Kinetics and Inhibition of Reductive Dechlorination of Trichloroethene,cis-1,2-Dichloroethene and Vinyl Chloride in a Continuously Fed Anaerobic Biofilm Reactor

2011 ◽  
Vol 45 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Sudeep C. Popat ◽  
Marc A. Deshusses
Keyword(s):  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Biofilm Reactor

scholarly journals Auxiliary Substrates for Elimination of Trichloroethene, Monochlorobenzene, and Benzene in a Sequential Anaerobic–Aerobic GAC Biobarrier

2007 ◽  
Vol 7 (1 & 2) ◽  
pp. 68
Author(s):  
M. Gozan ◽  
A. Mueller ◽  
A. Tiehm
Keyword(s):  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Biological Degradation ◽  
Anaerobic Conditions ◽  
Batch Studies ◽  
Second Stage ◽  
Competitive Reactions ◽  
Novel Concept ◽  
Tce Degradation ◽  
Granulated Activated Carbon

Sequential anaerobic-aerobic barrier is a novel concept for groundwater bioremediation. Trichloroethene (TCE), monochlorobenzene (MCB), and benzene (BZ) were used as model contaminants representing contaminant cocktails frequently found in the contaminated subsurface. The autochthonous microflora from a contaminated field was inoculated to eliminate model contaminants in a set of sequential anaerobic–aerobic granulated activated carbon (GAC) columns and batch studies. In the anaerobic column, the TCE was reductively dechlorinated through cis-dichloroethene (cis-DCE), vinyl chloride (VC), and ethene (ETH). Ethanol and sucrose as auxiliary substrates were added to donate electrons. In the second stage, MCB, BZ, and the lower chlorinated metabolites of TCE degradation, i.e. cis-Dichloroethene (cisDCE) and vinyl chloride (VC), were oxidatively degraded with addition of hydrogen peroxide and nitrate. This paper examines the influence of auxiliary substrates on the biological degradation of model pollutants. In the anaerobic barrier, the auxiliary substrates supply should be maintained low but stoichiometrically adequate for supporting reductive dechlorination. Supplying higher amount of auxiliary substrates provoked competitive reactions in anaerobic conditions, such as sulfate reduction and methanogenesis. If the auxiliary substrates are not utilized completely in the anaerobic phase, the remaining compounds flow into the aerobic phase. This led to unwanted conditions, i.e. oxidation of auxiliary substrates instead of pollutant elimination, and a higher consumption of electron acceptors. In the aerobic barrier, in particular, ethene proved to be a suitable auxiliary substrate for cometabolic degradation of cisDCE.

Sequential anaerobic/aerobic biodegradation of chlorinated hydrocarbons in activated carbon barriers

2002 ◽  
Vol 2 (2) ◽  
pp. 51-58 ◽  
Author(s):  
A. Tiehm ◽  
M. Gozan ◽  
A. Müller ◽  
H. Schell ◽  
H. Lorbeer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Biological Activity ◽  
Activated Carbon ◽  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Chlorinated Hydrocarbons ◽  
Aerobic Biodegradation ◽  
Anaerobic Conditions ◽  
Biological Activated Carbon ◽  
Batch Tests

The aim of this study is to develop a long lasting, sequential anaerobic/aerobic biological activated carbon barrier. In the biobarrier, pollutant adsorption on granular activated carbon (GAC) and biodegradation occur simultaneously. Trichloroethene (TCE), chlorobenzene (CB), and benzene were used as model pollutants. In the first barrier, that was operated under anaerobic conditions with sucrose and ethanol as auxiliary substrates, TCE was completely converted to lower chlorinated metabolites, predominantly cis-dichloroethene (cis-DCE). The reductive dechlorination process was stable for about 300 d, although the concomitant sulphate-reducing and methanogenic processes varied considerably. In the second barrier, that was operated with addition of hydrogen peroxide and nitrate, dechlorination was limited by a lack of oxygen and restricted mainly to CB biodegradation. Additional aerobic batch tests revealed that the metabolites of anaerobic TCE dechlorination, i.e. cis-DCE and vinyl chloride, were oxidatively dechlorinated in the presence of suitable auxiliary substrates such as ethene, CB, benzene, or sucrose and ethanol. During periods of low biological activity, elimination of TCE and CB occurred by adsorption in the GAC barriers. The pre-sorbed pollutants were available for subsequent biodegradation resulting in a bioregeneration of the activated carbon barriers.

Reductive Dechlorination of the Vinyl Chloride Surrogate Chlorofluoroethene in TCE-Contaminated Groundwater

2005 ◽  
Vol 39 (17) ◽  
pp. 6777-6785 ◽  
Author(s):  
Elliot Ennis ◽  
Ralph Reed ◽  
Mark Dolan ◽  
Lewis Semprini ◽  
Jonathan Istok ◽  
...  
Keyword(s):  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Contaminated Groundwater

scholarly journals Genetic Identification of a Putative Vinyl Chloride Reductase in Dehalococcoides sp. Strain BAV1

2004 ◽  
Vol 70 (10) ◽  
pp. 6347-6351 ◽  
Author(s):  
Rosa Krajmalnik-Brown ◽  
Tina Hölscher ◽  
Ivy N. Thomson ◽  
F. Michael Saunders ◽  
Kirsti M. Ritalahti ◽  
...  
Keyword(s):  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Complete Sequence ◽  
Mixed Cultures ◽  
Genetic Identification ◽  
Degenerate Primers ◽  
Transcription Analysis ◽  
Reductive Dehalogenase ◽  
Conserved Regions ◽  
Rdase Genes

ABSTRACT Dehalococcoides sp. strain BAV1 couples growth with the reductive dechlorination of vinyl chloride (VC) to ethene. Degenerate primers targeting conserved regions in reductive dehalogenase (RDase) genes were designed and used to PCR amplify putative RDase genes from strain BAV1. Seven unique RDase gene fragments were identified. Transcription analysis of VC-grown BAV1 cultures suggested that bvcA was involved in VC reductive dechlorination, and the complete sequence of bvcA was obtained. bvcA was absent in Dehalococcoides isolates that failed to respire VC, yet was detected in four of eight VC-respiring mixed cultures.

Sign in / Sign up

Export Citation Format

Share Document