Nasser, A., Division of Enviromental Sciences, School of Applied Sciences, The Hebrew University, Jerusalem 91904, Israel
Weinberg, D., Division of Enviromental Sciences, School of Applied Sciences, The Hebrew University, Jerusalem 91904, Israel
Dinoor, N., Division of Enviromental Sciences, School of Applied Sciences, The Hebrew University, Jerusalem 91904, Israel
Fattal, B., Division of Enviromental Sciences, School of Applied Sciences, The Hebrew University, Jerusalem 91904, Israel
Adin, A., Division of Enviromental Sciences, School of Applied Sciences, The Hebrew University, Jerusalem 91904, Israel

Filtration is considered a mandatory operation unit for the production of pathogen free drinking water from surface sources. This study was undertaken to determine the removal efficiency of enteric pathogenic viruses (hepatitis A virus and poliovirus) by high rate filtration and to determine the suitability of F+bacteriophages as index for the removal of these pathogens. Ajar test was used to determine the optimal flocculation dose to be used in the high rate filtration experiments. At an alum concentration of 30 mg/l, the greatest reduction was observed for HAV (88.4%) as compared with poliovirus 1 (47%) and tumidity (61%). Addition of 1 mg/l cationic polyelectrolyte improved the reduction of HAV to 98.3% by flocculation, while the removal of polio 1 and turbidity was not improved. The presence of humic acid at a concentration of 15.3 mg/l interfered with flocculation performance of HAV and tumidity, while the addition of the cationic polyelectrolyte reduced the interference appreciably. High rate filtration (20 m/hr) using a 100 cm long sand column, resulted in reduction of 99%, 93% and 80% of tumidity, MS2 and poliovirus 1, respectively. Addition of polyelectrolyte enhanced the removal of viruses and tumidity. In the presence of humic acid no virus removal was observed by high rate filtration, whereas turbidity removal was unaffected. The removal of MS2 was similar to that of HAV rather than poliovirus 1. High rate filtration was found efficient for the removal of pathogenic viruses and tumidity from surface water. Under all conditions tested the removal of turbidity was greater than that of viruses.