao Y, Xiao Y, Luo J, Wang G, Ström J, Suuberg E. High-frequency fluctuations of indoor pressure: A potential driving force for vapor intrusion in urban areas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 710:136309. [PMID: 31926413 PMCID: PMC7532941 DOI: 10.1016/j.scitotenv.2019.136309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/21/2019] [Accepted: 12/22/2019] [Indexed: 06/10/2023]
Abstract
In this study, we examine the impact of a building's indoor pressure fluctuations in drawing subsurface volatile contaminants into the building, and how the presence of an impervious pavement surrounding the building influences this. Even in the absence of communication between the subsurface soil gas and ambient air fluctuations of building indoor pressure can cause upward advection of contaminated soil gas from the subfoundation zone into a building. For cases with the paved ground surface, the simulated volumetric soil gas entry rates are lower than steady-state cases with constant -5 indoor-outdoor pressure difference, by at least half an order of magnitude. When the indoor pressure fluctuation rate exceeds about 5 Pa/h (which corresponds a sinusoidal fluctuation with a period of 2 h), the predicted indoor air concentration of paved scenarios will be higher than the conventional case. When both the building foundation and surrounding pavement block diffusional escape of the volatile soil gas contaminants to the atmosphere, high subfoundation soil gas contaminant concentrations can exist, and contaminant entry into the building through foundation breaches is enhanced beyond what would be expected from diffusion as the building undergoes normal pressure cycling. Upward advection into the building may be induced even when the indoor pressure appears, based on limited measurements, to be higher than that in the subslab, particularly when the indoor pressure in the building quickly fluctuates. This represents a limitation on VI mitigation approaches that rely on indoor pressurization, if those approaches cannot at the same time control significant fluctuation of indoor pressure.
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Affiliation(s)
- Yijun Yao
- 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.
| | - Yuting Xiao
- 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
| | - Jian Luo
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Genfu Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jonathan Ström
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - Eric Suuberg
- School of Engineering, Brown University, Providence, RI 02912, USA
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Dhote M, Kumar A, Jajoo A, Juwarkar A. Assessment of hydrocarbon degradation potentials in a plant-microbe interaction system with oil sludge contamination: A sustainable solution. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2017; 19:1085-1092. [PMID: 28541720 DOI: 10.1080/15226514.2017.1328388] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A pot culture experiment was conducted for 90 days for the evaluation of oil and total petroleum hydrocarbon (TPH) degradation in vegetated and non-vegetated treatments of real-field oil-sludge-contaminated soil. Five different treatments include (T1) control, 2% oil-sludge-contaminated soil; (T2), augmentation of microbial consortium; (T3), Vertiveria zizanioides; (T4), bio-augmentation along with V. zizanioides; and (T5), bio-augmentation with V. zizanioides and bulking agent. During the study, oil reduction, TPH, and degradation of its fractions were determined. Physico-chemical and microbiological parameters of soil were also monitored simultaneously. At the end of the experimental period, oil content (85%) was reduced maximally in bio-augmented rhizospheric treatments (T4 and T5) as compared to control (27%). TPH reduction was observed to be 88 and 89% in bio-augmented rhizospheric soil (T4 and T5 treatments), whereas in non-rhizospheric and control (T2 and T1), TPH reduction was 78 and 37%, respectively. Degradation of aromatic fraction after 90 days in bio-augmented rhizosphere of treatments T4 and T5 was found to 91 and 92%, respectively. In microbial (T2) and Vertiveria treatments (T3), degradation of aromatic fraction was 83 and 68%, respectively. A threefold increase in soil dehydrogenase activity and noticeable changes in organic carbon content and water-holding capacity were also observed which indicated maximum degradation of oil and its fractions in combined treatment of plants and microbes. It is concluded that the plant-microbe soil system helps to restore soil quality and can be used as an effective tool for the remediation of oil-sludge-contaminated sites.
