Biological improvement of sandy soil by microbial induced carbonate precipitation

Microbial-induced calcite precipitation (MICP) is a relatively green andsustainable soil improvement technique. It refers to a chemical reaction network thatis managed and controlled within soil through biological activity and whosebyproducts alter the engineering properties of soil. To treat soil, first, the microbialpopulation in-situ is augmented by the injection of additional urease positivebacteria and then reagents are added. A series of laboratory test was carried out toinvestigate the potential application of the technique in improving the strength andimpermeability of a sand specimen and utilized techniques, materials, methods andempirical process during the test are explained. The results showed that as a result ofthe calcite precipitation, shear wave velocity increased up to 1000m/s and UCSstrength increased to about 300Kpa and permeability of soil decreased significantlyupon MICP treatment.