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 (120 m/d) and a high rate (240 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 254 nm (uv254) and dissolved organic carbon (doc) parameters were investigated. besides, the specific ultraviolet absorbance (suva) was calculated from the ratio of uv254 to doc. results: the results showed that the multimedia filter (mmf) at 120 and 240 m/d filtration rate had higher removal efficiency compared with a control smf in removing measured parameters (p<0.05). 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.