Anaerobic biotransformation of chlorinated alkenes

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1994

OSTI ID:6530117

Zhuang, P

Chlorinated alkenes are widely found in contaminated subsurface soil and groundwater. The highly chlorinated alkene (i.e., PCE) is not subject to aerobic biotransformation. The aim of this research was to explore the potential of using anaerobic processes (i.e., denitrification, sulfate-reduction and methanogenesis) for chlorinated alkenes biotransformation. Contaminated soil samples were used throughout this study. Soil microcosms simulating field anoxic conditions with various nutrients amendment, liquid microcosms as well as enrichment liquid cultures were developed to delineate the dechlorination process. The effect of biomass, chlorinated alkenes concentration and site specific conditions (e.g., temperature and pH) on the dechlorination and the primary metabolic process was investigated. The role of sorption and nutritional needs (i.e., electron donor) were also studied. A preliminary study revealed that denitrification was the least affected by low temperatures as compared to sulfate-reduction and methanogenesis. Although dechlorination took place under sequential denitrifying and methanogenic conditions and under sulfate-reducing conditions, further studies concluded that fermentative and methanogenic bacteria were responsible for the observed dechlorination. In most cases, dechlorination of PCE or TCE resulted in the accumulation of cDCE. However, a VC-producing culture was developed from the PCE-contaminated soil. In general, the dechlorination process could be enhanced by increasing electron donor and biomass concentration. At relatively low concentrations, the dechlorination rate was also increased with increasing chlorinated alkene concentration. Dechlorination even proceeded at high chlorinated alkene concentrations when methane production was inhibited. However, as the concentration of the chlorinated alkenes increased, severe toxicity eventually halted the dechlorination process.

• Research Organization: Clarkson Univ., Potsdam, NY (United States)
• OSTI ID: 6530117
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
550500 -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ALKANES
ALKENES
ANAEROBIC CONDITIONS
BACTERIA
BIODEGRADATION
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
DECHLORINATION
DECOMPOSITION
DEHALOGENATION
DENITRIFICATION
FEASIBILITY STUDIES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
METHANE
METHANOGENIC BACTERIA
MICROORGANISMS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
REMEDIAL ACTION
SOILS
SULFATE-REDUCING BACTERIA