The Most Effective Way to Disinfect Cooling Towers

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.

Chlorine Dioxide Vs. MIOX’s Hypochlorite Generator

More effective on tough-to-kill organisms, MIOX Mixed Oxidant Solution provides all the benefits of chlorine dioxide, without the hazards of chemical storage or explosion risk.  Biofilm control is easily achieved using only simple table salt and water and your base chemicals – no more strong acid or sodium chlorite.  So you get better control and improved safety all at 1/10th of the cost of chlorine dioxide!

Video Transcription:
Chlorine Dioxide: the solution and the precursor are extremely hazardous.

It’s so explosive that the US department of transportation won’t even allow you to transport it (unless it’s been stabilized or dilute the CIO2 solutions to 3000 parts per million). It’s so risky, that gas masks are required when off-gassing is higher than .1 parts per million in the air. It’s so reactive that its precursors violently react to organic material like: wood, paper, oil, even gummy bears.

It off-gasses so quickly, it may not be effective in certain applications. And to top it off, Chlorine Dioxide is very expensive.

Now there’s a better solution. In most applications, MIOX is as effective as Chlorine Dioxide for biofilm removal and water disinfection including:

  • Sulfur-reducing bacteria (SRB)
  • Acid-producing bacteria (APB)
  • Hydrogen sulfide
  • Cryptosporidium Parvum Oocyst
  • Giardia muris cyst
  • Pseudomonas aeruginosa
  • Legionella Pneumophila  

And MIOX is much safer. You can generate MIOX on site using salt, water, and electricity. And MIOX is much more cost-effective: up to 10x cheaper than Chlorine Dioxide. Chlorine Dioxide may be offered by your water treater, and it may work well. But is it really worth the risk or substantial cost?

Case Study: How This Centralized Cooling Plant Controls Bacteria

This customer wanted a safe, sustainable and “chemical free” biocide for their cooling towers and closed loop, and so they decided to try our MIOX Mixed Oxidant Solution (MOS) in a phased test.

After the test was rolled out and the systems were in place, it was discovered that more biocide had been used than previously documented at this location. As a result, the MIOX system was not the proper size to handle the necessary volume, so there was concern that it wouldn’t be able to achieve optimal operation.

The results?

The client replaced their proprietary biocides (stabilized bromine and glutaraldehyde) and got greater microbial control, despite the undersized MIOX system in the test phase.

How is that possible?

Read the full case study here.

How MIOX’s Electrolysis Process Works


Video Transcription:
The MIOX electrolysis process of on-site chemistry generation begins when salt and water are combined to form a brine solution. Alternatively, an industrial brine byproduct or seawater can be used as feedstock.

The brine solution is fed into a MIOX electrolytic cell. Our proprietary electrolysis process converts the dilute brine into a disinfectant by passing an electrical current through the solution inside the electrolytic cell, converting chloride ions into chlorine-based disinfection chemistries.

MIOX on-site chemistry generation processes are safe, cost-effective, and deliver superior disinfectants to industries around the world.

Tech Brief: Electrochemical Generated Disinfectants by Dr. Andrew Boal

MIOX electrochemical generators, or On-Site Generator (OSG), combine salt, water and power to generate your water disinfection on site and on demand.

The electrolytic cell, where the oxidants are produced, is central to the OSG process. Electrolytic cells consist of two electrodes, the anode and cathode. The cells are arranged so both electrodes make contact with the water and brine solution mixture. When the OSG is activated, an electrical current flows through the cell, causing chemical reactions on the surfaces of both electrodes that eventually produce the disinfectant.

MIOX electrolytic cells are developed with a proprietary geometrical design, electrolytic scheme, and solution flow characteristics. This proprietary knowledge is what allows MIOX to lead the hypochlorite market in terms of efficacy, stability, ease of use, safety and, in most cases, cost.

MIOX works in partnership with your site and current water treatment professional. We offer flexible procurement options ranging from capital sale, lease and rentals.

Read our Tech Brief: Electrochemical Generated Disinfectants by Dr. Andrew Boal for the full chemical reaction, technical explanation and applications breakdown. Click here to access. the PDF online.

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MIOX’s Mixed Oxidant Solution: How it Works

MIOX’s Mixed Oxidant Solution is different from other forms of chlorine and biocides.

We put together a technical briefing that showcases the chemical and microbiological analyses differences between MIOX’s Mixed Oxidant Solution (MOS) to other biocides and forms of aqueous chlorine.

As a leader in on-site generation (OSG) innovation, MIOX learned early on that the electrolytic cell inputs and operational parameters could be tuned to produce aqueous chlorine solutions with substantially different oxidation and disinfection properties.

