Hydraulic conductivity of compacted soils controlled by microbial activity
Environmental Technology
|June 25, 2014
Summary
Microbial activity can clog soil pores, reducing hydraulic conductivity in compacted silt-bentonite. Antibiotics restored flow, showing potential for biomediated control of contaminant transport in liners.
Area of Science:
- Environmental Science
- Geotechnical Engineering
- Microbiology
Background:
- Hydraulic conductivity is crucial for understanding liquid flow in porous media and contaminant transport.
- Microbial activity within soil pores can significantly alter subsurface flow dynamics.
Purpose of the Study:
- To investigate the impact of microbial growth and decay on the hydraulic conductivity of compacted silt-bentonite.
- To explore the potential of biomediated reactions for controlling flow rates in soil liners.
Main Methods:
- Long-term permeation tests were conducted on silt-bentonite mixtures using distilled water and a nutrient solution.
- The effects of microbial activity were assessed by monitoring hydraulic conductivity over time.
- Antibiotics and antifungals were injected to observe their impact on microbial activity and hydraulic conductivity.
Main Results:
- Hydraulic conductivity decreased over time due to bioclogging as microbial growth occurred.
- The injection of antibiotics and antifungals led to a recovery in hydraulic conductivity, indicating microbial decay.
- Biomediated reactions were shown to influence the flow rate through compacted soil.
Conclusions:
- Microbial processes, specifically bioclogging, significantly reduce hydraulic conductivity in compacted silt-bentonite.
- Controlling microbial activity through agents like antibiotics offers a method to manage and restore hydraulic conductivity.
- These findings suggest that biomediated reactions can be harnessed to regulate flow in engineered soil barriers.
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