Ozone Laundry Systems: Facts vs. Fallacy (Part 2)

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Over the last twenty years I have witnessed Ozone laundry companies come and go.  I have witnessed outlandish claims from some of these companies, and quite frankly am tired of listening to the outright lies and fallacies that some of these companies are stating.

I would like to look at some of the facts and hope to help our readers make an educated decision about ozone laundry.

This month, let’s look at the two major design differences.

Some ozone laundry companies have taken the path of the “fine bubble diffuser” to inject ozone into the wash water, while other have chosen the Direct Venturi Injection as their means of transferring the ozone gas into the water.  There are claims by manufacturers of advantages to both, so we should look at the design criteria of each and pick what is best for your application.

Ozone gas is dissolved into water by utilizing pressure.   It does not take a lot of pressure to start dissolving ozone into water.  In the industry we call the ability to dissolve gas into water “Mass Transfer.”  The efficiency of Mass Transfer of either style of injection device is highly dependant upon the design criteria of the device.

The idea of the fine bubble diffusion injection method used on washing machines is borrowed from the bottled water industry.  In bottled water plants, ozone in introduced into a large column (or tank) of water.  These are usually in excess of 15 feet tall. Water flows in to the top of the tank and exits the tank through the bottom.  The fine bubble diffuser is placed in the bottom of the tank.  Ozone is introduced thru that diffuser in the bottom of the tank. Water in introduced in to the top of the tank and flows downward, where it exits out the bottom of the tank.  As the ozone bubbles rise, they are violently thrashed around due to the counter flow if the water flowing thru the tank.  This turbulence lends for a pretty decent mass transfer of the ozone gas into the water.  The tanks used in the Las Vegas water treatment plant are 32 feet tall.  Remember that pressure is needed to transfer the ozone into the water solution.  Every inch of water column used adds more pressure to the diffuser stone, located in the bottom of the tank.  Therefore the taller the tank, the more pressure created at the bottom of the tank from the weight of the column of water, and the better the mass transfer of the ozone into the water.

Once the un-dissolved ozone reached the top of the tank, it is removed thru an air vent and destroyed by passing thru an ozone destruct system.

All in all, this is a very safe and effective way to dissolve ozone in to water.

However, when the designers of the fine bubble diffusion systems implemented this type of system on a washer/extractor,  they left out a couple key ingredients.

First, the column of water in a washer/extractor is nowhere near that of a 32 foot tall water tank.  It is more like 12 inches.  This allows for a much lower Mass Transfer efficiency of the ozone gas.  Several ozone engineers that have studied this design have figured that the efficiency is somewhere in the 25-40% range at best.  That means in the best case scenario, 60% of the ozone gas does not get dissolved.  This is important in that 1% of un-dissolved ozone gas can easily make a room unsafe for the laundry workers.   In the bottled water design, you have the ability to capture this un-dissolved gas and destroy it.  The main problem here is that the designers somehow forgot to include this important piece of the puzzle.  Common sense tells you that if you force air(or Ozone) into an unsealed vessel, air (or Ozone) will escape out the vents of the machine on into the laundry room where it comes into contact with the laundry workers.  Some companies have tried to cover up this major design error by installing an ambient ozone room monitor that in theory shuts off the ozone generators when this level is reached.  In reality, the ozone generator is only on a few seconds before it is shut down due to over saturation of ambient ozone in the room.  Then many times it takes several minutes for the room sensor to reset and let the system turn on the ozone generator again.  I have witnessed the ozone generator being in operation for all of 45 seconds during a 7 minute wash step.  That’s not going to kill many “Super Bugs”.  I recently attended an ozone conference where the guest speaker said that a fine bubble diffusion system on a washer/extractor was “So easy to Build, that even a Caveman could do it”

It is not only that it is easy to build, it is also cheap to build this type of system.  That is why there are so many on the market, and the low price keeps the attention of the potential uneducated buyer.

The Venturi Injection System uses the pressure of the water stream in the piping to create suction.  When applied to this suction port, 85-90% of the ozone gas is instantly dissolved in to the water.  Since we still have this water and un-dissolved gas contained inside the water piping, it can easily be run thru an Ozone Degassing chamber that removes the un-dissolved ozone gas where it can be destroyed.   The end results are 100% dissolved ozonated water going to the washing machine.  This is an over-simplification of the process.  But it should get the point across without going into all the hydraulic engineering facts that make this a much more reliable and stable way to dissolves ozone into water. The disadvantage of the Venturi Injection System is that it costs more to build this type of system.

Another reason not to consider the fine bubble diffusion type of technology is the time it takes to build up to concentration.  Those of you operating commercial laundries know that you never want to fill up a washer with cold water then steam up the temperature to 160 degrees, because it takes too long.  I know there are some cases where this is unavoidable.  But normally you would fill your washer up with your standard hot water usually 130-140 degrees, then add steam injection to raise the temperature in those wash steps where you need a little higher temperature.  The same is true with the fine bubble diffuser.  A Venturi Injection system instantly fills the washer with highly concentrated ozonated water that instantly starts the cleaning and sanitizing process.  It can take as much as 20 minutes for a fine bubble diffusion system to reach the ozone levels where the Venturi Injection system starts.  None of us have that much extra time available in our wash cycle.

