Method of water purification

Abstract

The invention provides a method for the removal of biological species, such as Cryptosporidium , from water using aluminum based media which contains surface Al—OH groups.

1 - 26 . (canceled)  
     
     
         27 . A method for the removal of  Cryptosporidium  from water comprising the steps of contacting the water with a medium comprising particulate alumina having surface Al—OH groups occurring at an average rate of 1 hydroxyl group per 0.25 nm to 1 hydroxyl group per 0.18 nm 2  for a time from 5 seconds to 1 hour so as to effect at least a 1 log reduction of  Cryptosporidium  present in the water by adsorption thereof onto said alumina.  
     
     
         28 . The method according to  claim 27 , wherein the water has been pre-treated prior to contact with the medium.  
     
     
         29 . The method according to  claim 27 , wherein the medium is contained in discrete filter beds, each filter bed comprising particles of alumina in different size ranges.  
     
     
         30 . The method according to  claim 27 , wherein the medium is contained in a cartridge.  
     
     
         31 . The method according to  claim 28 , wherein the medium contained in a filter bed is used as a polishing filter.  
     
     
         32 . The method according to  claim 27 , wherein the medium is contained in a water permeable bag which is immersed in water to effect reduction of  Cryptosporidium.    
     
     
         33 . The method according to  claim 30 , wherein the water is brought into contact with the medium under gravity flow.  
     
     
         34 . The method according to  claim 27 , comprising alumina having a particle size of about 0.5 mm to 1.5 mm.