1
|
Sookhak Lari K, Davis GB, Rayner JL, Bastow TP, Puzon GJ. Natural source zone depletion of LNAPL: A critical review supporting modelling approaches. WATER RESEARCH 2019; 157:630-646. [PMID: 31004979 DOI: 10.1016/j.watres.2019.04.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/23/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Natural source zone depletion (NSZD) of light non-aqueous phase liquids (LNAPLs) includes partitioning, transport and degradation of LNAPL components. NSZD is being considered as a site closure option during later stages of active remediation of LNAPL contaminated sites, and where LNAPL mass removal is limiting. To ensure NSZD meets compliance criteria and to design enhanced NSZD actions if required, residual risks posed by LNAPL and its long term behaviour require estimation. Prediction of long-term NSZD trends requires linking physicochemical partitioning and transport processes with bioprocesses at multiple scales within a modelling framework. Here we expand and build on the knowledge base of a recent review of NSZD, to establish the key processes and understanding required to model NSZD long term. We describe key challenges to our understanding, inclusive of the dominance of methanogenic or aerobic biodegradation processes, the potentially changeability of rates due to the weathering profile of LNAPL product types and ages, and linkages to underlying bioprocesses. We critically discuss different scales in subsurface simulation and modelling of NSZD. Focusing on processes at Darcy scale, 36 models addressing processes of importance to NSZD are investigated. We investigate the capabilities of models to accommodate more than 20 subsurface transport and transformation phenomena and present comparisons in several tables. We discuss the applicability of each group of models for specific site conditions.
Collapse
Affiliation(s)
- Kaveh Sookhak Lari
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia; School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia.
| | - Greg B Davis
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia; School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - John L Rayner
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
| | - Trevor P Bastow
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
| | - Geoffrey J Puzon
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
| |
Collapse
|
2
|
Yao Y, Mao F, Xiao Y, Luo J. Modeling capillary fringe effect on petroleum vapor intrusion from groundwater contamination. WATER RESEARCH 2019; 150:111-119. [PMID: 30508708 DOI: 10.1016/j.watres.2018.11.038] [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: 08/10/2018] [Revised: 11/06/2018] [Accepted: 11/16/2018] [Indexed: 06/09/2023]
Abstract
At contaminated sites, indoor inhalation of volatile organic compounds from groundwater contamination, known as vapor intrusion (VI), is an important exposure pathway to determine groundwater cleanup level. Based on empirical analysis, US EPA concluded that there is a low probability for vapors from fuel hydrocarbons dissolved in groundwater to induce indoor concentrations that exceed risk-based standards, and recommended 6 feet vertical building-source separation distance as the risk screening tool for such cases. In this study, we examine this recommendation by performing numerical modeling to investigate the detailed effects of the capillary fringe on petroleum vapor biodegradation and attenuation. First, the numerical model is validated by comparison with laboratory data and field measurements in US EPA's database. Then the verified model is used to simulate two scenarios involving the capillary fringe effect, one with a groundwater source at various depth and the other with a soil gas source located above the groundwater level. For a groundwater contaminant source, the capillary fringe plays a significant role in VI by controlling the soil moisture content and oxygen availability, thus affecting the soil gas concentration biodegradation and attenuation. Specifically, the capillary fringe effect can significantly decrease the indoor air concentration by decreasing upward diffusion rates of hydrocarbon, increasing the thickness of the aerobic zone, and enhancing aerobic biodegradation. As a result, it is highly unlikely for sources located at groundwater level to induce unacceptable vapor intrusion risks, supporting US EPA's recommendation. Moreover, the simulations suggest that the vertical smear zone of residual light non-aqueous liquid contamination, induced by temporal fluctuations of groundwater level, may lead to a potential threat to indoor air quality for a short vertical source-building separation distance, and thus requires more attention. The sensitivity test of the numerical model also indicates that it is the vertical separation distance between building foundation and the top of the smear zone instead of the smear zone thickness that should be given more attention during the investigation.