These observations, coupled with extensive engineering and microbiological research, allowed MIOX to develop a unique OSG product line capable of producing highly reliable MOS.

Click here to read the full tech brief.
Technical Brief: Electrochemical Generated Disinfectants
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Case Study: How a Cooling Plant Dramatically Increased Safety and Reduced Costs

How did this centralized cooling plant transform their underperforming cooling towers and turn them into the biggest safety improvement in the facility’s history?

The funny thing about this installation was that after rolling out a 30-week testing phase with MIOX to monitor performance, we discovered they were using a lot more biocide than originally thought. That meant that the size of the on-site chemical generators they were using in this test phase were actually smaller than what they actually needed.

But this is where things got interesting.

Even though the generators were too small, MIOX performed just as well as their old solution, but did it at a fraction of the cost, and while drastically improving the entire plant’s safety.

They used to receive deliveries of five 650-gallon chemical totes and chlorine dioxide. With MIOX, they were replaced with one delivery of table salt. With MIOX’s patented Mixed Oxidant Solution, all you need is: salt, water, and electricity to generate the chemicals on-site.

Click here to read the full case study that includes the breakdown of chemical levels and cost comparisons before and after the deployment.

Cost effective replacement for chlorine gas and hypochlorite

Businesses and communities around the world are replacing their chlorine gas and bulk hypochlorite systems with MIOX hypochlorite generators.  

The most cost effective replacement for chlorine gas, MIOX won’t break the bank when you convert from your gas system.  Using only salt and water for generation, there are no hazardous chemicals to store greatly improving safety and handling for your employees and neighboring communities.

Watch Chlorine Gas Video!

We have over twenty years of experience in the water disinfection market, thousands of MIOX installations in over 50 countries, and we clean over 8 billion gallons of water per day.

This is the MIOX difference:


  • Eliminate hazardous chemicals stored on-site.


  • Fresh, active disinfectant
  • Avoid chemical degradation rom time and heat.


  • Reduce trucking by 80%
  • Eliminate handling of hazardous material and substitute with table salt

Click here to see our hypochlorite systems offerings.


A Safe Alternative to Chlorine Gas

Video Transcription:
Are you aware that a well-known chemical weapon has been the go-to solution for disinfection… in our own backyard?

For years, Chlorine gas has been used as a disinfectant for many industries. The reason? Its low perceived cost. But in reality, its multiple risk factors give it a much higher actual cost when factoring in insurance and safety-related expenses. At MIOX, we have a better solution: on site chemical generation.

MIOX on site generation is safer than Chlorine gas because the primary ingredient is nothing more than table salt. And the solution is less than 1% concentration. It’s easier thanks to an automated process that produces oxidant only when needed. And because it’s inherently safe, it’s less costly than Chlorine gas over the long-term. With a unique chemistry that outperforms other disinfectants, MIOX is the best, most reliable disinfection solution in the industry. And it’s the safer, more responsible choice.

MIOX Industrial Video

How MIOX Works in Cooling Towers

Video Transcription:
If you’re thinking that you can’t save money while improving water quality in your cooling tower, then think again. Reality is: you have biological growth in your cooling system. Even if it’s not apparent or easy to see. To make matters worse, you’re paying too much for your bulk hypochlorite or your biocide.

Imagine cutting that cost by more than half and improving your results at the same time. Now you can with MIOX. MIOX is cheaper because your chemical is generated on-site. We don’t have trucking. Your disinfectant is made fresh each day. The only operating costs are salt and electricity. It’s more effective so you don’t need as much, and it doesn’t degrade like bleach.

MIOX is generated using environmentally-friendly ingredients: salt, water, and electricity. It’s so safe that it offers no health or safety hazards to your site or your people whatsoever. A <1% concentration means no PPE, no reporting, and an HMIS rating of:

1 for health
0 for flammability
0 physical hazard

In other words, it’s safer than hand sanitizer. Here’s how it works in your tower: MIOX replaces all biocides used in your water systems. MIOX offers a combination of bleach and peroxide which is as effective as chlorine dioxide. The peroxide creates fissures in the biofilm, allowing the hypochlorite to kill underneath the slime layer. This reduces chemical dosing and lowers the ORP, in turn, lowering the corrosivity of water and allowing inhibitors to be more effective. And for alkaline programs where bromine is used, MIOX is effective at elevated pHs.

A recent industrial client used MIOX and increased their production capacity by 7%, producing millions in additional savings. MIOX can offer you a solution that’s cheaper, safer, and more effective — making your job easier, and making you look like a hero.