Methods and articles for maintaining hydantoinylated polymers in a biocidally active state

Abstract

A composition and the method for sustaining the biocidal activity of chlorinated polystyrene hydantoin beads. The method comprises supplying a continuous low level halogen concentration to the chlorinated polystyrene hydantoin beads in the water to be treated that flows in contact with the chlorinated polystyrene hydantoin beads, resulting in treated water suitable for drinking.

1 . An article, comprising: 
 a source of chlorine and/or bromine, wherein the article delivers a total free chlorine and/or free bromine concentration of about 0.1 ppm to about 10 ppm in a flowing water stream averaging about 10 ml per minute to about 3 liters per minute.    
     
     
         2 . The article of  claim 1 , wherein the chlorine concentration is about 0.1 ppm to about 3 ppm.  
     
     
         3 . The article of  claim 1 , wherein the bromine concentration is about 0.2 ppm to about 4 ppm.  
     
     
         4 . The article of  claim 1 , wherein the flowing water stream averages about 10 ml per minute to about 250 ml per minute.  
     
     
         5 . The article of  claim 1 , wherein the chlorine and/or bromine source is a halohydantoin.  
     
     
         6 . The article of  claim 5 , wherein the halohydantoin is at least one of 1,3,dichloro-5,5-dimethylhydantoin or 1,3,dibromodimethylhydantoin.  
     
     
         7 . The article of  claim 5 , wherein the halohydantoin is at least one of 1-chloro-3-bromo-5,5-dimethylhydantoin or 1-bromo-3-chloro-5,5-dimethylhydantoin.  
     
     
         8 . The article of  claim 1 , wherein the chlorine source is a chlorinated isocyanurate or a metal salt of a chlorinated isocyanurate.  
     
     
         9 . The article of  claim 8 , wherein the chlorinated isocyanurate or metal salt of a chlorinated isocyanurate is at least one of trichloroisocyanuric acid, dichloroisocyanuric acid, potassium trichloroisocyanurate, sodium trichloroisocyanurate, potassium dichloroisocyanurate, or sodium dichloroisocyanurate.  
     
     
         10 . The article of  claim 1 , wherein the chlorine and/or bromine source is an N-halooxazolidinone.  
     
     
         11 . The article of  claim 10 , wherein the N-halooxazolidinone is at least one of 3-chloro-2,2-dialkyl-4,4-dimethyl-1,3-oxazolidinone, 3-chloro-4,4-dimethyl-2-oxazolidinone, 3-bromo-4,4-dimethyl-2-oxazolidinone, 3-chloro-4-ethyl-4-methyl-2-oxazolidinone, 3-bromo-4-ethyl-4-methyl-2-oxazolidinone, 3-chloro-4-methyl-2-oxazolidinone, 3-bromo-4-methyl-2-oxazolidinone, 3-chloro-2-oxazolidinone, or 3-bromo-2-oxazolidinone.  
     
     
         12 . The article of  claim 1 , wherein the chlorine and/or bromine source is an N,N′-dihaloimidazolidinone.  
     
     
         13 . The article of  claim 12 , wherein the N,N′-dihaloimidazolidinone is at least one of 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone, 1,3-dibromo-4,4,5,5-tetramethyl-2-imidazolidinone, 1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone, 1,3-dichlor-2,2,5,5-tetramethyl-4-imidazolidinone, 1,3-dibromo-2,2,5,5-tetramethyl-4-imidazolidinone, or 1-bromo-3-chloro-2,2,5,5-tetramethyl-4-imidazolidinone.  
     
     
         14 . The article of  claim 1 , wherein the chlorine and/or bromine source is an N-halosuccinimide.  
     
     
         15 . The article of  claim 14 , wherein the N-halosuccinimide is N-chlorosuccinimide.  
     
     
         16 . The article of  claim 14 , wherein the N-halosuccinimide is N-bromosuccinimide.  
     
     
         17 . The article of  claim 1 , wherein the chlorine and/or bromine source is an N-halomelamine.  
     
     
         18 . The article of  claim 17 , wherein the N-halomelamine is trichloromelamine.  
     
     
         19 . The article of  claim 1 , wherein the chlorine and/or bromine source is an N-haloglycoluril.  
     
     
         20 . The article of  claim 19 , wherein the N-haloglycoluril is at least one of tetrachloroglycoluril or tetrachlorodimethylglycoluril.  
     
     
         21 . The article of  claim 19 , wherein the N-haloglycoluril is at least one of tetrabromoglycoluril or tetrabromodimethylglycoluril.  
     