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Affiliation(s)
- Monika Dhote
- a Eco-system Division, National Environmental Engineering Research Institute (NEERI) , Nagpur , India
- b School of Biotechnology , Devi Ahilya University , Indore , India
- c School of Life Sciences , Devi Ahilya University , Indore , India
| | - Anil Kumar
- b School of Biotechnology , Devi Ahilya University , Indore , India
| | - Anjana Jajoo
- c School of Life Sciences , Devi Ahilya University , Indore , India
| | - Asha Juwarkar
- a Eco-system Division, National Environmental Engineering Research Institute (NEERI) , Nagpur , India
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Persichetti G, Grimaldi IA, Testa G, Bernini R. Multifunctional optofluidic lab-on-chip platform for Raman and fluorescence spectroscopic microfluidic analysis. LAB ON A CHIP 2017; 17:2631-2639. [PMID: 28664956 DOI: 10.1039/c7lc00460e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A multifunctional lab-on-a-chip platform for spectroscopic analysis of liquid samples based on an optofluidic jet waveguide is reported. The optofluidic detection scheme is achieved through the total internal reflection arising in a liquid jet of only 150 μm diameter, leading to highly efficient signal excitation and collection. This results in an optofluidic chip with an alignment-free spectroscopic detection scheme, which avoids any background from the sample container. This platform has been designed for multiwavelength fluorescence and Raman spectroscopy. The chip integrates a recirculation system that reduces the required sample volume. The evaluation of the device performance has been accomplished by means of fluorescence measurements performed on eosin Y in water solutions, achieving a limit of detection of 33 pM. The sensor has been applied in Raman spectroscopy of water-ethanol solutions, leading to a limit of detection of 0.18%. As additional application, analysis of riboflavin using fluorescence detection demonstrates the possibility of detecting this vitamin at the 560 pM level (0.21 ng l-1). Although measurements have been performed by means of a compact and low-cost spectrometer, in both cases the micro-jet optofluidic chip achieved similar performances if not better than high-end benchtop based laboratory equipment. This approach paves the way towards portable lab-on-a-chip devices for high sensitivity environmental and biochemical sensing, using optical spectroscopy.
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Affiliation(s)
- G Persichetti
- Institute for Electromagnetic Monitoring of the Environment (IREA), National Research Council (CNR), Naples, Italy.
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Wilson JT, Adair C, White H, Howard RL. Effect of Biofuels on Biodegradation of Benzene and Toluene at Gasoline Spill Sites. GROUND WATER MONITORING & REMEDIATION 2016; 36:50-61. [PMID: 32699493 PMCID: PMC7375322 DOI: 10.1111/gwmr.12187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The risk that benzene and toluene from spills of gasoline will impact drinking water wells is largely controlled by the natural anaerobic biodegradation of benzene and toluene. Benzene and toluene, as well as ethanol and other biofuels, are degraded under anaerobic conditions to the same pool of degradation products. Biodegradation of biofuels may produce concentrations of degradation products that make the thermodynamics for degradation of benzene and toluene infeasible under methanogenic conditions and produce larger plumes of benzene and toluene. This study evaluated the concentrations of fuel alcohols that are necessary to inhibit the anaerobic degradation of benzene and toluene under methanogenic conditions. At two ethanol spill sites, concentrations of ethanol greater ≥42 mg/L inhibited the anaerobic degradation of toluene. The pH and concentrations of acetate, dissolved inorganic carbon, and molecular hydrogen were used to calculate the Gibbs free energy for the biodegradation of toluene. In general, the anaerobic biodegradation of toluene was not thermodynamically feasible in water with ≥42 mg/L ethanol. In a microcosm study, when the concentrations of ethanol were ≥14 mg/L or the concentrations of n-butanol were ≥16 mg/L, the biodegradation of the alcohols consistently produced concentrations of hydrogen, dissolved inorganic carbon, and acetate that would preclude natural anaerobic biodegradation of benzene and toluene by syntrophic organisms. In contrast, iso-butanol and n-propanol only occasionally produced conditions that would preclude the biodegradation of benzene and toluene.