Collapse
Affiliation(s)
- Yijun Yao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China.
| | - Fang Mao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China
| | - Yuting Xiao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China
| | - Jian Luo
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
| |
Collapse
|
3
|
Ma Y, Dong B, Bai Y, Zhang M, Xie Y, Shi Y, Du X. Remediation status and practices for contaminated sites in China: survey-based analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:33216-33224. [PMID: 30255269 DOI: 10.1007/s11356-018-3294-2] [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: 07/01/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
This study aims to determine the current remediation status of contaminated sites in China to support future decision-making for the cleanup of contaminated sites. A survey was conducted in which a questionnaire was administered to 76 remediation practitioners working across China. The major driving force behind remediation was the redevelopment of contaminated brownfield land for residential purposes, mostly funded by profit-driven developers, particularly in Beijing. A large proportion of brownfield sites have been contaminated with organic compounds, reflecting past land use by chemical plants. Risk assessments of contaminated sites are typically based on the guidelines from China's Ministry of Ecology and Environment, the United States Environmental Protection Agency, and local governments. The most frequently used criteria to assess site contamination in China are environmental quality standards, screening values, or both. The majority of remediation efforts use low-technology approaches to treat contaminated soil (e.g., cement kiln, in situ and ex situ solidification/stabilization, landfill, and mechanical soil aeration), while sophisticated, high-technology approaches (e.g., in situ and ex situ thermal desorption, in situ chemical treatment, and bioventing) are less often used. The implementation of the latter, while limited, illustrates that the necessary technology exists to support optimal land remediation in China. In addition to high-technology remediation methods, 6W/1H ideology can be employed when assessing contaminated site for remediation. Graphical abstract ᅟ.
Collapse
Affiliation(s)
- Yan Ma
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, People's Republic of China
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Binbin Dong
- Beijing Solid Waste Treatment Co. Ltd., Beijing, 100101, People's Republic of China
| | - Yanying Bai
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Meng Zhang
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, People's Republic of China
| | - Yunfeng Xie
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Yi Shi
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Xiaoming Du
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
| |
Collapse
|
4
|
Wang JH, Li HY, Chen YP, Liu SY, Yan P, Shen Y, Guo JS, Fang F. Estimation of oxygen effective diffusion coefficient in a non-steady-state biofilm based on response time. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:9797-9805. [PMID: 29372520 DOI: 10.1007/s11356-018-1227-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/04/2018] [Indexed: 06/07/2023]
Abstract
In wastewater treatment, oxygen effective diffusion coefficient (D eff ) is a key parameter in the study of oxygen diffusion-reaction process and mechanism in biofilms. Almost all the reported methods for estimating the D eff rely on other biokinetic parameters, such as substrate consumption rate and reaction rate constant. Then, the estimation was complex. In this study, a method independent of other biokinetic parameters was proposed for estimating the dissolved oxygen (DO) D eff in biofilms. It was based on the dynamic DO microdistribution in a non-steady-state inactive biofilm, which was measured by the oxygen transfer modeling device (OTMD) combining with an oxygen microelectrode system. A pure DO diffusion model was employed, and the expression of the DO D eff was obtained by applying the analytical solution of the model to a selected critical DO concentration. DO D eff in the biofilm from the bioreactor was calculated as (1.054 ± 0.041) × 10-9 m2/s, and it was in the same order of magnitude with the reported results. Therefore, the method proposed in this study was effective and feasible. Without measurement of any other biokinetic parameters, this method was convenient and will benefit the study of oxygen transport-reaction process in biofilms and other biofouling deposits. Graphical abstract ᅟ.
Collapse
Affiliation(s)
- Jian-Hui Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| | - Hai-Yan Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China.
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
| | - Shao-Yang Liu
- Department of Chemistry and Physics, Troy University, Troy, AL, 36082, USA
| | - Peng Yan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| | - Yu Shen
- National Base of International Science and Technology Cooperation for Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing, 400067, China
| | - Jin-Song Guo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China.