     
         22 . The article of  claim 1 , wherein the chlorine and/or bromine source is a sulfonhalamide.  
     
     
         23 . The article of  claim 22 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonchloramide (chloramine T), p-toluenesulfondichloramide (dichloramine T), sodium benzenesulfonchloramide (chloramine B), p-sulfondichloramidobenzoic acid, or N-chloro-N-methyl-p-toluenesulfonamide.  
     
     
         24 . The article of  claim 22 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonbromamide (bromoamine T), p-toluenesulfondibromoamide (dibromamine T), sodium benzenesulfonbromoamide (bromamine B), p-sulfondibromamidobenzoic acid, or N-bromo-N-methyl-p-toluenesulfonamide.  
     
     
         25 . The article of  claim 1 , wherein the chlorine and/or bromine source is a cyclic N-halamine.  
     
     
         26 . The article of  claim 25 , wherein the cyclic N-halamine is at least one of 1,3,5-trichloro-2,4-dioxohexahydrotriazine, 1,3,5-tribromo-2,4-dioxohexahydrotriazine, 1-chloro-2,2,6,6-tetramethylpiperidine, 1-bromo-2,2,6,6-tetramethylpiperidine, 1,4-dichloro-2,2,5,5-tetramethyl-3,6-piperazinedione, 1,4-dibromo-2,2,5,5-tetramethyl-3,6-piperazinedione, 1-chloro-2,2,6,6-tetramethyl-4-piperidone, or 1-bromo-2,2,6,6-tetramethyl-4-piperidone.  
     
     
         27 . The article of  claim 1 , wherein the chlorine and/or bromine source is an acyclic N-halamine.  
     
     
         28 . The article of  claim 27 , wherein the acyclic N-halamine is N,N′-dichloroazodicarbonamidine (Chloroazodin).  
     
     
         29 . The article of  claim 27 , wherein the acyclic N-halamine is N,N′-dibromoazodicarbonamidine.  
     
     
         30 . The article of  claim 1 , wherein the chlorine source is a solid metal salt of hypochlorous acid.  
     
     
         31 . The article of  claim 30 , wherein the solid metal salt of hypochlorous acid is at least one of calcium hypochlorite or lithium hypochlorite.  
     
     
         32 . The article of  claim 1 , wherein the bromine source is a metal salt of hypobromous acid.  
     
     
         33 . The article of  claim 32 , wherein the metal salt of hypobromous acid is at least one of calcium hypobromite, sodium hypobromite, lithium hypobromite, or potassium hypobromite.  
     
     
         34 . The article of  claim 1 , wherein the bromine source is a bromide salt from at least one of sodium bromide, lithium bromide, or potassium bromide.  
     
     
         35 . The article of  claim 1 , wherein the chlorine source is a chloride salt from at least one of sodium chloride, lithium chloride, or potassium chloride.  
     
     
         36 . The article of  claim 1 , wherein the chlorine source is sodium hypochlorite.  
     
     
         37 . The article of  claim 1 , wherein the chlorine source is a metal salt of oxychlorosene.  
     
     
         38 . The article of  claim 37 , wherein the metal salt of oxychlorosene is sodium oxychlorosene.  
     
     
         39 . The article of  claim 1 , further comprising an adjuvant or tableting aid.  
     
     
         40 . The article of  claim 39 , wherein the adjuvant or tableting aid is one from at least calcium phosphate, dicalcium phosphate, tricalcium phosphate, a polyfluorinated polymer, lactose, a fatty acid, a wax, calcium stearate, magnesium stearate, talc, starch, calcium carbonate, sucrose, glucose, mannitol, sorbitol, bentonite, carboxymethylcellulose, methylcellulose, hydroxethylcellulose, hydroxypropylcellulose, sodium metaphosphate, or polytetrafluoroethylene.  
     
     
         41 . An article comprising: 
 a compressed, monolithic mixture of a chlorine and/or bromine source and at least one adjuvant, wherein the article has a density of about 1.4 grams per cubic centimeter to about 4 grams per cubic centimeter.    
     
     
         42 . The article of  claim 41 , comprising an adjuvant from at least one of calcium phosphate, dicalcium phosphate, tricalcium phosphate, a polyfluorinated polymer, lactose, a fatty acid, a wax, calcium stearate, magnesium stearate, talc, starch, calcium carbonate, sucrose, glucose, mannitol, sorbitol, bentonite, carboxymethylcellulose, methylcellulose, hydroxethylcellulose, hydroxypropylcellulose, sodium metaphosphate, or polytetrafluoroethylene.  
     
