Abstract: Micro organisms are wide spread in nature and when found in drinking water are known to be major precursors of many diseases. Their removal can be achieved through filtration in packed columns, thus reducing the amount of chemicals used for the disinfection of drinking water. Pozzolan from Djoungo (Cameroon) was tested as a potential filtration media for removing E. coli, the indicator of faecal contamination in ground and surface waters. Filtration experiments were carried out at room temperature (24±2°C) and microbial concentration was determined by the spread plate technique. Filtration tests were performed on 2 granular size media (450 and 900 μm mean size) at constant velocity (0.22 m h-1), at different pH (5-9) and ionic strengths (10-4-10-2 M). The aluminium sulphate concentration of 2.5 mg L-1 was used while the microbial concentration was fixed at 1.46x102 cells mL-1. Results showed that the best microbial retention was obtained at pH 5 and at a high ionic strength of 10-2 M KCl with coagulant dose (2.5 mg L-1). The 450 μm mean diameter media presented a better efficiency compared to the coarse one.