Patent ID: 7157009

Claim:
A method for removing Cryptosporidium oocysts or Giardia cysts from recreational water containing a halogenating agent, comprising: adding chitosan to the water comprising Cryptosporidium oocysts or Giardia cysts and a halogenating agent, wherein the Cryptosporidium oocysts or Giardia cysts have been exposed to the halogenating agent for a period of time effective to oxidize at least a portion of the Cryptosporidium oocysts or Giardia cysts, before adding the chitosan to the water; allowing the Cryptosporidium oocysts or Giardia cysts and the chitosan to form stabilized flocs in the water; and filtering the flocs of the Cryptosporidium oocysts or Giardia cysts and chitosan to remove the Cryptosporidium oocysts or Giardia cysts from the water.