     
         43 . The article of  claim 41 , wherein the adjuvant is magnesium oxide.  
     
     
         44 . The article of  claim 41 , wherein the chlorine and/or bromine source is a halohydantoin.  
     
     
         45 . The article of  claim 44 , wherein the halohydantoin is at least one of 1,3,dichloro-5,5-dimethylhydantoin or 1,3,dibromodimethylhydantoin.  
     
     
         46 . The article of  claim 44 , wherein the halohydantoin is at least one of 1-chloro-3-bromo-5,5-dimethylhydantoin or 1-bromo-3-chloro-5,5-dimethylhydantoin.  
     
     
         47 . The article of  claim 41 , wherein the chlorine source is a chlorinated isocyanurate or a metal salt of a chlorinated isocyanurate.  
     
     
         48 . The article of  claim 47 , wherein the chlorinated isocyanurate or metal salt of a chlorinated isocyanurate is at least one of trichloroisocyanuric acid, dichloroisocyanuric acid, potassium trichloroisocyanurate, sodium trichloroisocyanurate, potassium dichloroisocyanurate, or sodium dichloroisocyanurate.  
     
     
         49 . The article of  claim 41 , wherein the chlorine and/or bromine source is an N-halooxazolidinone.  
     
     
         50 . The article of  claim 49 , wherein the N-halooxazolidinone is at least one of 3-chloro-2,2-dialkyl-4,4-dimethyl-1,3-oxazolidinone, 3-chloro-4,4-dimethyl-2-oxazolidinone, 3-bromo-4,4-dimethyl-2-oxazolidinone, 3-chloro-4-ethyl-4-methyl-2-oxazolidinone, 3-bromo-4-ethyl-4-methyl- 2 -oxazolidinone, 3-chloro-4-methyl-2-oxazolidinone, 3-bromo-4-methyl-2-oxazolidinone, 3-chloro-2-oxazolidinone, or 3-bromo-2-oxazolidinone.  
     
     
         51 . The article of  claim 41 , wherein the chlorine and/or bromine source is an N,N′-dihaloimidazolidinone.  
     
     
         52 . The article of  claim 51 , wherein the N,N′-dihaloimidazolidinone is at least one of  1 ,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone,  1 ,3-dibromo-4,4,5,5-tetramethyl-2-imidazolidinone, 1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone, 1,3-dichlor-2,2,5,5-tetramethyl-4-imidazolidinone,  1 ,3-dibromo-2,2,5,5-tetramethyl-4-imidazolidinone, or 1-bromo-3-chloro-2,2,5,5-tetramethyl-4-imidazolidinone.  
     
     
         53 . The article of  claim 41 , wherein the chlorine and/or bromine source is an N-halosuccinimide.  
     
     
         54 . The article of  claim 53 , wherein the N-halosuccinimide is N-chlorosuccinimide.  
     
     
         55 . The article of  claim 53 , wherein the N-halosuccinimide is N-bromosuccinimide.  
     
     
         56 . The article of  claim 41 , wherein the chlorine and/or bromine source is an N-halomelamine.  
     
     
         57 . The article of  claim 56 , wherein the N-halomelamine is trichloromelamine.  
     
     
         58 . The article of  claim 41 , wherein the chlorine and/or bromine source is an N-haloglycoluril.  
     
     
         59 . The article of  claim 58 , wherein the N-haloglycoluril is at least one of tetrachloroglycoluril or tetrachlorodimethylglycoluril.  
     
     
         60 . The article of  claim 58 , wherein the N-haloglycoluril is at least one of tetrabromoglycoluril or tetrabromodimethylglycoluril.  
     
     
         61 . The article of  claim 41 , wherein the chlorine and/or bromine source is a sulfonhalamide.  
     
     
         62 . The article of  claim 61 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonchloramide (chloramine T), p-toluenesulfondichloramide (dichloramine T), sodium benzenesulfonchloramide (chloramine B), p-sulfondichloramidobenzoic acid, or N-chloro-N-methyl-p-toluenesulfonamide.  
     
     
         63 . The article of  claim 61 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonbromamide (bromoamine T), p-toluenesulfondibromoamide (dibromamine T), sodium benzenesulfonbromoamide (bromamine B), p-sulfondibromamidobenzoic acid, or N-bromo-N-methyl-p-toluenesulfonamide.  
     
     
         64 . The article of  claim 41 , wherein the chlorine and/or bromine source is a cyclic N-halamine.  
     
