Biocementation of sand by Sporosarcina pasteurii strain and technical-grade cementation reagents through surface percolation treatment method

The use of microbially induced carbonate precipitation (MICP) to produce biocementitious material for soil stabilization has emerged in recent decades as a sustainable alternative approach to conventional methods. However, the use of standard analytical-grade reagents for various MICP studies makes this technology very expensive and unsuitable for field-scale consideration. In this present study, the feasibility of using commercially available and inexpensive technical-grade reagents for the cultivation of ureolytic bacteria and enhancement of soil stabilization was investigated. Low-cost growth media prepared in deionized water and tap water were used to cultivate Sporosarcina pasteurii as a replacement to standard laboratory-grade media. Biocement treatment was carried out on sand columns using different concentrations (0.25-1.0 M) of technical-grade and analytical-grade cementation solutions via surface percolation method. After 92 h of treatment, the columns were cured for 3 weeks at room temperature (26 +/- 2 degrees C) before analysing their respective surface strengths, CaCO3 content, pH of effluents and sand microscopic structures. The results indicated that the growth of bacteria in low-cost cultivation medium was similar to that observed in the standard cultivation medium. Surface strengths and CaCO3 contents of the consolidated samples were in the ranges of 11448.00 +/- 69.00-4826.00 +/- 00 kPa and 5.56 +/- 1.15-33.24 +/- 0.59%, respectively. Overall, the obtained results of the current study encourage future MICP studies to utilize commercially available technical-grade reagents for economical MICP field-scale trials. (C) 2019 Elsevier Ltd. All rights reserved.