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.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional Patent Application No. 60 / 507,735, filed Oct. 1, 2003, incorporated herein by reference.FIELD OF THE INVENTION

[0002] The invention is related to water purification systems, including systems employing polymers having pendant heterocyclic amine groups, such as polystyrene having pendant hydantoin and halogenated hydantoin groups, and to the compositions and methods for maintaining the polymers in a biocidally active state. BACKGROUND OF THE INVENTION

[0003] Heterocyclic N-halamine groups are known to have biocidal properties that can be put to use in water purification. Heterocyclic N-halamine groups that are attached to a polystyrene polymer are described in U.S. Pat. No. 5,490,983. A crosslinked polystyrene polymer having similar pendant heterocyclic N-halamine groups is described in U.S. Pat. No. 6,548,054. The crosslinked version of the polystyrene polymer is typically provided in be...

Examples

example 1

Sustaining Biocidal Efficacy of HPSH Beads with Diluted Bleach

[0049] Two beds arranged as shown in FIG. 1, each containing 20 g of chlorinated HPSH beads (16.9% wt / wt of Cl+ (Cl+ is the chlorine attached to a nitrogen on the hydantoin available for the biodemand)) and confirmed to be of a biocidal state achieving a 4-log reduction value (LRV) in poliovirus and a 6-LRV in Klebsiella terrigena (as determined using the methods described in the USEPA Guide Standard and Protocol for Testing Microbiological Purifiers: Report of Task Force, 1987), were challenged with feed water having the characteristics of 1,500 mg / L total dissolved solids as sea salts, 10 mg / L of total organic carbon as humic acid, and a pH of 9.0 adjusted using NaOH and HCl. Each bed was continuously challenged at 60 ml / min. One bed was designated the control and continuously challenged only with the feed water. The other bed was continuously challenged with feed water that was adjusted to 2 ppm free chlorine (as meas...

example 2

Sustaining Biocidal Efficacy of HPSH Beads with Trichloromelamine and Magnesium Oxide Tablet

[0050] A commercially available gravity feed ceramic drinking water system as shown in FIG. 2 (Doulton Berkefeld) was used along with a 20 gram cartridge of HPSH polymer (having 16% Cl+ wt / wt) attached to the outlet of the ceramic filter. The system was challenged with feed water having the characteristics of 1,500 mg / L total dissolved solids as sea salts, 10 mg / L of total organic carbon as humic acid, and a pH of 9.0 adjusted using NaOH and HCl. The system was allowed to run daily at 10 liters per day at an average flow rate of 10 ml / min using chlorine-free tap water and challenged weekly using the above challenge water until the poliovirus log reduction dropped below a complete kill of 4-LRV (as determined using the methods described in the USEPA Guide Standard and Protocol for Testing Microbiological Purifiers: Report of Task Force, 1987). Prior to the introduction of an article that rele...

example 3

Activating Biocidal Efficacy of PSH Beads with Trichloromelamine Tablet

[0052] Two beds, each containing 22 g of PSH polymer in bead form (0% wt / wt of Cl+) arranged as shown in FIG. 1, were challenged with municipally treated drinking water that was processed through an activated carbon block commonly sold into retail markets for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of free chlorine and had a hardness of 0.07 ppm (as total CaCO3 using HACH hardness method 8030). One bed was designated the control and continuously challenged only with the feed water. The other bed was continuously challenged with feed water that flowed over a solid ½-inch diameter, 550 mg, compressed tablet of compacted powdered trichloromelamine (Parr Pellet Press, Parr Instruments Co.) having a density of 1.3678 g / cc. The feed water after the pellet contained 0.10 ppm to about 0.30 ppm of free chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH Cor...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional Patent Application No. 60 / 507,735, filed Oct. 1, 2003, incorporated herein by reference.FIELD OF THE INVENTION

[0002] The invention is related to water purification systems, including systems employing polymers having pendant heterocyclic amine groups, such as polystyrene having pendant hydantoin and halogenated hydantoin groups, and to the compositions and methods for maintaining the polymers in a biocidally active state. BACKGROUND OF THE INVENTION

[0003] Heterocyclic N-halamine groups are known to have biocidal properties that can be put to use in water purification. Heterocyclic N-halamine groups that are attached to a polystyrene polymer are described in U.S. Pat. No. 5,490,983. A crosslinked polystyrene polymer having similar pendant heterocyclic N-halamine groups is described in U.S. Pat. No. 6,548,054. The crosslinked version of the polystyrene polymer is typically provided in be...

Examples

example 1

Sustaining Biocidal Efficacy of HPSH Beads with Diluted Bleach

[0049] Two beds arranged as shown in FIG. 1, each containing 20 g of chlorinated HPSH beads (16.9% wt / wt of Cl+ (Cl+ is the chlorine attached to a nitrogen on the hydantoin available for the biodemand)) and confirmed to be of a biocidal state achieving a 4-log reduction value (LRV) in poliovirus and a 6-LRV in Klebsiella terrigena (as determined using the methods described in the USEPA Guide Standard and Protocol for Testing Microbiological Purifiers: Report of Task Force, 1987), were challenged with feed water having the characteristics of 1,500 mg / L total dissolved solids as sea salts, 10 mg / L of total organic carbon as humic acid, and a pH of 9.0 adjusted using NaOH and HCl. Each bed was continuously challenged at 60 ml / min. One bed was designated the control and continuously challenged only with the feed water. The other bed was continuously challenged with feed water that was adjusted to 2 ppm free chlorine (as meas...

example 2

Sustaining Biocidal Efficacy of HPSH Beads with Trichloromelamine and Magnesium Oxide Tablet

[0050] A commercially available gravity feed ceramic drinking water system as shown in FIG. 2 (Doulton Berkefeld) was used along with a 20 gram cartridge of HPSH polymer (having 16% Cl+ wt / wt) attached to the outlet of the ceramic filter. The system was challenged with feed water having the characteristics of 1,500 mg / L total dissolved solids as sea salts, 10 mg / L of total organic carbon as humic acid, and a pH of 9.0 adjusted using NaOH and HCl. The system was allowed to run daily at 10 liters per day at an average flow rate of 10 ml / min using chlorine-free tap water and challenged weekly using the above challenge water until the poliovirus log reduction dropped below a complete kill of 4-LRV (as determined using the methods described in the USEPA Guide Standard and Protocol for Testing Microbiological Purifiers: Report of Task Force, 1987). Prior to the introduction of an article that rele...

example 3

Activating Biocidal Efficacy of PSH Beads with Trichloromelamine Tablet

[0052] Two beds, each containing 22 g of PSH polymer in bead form (0% wt / wt of Cl+) arranged as shown in FIG. 1, were challenged with municipally treated drinking water that was processed through an activated carbon block commonly sold into retail markets for the removal of chlorine taste and odor. The water contained less than 0.02 ppm of free chlorine and had a hardness of 0.07 ppm (as total CaCO3 using HACH hardness method 8030). One bed was designated the control and continuously challenged only with the feed water. The other bed was continuously challenged with feed water that flowed over a solid ½-inch diameter, 550 mg, compressed tablet of compacted powdered trichloromelamine (Parr Pellet Press, Parr Instruments Co.) having a density of 1.3678 g / cc. The feed water after the pellet contained 0.10 ppm to about 0.30 ppm of free chlorine (as measured by N,N-diethylphenylenediamine (DPD) reagent using HACH Cor...

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