ABSTRACT
This work was carried out to determine the efficiency of slow sand filtration. Graded sand obtained using BS Sieve Numbers 25, 36, 72, 100 and 200 and another obtained using BS Sieve number 14 constructed locally were used. Influent and effluent samples were analysed at intervals for pH, turbidity and bacteriology (Coliform test), so as to determine the filter efficiency. The media obtained using BS set of sieves produced effluent of about 90% removal in coliform, 75% removal in Turbidity and an insignificant change in pH, where as that obtained using BS sieve No, 14 gave an effluent of about 80% removal in coliform, 25% removal in Turbidity and an insignificant change in pH, In the absence of a total coliform removal, disinfection as a measure of safety should be employed.