Modeling Aerobic Biodegradation in the Capillary Fringe

Date

2015-02-03

Author

Luo, Jian
Kurt, Zöhre
Hou, Deyi
Spain, Jim C.

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

129
views

0
downloads

Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone.

Subject Keywords

Air, Transport, Volatilization, 1,2-dichlorobenzene, Chlorobenzene, Unsaturated zone, Hydrocarbon vapors, Oxygen-limited biodegradation, Soil vapor intrusion

URI

https://hdl.handle.net/11511/49280

Journal

ENVIRONMENTAL SCIENCE & TECHNOLOGY

DOI

https://doi.org/10.1021/es503086p

Collections

Department of Environmental Engineering, Article

Suggestions

OpenMETU
Core

Biodegradation of cis-Dichloroethene and Vinyl Chloride in the Capillary Fringe Kurt, Zöhre; Spain, Jim C. (2014-11-18) Volatile chlorinated compounds are major pollutants in groundwater, and they pose a risk of vapor intrusion into buildings. Vapor intrusion can be prevented by natural attenuation in the vadose zone if biodegradation mechanisms can be established. In this study, we tested the hypothesis that bacteria can use cis-dichloroethene (cis-DCE) or vinyl chloride (VC) as an electron donor in the vadose zone. Anoxic water containing cis-DCE or VC was pumped continuously beneath laboratory columns that represented the...
Accurate formation energies of charged defects in solids: A systematic approach Vinichenko, Dmitry; Sensoy, Mehmet Gokhan; Friend, Cynthia M.; Kaxiras, Efthimios (2017-06-30) Defects on surfaces of semiconductors have a strong effect on their reactivity and catalytic properties. The concentration of different charge states of defects is determined by their formation energies. First-principles calculations are an important tool for computing defect formation energies and for studying the microscopic environment of the defect. The main problem associated with the widely used supercell method in these calculations is the error in the electrostatic energy, which is especially pronou...
Investigation of Turkey's carbon dioxide problem by numerical modeling Can, Ali; Tokdemir, Turgut; Department of Engineering Sciences (2006) CO2 emission is very important, because it is responsible for about 60% of the "Greenhouse Effect". The major objectives of this study were to prepare a CO2 emission inventory of Turkey based on districts and provinces by using the fuel consumption data with respect to its sources, to find the CO2 uptake rate of forests in Turkey based on provinces and districts, and to estimate the ground level concentration of CO2 across Turkey using U.S. EPA's ISCLT3 model for the preparation of ground level concentratio...
Modeling of carbon dioxide sequestration in a deep saline aquifer Başbuğ, Başar; Gümrah, Fevzi; Department of Petroleum and Natural Gas Engineering (2005) CO2 is one of the hazardous greenhouse gases causing significant changes in the environment. The sequestering CO2 in a suitable geological medium can be a feasible method to avoid the negative effects of CO2 emissions in the atmosphere. CO2 sequestration is the capture of, separation, and long-term storage of CO2 in underground geological environments. A case study was simulated regarding the CO2 sequestration in a deep saline aquifer. The compositional numerical model (GEM) of the CMG software was used to ...
Experimental and numerical analysis of dry forward combustion with diverse well configuration Akın, Serhat; Kök, Mustafa Verşan (2002-07-01) In situ combustion is a thermal recovery technique where energy is generated by a combustion front that is propagated along the reservoir by air injection. Most of the previously conducted studies report thermal and fluid dynamics aspects of the process. Modeling in situ combustion process requires extensive knowledge of reservoir data as well as reaction kinetics data. Unfortunately, limited kinetic data are available on the rates and the nature of partial oxidation reactions and the high-temperature combu...

Citation Formats

J. Luo, Z. Kurt, D. Hou, and J. C. Spain, “Modeling Aerobic Biodegradation in the Capillary Fringe,” ENVIRONMENTAL SCIENCE & TECHNOLOGY, pp. 1501–1510, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49280.