Chitosan-coated fibers to satisfy nsf50 test standard for spas and pools

Abstract

A fibrous filter media is provided for meeting NSF 50 requirements for water turbidity in pools, hot tubs and spas which includes a sheet of nonwoven fibers coated with chitosan, wherein the sheet may be pleated or present in a stacked layer configuration.

1 . A method of treating pool and spa water, comprising:
 providing a quantity of water to be filtered;   providing a filter including filter media;   circulating said quantity of water through said filter media,   wherein said filter media comprises nonwoven fibers and chitosan, wherein the chitosan has been deposited on said nonwoven fibers at a level of 0.5% to 8.0% by weight and wherein said filter indicates a turbidity remaining value (TR) of less than 0.3 after a fifth turnover of water volume wherein the testing conditions comprise: (1) water temperature 24+/−6° C.; (2) turbidity before addition of silica (TB1)<2 nephelometric turbidity units; (3) turbidity after adding silica (TB2)=45+/−10 nephelometric turbidity units; (4) flow rate is 0.16 liters per minute; (5) water volume is 1.6 liters; (6) turnover time is 10 minutes; (7) turbidity after one turnover of said water volume is TB3; wherein TR=(TB3−TB1)/(TB2−TB1).   
     
     
         2 . The method of claim  14  wherein said filter media comprises a pleated sheet. 
     
     
         3 . The method of claim  14  wherein said filter media comprises a sheet stacked in layers. 
     
     
         4 . The method of claim  14  wherein said chitosan level is in the range of about 2.0% to 4.0% by weight. 
     
     
         5 . The method of claim  14  wherein said fibers comprise bicomponent polyester fibers in a sheath-core configuration.