     
         65 . The article of  claim 64 , wherein the cyclic N-halamine is at least one of 1,3,5-trichloro-2,4-dioxohexahydrotriazine, 1,3,5-tribromo-2,4-dioxohexahydrotriazine, 1-chloro-2,2,6,6-tetramethylpiperidine, 1-bromo-2,2,6,6-tetramethylpiperidine, 1,4-dichloro-2,2,5,5-tetramethyl-3,6-piperazinedione, 1,4-dibromo-2,2,5,5-tetramethyl-3,6-piperazinedione, 1-chloro-2,2,6,6-tetramethyl-4-piperidone, or 1-bromo-2,2,6,6-tetramethyl-4-piperidone.  
     
     
         66 . The article of  claim 41 , wherein the chlorine and/or bromine source is an acyclic N-halamine.  
     
     
         67 . The article of  claim 66 , wherein the acyclic N-halamine is N,N′-dichloroazodicarbonamidine (Chloroazodin).  
     
     
         68 . The article of  claim 66 , wherein the acyclic N-halamine is N,N′-dibromoazodicarbonamidine.  
     
     
         69 . The article of  claim 41 , wherein the chlorine source is a solid metal salt of hypochlorous acid.  
     
     
         70 . The article of  claim 69 , wherein the solid metal salt of hypochlorous acid is at least one of calcium hypochlorite or lithium hypochlorite.  
     
     
         71 . The article of  claim 41 , wherein the bromine source is a metal salt of hypobromous acid.  
     
     
         72 . The article of  claim 71 , wherein the metal salt of hypobromous acid is at least one of calcium hypobromite, sodium hypobromite, lithium hypobromite, or potassium hypobromite.  
     
     
         73 . The article of  claim 41 , wherein the bromine source is a bromide salt from at least one of sodium bromide, lithium bromide, or potassium bromide.  
     
     
         74 . The article of  claim 41 , wherein the chlorine source is a chloride salt from at least one of sodium chloride, lithium chloride, or potassium chloride.  
     
     
         75 . The article of  claim 41 , wherein the chlorine source is sodium hypochlorite.  
     
     
         76 . The article of  claim 41 , wherein the chlorine source is a metal salt of oxychlorosene.  
     
     
         77 . The article of  claim 76 , wherein the metal salt of oxychlorosene is sodium oxychlorosene.  
     
     
         78 . A composition, comprising: 
 a chlorine and/or bromine source capable of delivering free chlorine and/or free bromine in water within a concentration range capable of sustaining the biocidal activity of N-halohydantoinylated beads without rendering the water undrinkable.    
     
     
         79 . The composition of  claim 78 , wherein the free chlorine concentration is about 0.1 ppm to about 3 ppm.  
     
     
         80 . The composition of  claim 78 , wherein the free bromine concentration is about 0.2 ppm to about 4 ppm.  
     
     
         81 . The article of  claim 78 , wherein the chlorine and/or bromine source is a halohydantoin.  
     
     
         82 . The article of  claim 81 , wherein the halohydantoin is at least one of 1,3,dichloro-5,5-dimethylhydantoin or 1,3,dibromodimethylhydantoin.  
     
     
         83 . The article of  claim 81 , wherein the halohydantoin is at least one of 1-chloro-3-bromo-5,5-dimethylhydantoin or 1-bromo-3-chloro-5,5-dimethylhydantoin.  
     
     
         84 . The article of  claim 78 , wherein the chlorine source is a chlorinated isocyanurate or a metal salt of a chlorinated isocyanurate.  
     
     
         85 . The article of  claim 84 , wherein the chlorinated isocyanurate or metal salt of a chlorinated isocyanurate is at least one of trichloroisocyanuric acid, dichloroisocyanuric acid, potassium trichloroisocyanurate, sodium trichloroisocyanurate, potassium dichloroisocyanurate, or sodium dichloroisocyanurate.  
     
     
         86 . The article of  claim 78 , wherein the chlorine and/or bromine source is an N-halooxazolidinone.  
     
     
         87 . The article of  claim 86 , wherein the N-halooxazolidinone is at least one of 3-chloro-2,2-dialkyl- 4 , 4 -dimethyl-1,3-oxazolidinone, 3-chloro-4,4-dimethyl-2-oxazolidinone, 3-bromo-4,4-dimethyl-2-oxazolidinone, 3-chloro-4-ethyl-4-methyl-2-oxazolidinone, 3-bromo-4-ethyl-4-methyl-2-oxazolidinone, 3-chloro-4-methyl-2-oxazolidinone, 3-bromo-4-methyl-2-oxazolidinone, 3-chloro-2-oxazolidinone, or 3-bromo-2-oxazolidinone.  
     
