Current technology for biological control of cooling tower water uses various oxidizing and nonoxidizing chemical products known as biocides. Biocides, used to kill microorganisms, are meant to be toxic. While often effective at killing the microorganisms, biocides also present users with health and safety concerns, adverse environmental impacts, and chemical compatibility issues with products used for corrosion and scale control.

To eliminate the problems associated with transport, storage, handling and use of chemical biocides, ProChemTech International Inc., Brockway, Pa., developed its ElectroBrom biocide system. ElectroBrom produces an on-site aqueous solution of bromine biocide, produced by electrolysis of a nonhazardous precursor aqueous salt solution that is U.S. Environmental Protection Agency-registered.

According to ProChemTech, in comparison to current chemical biocide technology, the ElectroBrom system offers advantages. Because the precursor salt solution is U.S. EPA-registered and non-hazardous, accidental chemical spills during transport and storage or employee injuries from handling chemicals are not concerns. Also according to the company, bromine is more effective than chlorine at typical cooling water pH values, and it also has a lower vapor pressure than ozone, chlorine and chlorine dioxide, so less product escapes into the air.

The bromine system's active product is made as it is needed, which means product cannot degrade in storage. The bromine biocide reverts to bromide ion in a short time, so there is no toxic blowdown. It provides the continuous halogenation recommended by OSHA and the Cooling Technologies Institute for the control of Legionnaires' disease.

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