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Benzene degradation coupled with chlorate reduction in a soil column study
N C G Tan1, W van Doesburg, A A M Langenhoff
1Department Agrotechnology and Food Sciences Laboratory of Microbiology, Wageningen University and Research center, Hesselink van Suchtelenweg 4, 6703 CT, Wageningen, The Netherlands. nico.tan@wur.nl
Biodegradation
|February 3, 2006
Summary
This study shows that chlorate reduction in soil columns effectively stimulates benzene biodegradation. The produced oxygen activates benzene, leading to high degradation rates without breakthrough.
Area of Science:
- Environmental Science
- Microbiology
- Environmental Chemistry
Background:
- Persistent pollutants like benzene pose environmental challenges.
- Electron acceptors are crucial for anaerobic degradation processes.
- Oxygen production via reduction of electron acceptors can activate recalcitrant compounds.
Purpose of the Study:
- To investigate chlorate as an electron acceptor for stimulating benzene degradation in anoxic soil.
- To determine the efficiency and rate of benzene biodegradation coupled with chlorate reduction.
- To establish a column study demonstrating high-rate benzene biodegradation under these conditions.
Main Methods:
- Operation of a benzene-polluted soil column amended with chlorate over 500 days.
- Monitoring benzene removal and chlorate reduction.
- Mass balance calculations to quantify reactant stoichiometry.
- Application of higher loading rates to determine maximal degradation capacity.
Main Results:
- Immediate benzene degradation observed upon column startup.
- Complete benzene removal was sustained, recovering after chlorate omission or high concentration.
- A stoichiometric ratio of 5 moles of chlorate reduced per mole of benzene degraded was determined.
- High benzene degradation rates were achieved, averaging 31 micromol l(-1) h(-1) with a maximum of 78 micromol l(-1) h(-1).
Conclusions:
- Anaerobic chlorate reduction effectively produces oxygen, activating benzene for biodegradation.
- This study presents the first column evidence of high-rate benzene biodegradation coupled with anaerobic chlorate reduction.
- The process demonstrates a promising strategy for remediating benzene-contaminated anoxic environments.