Investigation on Removal of Coliform from Groundwater Using Sandy Filters Modified with Nanoscale Zerovalent Iron (Case Study: Ilam City)

Background & objectives: In recent years, iron nanoparticles have been successfully used to remove water pollutants. Fecal coliform is one of the parameters that reduces water quality and its removal is essential. The aim of the present study is using nanoscale zerovalent iron particles to enhance the usual sand filters in removal of fecal coliform of groundwater in Ilam city. Methods: Water samples were collected from several active wells in Ilam city. The parameters of hardness, probable and fecal coliforms were measured. Afterward, samples of fecal coliform contaminated-water were passed through filters with different values of zerovalent iron nanoparticles (0.5-3 gr) and parameters were remeasured. Results: The results of this study showed that by increase of iron nanoparticles, the removal efficiency of coliform was increased, so that, in most samples, by increasing the iron nanoparticles to 3 gr, the coliform content reached to zero. The degree of hardness was initially reduced when the amount of iron nanoparticles increased, but over time, the reduction trend was halted. Conclusion: In general, the results indicate that not only zero-valent iron nanoparticles are capable enough to remove microbial contamination from water, but also they can be used to completely purify the groundwater and also to reduce other contaminants including chemical pollutants to a permissible threshold, especially in small regions where complex water treatment plants may not be available.