POSTER MICP Symposium Barrett Poster
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Investigating Microbially Induced Calcite Precipitation for Fracture
Permeability Reduction in RocksNicholas Bucci, Huijie Lu PhD, Ehsan Ghazanfari PhD.
Civil and Environmental Engineering
ABSTRACT APPARATUS RESULTS
Barrett Research Scholarships
Microbially Induced Calcite Precipitation (MICP) is a bio-
geochemical process that produces calcium carbonate precipitation
within a pours media matrix such as soil, or bedrock. Preventing
contaminant migration via fracture networks in bedrock is extremely
important for preserving our precious groundwater resources. MICP
offers an attractive alternative method for permeability reduction to
traditional grouting/cementation technologies due to its low
viscosity reagents and low-pressure application technique. The
effectiveness of MICP for rock fracture sealing and permeability
reduction is being comprehensively evaluated for the distribution
patterns of CaCO3 precipitation, and the resistance of precipitates to
long-term persistent changes in temperature, pressure, and
groundwater flows in subsurface environments. This research is
exploring and developing the necessary laboratory methodologies,
apparatuses, and procedures required to generate accurate data in
support of MICP use in situ.
Pre-MICP Computed Tomography Scan:
Skyscan 1173 High Energy Micro-CT
Vacuum Chamber Saturation
Pre-MICP Constant Head Hydraulic Conductivity Test
ASTM D5084-10 =
1 bacterial broth flush (Sporosarcina Pasteurii)
2 reagent flushes ( 1M CO(NH2)2 + 1M CaCl2(2H2O) + 1000mL H2O)
Post-MICP Computed Tomography Scan:
Post-MICP Constant Head Hydraulic Conductivity Test
CT Image Analysis
Effluent Concentration Analysis
Break down apparatus, visually observe the rock core.
Lucas Howard, Robert Caulk, Max Graves, Andrea Pearce, Joan
Rosebush, Sara Dorr, Austin Grant, Kira Kelley, Anna Waldron
The test apparatus was loosely modeled after an Autolab 1500 tri-axial
cell, and optimized for the needs of this research.
Top and bottom core holders were fabricated from plastic rather than
expensive and excessively durable titanium or aluminum.
Fluid confining pressure was removed due to low pressure reagent flow
High resolution cross sectional
images were generated using a
Skyscan 1173 High Energy
Micro-CT scanner. A software
uses data collected from
penetrative X-rays with complex
algorithms which allows these
cross sections to be created.
Small changes in fracture
aperture are visible at this
printed resolution, however the
images must be digitally
observed at full resolution and
zoom in order to begin
volumetrically quantifying the
precipitation within the fracture.
* This research is ongoing
Groundwater contaminants can originate from septic
tanks, nuclear waste disposal, and anything in
between. These contaminants easily migrate through
shallow soils and into bedrock fracture networks
until ending up in a groundwater resources that may
end up being consumed by humans.
A constant head Hydraulic
Conductivity Test was
performed in accordance to
ASTM D5084-10 on the first
sandstone rock core before
and after MICP treatment in
order to quantify the changes
in permeability that occurred.
The test involves flowing
water through the rock core
by means of head pressure
and recording the effluent
flow rate. Three trials were
performed to ensure results
were precise and to calculate a
more accurate average value.
K value:Pre MICP = (9.5452 +/- stdev)*m/sPost MICP = (1.5355 +/- stdev)*m/s
Preliminary results suggest permeability reductions
as high as 84% after being treated with MICP.