Evaluation and Utilization of Aged Bacteria in MICP Technology

Area of Science:

• Microbiology
• Geochemistry
• Materials Science

Background:

• Aging of cultured urease-producing microorganisms impacts carbonate production.
• Previous research established apparent viability (Rcv) as a metric.

Purpose of the Study:

• To optimize carbonate production using a blending method for aged urease-producing microorganisms.
• To investigate the properties and behavior of a soil-biocement-liquid (BCS) system.
• To correlate carbonate content with microbial activity and soil adsorption.

Main Methods:

• Blending method optimization for aged microorganisms.
• Carbonate content analysis using acid dissolution.
• Penetration tests on soil-biocement-liquid (BCS) specimens.
• Measurement of optical density (OD) of viable bacteria.

Main Results:

• Significantly higher carbonate content was produced than the calcium chloride dihydrate (CaCl2 2H2O) used, indicating carbonate hydrate formation.
• Carbonate content depth distribution (C-profile) in BCS was measured.
• The C-profile was attributed to adsorption via the diffuse double layer of microorganisms.
• Formulas were derived to estimate precursor-carbonate (precursor CPR), viable OD, and adsorbed soil from C.

Conclusions:

• The blending method effectively enhances microbial carbonate precipitation.
• Microbial activity and soil adsorption can be estimated from carbonate content distribution in BCS.
• The study provides insights into the microscopic behavior of the BCS system.