Page 1

WAL S.A. Summary of test data for the WAL SafeWater Elite Filtration Canister using a disinfecting cartridge containing HaloPure media. Testing conducted by an independent microbiological laboratory

Purpose Evaluate production units of the WAL SafeWater Elite devices to meet USEPA bacteria and virus reduction to 1500L volume capacity. The USEPA Purifier Guide Standard (USEPA PGS) requires a 6-log reduction of bacteria (Klebsiella terrrigena) and virus (Poliovirus and Rota virus) at 0%, 25%, 50%, 75%, and 100% of the volume capacity of the device. To test for safety margin testing was extended to include 120% and 135% volume capacity. The following modifications to the USEPA PGS were made to reflect the water conditions in India: after 50% India water formulation was used as the stressed water rather than GTW2 and the water temperature was adjusted to 20 – 25 ˚C rather than 4˚C. Procedure Three production Elite (WB) devices were assembled in a Washington State drinking water test laboratory in June of 2011. On a daily basis 10 – 40 liters of test water with an added 107 cfu/100mL of Klebsiella bacteria were filtered through each WB. The USEPA PGS test water from 0 - 50% volume capacity is composed of dechlorinated municipal tap water, after 50% volume capacity test water is altered to present a more stressed environment for halogen disinfection technologies. Stressed test water is formulated to have an increased halogen demand with increased total dissolved solids (TDS) and total organic carbon (TOC) (table 1). The complete test protocol details are given in Appendix A. Each device was tested at 0%, 25%, 50%, 75%, 100%, 120%, and 135% capacity of 1500L (0L, 375L, 750L, 1125L, 1500L, 1800L, and 2025L) with a challenge suspension of 107cfu/100mL of Klebsiella bacteria and a combined 107/L Polio-Rota virus. Two stagnation samples were also collected after the 50% and 75% challenges. During challenges the entire assembled device is first cleaned then challenge water is poured into the top reservoir and allowed to filter into the bottom reservoir. A 100mL sample is collected directly into sodium thiosulfate (to inactivate residual bromine) after all the samples the first volume out was collected into sodium thiosulfate. Influent and effluent water samples are analyzed within 1-hour of collection for bacteria and virus quantification. The ceramic pre-filtration component was scrubbed before each challenge and at least once per week.

Table 1: Stressed Test Water (India water) and Microorganisms Used Stressed Test Water

Value

Units

Halogen

0

ppm

pH

6.5 – 8.5

TOC (humic acid)

3–5

ppm

Turbidity

0.1 – 1

NTU

Temperature

19 – 21

Celsius

TDS (sea salts)

500 – 600

ppm

Hardness (CaCO3)

190 – 210

ppm

Microorganism

ATCC#

Klebsiella terrigena

33257

Polio virus

VR-192

Rota virus

VR-899


Test Results All three of the Elite devices met the 6-log reduction of bacteria and 4-log reduction of virus to the 1800L volume capacity (120%) as seen in table 2 and charts 1 & 2. At 2025L (135%) all three devices had Klebsiella breakthrough, with device 1 still meeting the 6- log reduction but devices 2 and 3 having 5.8 and 4.7 LRV respectively. Reported flow rates in table 3 reflect the cumulative flow rate over 1-hour and 4-hours of filtration, as the head pressure of water drops in the device the flow rate decreases. Table 2: Log reduction values (LRV) for Bacteria and Virus

% Capacity of 1500L 0 25 50 75 100 120 135

WAL Elite-1 Polio-Rota Kleb LRV LRV 7.41 4.47 7.58 4.24 6.98 4.51 7.90 ≥3.35* 7.56 4.54 7.46 4.00 6.10 ≥3.70*

WAL Elite-2 Polio-Rota Kleb LRV LRV 7.41 4.47 7.58 4.24 6.98 4.51 7.90 ≥3.35* 7.56 4.07 6.86 4.00 5.80 ≥3.70*

* Polio-Rota Challenge < 10 pfu/mL

WAL Elite-3 Polio-Rota Kleb LRV LRV 7.41 4.47 7.58 4.24 6.98 4.51 7.90 ≥3.35* 6.95 4.54 7.45 4.24 4.74 ≥3.70*

4

Table 3: Flow rates after top reservoir is filled once with 9L of water, measured after 1 hour and 4 hours WAL Elite-1 % Capacity of 1500L 0 25 50 75 100 120 135

1 hour n/a 55 50 n/a 32 75 33

4 hours 67 32 35 22 23 32 33

WAL Elite-2 1 hour n/a 40 17 n/a 33 43 8

4 hours 27 30 18 24 23 24 29

WAL Elite-3 1 hour n/a 58 33 n/a 21 32 5

4 hours 55 32 24 16 22 25 31

Table 4: Residual bromine after top reservoir is filled once with 9L of water, measured after 1 hour and 4 hours WAL Elite-1 % Capacity of 1500L 0 25 50 75 100 120 135

1 hour n/a 0.37 0.33 0.06 0.20 0.21 0.07

4 hours 0.35 0.21 0.20 0.04 0.13 0.07 0.04

WAL Elite-2 1 hour n/a 0.38 0.22 0.05 0.18 0.08 0.06

4 hours 0.55 0.21 0.22 0.03 0.10 0.05 0.04

WAL WElite-3 1 hour n/a 0.37 0.22 0.05 0.11 0.12 0.12

4 hours 0.43 0.23 0.15 0.03 0.08 0.05 0.05

WAL Elite BacVirus summary  

The following modifications to the USEPA PGS were made to reflect the water conditions in India: after 50% India water formulation was used...

Read more
Read more
Similar to
Popular now
Just for you