A review on qualitative interaction among the parameters affecting ureolytic microbial-induced calcite precipitation

Ground improvement by the biological method is considered to be one of the most preferred sustainable methods for improving engineering properties of soil in comparison to the physical, mechanical and chemical methods. One of such biological method, ureolytic microbial-induced calcite precipitation (UMICP), utilizes urease active bacteria to precipitate calcium carbonate to act as a binding material connecting soil grains. The state-of-the-art presents UMICP process is affected by various parameters briefly categorized under four major sections, viz., biological, chemical, geotechnical and environmental conditions. The critical review of the available literature elaborates the influence of each parameter. Limited studies have attempted to explore the interaction among the bio-geo-chemical parameters affecting the UMICP. With this in view, the current review article aims to elucidate the effect of most adopted factors from different sections to attain efficient process outcome. Further, an attempt has been made in terms of mapping the influence of factors by a process chart, which is deemed to be handy for a qualitative understanding of the interrelationship among these factors. The process chart can be useful for the researchers to understand the way forward in planning the process to scale the experimentation. Challenges to overcome for the sustainable future and possible solutions at field scale have also been described in brief.