Biological mineralization processes have shown promise in addressing common soil engineering problems. In stabilization of soils using biomineralization, a microbial process is employed to produce mineral crystals between soil grains or clods that bind them together into a solid mass. An example of this process is the microbial-induced calcite precipitation (MICP). MICP can have several forms, including bioaugmentation and biostimulation of ureolytic microorganisms, sulfate reducing microorganisms, iron reducing microorganisms, denitrifying bacteria, and others. The process needs careful application; if crusts develop too thick or strong, revegetation of slopes may not be feasible. In this study, laboratory and field experiments were performed to demonstrate the  effectiveness of MICP treatment to produce soil crusting that can mitigate soil erosion potential while still allowing revegetation after construction or wildfire. Both wind and water erosion of slopes poses problems to highways after construction or fires. As wind erodes the surface, the fine particulate matter created from burned organics easily becomes airborne, reducing air quality and visibility. Unfortunately, no technical or silvicultural measures for large areas are currently available that could be put into place to make a forest fire area safe from erosion with reasonable amount of time and effort. This study expands the knowledge of MICP treatments on various soil types, particularly soils subjected to wildfire and new construction, through the development of a versatile technology, herein referred to as BioCaN (biological soil treatments with calcium and nitrogen).  Different BioCaN soil applications were applied to burned, unburned, and clean sand soils in factorially designed laboratory experiments to test soil performance enhancement on key soil engineering properties.  Naturally simulated conditions were created to test treated soils for wind erosion resistance, rainfall impact/sheet flow resistance, seed germination, vegetation reestablishment, and surface strength crust development. The developed BioCaN technology should be a valuable tool to add to the erosion control toolbox. Although not usable in every condition, the BioCaN treatment is effective after fires, on sandy and clayey soils, and on steep and gentle slopes. It aids in revegetation, and, in some situations, may even accelerate revegetation. The technology does have some environmental impacts, but these are similar to those associated with other erosion control technologies. When faced with difficult erosion and revegetation problems, DOT managers will benefit from considering BioCaN for evaluation and implementation, depending on the specifics of the situation.

The final report is available.