International Journal of Engineering and Technology

Today, microbial contamination of surface waters and groundwater is a serious health problem that can lead to dangerous diseases. In this research, the transmission and retention of Escherichia coli bacteria (E. coli) was simulated as an index of groundwater pollution in soil saturation conditions, considering the importance of preferential flow using synthetic macropores (different diameters of macropores including 0, 1 and 2 cm) and using HYDRUS-2D model.Also, the effect of different salinity levels of water (including electrical conductivity of 1, 2 and 4 dSm-1) on the transmission of E. coli bacteria was investigated. Thepreferential flow system was prepared and designed using two sand size including fine sand and coarse sand in the columns. The results showed that the retention of E. coli increased with the ionic strength of the solution, while the effect of E. coli in the fine sand was greater than that of coarse sand. This bacterial transfer behavior was well described by numerical simulations. The importance of preferential flow in bacterial transfer showed that it increases at higher ionic strength, even if overall transmission is reduced. Although the bacterial transmission is facilitated in salinity, the results of this study showed that an increasing in ionic strength of the soil solution increased the amount of bacterial purification that could be effective in controlling groundwater contamination with saline water management.