Modeling anaerobic dechlorination of polychlorinated biphenyls

Demirtepe, Hale
This study aims to investigate the fate of polychlorinated biphenyls (PCBs) in sediments via using an anaerobic dechlorination model (ADM). PCBs are ubiquitous environmental pollutants, accumulated mostly in aquatic sediments. Significant attention was placed on the anaerobic dechlorination of PCBs since this process leads to the conversion of highly-chlorinated biphenyls to lower chlorinated ones, resulting in less toxic and more biodegradable congeners. An ADM was developed previously for the identification and quantification of anaerobic dechlorination pathways. In the present study, this model was improved and applied to laboratory and environmental sediment PCB data from Baltimore Harbor (BH), Maryland, USA, where PCB contamination has been recorded. The laboratory PCB data was from a 500 day microcosm study conducted with BH sediments which was used to validate the model, as well as to gather information on dominant dechlorination pathways affecting the sediments. ADM predicted the laboratory PCB data almost perfectly and subsequently very well predicted the environmental sediment PCB profiles. A complete identification and quantification of the anaerobic dechlorination pathways occurring in the BH sediments is achieved with this study for the first time. The significant similarity between the sediment sample PCB profiles and the model predicted profiles reveals that the BH sediments have undergone anaerobic dechlorination via a combination of previously identified dechlorination activities (N, P, M) with selective pathways. Model findings are consistent with microbial analysis of the sediments. Better understanding of anaerobic dechlorination mechanisms should aid in predicting natural attenuation of PCBs or developing bioremediation strategies for contaminated sites.


Evaluation of PCB dechlorination pathways in anaerobic sediment microcosms using an anaerobic dechlorination model
Demirtepe, Hale; Kjellerup, Birthe; Sowers, Kevin R.; İmamoğlu, İpek (Elsevier BV, 2015-10-15)
A detailed quantitative analysis of anaerobic dechlorination (AD) pathways of polychlorinated biphenyls (PCBs) in sediment microcosms was performed by applying an anaerobic dechlorination model (ADM). The purpose of ADM is to systematically analyze changes in a contaminant profile that result from microbial reductive dechlorination according to empirically determined dechlorination pathways. In contrast to prior studies that utilized modeling tools to predict dechlorination pathways, ADM also provides quant...
Modeling natural attenuation of petroleum hydrocarbons (btex) in heterogeneous aquifers
Uçankuş, Tuğba; Ünlü, Kahraman; Department of Environmental Engineering (2005)
Natural Attenuation can be an effective cleanup option for remediation of Groundwater contamination by BTEX. One of the important aspects of the methodology that has been recognized recently is that mass removal rates, the most important parameters used to determine effectiveness of the methodology, is controlled by groundwater flow regime, which to a large extent controlled by aquifer heterogeneity. Considering this recognition, the primary objective of this research is to quantitatively describe the relat...
Transport of metals leaching from land-disposed oil field wastes
Ünlü, Kahraman (SAGE Publications, 1998-12-01)
The potential for groundwater contamination by metals leaching from land-disposed oil field exploration and production (E&P) wastes is an environmental concern. In this study a geochemical transport model is adopted to consider multispecies metal migration. Objectives are to characterize the chemical composition of E&P wastes, to evaluate the mobility and pollution potential of metals in E&P wastes and to investigate the utility of simplified modelling approaches. A chemical transport model coupling a hydro...
Modeling of catalytic ozonation process in a three-phase reactor
Erol, Funda; Oezbelge, Tuelay A.; Oezbelge, H. Oender (Informa UK Limited, 2009-01-01)
In this research, the main objective was to determine the flow characteristics of a three-phase reactor in order to use this knowledge in the modeling of catalytic ozonation of aqueous dye solutions. Therefore, the stimulus-response method was used in the tracer experiments; thus, the degree of liquid mixing in the reactor was estimated by means of residence time distribution, Peclet number and axial dispersion coefficient in the presence and the absence of the catalyst. Experimental data were obtained by p...
A simplified approach for slope stability analysis of uncontrolled waste dumps
TÜRER, DİLEK; Türer, Ahmet (SAGE Publications, 2011-02-01)
Slope stability analysis of municipal solid waste has always been problematic because of the heterogeneous nature of the waste materials. The requirement for large testing equipment in order to obtain representative samples has identified the need for simplified approaches to obtain the unit weight and shear strength parameters of the waste. In the present study, two of the most recently published approaches for determining the unit weight and shear strength parameters of the waste have been incorporated in...
Citation Formats
H. Demirtepe, “Modeling anaerobic dechlorination of polychlorinated biphenyls,” M.S. - Master of Science, Middle East Technical University, 2012.