Modeling the effects of microbial competition and hydrodynamics on the dissolution and detoxification of dense nonaqueous phase liquid contaminants.
The real significance and engineering potential for bioenhanced dissolution of chlorinated ethene dense nonaqueous phase liquid (DNAPL) contaminants are currently not well understood, in part because they can be influenced by a complex set of factors, including microbial competition for growth substrates. Mathematical simulations were performed to evaluate the effects of competition between Dehalococcoides ethenogenes and Desulfuromonas michiganensis for the electron acceptor tetrachloroethene (PCE) on the distribution of dehalorespirers, PCE dissolution, and the extent of PCE detoxification. The modeling results demonstrate that the outcome of competition between populations for growth substrates can have a significant impact on bioenhancement and, thus, on DNAPL source zone longevity and identify the key factors in determining the outcome of competition and its effects on DNAPL dissolution. The potential for bioenhancement is greatest at lower groundwater velocities. At higher velocities, kinetic properties play a key role in determining which population dominates and where, and the amount of bioenhancement that is realized. Engineered bioremediation techniques that maintain multiple dehalorespiring populations may offer the best approach for optimizing the twin cleanup goals of reduced source zone longevity and complete detoxification while maximizing the utilization of added electron donors.
Becker
Jennifer G
JG
Department of Environmental Science, University of Maryland, College Park, Maryland 20742, USA. jgbecker@umd.edu
Seagren
Eric A
EA
D001419:Bacteria / Q000378:metabolism*; D004980:Ethane / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism* / Q000633:toxicity; D008962:Models, Theoretical; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
D006843:Hydrocarbons, Chlorinated; D014874:Water Pollutants, Chemical; C016134:tetrachloroethane; D004980:Ethane