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Bacteria in Machine Coolant

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Bacteria in Machine Coolant


Dirty machine coolant    60x

We received machine coolant that was unusually cloudy.  Under a microscope, we found these growths.  These are mold and bacteria colonies with millions of individual members.  This type of bacteria growth in Machine Coolant can be avoided by Filtering machine coolant.  For other benefits of filtering Machine Coolant, or for some more information on coolant filtration visit our Machine Coolant Filtration Index.  We offer several different styles of Machine Coolant Filtration Units to help reduce particles and bacteria in your machine coolant.  Shop for our standard models of Machine Coolant Filter units or contact us to build you a custom model to fit your specific filtering needs.

Bacteria can be good or bad

E. Coli is the most well studied organism. It is a normal resident of your intestine and provides you with vitamin K and some of the B vitamins.  It can also cause severe poisoning and death in food such as undercooked meats. 

Dangerous bacteria

We took samples to two labs for analysis.  The first lab said it had 1 million to 10 million per cc.  The next lab identified heterotrophic bacteria.  These are bacteria that eat organic carbon and live at human body temperatures.  Organic carbon includes rubber, plastic, Plexiglas, insulation and human flesh.  The count was 240,000 per ml.  They definitely identified two disease-causing organisms.   We took Pictures of both that were stained for clarity and photographed at 1,000 x. 



Staphylococcus bacteria

Aspergillis Niger Mold

Staphylococci cause abscesses, boils, and infections of the skin. They produce infection in any organ of the body. These bacteria are largely resistant to antibiotics.

 Severe reactions may occur among workers exposed to large amounts of molds in occupational settings. Aspergillis can produce severe disease involving a variety of body tissues.  Superficial infections are generally limited to the outer layers of skin and hair.  Cutaneous infections are deeper in the epidermis, hair and nails. Some infections involve muscles.  Infections may be systemic, originating in the lungs.  Some mycoses are opportunistic, and may involve a variety of body sites.

Control by sanitation is difficult. Disease can be reduced by good hygiene.  No vaccines are currently available.  There are antifungals but some are very toxic to the host and must be used with caution

Sump odors

Badly maintained sumps start to smell after a few weeks, or even days. Some machine shops even reported that when their machines start up, not only does the shop reek of rotten eggs (the infamous Monday morning smells) but that they can see a cloud of green haze linger about the machine. In addition, workers develop rashes, eye or lung irritation, and other health problems.

The problem is bacteria. There are many species of bacteria that can live in  sump, most of which like oxygen environments, but some of which don’t. There are also many varieties of fungi that live there too. And once enough bacteria have congregated in one place, they have a way of signaling each other (called quorum sensing) so that they form a colony.  One of the things these colonies do to protect themselves is start producing a protein carbohydrate complex that science calls a biofilm, and the rest of us call slime, or mucus. Once a biofilm has formed, the only way known to get rid of it is to scrape it off.

Biofilm are far more prevalent than we used to think. Scum on your tub, tartar on your teeth, and your congested sinuses are all forms of biofilms. Cystic fibrosis and serious pneumonia are forms of biofilms that kill (where most current research is focused). In the case of the lowly machine sump, you see the biofilm as the skin on the surface of the sump, different from what many of us used to call tramp oils.

Bacteria exude waste products while they live (including acids), and decay when they die.  Their life cycle can last from 20 minutes for warm aerobes, to as long several hours for oxygen hating anaerobes.  Some bacteria can do both, which makes the job of identifying them harder. Decay products include HCl and H2S, and these are the acids that help degrade the machine coolant. 

Bacteria are present everywhere: in the skin we shed, in the air we breathe, and in the water we mix with the machine coolant. As soon as a layer of oil collects in the sump, an oxygen dead layer forms (because aerobic bacteria consume the oxygen as part of their metabolic cycle) and the anaerobic bacteria start to thrive.  In fact, they like to consume the oil itself as a food source. 

Many companies have tried to combat bacteria using outright biocides, usually compounds that interfere with the metabolism of the bacteria itself.  Unfortunately, these substances can also be dangerous for people.  Worse, once the bacteria have had the chance to form a biofilm, even the most powerful biocides can’t touch them.  Only physical removal has a chance.  Most bacteria are small enough to be filtered out of the machine coolant. 

