Patent ID: 8632794

Claim:
A method for controlling microbial or biofilm growth in a medium, the method comprising: mixing a nitrogen-containing compound comprising a salt of the formula Y x− [NH 2 R 3 R 4 ] + x , wherein Y x− is a basic form of an acid Y that contains at least one moiety selected from the group consisting of a primary amine moiety, a secondary amine moiety, a tertiary amine moiety, an amide moiety, an imide moiety, a sulfamide moiety, a sulfimide moiety, and an amineimine moiety; and [NH 2 R 3 R 4 ] + is an acidic form of a base NHR 3 R 4 wherein: R 3 and R 4 are each independently selected from the group consisting of H and C 1-8 alkyl, or R 3 and R 4 , together with the nitrogen atom to which they are attached, form a 5- to 10-member heterocyclic ring optionally substituted by one or more groups selected from C 1-6 alkyl, C 3-8 cycloalkyl, halogen, hydroxy, —OC 1-6 alkyl or —OC 3-8 cycloalkyl; and x is 1 to 3, and an aqueous solution of a hypochlorite oxidant to form a biocide comprising a salt of the formula Y x− [NHR 3 R 4 Cl] + x , wherein the molar ratio of said nitrogen-containing compound to said hypochlorite is at least 1:1, and after said mixing, applying said biocide to said medium, wherein said biocide has a pH of between 10.5 and 11.5 immediately prior to being applied to said medium.