Researchers at the Indian Institute of Technology (IIT) Mandi have developed a sustainable technique for soil stabilization using a harmless bacteria called S. Pasteury which hydrolyses urea to precipitate calcite. According to an IIT Mandi release, the process does not involve hazardous chemicals and natural resources can be used in a sustainable manner.
Traditionally, mechanical processes such as compression and chemical processes such as the injection of chemical grout fluid into the soil have been used for soil stabilization.
Soil stabilization is the process of providing long lasting strength to the soil by artificial means. It is used when construction work has to be done on an unstable base or to protect the soil from erosion.
In this method, bacteria are used to produce calcium carbonate (calcite) within soil pores, which binds the individual grains together, thereby increasing soil strength, the statement said.
In the past decades, an environmentally friendly and sustainable soil stabilization technique – microbial induced calcite precipitation (MICP) – has been investigated worldwide.
Speaking about his research, Dr. Uday, (Assistant Professor), School of Engineering, said, – Our study aims to improve the shear strength of soils at area scale, in hilly areas and during soil erosion. It will be helpful in designing microbial methods to protect against erosion. We are also working on the production of micro-organism-driven building materials from mine waste.
His experimental setup consisted of a column of sand through which a mixture of bacteria and a cementing solution of urea, calcium chloride, nutrient broth, etc.
The statement further said: – The use of urea is particularly attractive as it does not contain hazardous chemicals and natural resources can be used in a sustainable manner.
The research team’s findings have also been published in the journal “Geotechnical and Geo-Environmental Engineering of the American Society of Civil Engineers”.
Elaborating on the research work, Mr. Mori said – Calcite Precipitation Efficiency (CPE) depends on several parameters including but not limited to the concentration of cementing solution, its flow rate through the column, supply rate, applied pore volume, and so on. Characteristics of sand grains. We set out to understand the effects of different parameters on CPE.