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Affiliation(s)
- John T. Wilson
- Scissortail Environmental Solutions, LLC, 2013 Foster Drive, Ada, OK 74820
| | - Cherri Adair
- U.S. EPA/ORD/NRMRL/GWERD, R.S. Kerr Center Drive, Ada, OK 74820; 580 436 8969
| | - Hal White
- U.S. EPA/OSWER/OUST, 1215 Jefferson Davis Highway, Arlington, VA 22202
| | - Robert L. Howard
- Virginia Certified Professional Geologist, MS, is at Virginia Department of Environmental Quality, Blue Ridge Regional Office, 3019 Peters Creek Road, Roanoke, VA 24019
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Ramos DT, Lazzarin HSC, Alvarez PJJ, Vogel TM, Fernandes M, do Rosário M, Corseuil HX. Biodiesel presence in the source zone hinders aromatic hydrocarbons attenuation in a B20-contaminated groundwater. JOURNAL OF CONTAMINANT HYDROLOGY 2016; 193:48-53. [PMID: 27636988 DOI: 10.1016/j.jconhyd.2016.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/15/2016] [Accepted: 09/05/2016] [Indexed: 06/06/2023]
Abstract
The behavior of biodiesel blend spills have received limited attention in spite of the increasing and widespread introduction of biodiesel to the transportation fuel matrix. In this work, a controlled field release of biodiesel B20 (100L of 20:80 v/v soybean biodiesel and diesel) was monitored over 6.2years to assess the behavior and natural attenuation of constituents of major concern (e.g., BTEX (benzene, toluene, ethyl-benzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons)) in a sandy aquifer material. Biodiesel was preferentially biodegraded compared to diesel aromatic compounds with a concomitant increase in acetate, methane (near saturation limit (≈22mgL-1)) and dissolved BTEX and PAH concentrations in the source zone during the first 1.5 to 2.0years after the release. Benzene and benzo(a)pyrene concentrations remained above regulatory limits in the source zone until the end of the experiment (6.2years after the release). Compared to a previous adjacent 100-L release of ethanol-amended gasoline, biodiesel/diesel blend release resulted in a shorter BTEX plume, but with higher residual dissolved hydrocarbon concentrations near the source zone. This was attributed to greater persistence of viscous (and less mobile) biodiesel than the highly-soluble and mobile ethanol in the source zone. This persistence of biodiesel/diesel NAPL at the source zone slowed BTEX and PAH biodegradation (by the establishment of an anaerobic zone) but reduced the plume length by reducing mobility. This is the first field study to assess biodiesel/diesel blend (B20) behavior in groundwater and its effects on the biodegradation and plume length of priority groundwater pollutants.
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Affiliation(s)
- Débora Toledo Ramos
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Florianópolis, Santa Catarina, Brazil
| | - Helen Simone Chiaranda Lazzarin
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Florianópolis, Santa Catarina, Brazil
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, MS-317, 6100 Main St, Houston, TX 77005, USA
| | - Timothy M Vogel
- Environmental Microbial Genomics Group, Laboratoire Ampère, CNRS UMR5005, Ecole Centrale de Lyon, Université de Lyon, Ecully, France
| | - Marilda Fernandes
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Florianópolis, Santa Catarina, Brazil
| | - Mário do Rosário
- Petróleo Brasileiro Petrobras, Research Centre (CENPES), Rio de Janeiro, Rio de Janeiro, PO Box 21941598, Brazil
| | - Henry Xavier Corseuil
- Federal University of Santa Catarina, Department of Sanitary and Environmental Engineering, Florianópolis, Santa Catarina, Brazil.
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8
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Kurt Z, Mack EE, Spain JC. Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10172-10178. [PMID: 27523982 DOI: 10.1021/acs.est.6b02525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants.
