EVALUATION OF GIARDIA CYST REMOVAL VIA PORTABLE WATER FILTRATION DEVICES

Two portable water filtration devices were evaluated for their effectiveness in removing potentially pathogenic Giardia cysts using a rigorous testing schedule that simulated in-field use. The units were challenged daily with untreated surface water containing known concentrations of Giardia cysts and 2 motile, nonpathogenic protozoans according to a defined protocol, which included both use and nonuse periods. Detection and quantitation of any challenge organisms were achieved by concentrating the filtration unit effluents by membrane filtration, backflushing the polycarbonate membranes, centrifuging the resulting backflush, and examining the concentrate microscopically. At no time during the 26 day testing period were any Giardia cysts or other challenge protozoans isolated from the filtration unit effluents. The 2 portable filtration devices tested are efficient in removing high concentrations of Giardia cysts and other protozoans.