Microbial biofilms are ubiquitous within porous media and the dynamics of their growth influence surface and subsurface flow patterns which impacts the physical properties of porous media and large-scale transport of solutes. A two-dimensional pore-scale numerical model was used to evaluate the impact of biofilm-induced flow heterogeneities on conservative transport. Our study integrates experimental biofilm images of Paenibacillus 300A strain in a microfluidic device packed with cylindrical grains in a hexagonal distribution, with mathematical modeling. Biofilm is represented as a synthetic porous structure with locally varying physical properties that honors the impact of biofilm on the porous medium. We find that biofilm plays a major role in shaping the observed conservative transport dynamics by enhancing anomalous characteristics. More specifically, when biofilm is present, the pore structure in our geometry becomes more spatially correlated. We observe intermittent behavior in the Lagrangian velocities that switches between fast transport periods and long trapping events. Our results suggest that intermittency enhances solute spreading in breakthrough curves which exhibit extreme anomalous slope at intermediate times and very marked late solute arrival due to solute retention. The efficiency of solute retention by the biofilm is controlled by a transport regime which can extend the tailing in the concentration breakthrough curves. These results indicate that solute retention by the biofilm exerts a strong control on conservative solute transport at pore-scale, a role that to date has not received enough attention.

微生物生物膜在多孔介质中无处不在，它们的生长动力学会影响表面和表面下的流动模式，从而影响多孔介质的物理性质和溶质的大规模传输。二维孔隙尺度数值模型用于评估生物膜诱导的流动异质性对保守运输的影响。我们的研究整合了类芽孢杆菌 300A 的实验生物膜图像用数学建模在填充有六边形分布的圆柱形颗粒的微流体装置中产生应变。生物膜被表示为具有局部变化的物理特性的合成多孔结构，以体现生物膜对多孔介质的影响。我们发现生物膜通过增强异常特征在塑造观察到的保守运输动力学方面发挥着重要作用。更具体地说，当生物膜存在时，我们几何中的孔隙结构在空间上变得更加相关。我们观察到拉格朗日速度的间歇性行为，它在快速传输周期和长捕获事件之间切换。我们的结果表明，间歇性增强了突破曲线中的溶质扩散，这些曲线在中间时间表现出极端的异常斜率，并且由于溶质保留而非常显着地延迟溶质到达。生物膜的溶质保留效率受传输机制控制，该机制可以延长浓度突破曲线中的拖尾。这些结果表明，生物膜对溶质的保留对孔隙尺度的保守溶质运输施加了强有力的控制，这一作用迄今为止尚未受到足够的关注。