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing, 400045, China
| |
Collapse
|
5
|
Li M, Qian WJ, Gao Y, Shi L, Liu C. Functional Enzyme-Based Approach for Linking Microbial Community Functions with Biogeochemical Process Kinetics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11848-11857. [PMID: 28891285 DOI: 10.1021/acs.est.7b03158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The kinetics of biogeochemical processes in natural and engineered environmental systems is typically described using Monod-type or modified Monod-type models. These models rely on biomass as surrogates for functional enzymes in microbial communities that catalyze biogeochemical reactions. A major challenge of applying such models is the difficulty of quantitatively measuring functional biomass for the constraining and validation of the models. However, omics-based approaches have been increasingly used to characterize microbial community structure, functions, and metabolites. Here, we propose an enzyme-based model that can incorporate omics data to link microbial community functions with biogeochemical process kinetics. The model treats enzymes as time-variable catalysts for biogeochemical reactions and applies a biogeochemical reaction network to incorporate intermediate metabolites. The sequences of genes and proteins from metagenomes, as well as those from the UniProt database, were used for targeted enzyme quantification and to provide insights into the dynamic linkage among functional genes, enzymes, and metabolites that are required in the model. The application of the model was demonstrated using denitrification, as an example, by comparing model simulations with measured functional enzymes, genes, denitrification substrates, and intermediates.
Collapse
Affiliation(s)
- Minjing Li
- School of Environmental Studies, China University of Geosciences , Wuhan 430074, China
| | - Wei-Jun Qian
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Yuqian Gao
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Liang Shi
- School of Environmental Studies, China University of Geosciences , Wuhan 430074, China
| | - Chongxuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Science and Engineering, Southern University of Science and Technology , Shenzhen 518055, China
| |
Collapse
|
6
|
Wang JH, Chen YP, Dong Y, Wang XX, Guo JS, Shen Y, Yan P, Ma TF, Sun XQ, Fang F, Wang J. A new method to measure and model dynamic oxygen microdistributions in moving biofilms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 229:199-209. [PMID: 28599204 DOI: 10.1016/j.envpol.2017.05.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 04/11/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Biofilms in natural environments offer a superior solution to mitigate water pollution. Artificially intensified biofilm reactors represented by rotating biological contactors (RBCs) are widely applied and studied. Understanding the oxygen transfer process in biofilms is an important aspect of these studies, and describing this process in moving biofilms (such as biofilms in RBCs) is a particular challenge. Oxygen transfer in RBCs behaves differently than in other biological reactors due to the special oxygen supply mode that results from alternate exposure of the biofilm to wastewater and air. The study of oxygen transfer in biofilms is indispensable for understanding biodegradation in RBCs. However, the mechanisms are still not well known due to a lack of effective tools to dynamically analyze oxygen diffusion, reaction, and microdistribution in biofilms. A new experimental device, the Oxygen Transfer Modeling Device (OTMD), was designed and manufactured for this purpose, and a mathematical model was developed to model oxygen transfer in biofilm produced by an RBC. This device allowed the simulation of the local environment around the biofilm during normal RBC operation, and oxygen concentrations varying with time and depth in biofilm were measured using an oxygen microelectrode. The experimental data conformed well to the model description, indicating that the OTMD and the model were stable and reliable. Moreover, the OTMD offered a flexible approach to study the impact of a single-factor on oxygen transfer in moving biofilms. In situ environment of biofilm in an RBC was simulated, and dynamic oxygen microdistributions in the biofilm were measured and well fitted to the built model description.
Collapse
Affiliation(s)
- Jian-Hui Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Yang Dong
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Xi-Xi Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jin-Song Guo
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Yu Shen
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; National Base of International Science and Technology Cooperation for Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China
| | - Peng Yan
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Teng-Fei Ma
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Xiu-Qian Sun
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jing Wang
- Chongqing Jianzhu College, Chongqing 400072, China
| |
Collapse
|