Time-Lapse Electrical Geophysical Monitoring of Amendment-Based Biostimulation

Area of Science:

• Environmental Geophysics
• Hydrogeology
• Bioremediation

Background:

• Biostimulation accelerates microbial remediation of groundwater contaminants.
• Effective amendment emplacement and monitoring are crucial for remediation success.
• Traditional sampling methods are costly and provide limited data.

Purpose of the Study:

• To demonstrate the utility of time-lapse electrical resistivity tomography (ERT) for monitoring amendment emplacement and biogeochemical processes in groundwater remediation.
• To validate ERT's ability to quantitatively assess amendment distribution and geochemical properties.

Main Methods:

• Field application of time-lapse ERT during a biostimulation remediation project.
• Calibration of petrophysical relations using geochemical fluid sampling.
• Validation of ERT predictions against sequestered fluid sample results.
• Augmentation of data with crosshole radar and borehole geophysical logging.

Main Results:

• ERT successfully delineated amendment transport for 10 months post-emplacement.
• Observed changes in electrical properties indicated subsequent mineral precipitation.
• Field validation confirmed ERT's potential for quantitative assessment of geochemical properties.

Conclusions:

• Time-lapse ERT is a cost-effective geophysical tool for monitoring amendment emplacement and remediation performance.
• ERT complements limited field sampling, improving spatial and temporal monitoring capabilities.
• Electrical geophysics offers quantitative insights into amendment-related geochemical changes during bioremediation.