     
         88 . The article of  claim 78 , wherein the chlorine and/or bromine source is an N,N′-dihaloimidazolidinone.  
     
     
         89 . The article of  claim 88 , wherein the N,N′-dihaloimidazolidinone is at least one of 1,3-dichloro-4,4,5,5-tetramethyl-2-imidazolidinone, 1,3-dibromo-4,4,5,5-tetramethyl-2-imidazolidinone, 1-bromo-3-chloro-4,4,5,5-tetramethyl-2-imidazolidinone, 1,3-dichlor-2,2,5,5-tetramethyl-4-imidazolidinone, 1,3-dibromo-2,2,5,5-tetramethyl-4-imidazolidinone, or 1-bromo-3-chloro-2,2,5,5-tetramethyl-4-imidazolidinone.  
     
     
         90 . The article of  claim 78 , wherein the chlorine and/or bromine source is an N-halosuccinimide.  
     
     
         91 . The article of  claim 90 , wherein the N-halosuccinimide is N-chlorosuccinimide.  
     
     
         92 . The article of  claim 90 , wherein the N-halosuccinimide is N-bromosuccinimide.  
     
     
         93 . The article of  claim 78 , wherein the chlorine and/or bromine source is an N-halomelamine.  
     
     
         94 . The article of  claim 93 , wherein the N-halomelamine is trichloromelamine.  
     
     
         95 . The article of  claim 78 , wherein the chlorine and/or bromine source is an N-haloglycoluril.  
     
     
         96 . The article of  claim 95 , wherein the N-haloglycoluril is at least one of tetrachloroglycoluril or tetrachlorodimethylglycoluril.  
     
     
         97 . The article of  claim 95 , wherein the N-haloglycoluril is at least one of tetrabromoglycoluril or tetrabromodimethylglycoluril.  
     
     
         98 . The article of  claim 78 , wherein the chlorine and/or bromine source is a sulfonhalamide.  
     
     
         99 . The article of  claim 98 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonchloramide (chloramine T), p-toluenesulfondichloramide (dichloramine T), sodium benzenesulfonchloramide (chloramine B), p-sulfondichloramidobenzoic acid, or N-chloro-N-methyl-p-toluenesulfonamide.  
     
     
         100 . The article of  claim 98 , wherein the sulfonhalamide is at least one of sodium p-toluenesulfonbromamide (bromoamine T), p-toluenesulfondibromoamide (dibromamine T), sodium benzenesulfonbromoamide (bromamine B), p-sulfondibromamidobenzoic acid, or N-bromo-N-methyl-p-toluenesulfonamide.  
     
     
         101 . The article of  claim 78 , wherein the chlorine and/or bromine source is a cyclic N-halamine.  
     
     
         102 . The article of  claim 101 , wherein the cyclic N-halamine is at least one of 1,3,5-trichloro-2,4-dioxohexahydrotriazine, 1,3,5-tribromo-2,4-dioxohexahydrotriazine, 1-chloro-2,2,6,6-tetramethylpiperidine, 1-bromo-2,2,6,6-tetramethylpiperidine, 1,4-dichloro-2,2,5,5-tetramethyl-3,6-piperazinedione, 1,4-dibromo-2,2,5,5-tetramethyl-3,6-piperazinedione, 1-chloro-2,2,6,6-tetramethyl-4-piperidone, or 1-bromo-2,2,6,6-tetramethyl-4-piperidone.  
     
     
         103 . The article of  claim 78 , wherein the chlorine and/or bromine source is an acyclic N-halamine.  
     
     
         104 . The article of  claim 103 , wherein the acyclic N-halamine is N,N′-dichloroazodicarbonamidine (Chloroazodin).  
     
     
         105 . The article of  claim 103 , wherein the acyclic N-halamine is N,N′-dibromoazodicarbonamidine.  
     
     
         106 . The article of  claim 78 , wherein the chlorine source is a solid metal salt of hypochlorous acid.  
     
     
         107 . The article of  claim 106 , wherein the solid metal salt of hypochlorous acid is at least one of calcium hypochlorite or lithium hypochlorite.  
     
     
         108 . The article of  claim 78 , wherein the bromine source is a metal salt of hypobromous acid.  
     
