Summary
The study will help in designing microbial methods to improve soil shear strength at the field scale to protect the soil from erosion in hilly areas and during geo-disasters
The findings of the research team have been recently published in the journal ‘Geotechnical and Geo-environmental Engineering of the American Society of Civil Engineers (ASCE)’
A team of researchers from Indian Institute of Technology (IIT) Mandi has developed sustainable techniques for soil stabilisation using a harmless bacteria called S. Pasteurii that hydrolyses urea to precipitate calcite.
The process does not involve hazardous chemicals and natural resources can be used sustainably. The findings of the research team have been recently published in the journal ‘Geotechnical and Geo-environmental Engineering of the American Society of Civil Engineers (ASCE)’.
Soil stabilisation is the process of conferring long-term permanent strength to the soil by artificial means. It is used when construction work must be carried out on unstable grounds or to protect soil from erosion. Traditionally, mechanical processes such as compression and chemical processes such as the injection of chemical grout fluids into the soil are used for soil stabilisation.
K V Uday, assistant professor, School of Engineering, who led the research, said, “Our study will be helpful in designing microbial methods to improve soil shear strength at the field scale to protect the soil from erosion in hilly areas and during geo-disasters. We are also working on the microbe-driven production of construction material from quarry waste.”
In the past decades, an eco-friendly and sustainable soil stabilisation technique – Microbial Induced Calcite Precipitation (MICP) – is being investigated worldwide. In this method, bacteria are used to produce calcium carbonate (calcite) within soil pores, which cements the individual grains together, thereby enhancing the soil/ground strength.
“While there are studies worldwide on the development of MICP techniques for soil stabilisation, the factors that affect the efficacy of the process are still not completely understood,” added Uday.
The researchers used a harmless bacteria called S. Pasteurii that hydrolyse urea to precipitate calcite. The use of urea is particularly attractive because it does not involve hazardous chemicals and natural resources can be used sustainably. Their experimental setup consisted of a column of sand through which was percolated a mixture of the bacteria and cementing solution comprising urea, calcium chloride, nutrient broth, etc.
“The Calcite Precipitation Efficiency (CPE) depends on a number of parameters including and not limited to the concentration of the cementing solution, its flow rate through the column, the supply rate, applied pore volume, and the sand grain characteristics. We set out to understand the effects of various parameters on the CPE,” said MS scholar Deepak Mori who co-authored the research journal.
Last updated on 11 Apr 2022