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Affiliation(s)
- Zohre Kurt
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0512, United States
- Institute of Scientific Research and High Technology Services , Calle Pullpn, Panamá, Panama
| | - E Erin Mack
- DuPont, Corporate Remediation Group, P.O. Box 6101, Glasgow 300, Newark, Delaware 19714-6101, United States
| | - Jim C Spain
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0512, United States
- Center for Environmental Diagnostics and Bioremediation, University of West Florida , Pensacola, Florida 32514-5751, United States
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Ma J, Yang Y, Dai X, Chen Y, Deng H, Zhou H, Guo S, Yan G. Effects of adding bulking agent, inorganic nutrient and microbial inocula on biopile treatment for oil-field drilling waste. CHEMOSPHERE 2016; 150:17-23. [PMID: 26891352 DOI: 10.1016/j.chemosphere.2016.01.123] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 01/29/2016] [Accepted: 01/31/2016] [Indexed: 06/05/2023]
Abstract
Contamination from oil-field drilling waste is a worldwide environmental problem. This study investigated the performance of four bench-scale biopiles in treating drilling waste: 1) direct biopile (DW), 2) biopile plus oil-degrading microbial consortium (DW + M), 3) biopile plus microbial consortium and bulking agents (saw dust) (DW + M + BA), 4) biopile plus microbial consortium, bulking agents, and inorganic nutrients (Urea and K2HPO4) (DW + M + BA + N). Ninety days of biopiling removed 41.0%, 44.0%, 55.7% and 87.4% of total petroleum hydrocarbon (TPH) in the pile "DW", "DW + M", "DW + M + BA", and "DW + M + BA + N" respectively. Addition of inorganic nutrient and bulking agents resulted in a 56.9% and 26.6% increase in TPH removal efficiency respectively. In contrast, inoculation of hydrocarbon-degrading microorganisms only slightly enhanced the contaminant removal (increased 7.3%). The biopile with stronger contaminant removal also had higher pile temperature and lower pile pH (e.g., in "DW + M + BA + N"). GC-MS analysis shows that biopiling significantly reduced the total number of detected contaminants and changed the chemical composition. Overall, this study shows that biopiling is an effective remediation technology for drilling waste. Adding inorganic nutrients and bulking agents can significantly improve biopile performance while addition of microbial inocula had minimal positive impacts on contaminant removal.
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Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China; College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yongqi Yang
- College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Xiaoli Dai
- College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yetong Chen
- College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Hanmei Deng
- College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Huijun Zhou
- College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Shaohui Guo
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China; College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Guangxu Yan
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China; College of Chemical Engineering, China University of Petroleum-Beijing, Beijing, 102249, China.
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Ziegler BA, McGuire JT, Cozzarelli IM. Rates of As and Trace-Element Mobilization Caused by Fe Reduction in Mixed BTEX-Ethanol Experimental Plumes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13179-89. [PMID: 26486694 DOI: 10.1021/acs.est.5b02341] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Biodegradation of organic matter, including petroleum-based fuels and biofuels, can create undesired secondary water-quality effects. Trace elements, especially arsenic (As), have strong adsorption affinities for Fe(III) (oxyhydr)-oxides and can be released to groundwater during Fe-reducing biodegradation. We investigated the mobilization of naturally occurring As, cobalt (Co), chromium (Cr), and nickel (Ni) from wetland sediments caused by the introduction of benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol mixtures under iron- and nitrate-reducing conditions, using in situ push-pull tests. When BTEX alone was added, results showed simultaneous onset and similar rates of Fe reduction and As mobilization. In the presence of ethanol, the maximum rates of As release and Fe reduction were higher, the time to onset of reaction was decreased, and the rates occurred in multiple stages that reflected additional processes. The concentration of As increased from <1 μg/L to a maximum of 99 μg/L, exceeding the 10 μg/L limit for drinking water. Mobilization of Co, Cr, and Ni was observed in association with ethanol biodegradation but not with BTEX. These results demonstrate the potential for trace-element contamination of drinking water during biodegradation and highlight the importance of monitoring trace elements at natural and enhanced attenuation sites.
