Patent ID: 7285224

Claim:
A process for killing microorganisms and controlling biofouling in high chlorine demand water, which comprises mixing a solution of sodium hypochlorite and a solution of ammonium bromide, in a molar ratio calculated as N/Cl of at least 1:1, to form a biocidal mixture, the concentration of said mixture being 0.1% to 1.0% as Cl 2 , and adding said biocidal mixture to said high chlorine demand water, said mixture having a pH of 8.0 to 12.5, said mixture being characterized in that it has at least one of (a) a higher efficacy than bromochlorodimethylhydantoin against Pseudomonas sp. in water containing 100 mg/l CWC at pH 9.0 after a contact time of 5 hours and (b) a higher efficacy than dibromonitrilopropionamide hours.