     
         109 . The article of  claim 108 , wherein the metal salt of hypobromous acid is at least one of calcium hypobromite, sodium hypobromite, lithium hypobromite, or potassium hypobromite.  
     
     
         110 . The article of  claim 78 , wherein the bromine source is a bromide salt from at least one of sodium bromide, lithium bromide, or potassium bromide.  
     
     
         111 . The article of  claim 78 , wherein the chlorine source is a chloride salt from at least one of sodium chloride, lithium chloride, or potassium chloride.  
     
     
         112 . The article of  claim 78 , wherein the chlorine source is sodium hypochlorite.  
     
     
         113 . The article of  claim 78 , wherein the chlorine source is a metal salt of oxychlorosene.  
     
     
         114 . The article of  claim 113 , wherein the metal salt of oxychlorosene is sodium oxychlorosene.  
     
     
         115 . The article of  claim 78 , further comprising an adjuvant or tableting aid.  
     
     
         116 . The article of  claim 115 , wherein the adjuvant or tableting aid is one from at least calcium phosphate, dicalcium phosphate, tricalcium phosphate, a polyfluorinated polymer, lactose, a fatty acid, a wax, calcium stearate, magnesium stearate, talc, starch, calcium carbonate, sucrose, glucose, mannitol, sorbitol, bentonite, carboxymethylcellulose, methylcellulose, hydroxethylcellulose, hydroxypropylcellulose, sodium metaphosphate, or polytetrafluoroethylene.  
     
     
         117 . A water treatment system, comprising: 
 the articles or compositions of any one of claims  1 ,  41 , or  78  within a first compartment in liquid communication with a second compartment having a heterocyclic N-halamine polymer.    
     
     
         118 . The water treatment system of  claim 117 , wherein the heterocyclic N-halamine polymer is a N-halohydantoinylated polymer.  
     
     
         119 . A method for making the articles or compositions of any one of claims  1 ,  41 , or  78 , comprising: 
 forming the article by compressing a chlorine and/or bromine source into a compressed material, said material capable of delivering free chlorine and/or free bromine in water within a concentration range capable of sustaining the biocidal activity of N-halohydantoinylated beads without rendering the water undrinkable.    
     
     
         120 . A method for halogenating a polymer having pendant heterocyclic amine groups, comprising: 
 placing a composition containing at least one halogen source within a first compartment in liquid communication with a second compartment having a polymer having pendant heterocyclic N-halamine groups and allowing water to flow from the first compartment to the second compartment.    
     
     
         121 . The method of  claim 120 , wherein the composition supplies a continuous concentration of free halogen.  
     
     
         122 . The method of  claim 121 , wherein the free halogen concentration in water is about 0.1 ppm to about 4 ppm.  
     
     
         123 . The method of  claim 122 , wherein the polymer having pendant heterocyclic amine groups is a N-halohydantoinylated polymer.  
     
     
         124 . A method for sustaining the biocidal activity of chlorinated polystyrene hydantoin beads, comprising supplying a continuous halogen concentration to the chlorinated polystyrene hydantoin beads in the water to be treated that flows in contact with the chlorinated polystyrene hydantoin beads resulting in treated water suitable for drinking.  
     
     
         125 . A method for sustaining the biocidal activity of a N-halamine polymer, comprising supplying a continuous free chlorine and/or bromine concentration from about 0.1 ppm to about 4 ppm in the water to be treated that flows in contact with the N-halamine polymer resulting in treated water suitable for drinking.  
     
     
         126 . The method of  claim 125 , wherein the N-halamine polymer is a N-halohydantoinylated polymer.  
     
     
         127 . An article, comprising trichloromelamine, a buffer, and sodium bicarbonate.  
     
     
         128 . The article of  claim 127 , wherein the trichloromelamine comprises about 25% to about 85% by weight.  
     
     
         129 . The article of  claim 127 , wherein the buffer comprises about 1% to about 50% by weight.  
     
     
         130 . The article of  claim 127 , wherein the sodium bicarbonate comprises about 0.5% to about 33% by weight.  
     
     
         131 . The article of  claim 127 , wherein the buffer is a sodium based phosphate buffer.  
     
     
         132 . The article of  claim 131 , wherein the buffer is dibasic sodium phosphate, monobasic sodium phosphate, tribasic sodium phosphate or sodium hexametaphosphate.  
     
     
         133 . The article of  claim 127 , wherein the buffer is a potassium based phosphate buffer.  
     
     
         134 . The article of  claim 133 , wherein the buffer is dibasic potassium phosphate or monobasic potassium phosphate.