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Eliminate Bacteria in Coolant



Metalworking fluid is a blend of many chemicals that’s main job is to help oil emulsify into water. Many years ago, this fluid contained carcinogens, until 1970 when it was outlawed from both sale and dumping down the drain.

Without the carcinogens, metalworking fluid is not resistant to bacteria growth and in the right conditions, in a short amount of time, sumps can go from having only a few hundred microbes per milliliter to over 1million!

Solutions to Combat Bacteria

There are a few ways to try and eliminate, or lower the bacteria count within metalworking coolant, but only one way to kill all bacteria and fungus—ozone treatment.
An alternative method used most often is chemical treatment with biocides. Unfortunately, this is only a ‘band-aid solution’—much like painting rusted metal. The chemicals do interfere with the bacteria’s metabolism, but once a biofilm has formed on the coolant, they won’t work. More importantly, biocides are dangerous to employees, expensive, reduce coolant life, and ultimately do not eliminate the problem.

Eliminate Bacterian in Coolant |

Another method used in machining operations is by skimming and filtration. These systems do work as part of a fluid management program, but do not eliminate the bacteria without ozone treatment. The only effective solution is to add an ozone generator to these systems.

Tramp Oil in Tank Cropped |

The Science of Ozone Treatment

So how does that work? Ozone is directly injected into the coolant killing bacteria, viruses, yeast, fungus and molds, while eliminating coolant sump odors. PRAB uses an ozone treatment called the ‘Coolant Manager’ that works in conjunction with each of its coolant recycling systems.

How Ozone Works |


The PRAB Guardian Coolant Recycling Systems removes tramp oil and dirty particulate from the coolant, which eliminates the bacterium ‘breeding ground’, and then the Coolant Manager (ozone generator) breaks down the organic matter by breaking through the cell membrane and interfering with the bacteria cell’s metabolism—killing the bacteria—keeping the coolant healthy and extending its life.

The Coolant Management system not only kills bacteria, but during the filtration process, it automatically adjusts the coolant concentrate when needed, so that there is less operator monitoring and less downtime.

Coolant Manager |
Coolant Manager


Ozone has been used for purification since the late 1800’s. It can be made several ways, but the most common is by ultraviolet light. Ozone is the most effective and natural choice for coolant bacteria control—eliminating the need for biocide.

The Positive Effects of Ozone Treatment on Metalworking Fluids

  • Extended Coolant Life
  • Elimination of Odors, Clogged Coolant Lines, and Slime in Sumps
  • Decreased Employee Health Issues


PRAB has divisions for metal chip processing, fluid filtration, conveyors, and industrial wastewater treatment product lines. If you wish to speak to, or make an appointment with one of our product specialists for any of these divisions, please contact PRAB at (269) 382-8200.