How chemotaxis-biofilms competition controls NAPL biodegradation and pore clogging
E007
Abstract
The remediation of non-aqueous phase liquids (NAPLs) in subsurface environments poses a persistent challenge due to the low solubility of these substances and the tendency of biofilms to induce pore clogging, both of which limit contaminant accessibility. In this seminar, I will present a new continuum-scale bioreactive transport model exploring how two key microbial strategies -chemotactic motility and biofilm formation – compete during NAPL biodegradation in porous media. By integrating NAPL dissolution, solute diffusion, chemotactic migration, microbial growth, and biofilm-induced pore clogging, the model reveals how microbial interactions govern both degradation efficiency and pore space accessibility. Our results show that biofilms development progressively restricts bacterial motility, driving the system towards a growth-dominated regime characterized by increased clogging and reduced contaminant accessibility. Concurrently, chemotactic bacteria inhibit clogging by out-competing biofilm formers; however, this comes at the cost of slower overall degradation. These findings underscore microbial competition as both a challenge and a potential control mechanism for bioremediation and for other subsurface processes, including underground gas storage, where controlling microbial activity and bioclogging is essential.