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The objective of this study was to assess the effects of pH, alkalinity, and hardness on theinactivation kinetics of MS2 phage with chlorine in synthetic and natural waters.Experiments characterizing the inactivation of MS2 phage with free chlorine have beenperformed at 20C in carbonate buffer solution (CBS), CBS spiked with hardness, andnatural surface waters containing hardness. Contrary to previous work conducted inphosphate buffer solutions, no pH effect was observed in CBS or in natural waters. Thissuggested that hypochlorous acid and hypochlorite ion have the same disinfectionefficacy in waters buffered by the carbonate system. Additionally, the presence ofcalcium and magnesium at levels typical of natural surface waters of medium to highhardness was found to enhance the inactivation kinetics of MS2 phage with free chlorineby a factor of at least two. In 1 mM CBS, four logs of inactivation were achieved at a CTvalue of 2 mg*min/L. In CBS spiked with 1.8 mM calcium or 1.8 mM magnesium, thesame inactivation was achieved at a CT value of less than 1 mg*min/L. This enhancedrate of inactivation correlated well with that found in natural surface waters with the samehardness levels. Additional experiments are being conducted to investigate similareffects with monochloramine. Includes 7 references.

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Edition: Vol. - No. Published: 11/01/2005 Number of Pages: 5File Size: 1 file , 150 KB