Transport of chemotactic bacteria in granular media with randomly distributed chemoattractant-containing NAPL ganglia: Modeling and simulation

•Bacterial chemotaxis may accelerate the remediation of NAPL with low solubility.•Chemotactic bacteria accumulate near oil ganglia to a greater extent.•Chemotaxis and preferential sorption to oil contribute to bacterial accumulation.•Bacterial transport in porous media with oil required model with two-site sorption.•Resolving chemoattractant gradients is vital to capturing the chemotactic velocity.