WAL S.A. Summary of the evaluation of the WAL SafeWater Elite gravity filtration system for cryptosporidium oocyst removal using a ceramic filter Testing conducted by Biovir Laboratories in Benicia California 11/30/2011 Summary Three WAL SafeWater Elite gravity filtration systems were tested to determine the removal of Cryptosporidium oocysts. The goal was to describe the log reduction in oocysts by the treatment devices. All three units demonstrated a greater than three-log reduction in oocysts under the test conditions. Discussion The test format involved one water type, a non-chlorinated water. A suspension of C. parvum oocysts was prepared in 3 L to deliver at least 106 oocysts/L. One liter of the oocysts-challenge water was added to each unit and allowed to flow under natural gravity. The entire effluent volume was collected over the run time to process the 1 L volume Following the challenge volume, each unit was arranged to receive water from a gravity feed reservoir system. Twenty liters of dechlorinated tap water was fed through each unit by gravity flow for 2 days. On the third day, another 1 L oocyst challenge was introduced into each device; the entire effluent volume was collected. The organism used in the challenge was Cryptosporidium parvum oocysts, and the challenge took place on 11/30/2010 Results The results are presented in Table 1. Oocysts were detected in the initial samples at time = 0. However, there were no oocysts detected in the time = day 3 samples. In all cases the oocysts were reduced by greater than 3.4 log. Table 1 Summary of Results Oocyst Reduction
Influent Effluent A, T0* Effluent B, T0 Effluent C, T0
Number Oocysts per 10 mL 48000.00 3.00 10.00 17.00
Influent Effluent A, T3* Effluent B, T3 Effluent C, T3
48000 0 0 0
Sample ID
Log10 Value
Log Reduction
4.68 0.48 1.00 1.23
4.20 3.68 3.45
*T0 = Beginning of the Challenge Test *T3 = Day Three of the Challenge Test
>4.68 >4.68 >4.68