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Affiliation(s)
- Brady A Ziegler
- Department of Geosciences, Virginia Tech , Blacksburg, Virginia, 24061 United States
| | - Jennifer T McGuire
- Department of Biology, University of St. Thomas , St. Paul, Minnesota, 55105 United States
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Ma J, Nossa CW, Alvarez PJJ. Groundwater ecosystem resilience to organic contaminations: microbial and geochemical dynamics throughout the 5-year life cycle of a surrogate ethanol blend fuel plume. WATER RESEARCH 2015; 80:119-129. [PMID: 25996759 DOI: 10.1016/j.watres.2015.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/31/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
The capacity of groundwater ecosystem to recover from contamination by organic chemicals is a vital concern for environmental scientists. A pilot-scale aquifer system was used to investigate the long-term dynamics of contaminants, groundwater geochemistry, and microbial community structure (by 16S rRNA gene pyrosequencing and quantitative real-time PCR) throughout the 5-year life cycle of a surrogate ethanol blend fuel plume (10% ethanol + 50 mg/L benzene + 50 mg/L toluene). Two-year continuous ethanol-blended release significantly changed the groundwater geochemistry (resulted in anaerobic, low pH, and organotrophic conditions) and increased bacterial and archaeal populations by 82- and 314-fold respectively. Various anaerobic heterotrophs (fermenters, acetogens, methanogens, and hydrocarbon degraders) were enriched. Two years after the release was shut off, all contaminants and their degradation byproducts disappeared and groundwater geochemistry completely restored to the pre-release states (aerobic, neutral pH, and oligotrophic). Bacterial and archaeal populations declined by 18- and 45-fold respectively (relative to the time of shut off). Microbial community structure reverted towards the pre-release states and alpha diversity indices rebounded, suggesting the resilience of microbial community to ethanol blend releases. We also found shifts from O2-sensitive methanogens (e.g., Methanobacterium) to methanogens that are not so sensitive to O2 (e.g., Methanosarcina and Methanocella), which is likely to contribute to the persistence of methanogens and methane generation following the source removal. Overall, the rapid disappearance of contaminants and their metabolites, rebound of geochemical footprints, and resilience of microbial community unequivocally document the natural capacity of groundwater ecosystem to attenuate and recover from a large volume of catastrophic spill of ethanol-based biofuel.
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Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing 102249, China; Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA.
| | | | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
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12
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Ma J, Deng Y, Yuan T, Zhou J, Alvarez PJJ. Succession of microbial functional communities in response to a pilot-scale ethanol-blended fuel release throughout the plume life cycle. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 198:154-160. [PMID: 25603154 DOI: 10.1016/j.envpol.2015.01.005] [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: 10/21/2014] [Revised: 01/08/2015] [Accepted: 01/10/2015] [Indexed: 06/04/2023]
Abstract
GeoChip, a comprehensive gene microarray, was used to examine changes in microbial functional gene structure throughout the 4-year life cycle of a pilot-scale ethanol blend plume, including 2-year continuous released followed by plume disappearance after source removal. Canonical correlation analysis (CCA) and Mantel tests showed that dissolved O2 (which was depleted within 5 days of initiating the release and rebounded 194 days after source removal) was the most influential environmental factor on community structure. Initially, the abundance of anaerobic BTEX degradation genes increased significantly while that of aerobic BTEX degradation genes decreased. Gene abundance for N fixation, nitrification, P utilization, sulfate reduction and S oxidation also increased, potentially changing associated biogeochemical cycle dynamics. After plume disappearance, most genes returned to pre-release abundance levels, but the final functional structure significantly differed from pre-release conditions. Overall, observed successions of functional structure reflected adaptive responses that were conducive to biodegradation of ethanol-blend releases.
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Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing 102249, China; Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA
| | - Ye Deng
- Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China; Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Tong Yuan
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Earth Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270, USA
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA.