The best strategy is to start fighting the bacteria right from the beginning.  Proper testing and machine coolant maintenance combined with removal of the tramp oil and machine coolant aeration though filtering will keep the machine coolant knocked down to next to nothing.  

No Stink, No smell

Many shops change machine coolant when it stinks.  Machine coolant stinks because it has bacteria in it that eat the oil and grease.  The bad smell is waste material from the bacteria.  Filtering machine coolant prevents bad smells because it prevents bacteria growth.  Bacteria live in the sludge in the bottom of the sump.  Filtering removes that sludge.  Bacteria eat oil and grease that accumulates in the sump.  Filtering removes the oil and grease.   Bacteria are in the air so you cannot keep them out of the sump completely.  However they grow and as they grow they get filtered out so you are always removing the greatest part of them.

Finally the bacteria that create the worst smell are anaerobic which is from the Greek meaning "without air" They grow best under water without air.  Filtering keeps the machine coolant stirred up and keeps mixing air in.  This keeps oxygen in the machine coolant and further prevents bacteria growth.  


Box of 10

only $91.40


Easy Bacteria Testing

Bug Check BF  -   Bacteria Test Kit

BF test kit for counting bacteria and fungi

> Simple

> Quick

> Easy-to-Use

> Self-Contained 

The simple easy-to-use test kit for counting total bacteria and fungi in all water-based fluids.  For more information on Bug Check BF, and other Coolant Testing Equipment refer to our Coolant testing Instruments Article.





     1      2      3    4      5      6    7

Samples taken from 4 saw grinders

# 1- Unused,  # 2- Grinder 1, # 3- Grinder 2, # 4- Grinder 3,  # 5- Grinder 4,  # 6- Drinking water,  # 7- Mud puddle

All water-based fluids are susceptible to microbial contamination - (bacteria, fungi, algae and mold).  High levels of contamination lead not only to foul odors but to microbial spoilage of your products and health concerns for your workers. 

West Coast Saws Bacteria Analysis – November 7, 2005

This is a shop that runs 2 and 3 shifts and changes its machine coolant every six months.  In spite of that they have extremely clean machine coolant because they manage it properly including constant filtering. 

Three bacteria colonies which means the machine coolant is very, very clean.  It is about as clean as distilled drinking water.   In addition the bacteria colonies grew very poorly which means the antibacterial properties of the machine coolant was just about perfect.  



Colonies show as little specs here. 

Samples from other sources for comparison 


           1         2            3             4              5               6            7

Samples taken from 4 saw grinders

# 1- Unused,  # 2- Grinder 1, # 3- Grinder 2, # 4- Grinder 3,  # 5- Grinder 4,  # 6- Drinking water,  # 7- Mud puddle 

 A well maintained sump is considerably cleaner than even drinking water.

Sump Soda

Sump Soda™ is a simple, convenient and professional strength tank-side additive for metalworking fluid.  It helps keep machine coolants fresher, cleaner smelling and lengthens their life.  Upon adding an appropriate dose to an infected foul smelling sump, Sump Soda will immediately destroy existing bacteria and fungi in the system.  In addition to this initial effect, Sump Soda will modify sump pH conditions by increasing the reserve alkalinity of the machine coolant, thereby inhibiting future growth of new bacteria.

USAGE RATE in finished machine coolants 

Add: 1 quart per 50 gallons

2.5 gallons per 1000 gallons 

After adding, allow system to recirculate for a few minutes.  Foul systems may require a double dose.  Continue usage monthly or on an “as needed” basis. 

Physical Specifications
Color                                      Yellow
Odor                                       Characteristic
Appearance                          Clear
pH 10:1 solution                  10.00-12.00
Density                                  9.746
Specific Gravity                   1.146 

Compatible with all major metalworking fluids:  Castrol, DA Stuart, Fuchs, Exxon, Mobil, ChemTool, Quaker, Houghton, Master, AW Chesterton, DoAll, ITW, Milacron, Hangsterfer's.

Benefits of using Sump Soda

•  Eliminates foul odors  (end smells on you and your clothes)

•  Extend machine coolant life (double or even triple fluid life when compared with unmanaged sumps, individual sumps results will vary)

•  Fights existing bugs (get rid of bacteria and fungi concerns)

•  Fortifies pH (prevent future bacteria growth and odors)

•  Contains no chlorine (safe for disposal)

•  Saves you money (lower material, disposal and labor related machine coolant costs)