Carbonate Mineral Precipitation for Soil Improvement Through Microbial Denitrification

• Published in: Geomicrobiology journal Vol. 34; no. 2; pp. 139 - 146
• Main Authors: Hamdan, Nasser, Kavazanjian, Edward, Rittmann, Bruce E., Karatas, Ismail
• Format: Journal Article
• Language: English
• Published: New York Taylor & Francis 07.02.2017; Taylor & Francis Ltd
• Subjects: Alkalinity; Bacteria; Batch reactors; Bearing capacity; Biogas; Bioreactors; By-products; Byproducts; Calcium; Calcium carbonate; Calcium carbonates; Carbonate minerals; carbonate precipitation; Carbonates; Cementation; Chemical precipitation; Denitrification; Earthquakes; Erosion; Geotechnical engineering; Hydraulic properties; Instability; Levees; Liquefaction; microbially induced carbonate precipitation (MICP); Nitrogen dioxide; pH effects; Pore water; Pseudomonas denitrificans; Reactors; Sand; Scour; Scouring; Seepage; Seismic activity; Seismic engineering; Seismic response; Seismic stability; Shallow foundations; Slope stability; Soil; Soil erosion; Soil mechanics; Soil microorganisms; Soil properties; Soils
• ISSN: 0149-0451; 1521-0529
• DOI: 10.1080/01490451.2016.1154117

Microbially induced carbonate precipitation (MICP) and associated biogas production may provide sustainable means of mitigating a number of geotechnical challenges associated with granular soils. MICP can induce interparticle soil cementation, mineral precipitation in soil pore space and/or biogas production to address geotechnical problems such as slope instability, soil erosion and scour, seepage of levees and cutoff walls, low bearing capacity of shallow foundations, and earthquake-induced liquefaction and settlement. Microbial denitrification has potential for improving the mechanical and hydraulic properties of soils because it promotes precipitation of calcium carbonate (CaCO 3 ) and produces nitrogen (N 2 ) gas without generating toxic by-products. We evaluated the potential for inducing carbonate precipitation in soil via bacterial denitrification using bench-scale experiments with the facultative anaerobe Pseudomonas denitrificans. Bench-scale experiments were conducted (1) without calcium in an N-rich bacterial growth medium in 2.0 L glass batch reactors and (2) with a source of calcium in sand-filled acrylic columns. Changes of pH, alkalinity, NO 3 − and NO 2 − in the batch reactors and columns, quantification of biogas production and observations of calcium-carbonate precipitation in the sand-filled columns indicate that denitrification led to carbonate precipitation and particle cementation in the pore water as well as a substantial amount of biogas production in both systems. These results document that bacterial denitrification has potential as a soil improvement mechanism.