A novel approach to onsite, high purity generation of a monochloramined amine (MCA), when
applied to cooling waters, has revealed equivalent performance attributes as associated with
chlorine dioxide applications for planktonic and sessile biological control. Loss of biocide feed
and subsequent loss of planktonic and sessile biological control can be easily restored without
the assistance or co-use of biodispersants / biopenetrants and non-oxidizing biocides.

During process inleakage of hydrocarbons, ammonia, amines, and hydrogen sulfide, biological growth regeneration will increase; however, it is only the biological activity that provides the demand on
the biocide, as it is a mild and selective oxidant like chlorine dioxide. Hence overall system-wide
biocide demands are far less with this novel approach to biological control in cooling waters,
allowing for microbiological control under very stressful conditions. That is, the corrosion rates,
heat exchanger heat extraction rates and cooling tower heat rejection rates were maintained
within acceptable limits, even though run through upsets had been incurred. The results of the
application and surveillance work will be provided in this paper.

KEY WORDS: Algae, Bacteria, Planktonic, Sessile, Legionella, Cooling Water Treatment,
Biocide, Oxidizing Biocide, Non – Oxidizing Biocide, Biodispersant, Biopenetrant, BromideActivated Chloramine (BAC), Monochloramine (MCA), Chlorine Dioxide, Chlorine, Bromine,
Oxidation Reduction Potential (ORP), Corrosion, Localized Corrosion Ratio (LCR),
Microbiologically Influenced Corrosion (MICC), Corrosion Coupons, Linear Polarization
Resistance (LPR), Carbon Steel (CS), Admiralty Brass (AdBr), Fouling Factor (FF), Heat
Transfer Coefficient (U), Heat Extraction, Heat Rejection, Fouling, Microbiological Fouling,
Post Settlement Fouling, Microbial Control, Microbial Growth, Biofilm Thickness, Biofilm
Loading, On-Line Monitoring, Slug Feed, Super Shot Feed, Minimum Inhibitory Concentration
(MIC), Contact Time (CT), Feed Time (FT), States of Operational Conditions of Cooling Water,
Apparent Retention Time (ART), Half Life (t1/2), Process Inleakage, Ammonia, Amines,
Hydrocarbons (HC), Hydrogen Sulfide (H2S).