Disinfection is a critical aspect of cooling tower water treatment for operational reasons like eliminating biofilm to maximize heat transfer efficiency and minimize microbial-induced corrosion.
We all know that cooling waters containing high levels of ammonia, which increases the complexity of the disinfection process, are commonly found in the ammonia production industry.
But here’s the thing…
Ammonia in cooling towers is commonly assumed to interfere with hypochlorite-based disinfection programs, which are in-turn expected to be insufficient alone to control microbial populations and require additives such as bromide or non-oxidizing biocides to provide sufficient disinfection.
There is a growing body of evidence demonstrating that disinfection of ammonia containing waters with on-site generated Mixed Oxidant Solution (MOS) can effectively control microbial populations in these waters without additives. MOS is an industry-proven disinfection technology which is produced on-site through the electrolysis of sodium chloride (salt) brines, providing cost-savings, improved disinfection efficacy, and increased worker safety.
Recently, a large ammonia production facility converted their cooling tower disinfection program from a chlorine gas/bromide combination to treatment with MOS only.
And we have a side-by-side comparison of these two disinfection programs at the same facility to show the real difference.
Read More from Andrew K. Boal, Ph.D…..
On-Site Generation: A Safe Replacement for Chlorine Gas in Water Disinfection Applications in Ammonia Production Facilities
Abstract Text: Disinfection is a critical component of industrial water treatment programs, and is especially the case in waters used in cooling towers. Cooling water that has not been properly disinfected can result in the growth of biofilms, which can damage equipment and allow for the proliferation of pathogenic bacteria which can result in increased human health risks. Chlorine gas is commonly used as the primary oxidative biocide in large scale industrial cooling water treatment programs, including many ammonia production facilities. While chlorine gas is inexpensive, facility managers are moving away from chlorine gas due to the hazards that this chemical presents not only to the work force, but also to surrounding communities. While there are several options for chemicals that can replace chlorine gas, On-Site Generated (OSG) systems are an ideal choice to deliver an oxidant for disinfection applications using the safest means possible. OSG processes work through the electrolysis of sodium chloride brines to produce sodium hypochlorite based oxidant solutions with active chlorine concentration of less than 0.8% and at a mild pH. These solutions are much less hazardous than bulk delivered oxidants, which are typically provided in concentrations of 10-15% with solution pH values of over 11. This presentation will provide an overview of OSG processes and systems and will describe in detail the replacement of chlorine gas with OSG systems for cooling water disinfection at a major ammonia production facility.