Which method is hinted to be less reliable compared to filtration for Cryptosporidium removal?

Chlorine treatment is suggested to be less reliable for the removal of Cryptosporidium compared to filtration methods. This is primarily because Cryptosporidium has a protective oocyst that is resistant to chlorine disinfection. While chlorine is effective against many pathogens, it does not consistently inactivate Cryptosporidium. As a result, using chlorine alone may not sufficiently reduce the concentration of these oocysts in drinking water, which poses a health risk if ingested.

Filtration methods, such as microfiltration or ultrafiltration, are designed to physically remove particles based on size. Since Cryptosporidium oocysts are relatively large (about 4-6 microns), filtration can effectively separate these pathogens from the water. This makes filtration a preferred method for ensuring the removal of Cryptosporidium in water treatment processes.

Therefore, while chlorine can be a part of a comprehensive water treatment strategy, it lacks the reliability needed for effective Cryptosporidium removal, reinforcing the importance of filtration as a primary control method for this specific contaminant.