Few bacteria live alone, they are most often found in water and on surfaces in the form of biofilm. Unlike most biocides, CLO2 can EFFECTIVELY penetrate the layer of biofilm without being used up in reacting with the inert sugars. This allows the CLO2 to act on the bacteria themselves, destroying the biofilm.
CLO2 is ONE of the disinfectants that are effective against Giardia Lambia and Cryptosporidium (protozoa parasites), which causes diseases such as cryptosporidiosis (diarrheal disease) in drinking water.
CLO2 kills microorganisms even whey they are INACTIVE
Source : https://www.scotmas.com/chlorine-dioxide/how-does-clo2-kill-bacteria.aspx