Electricity-reaction–diffusion system for microbially induced carbonate precipitation

Abstract

Microbially induced carbonate precipitation (MICP) has attracted attention as a novel soil-improvement technique. The precipitation and growth of calcium carbonate on the surface of sand and in its pores can be simulated using the recently proposed numerical simulation techniques. However, these simulations have not incorporated certain parameters, such as electrical properties and adsorption. The current study proposes a novel coupling system that considers the adsorption of microorganisms and dissolved ions due to the weak electrostatic field generated on the surface of sand. Additionally, the Michaelis–Menten model was introduced into the system for the enzymatic reaction of ureolytic bacteria, the Monod model for bacterial growth, and a chemotaxis model. To validate the proposed simulation model, previously reported experimental and computational results were compared with the suggested simulation results. Consequently, the calcium carbonate precipitation obtained with the simulation model was 0.335 μmol/mm3 at 10.3 h, which is close to that obtained by the experiment of 0.315 μmol/mm3. Moreover, the spatial distribution of calcium carbonate was consistent with the precipitation pattern of the active bonding structure obtained by the traditional experiment.