Water treatment system and filter

Abstract

A water treatment system is described in which an inlet is in fluid communication with an outlet. A first region including a halogen release system is located downstream from the inlet and upstream from the outlet. A second region including chitosan or a chitosan derivative is located downstream from the first region and upstream from the outlet. A filter including a housing containing the water treatment system is also described. A method for treating water in which water flows through the water treatment system is also described.

What is claimed is: 
     
         1 . A water treatment system comprising:
 an inlet in fluid communication with an outlet;   a first region located downstream from the inlet and upstream from the outlet, the first region comprising a halogen release system; and   a second region located downstream from the first region and upstream from the outlet, the second region comprising chitosan or a chitosan derivative.   
     
     
         2 . The water treatment system of  claim 1 , wherein the halogen release system comprises a halogenated resin. 
     
     
         3 . The water treatment system of  claim 1 , wherein the halogen release system comprises an iodine release system. 
     
     
         4 . The water treatment system of  claim 3 , wherein the iodine release system comprises an iodinated resin. 
     
     
         5 . The water treatment system of  claim 1 , wherein the chitosan or chitosan derivative comprises a halogenated chitosan or a halogenated chitosan derivative. 
     
     
         6 . The water treatment system of  claim 5 , wherein the halogenated chitosan or halogenated chitosan derivative comprises a chlorinated chitosan or a chlorinated chitosan derivative. 
     
     
         7 . The water treatment system of  claim 1 , wherein the halogen release system comprises a halogenated resin, and the chitosan or chitosan derivative comprises a halogenated chitosan or a halogenated chitosan derivative. 
     
     
         8 . The water treatment system of  claim 7 , wherein the halogen release system comprises an iodinated resin, and the chitosan or chitosan derivative comprises a chlorinated chitosan or a chlorinated chitosan derivative. 
     
     
         9 . The water treatment system of  claim 1 , wherein the second region comprises chitosan or a chitosan derivative and a second halogen release system. 
     
     
         10 . The water treatment system of  claim 9 , wherein the second halogen release system comprises an iodinated resin. 
     
     
         11 . The water treatment system of  claim 9 , wherein the second halogen release system comprises a chlorinated resin. 
     
     
         12 . The water treatment system of  claim 9 , wherein the second halogen release system comprises a source of trichloroisocyanuric acid. 
     
     
         13 . The water treatment system of  claim 1 , wherein the chitosan or chitosan derivative has a molecular weight from 100,000 Daltons to one million Daltons, and a percentage of deacetylation from 60% to 95%. 
     
     
         14 . The water treatment system of  claim 1 , wherein the system exhibits Log reduction values greater than a sum of Log reduction values for the component halogen release system and the component chitosan or chitosan derivative. 
     
     
         15 . The water treatment system of  claim 1 , wherein the system exhibits an initial Log reduction value for viruses of at least 4, and an initial Log reduction value for bacteria of at least 6. 
     
     
         16 . The water treatment system of  claim 1 , wherein the system exhibits an initial Log reduction value for viruses of at least 4, and a Log reduction value for viruses of at least 4 after a stagnation period. 
     
     
         17 . The water treatment system of  claim 16 , wherein the system exhibits an initial Log reduction value for viruses of greater than 5, and a Log reduction value for viruses of greater than 5 after a stagnation period. 
     
     
         18 . The water treatment system of  claim 1 , further comprising a third region located downstream from the second region and upstream from the outlet, the third region comprising a scavenger barrier selected from the group consisting of carbon, activated carbon, an anion exchange resin, and combinations of any thereof. 
     
     
         19 . The water treatment system of  claim 18 , wherein the halogen release system comprises an iodinated resin, and the scavenger barrier comprises a strong-base anion exchange resin. 
     
     
         20 . The water treatment system of  claim 18 , wherein the halogen release system comprises an iodinated resin, the chitosan or chitosan derivative comprises a chlorinated chitosan or a chlorinated chitosan derivative, and the scavenger barrier comprises a strong-base anion exchange resin. 
     
     
         21 . A filter comprising a housing containing the water treatment system of  claim 1 . 
     
     
         22 . The filter of  claim 21 , wherein the halogen release system comprises an iodinated resin. 
     
     
         23 . The filter of  claim 21 , wherein the chitosan or chitosan derivative comprises a chlorinated chitosan or a chlorinated chitosan derivative. 
     
     
         24 . The filter of  claim 21 , wherein the filter exhibits an initial Log reduction value for viruses of at least 4, and an initial Log reduction value for bacteria of at least 6. 
     
     
         25 . The filter of  claim 21 , further comprising a third region located downstream from the second region and upstream from the outlet, the third region comprising a scavenger barrier selected from the group consisting of carbon, activated carbon, an anion exchange resin, and combinations of any thereof. 
     
     
         26 . A method for treating water, the method comprising flowing water through the water treatment system of  claim 1 . 
     
     
         27 . The method of  claim 26 , wherein the system exhibits an initial Log reduction value for viruses of at least 4, and an initial Log reduction value for bacteria of at least 6. 
     
     
         28 . The method of  claim 26 , further comprising initiating a stagnation period, wherein the system has an initial Log reduction value for viruses of at least 4, and a Log reduction value for viruses of at least 4 after the stagnation period. 
     
     
         29 . The method of  claim 26 , wherein the halogen release system comprises an iodinated resin. 
     
     
         30 . The method of  claim 26 , wherein the chitosan or chitosan derivative comprises a chlorinated chitosan or a chlorinated chitosan derivative.