Bacteria transport in an unsaturated porous media: incorporation of air–water interface area model into transport modelling

The bacterial transport model into which the air–water interface (AWI) area model is incorporated is developed in this study. At the outset, the AWI area models are analysed to determine the appropriate model. In the analysis, three models are evaluated with the previously reported experimental data, and the modified form of the Niemet et al. (2002) model is selected as an appropriate AWI area model, which is then combined into the transport model. The bacterial transport model is used to fit the bacterial breakthrough data in an unsaturated porous media from the literature, and the fitting results show that the model matches well with the observed data at three different air contents by varying the specific AWI area. On the basis of the sorption‐related parameters determined from the literature, simulations are performed to examine bacterial transport in three different soils under unsaturated and transient flow conditions. The results illustrate that bacteria can travel to different depths in unsaturated soils depending on the soil type and water content. Even if the predictive model presented in this study is not comprehensive, it will help to understand bacterial transport behaviour in an unsaturated porous media.