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Ma J, Rixey WG, Alvarez PJJ. Increased fermentation activity and persistent methanogenesis in a model aquifer system following source removal of an ethanol blend release. WATER RESEARCH 2015; 68:479-486. [PMID: 25462754 DOI: 10.1016/j.watres.2014.10.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 10/06/2014] [Accepted: 10/10/2014] [Indexed: 06/04/2023]
Abstract
The increased probability of groundwater contamination by ethanol-blended fuel calls for improved understanding of how remediation efforts affect the fate and transport of constituents of concern, including the generation and fate of fermentation byproducts. A pilot-scale (8 m³) model aquifer was used to investigate changes in the concentrations of ethanol and its metabolites (methane and volatile fatty acids) after removal of the contamination source. Following the shut-off of a continuous release of a dissolved ethanol blend (10% v:v ethanol, 50 mg/L benzene, and 50 mg/L toluene), fermentation activity was surprisingly stimulated and the concentrations of ethanol metabolites increased. A microcosm experiment showed that this result was due to a decrease in the dissolved ethanol concentration below its toxicity threshold (∼2000 mg/L for this system). Methane generation (>1.5 mg/L of dissolved methane) persisted for more than 100 days after the disappearance of ethanol, despite clean air-saturated water flowing continuously through the tank at a relative high seepage velocity (0.76 m/day). Quantitative real-time PCR showed that functional genes associated with methane metabolism (mcrA for methanogenesis and pmoA for methanotrophy) also persisted in the aquifer material. Persistent methanogenesis was apparently due to the anaerobic degradation of soil-bound organic carbon (e.g., biomass grown on ethanol and other substrates). Overall, this study reflects the complex plume dynamics following source removal, and suggests that monitoring for increases in the concentration of ethanol metabolites that impact groundwater quality should be considered.
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Affiliation(s)
- Jie Ma
- Department of Civil and Environmental Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA
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Ma J, Luo H, Devaull GE, Rixey WG, Alvarez PJJ. Numerical model investigation for potential methane explosion and benzene vapor intrusion associated with high-ethanol blend releases. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 48:474-481. [PMID: 24354291 DOI: 10.1021/es403926k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ethanol-blended fuel releases usually stimulate methanogenesis in the subsurface, which could pose an explosion risk if methane accumulates in a confined space above the ground where ignitable conditions exist. Ethanol-derived methane may also increase the vapor intrusion potential of toxic fuel hydrocarbons by stimulating the depletion of oxygen by methanotrophs, and thus inhibiting aerobic biodegradation of hydrocarbon vapors. To assess these processes, a three-dimensional numerical vapor intrusion model was used to simulate the degradation, migration, and intrusion pathway of methane and benzene under different site conditions. Simulations show that methane is unlikely to build up to pose an explosion hazard (5% v/v) if diffusion is the only mass transport mechanism through the deeper vadose zone. However, if methanogenic activity near the source zone is sufficiently high to cause advective gas transport, then the methane indoor concentration may exceed the flammable threshold under simulated conditions. During subsurface migration, methane biodegradation could consume soil oxygen that would otherwise be available to support hydrocarbon degradation, and increase the vapor intrusion potential for benzene. Vapor intrusion would also be exacerbated if methanogenic activity results in sufficiently high pressure to cause advective gas transport in the unsaturated zone. Overall, our simulations show that current approaches to manage the vapor intrusion risk for conventional fuel released might need to be modified when dealing with some high ethanol blend fuel (i.e., E20 up to E95) releases.
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Affiliation(s)
- Jie Ma
- Department of Civil and Environmental Engineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
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Ma J, Nossa CW, Xiu Z, Rixey WG, Alvarez PJJ. Adaptive microbial population shifts in response to a continuous ethanol blend release increases biodegradation potential. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 178:419-425. [PMID: 23628885 DOI: 10.1016/j.envpol.2013.03.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/26/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
The fate of fuel releases largely depends on the poorly-understood response in microbial community structure and function. Here, we evaluate the impacts to the microbial community resulting from a pilot-scale continuous release (10 months) of a 10% v:v ethanol solution mixed with benzene and toluene (50 mg/L each). Microbial population shifts were characterized by pyrosequencing-based 16S rRNA analysis and by quantitative PCR targeting Bacteria, Archaea, and functional genes for methanogenesis (mcrA), acetogenesis (fhs) and aerobic degradation of aromatic hydrocarbons (PHE), which could occur in hypoxic micro-environments. The release stimulated microbial growth, increased species richness and diversity, and selected for genotypes involved in fermentative degradation (the relative abundance of mcrA and fhs increased 18- and 6-fold, respectively). The growth of putative hydrocarbon degraders and commensal anaerobes, and increases in microbial diversity and in degradation rates suggest an adaptive response that increases the potential for natural attenuation of ethanol blend releases.
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Affiliation(s)
- Jie Ma
- Department of Civil and Environmental Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA
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