Application of microbially induced calcium carbonate precipitation with urea hydrolysis to improve the mechanical properties of soil

Abstract

Microbially induced calcium carbonate precipitation (MICP) is a process that has emerged as an alternative and sustainable ground improvement approach in geotechnical and civil engineering for improving the mechanical properties of soil. Urease-producing bacteria accelerate the process of MICP by converting urea into ammonium and carbonates ions. Precipitated CaCO3 acts as a binder to adjacent soil particles, forming larger aggregates that eventually lead to increased soil strength and stiffness. In this review, we explore the importance of MICP to improve the mechanical properties of soil so that it will be more suitable for construction and environmental purposes. Furthermore, different treatment processes and environmental factors are also discussed that affect the production of urease and carbonate precipitation. This method has many features as compared to the conventional methods. For example, it is eco-friendly, improves vegetation, bears the lower operational cost, and is sustainable. MICP is mostly studied for lab-scale and limited to field-scale application. In order to achieve its large-scale application in natural and engineered conditions, we need to encourage collaboration among the microbiologists, geologists, and geotechnical engineers throughout the world.