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  Environmental Technology Verification Report, Physical Removal of Microbial Contaminants in Drinking Water, Watts Premier, Inc., WP-4V Point-of-Use Drinking Water Treatment System (46 pp, 1.39 MB) (EPA/600/R-06/131) July 2006
Verification Statement (PDF) (5 pp, 148 KB)

The Watts Premier WP-4V four-stage point-of-use reverse osmosis (RO) system was tested for removal of bacteria and viruses at NSF’s Drinking Water Treatment Systems Laboratory. Five systems were challenged with the bacteriophage viruses fr and MS2, and the bacterium Brevundimonas diminuta.

The virus challenges were conducted at three different pH settings (6, 7.5, and 9) to assess whether pH influences the performance of the RO membrane. The bacterium challenges were conducted only at pH 7.5.

The challenge concentrations ranged from 3.8 to 5.0 logs for the viruses, and 6.4 to 7.2 logs for the bacterium. The log reductions ranged from 1.3 to 6.4 log10 for B. diminuta, with an average of 2.1 log10 . The virus log reductions ranged from 1.4 to 3.6 log10 for fr, and 1.2 to 3.7 log10 for MS2. The average virus log10 reductions were 2.5 and 2.7, respectively.

The virus challenge data do not indicate that the pH of the challenge water influenced removal by the RO membrane.


Jeff Adams

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