Executive Summary:

Estimated Time to Read: 6 minutes

Summary:

• The paper compares the properties and efficacy of acidified chlorine and acidified chlorine dioxide in treating laboratory animal drinking water.
• Chlorine has a higher oxidation potential than chlorine dioxide, making it more reactive with a wider range of organic structures, while chlorine dioxide reacts more selectively with certain sulfur, nitrogen, and other oxidizable structures.
• Chlorine dioxide has a higher oxidation capacity, donating 5 electrons to oxidation compared to chlorine’s 2 electrons, making chlorine dioxide effective at lower concentrations (typically 4-20 times less) than chlorine.
• Chlorine dioxide demonstrates better efficacy in controlling oo-cysts (e.g., giardia and cryptosporidium) and biofilm in water systems, making it preferred over chlorine in such cases.
• Chlorine dioxide effectively controls bacterial levels in both concentrate and permeate in pure water systems, while chlorine has limited efficacy in killing and removing bacterial biofilms.
• The changeover to chlorine dioxide treatment in biofilm-containing systems may result in an initial spike in suspended bacterial loads as chlorine dioxide strips biofilm from the system walls.
• Chlorine dioxide does not corrode stainless steel (e.g., 304L) even in the presence of chloride, while chlorine can cause corrosion in crevices of stainless steel at low concentrations.
• Chlorine forms disinfection byproducts (DBPs), including potentially carcinogenic compounds, when reacting with organic compounds. Chlorine dioxide produces fewer DBPs and does not chlorinate organic compounds.
• Chlorine dioxide reacts differently with antibiotics compared to chlorine, resulting in the formation of different byproducts and preserving antibacterial activity.
• Animal acceptance studies suggest that mice avoid chlorine-treated spaces but exhibit no behavioral changes with chlorine dioxide. Human acceptance testing shows no taste or odor difference between water treated with chlorine dioxide (up to 8 ppm) and untreated water, while chlorine-treated water can have a distinct taste and odor.

Note: This summary provides an overview of the paper’s main points. For a detailed understanding, it is recommended to refer to the complete paper.