Influence of grain size distribution towards improvements of turbidity, colour and suspended particles in a riverbank filtration process - a column study

Abstract

Riverbank filtration (RBF) system is an efficient and natural treatment technology which, consists of high capacity pumping wells, located adjacent to river. It takes advantage of natural attenuation processes that occur as surface water infiltrate through the riverbed to produce potable water. This research determined the influence of media size distribution, and its hydraulic conductivity and porosity as filter media, of sand and gravel. The efficiency of column model for riverbank filtration system to remove turbidity, colour and suspended solids was also determined. The best condition of column model to remove contaminants with different flowrates and different types filter media used was identified through this research. The column study was conducted with three different types of filter media; C1 (sand), C2 (gravel) and C3 (sand + gravel) and with three different flowrates; 20 mL/min, 25 mL/min and 40 mL/min. Based on the results, C3 (sand + gravel) shows the highest percentage removal for turbidity, colour and suspended solids, which were 28.5%, 59.1%, 71.4% and 29.4%, respectively, although at difference flowrates. The highest percentage of removal of suspended solids (71.4%) occurs at 25 mL/min. The highest percentage of removal of colour (59.1%) occurs at 40 mL/min. Longer contact time might improve the removal of these contaminants.