WAL S.A. Test summary conducted by BioVir Laboratories to determine disinfection efficacy of the WAL SafeWater pitcher cartridge powered by HaloPure media for the challenge organisms bacteria and virus from municipally treated drinking water that may contain contamination 3 pages
INTRODUCTION On March 6, 2009, BioVir Laboratories of Benicia California tested the WAL SafeWater pitcher filter cartridge to demonstrate its’ disinfection efficacy. The units were tested to a protocol titled “Testing Protocol: Disinfecting Pitcher Cartridge”. In short, the units were continuously challenged with E. coli (a bacteria) and MS-2 coliphage (a virus) over a total volume of 450 L, the capacity of the filters. The effluents were sampled at various points throughout the capacity of the units to determine microbial removal. At the sample points, bromine residual levels in the effluent was also determined. Description of Challenge Water Dechlorinated Benicia tap water was fed into a holding tank where test water was prepared to the specifications of the protocol. The water was spiked the challenge organisms and then transferred to each feed tank using a transfer pump. Description of Challenge organisms E. coli. ATCC # 11229. From long term storage at -80oC, E. coli was propagated in trypticase soy broth. This initial culture was stored at 4oC and was used to start the daily cultures. The daily cultures were harvested, concentrated by centrifugation and washed in phosphate buffered water. The bacteria were added to a volume of test water to provide a minimum influent concentration of 1 x103 CFU/mL. Description of Test Run The challenge study was conducted from March 18, 2009 through April 6, 2009; testing assays for bacteria and phage ended by April 7, 2009. The six tested filters were conditioned according to manufacturer’s instruction. The units processed 36 L of water seeded with E. coli and MS-2 phage per day, with the exception of the first, second to last, and final days. On these three days, 38 L, 16 L, and 2 L were processed. On sample days (0%, 24%, 48%, 72%, and 100% of capacity), 2 L of seeded water was passed through the units, one liter at a time, and collected in the pitcher for each unit. The first liter was discarded. From the second liter, a 10 mL sample was taken for analysis. In addition, a 10 mL influent sample was taken from the seeded tank water. All samples were treated with 200 _L of a 0.2 N sodium thiosulfate solution to neutralize residual bromine. For E. coli analysis, triplicate 1 mL effluent samples were filtered and assayed on mFC. Phage analysis was conducted by double layer agar overlay and 1 mL and 0.1 mL effluent samples were assayed. Influent samples were appropriately diluted and assayed. Conclusion – The test resuls are presented in Tables 1 through 7. It shows that all units tested achieved a Log reduction of greater than 3 Log, (99.9%) of both bacteria and virus.
Page 2 / 3 Table 1. Microbial Reduction Results for Unit 090832 J Sample Pt % of capacity
0 24 48 72 100
Sample Pt % of capacity
0 24 48 72 100
Sample Pt % of capacity
0 24 48 72 100
Sample Pt % of capacity
0 24 48 72 100
Influent CFU/mL 1.8 x10
3
2.4 x10
3
2.5 x10
3
3.0 x10
3
3.7 x10
3
E. coli Effluent CFU/mL
Log Reduction
Influent PFU/mL
<1
3.26
8.0 x10
3
<1
3.9
4.5 x10
3
<1
3.65
2.3 x10
3
<1
3.36
3.1 x10
3
<1
3.49
1.7 x10
3
<1
3.23
<1 <1 <1 <1
3.38 3.40 3.48 3.57
MS-2 Phage Effluent Log PFU/mL Reduction
Table 2. Microbial Reduction Results for Unit 090832 K E. coli MS-2 Phage Influent Effluent Log Influent Effluent Log CFU/mL CFU/mL Reduction PFU/mL PFU/mL Reduction 3
1.8 x10 3 2.4 x10 3 2.5 x10 3 3.0 x10 3 3.7 x10
<1 <1 <1 <1 <1
3.26 3.38 3.40 3.48 3.57
3
8.0 x10 3 4.5 x10 3 2.3 x10 3 3.1 x10 3 1.7 x10
<1 <1 <1 <1 <1
3.9 3.65 3.36 3.49 3.23
Table 3. Microbial Reduction Results for Unit 090832M E. coli MS-2 Phage Influent Effluent Log Influent Effluent Log CFU/mL CFU/mL Reduction PFU/mL PFU/mL Reduction 3
1.8 x10 3 2.4 x10 3 2.5 x10 3 3.0 x10 3 3.7 x10
<1 <1 <1 <1 <1
3.26 3.38 3.40 3.48 3.57
3
8.0 x10 3 4.5 x10 3 2.3 x10 3 3.1 x10 3 1.7 x10
<1 <1 <1 <1 <1
3.9 3.65 3.36 3.49 3.23
Table 4. Microbial Reduction Results for Unit 090832 N E. coli MS-2 Phage Influent Effluent Log Influent Effluent Log CFU/mL CFU/mL Reduction PFU/mL PFU/mL Reduction 3
1.8 x10 3 2.4 x10 3 2.5 x10 3 3.0 x10 3 3.7 x10
<1 <1 <1 <1 <1
3.26 3.38 3.40 3.48 3.57
3
8.0 x10 3 4.5 x10 3 2.3 x10 3 3.1 x10 3 1.7 x10
<1 <1 <1 <1 <1
3.9 3.65 3.36 3.49 3.23
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Table 5. Residual Bromine in Effluents (mg/L) Sample Pt UNIT UNIT UNIT % of capacity J K M 0 24 48 72 100
1.10 0.60 0.46 0.60 0.51
0.92 0.57 0.41 0.33 0.75
1.12 0.63 0.50 0.39 0.62
UNIT N 0.81 0.29 0.37 0.32 0.88
Table 6. Filter Unit Flow Rates at Sample Point (mL/min) Sample Pt UNIT UNIT UNIT UNIT % of capacity J K M N 0 24 48 72 100
75.0 78.0 72.1 74.0 92.2
110.0 100.8 90.1 103.1 121.2
87.1 89.9 70.9 72.5 75.0
73.0 76.0 71.2 76.3 89.9
Table 6. Water Quality for Sample Days Sample Pt % of capacity
0 24 48 72 100
FAC (mg?L)
pH
Temp o (C)
TDS (mg/L)
TOC (mg/L)
0.01 0.03 0.00 0.01 0.02
7.66 7.91 7.98 7.90 7.49
18.2 20.7 19.4 20.1 20.2
241 237 242 235 213
0.61 1.6 0.86 0.74 1.5