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15 DEVELOPMENT OF A KINETIC MODEL FOR CONTINUOUS FLOW BIOREACTOR TREATMENT OF PETROLEUM CONTAMINATED SOILS Ronald Britto, Doctoral Candidate Joseph H. Sherrard, Professor and Department Chairman Dennis D. Truax, Associate Professor Department of Civil Engineering Mississippi State University Mississippi State University, Mississippi 39762 INTRODUCTION Significant quantities of petroleum compounds are released into the soil environment, either from leakages of underground storage tanks (USTs) or due to accidental spills. The EPA has recently reported that 100,000 UST leaks have been identified, and that the number might triple in the next several years.' Profiles of Army USTs, which are leaking, based on construction material, capacity, age and content have shown just how complex it will be to evaluate and undertake cleanup processes.2 The application of biological processes in controlling environmental problems has increased strongly during the past decade. A characteristic and important aspect of biological processes is the feature that pollutants are degraded into products which are part of natural cycles. The generation of more fundamental knowledge on microbiological degradation, and kinetics involved therein, offers the possibility of broadening the field of application, especially for degrading non-easily biodegradable pollutants. This creates the opportunity of developing biological methods for the treatment of hazardous and toxic wastes.3,4 The biological detoxification of hazardous wastes is still largely an underdeveloped technology, even though biological treatment of hazardous substances has been shown to be a viable option. Bacterial species are known to possess a variety of detoxification skills. Single bacterial species may not have the ability to convert a toxicant to carbon dioxide and water. However, a consortium of bacteria and fungus can.5 Further, it is possible to use naturally occurring microorganisms and to enhance their activity by modifying and controlling the environment. Specially developed microorganisms have not been shown to be necessary in all cases.6 For example, biodegradation has been shown to be a very effective cleanup technique for gasoline components in contaminated soils. At 20°C in a well-mixed, aerated environment, the U.S. EPA priority pollutant gasoline components tested, with the exception of benzene, were reduced to below detection limits (LOD = 1.0 ppb) within 6.8 hours in all respirometer vessels tested using the indigenous microbial flora. For benzene, concentrations were reduced more than 99.9% in the biological test vessels; a 37.5% reduction was observed in the abiotic control.7 On-site and in-situ bioremediation have been used for the treatment of residues from petroleum industries. Both these treatment methods are effective, but carry a number of limitations. These limitations may rise from the difficulty in establishing and maintaining the consortium of microorganisms needed due to problems with supplemental nutrient delivery and mixing. For, example, the effectiveness of in-situ treatment technologies can experience process limitations due to restrictions of method and rate of nutrient addition (e.g., oxygen, nitrogen). Removing the soil and treating it above ground is an alternative which minimizes this limitation. However, these systems are currently operated as batch systems. In this mode, the diverse microbial colony needed to provide effective treatment must establish the appropriate co-metabolism reactions while the size of the population increases to appropriate levels. Even if effective nutrient addition is achieved, this microbial acclimation to the waste can take a protracted period of time. Therefore, for this treatment approach to be effective, virtually all of the contaminated soil must be moved above ground; thereby requiring an extensive surface area which generally must be enclosed in a manner to restrict intrusion of precipitation. 47th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 133
Object Description
Purdue Identification Number | ETRIWC199215 |
Title | Development of a kinetic model for continuous flow bioreactor treatment of petroleum contaminated soils |
Author |
Britto, Ronald Sherrard, Joseph H. Truax, Dennis D. |
Date of Original | 1992 |
Conference Title | Proceedings of the 47th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,43678 |
Extent of Original | p. 133-142 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
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Color Depth | 8 bit |
Description
Title | page 133 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | 15 DEVELOPMENT OF A KINETIC MODEL FOR CONTINUOUS FLOW BIOREACTOR TREATMENT OF PETROLEUM CONTAMINATED SOILS Ronald Britto, Doctoral Candidate Joseph H. Sherrard, Professor and Department Chairman Dennis D. Truax, Associate Professor Department of Civil Engineering Mississippi State University Mississippi State University, Mississippi 39762 INTRODUCTION Significant quantities of petroleum compounds are released into the soil environment, either from leakages of underground storage tanks (USTs) or due to accidental spills. The EPA has recently reported that 100,000 UST leaks have been identified, and that the number might triple in the next several years.' Profiles of Army USTs, which are leaking, based on construction material, capacity, age and content have shown just how complex it will be to evaluate and undertake cleanup processes.2 The application of biological processes in controlling environmental problems has increased strongly during the past decade. A characteristic and important aspect of biological processes is the feature that pollutants are degraded into products which are part of natural cycles. The generation of more fundamental knowledge on microbiological degradation, and kinetics involved therein, offers the possibility of broadening the field of application, especially for degrading non-easily biodegradable pollutants. This creates the opportunity of developing biological methods for the treatment of hazardous and toxic wastes.3,4 The biological detoxification of hazardous wastes is still largely an underdeveloped technology, even though biological treatment of hazardous substances has been shown to be a viable option. Bacterial species are known to possess a variety of detoxification skills. Single bacterial species may not have the ability to convert a toxicant to carbon dioxide and water. However, a consortium of bacteria and fungus can.5 Further, it is possible to use naturally occurring microorganisms and to enhance their activity by modifying and controlling the environment. Specially developed microorganisms have not been shown to be necessary in all cases.6 For example, biodegradation has been shown to be a very effective cleanup technique for gasoline components in contaminated soils. At 20°C in a well-mixed, aerated environment, the U.S. EPA priority pollutant gasoline components tested, with the exception of benzene, were reduced to below detection limits (LOD = 1.0 ppb) within 6.8 hours in all respirometer vessels tested using the indigenous microbial flora. For benzene, concentrations were reduced more than 99.9% in the biological test vessels; a 37.5% reduction was observed in the abiotic control.7 On-site and in-situ bioremediation have been used for the treatment of residues from petroleum industries. Both these treatment methods are effective, but carry a number of limitations. These limitations may rise from the difficulty in establishing and maintaining the consortium of microorganisms needed due to problems with supplemental nutrient delivery and mixing. For, example, the effectiveness of in-situ treatment technologies can experience process limitations due to restrictions of method and rate of nutrient addition (e.g., oxygen, nitrogen). Removing the soil and treating it above ground is an alternative which minimizes this limitation. However, these systems are currently operated as batch systems. In this mode, the diverse microbial colony needed to provide effective treatment must establish the appropriate co-metabolism reactions while the size of the population increases to appropriate levels. Even if effective nutrient addition is achieved, this microbial acclimation to the waste can take a protracted period of time. Therefore, for this treatment approach to be effective, virtually all of the contaminated soil must be moved above ground; thereby requiring an extensive surface area which generally must be enclosed in a manner to restrict intrusion of precipitation. 47th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118. Printed in U.S.A. 133 |
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