EVALUATION OF A MICROBIOLOGICAL WATER PURIFIER FOR INACTIVATION OF VIRUSES, BACTERIA AND GIARDIA CYSTS

Development of the need for personal water treatment devices has evolv ed from consumer interest in improving and ensuring the quality of dri nking water. The need also extends to the quality of untreated or part ially treated waters such as that used by hikers, campers, recreationa l home and boat owners, and families or communities having individual home and small system water sources. It is essential that such devices be capable of removing all types of pathogenic microorganisms likely to be found in contaminated water. For this reason the U.S. Environmen tal Protection Agency has suggested such units be capable of removing Klebsiella terrigena, Giardia cysts and enteric viruses. Three identic al water purifiers were evaluated for the inactivation of rotavirus SA -11, hepatitis A virus, poliovirus type 1, the bacterial virus MS-2, K lebsiella terrigena and (Giardia muris cysts. The units depend upon a thermal cycler combined with activated carbon for removal of the test organisms. The units were challenged with the organisms suspended in t apwater after 4, 76 and 240 cycles of operation. The units were also t ested with a ''worst case'' water quality of 1500 mgA dissolved solids , 10 mg/l organic matter and with a water turbidity of 30 NTU. In all cases, complete inactivation of the viruses, bacteria and cysts occurr ed after operation of the 35-minute cycle. This resulted in a greater than 3-log (99.9%) inactivation of cysts, a greater than 6 log (99.999 9%) inactivation of K. terrigena and 4-log (99.99%) inactivation of vi ruses. In conclusion, these units would comply with criteria guideline s suggested by the U.S. Environmental Protection Agency for the operat ion of microbial water purifiers.