The Efficiency of Multi-Media Filtration in Drinking Water Treatment Plants for the Removal of Natural Organic Matter

Background: Filtration is a processing unit in a Drinking Water Treatment Plant (DWTP) that is used to remove particles from the water. This study is the result of pilot-scale research on Gravity Rapid Sand Filter (GRSF). The purpose of this paper was to evaluate the performance of the Triple Media Filter (TMF) (Granular Activated Carbon (GAC) + anthracite + garnet) and Dual-Media Filter (DMF) (anthracite + sand) in the removal of Natural Organic Matter (NOM) as a precursor of Trihalomethanes (THMs) and chlorination Disinfection by-Products (DBPs). Methods: Filtration rate was performed at conventional (۱۲۰ m/d) and a high rate (۲۴۰ m/d) and compared with full-sized Single Media Filter (SMF) with a sand media. The removal efficiency of turbidity, color, and UV absorption at a wavelength of ۲۵۴ nm (UV۲۵۴) and Dissolved Organic Carbon (DOC) parameters were investigated. Besides, the Specific Ultraviolet Absorbance (SUVA) was calculated from the ratio of UV۲۵۴ to DOC. Results: The results showed that the Multimedia Filter (MMF) at ۱۲۰ and ۲۴۰ m/d filtration rate had higher removal efficiency compared with a control SMF in removing measured parameters (p<۰.۰۵). Also, similar filters have shown the same efficiency relative to each other in different loading rates and there was an insignificant difference. Conclusion: MMF can significantly remove organic pollutants and control the formation of DBPs during water treatment. The study suggests that SMF should be replaced with MMF to improve water quality.

Keywords:

Natural Organic Matter (NOM) , Filtration , multi-media filter , Granular Activated Carbon (GAC) , Water Treatment