Abstract The biofilm plays an important role in NAPL bioremediation, natural attenuation and the flow behaviour of contaminant in porous media. Therefore, NAPL biodegradation in the presence of any bacteria in the porous media needs to be considered for more accurate prediction of contaminant remediation from the soil and groundwater. The complex interaction between the NAPL biodegradation/dissolution and physiochemical bacteria (biofilm) growth which depends on both time and space results in difficulties in simulation of NAPL bioremediation in the porous media. In this work, the natural attenuation process is simulated using three-dimensional pore network models to investigate natural bioremediation and dissolution of NAPL in presence of different heterogeneities arising from uncorrelated and correlated pore radii distribution. The impact of an additional phase (biofilm) on transport and NAPL dissolution is dynamically incorporated in the pore network model with simplifying assumptions such as fully available NAPL for biodegradation and dissolution. Under such assumptions, the results indicate that as pore scale heterogeneity (in the form of correlation length of pore radii of pore networks) increases, the biofilm growth decreases resulting in a reduction of NAPL bioremediation and dissolution. As such it is critical to consider pore scale heterogeneity in predicting bioremediation efficiency. Additionally, we found that Kozeny-Carman equation fail to predict the permeability changes due to biofilm growth/extinction.

中文翻译：

---

通过孔隙网络模型描绘的含水层自然衰减中生物膜生长、NAPL 生物降解和微尺度异质性的相互作用

摘要 生物膜在 NAPL 生物修复、自然衰减和污染物在多孔介质中的流动行为中起着重要作用。因此，需要考虑在多孔介质中存在任何细菌的情况下的 NAPL 生物降解，以更准确地预测土壤和地下水中的污染物修复。NAPL 生物降解/溶解与物理化学细菌（生物膜）生长之间复杂的相互作用取决于时间和空间，导致在多孔介质中模拟 NAPL 生物修复的困难。在这项工作中，使用三维孔隙网络模型模拟自然衰减过程，以研究在存在由不相关和相关的孔隙半径分布引起的不同异质性的情况下 NAPL 的自然生物修复和溶解。附加相（生物膜）对运输和 NAPL 溶解的影响通过简化假设动态纳入孔隙网络模型，例如完全可用的 NAPL 用于生物降解和溶解。在这样的假设下，结果表明，随着孔隙尺度异质性（以孔隙网络孔隙半径的相关长度的形式）增加，生物膜生长减少，导致 NAPL 生物修复和溶解减少。因此，在预测生物修复效率时考虑孔隙尺度的异质性至关重要。此外，我们发现 Kozeny-Carman 方程无法预测由于生物膜生长/灭绝引起的渗透性变化。