Finally, some Venturi Injection Systems on the market allow for larger than normal fill valves and water lines to be utilized.  This will allow for much faster fill times.  I have witnessed a 60 lb washer/extractor being filled in under 25 seconds, whereas the standard fill time was in excess of 2 minutes.  On a standard hospitality wash cycle with five fills, this would shorten your wash cycle by more than 7 minutes of total operating time.  Washing an average of ten loads per day, this type of ozone laundry system would easily eliminate over one hour of processing per day.

In the graph below, you can see two identical tests that show the concentration of ozone throughout a complete wash cycle.  Notice in the Venturi Injection System, the levels start off high and slowly dissipate before the water is drained in each bath.  You should also notice the effect of PH on each bath in the wash cycle.  During the detergent and bleach steps, the ozone is reduced as it is counteracted by the higher PH from the wash chemistry.  As the detergent and bleach are rinsed out, you can see that the ozone hangs around much longer.

In the fine bubble diffuser, you will notice that the ozone levels never reach above the 0.2 PPM of ozone in the water.  It is also evident that the higher PH makes it hard for the ozone to overcome when using a Fine Bubble Diffuser.

I am not stating that the fine bubble diffusion system does not work, or does not clean laundry, but rather, it is no where as effective as a properly designed Venturi Injection System.  Results will be more consistent with the Venturi Injection System than a comparable Fine Bubble Diffusion System. 

Next month we will discuss “How to tell if your Ozone Laundry System is working”, and “How do we know if ozone will really kill the Super Bugs”.

I invite you to email me with questions and topics that you would like to see covered in our monthly article


Mark E. Moore, CEO

ArtiClean Ozone Laundry Systems  

REM Laundry Equipment, Inc.                                                                                                                                

m.moore@articlean.com

Mark E. Moore is a 30 year veteran of the Industrial Laundry Equipment Industry.  He is the owner of REM Laundry Systems, a Commercial Laundry Equipment Distributor/Laundry Consultation Group with over 40 employees and offices located in Versailles, KY and Nashville, TN.  He has worked with and consulted for several Ozone Laundry companies over the last 20+ years.  He formed ArtiClean Ozone Laundry System with a vision of creating a better ozone laundry system.   Today, ArtiClean is the largest Ozone Laundry Company in the world with distribution networks in North America, South America, Europe, Asia and Australia.

  • themanglerman said,

    Very informative article on the different types of Ozone. I assume you’ve tested other types before you made assumptions on which is the better system? How does Ozone do at killing bacterias, etc, since it washes in lower temps?

    Thanks, great article.

  • Mark Moore said,

    Thanks for your insight!
    Yes we have tested both types of systems both in the field and also in our test lab. Unlike others in the industry, I would never state anything that we could not back up with factual information.
    Stay Tuned for the next article as we will cover the bacteria killing abilities of Ozone.

  • B-dog said,

    Very interesting article, I didn’t realize there was that big of a difference between the two types of systems. I am a little confused on a couple things though. You said “Since we still have this water and un-dissolved gas contained inside the water piping, it can easily be run thru an Ozone Degassing chamber that removes the un-dissolved ozone gas where it can be destroyed. The end results are 100% dissolved ozonated water going to the washing machine.” With the Venturi method having a much higher concentration of ozone in the water when it goes into the washer, wouldn’t you have a higher level of ozone gas escaping through the washing machine vents than the diffusion system, causing a greater risk to the people in the laundry?

  • Rip G. Rice said,

    MEMO TO: THE LAUNDRY FORUM
    FROM : Rip G. Rice, Ph.D., Consultant in Ozone Technologies
    DATE: : December 10, 2010
    SUBJECT: OZONE LAUNDRY SYSTEMS: FACTS vs FALLACIES — Parts 1 and 2
    It was a real pleasure for me to read part I of this proposed series because it really is time for someone, supposedly “skilled in the arts” of laundry and ozone to begin documenting and setting straight the facts about ozone as applied to laundry systems. The plan outlined by Mr. Mark Moore in Part I is ambitious, and offers the possibility for the creation of an authoritative text book on the subject that could become a very valuable reference for those in the laundry industry who are eager to learn about this relative newcomer (ozone technology) to the laundering industry. And so I was anxiously awaiting the second chapter in the ozone story by Mr. Moore.

    However when Part 2 appeared, I was disappointed at what was being said about ozone technology — some of the statements made are truths about treating drinking water (including bottled water) with ozone. However in applying those technologies to laundering systems, some of these truths become falsehoods or fallacies, as I shall point out below. Worse, Mr. Moore vehemently condemns what he believes to be “lies” and then tries to make his case by imposing unintended (hopefully) “lies” of his own.

    Actually, “lies” may not be the appropriate word. To me, “lies” implies an intent to deceive, and I do not believe that Mr. Moore has that intent. My belief is that he may a well-intended (but over-zealous) vendor of this new and always advancing new technology that might be guilty of making claims for ozone without considering all of the known physical and chemical properties of this new technology. Hopefully that is what is happening here.

    Mr. Moore zealously condemns bubble diffusion contacting in a laundry washer as a technical approach to the use of ozone that must be doomed to failure because he believes that ozone will off-gas from such washer design systems, thereby endangering laundry workers. He builds his case based on known mass transfer facts about ozone (which have very little applicability to ozone laundering as I shall point out). However, he stands silent on the much more significant effects of ozone demand (of laundry water and of soiled laundry in the washer), of agitation (causing degassing of dissolved ozone), of increasing temperature (causing more rapid decomposition of ozone), and of the considerable benefits of having some gas phase ozone present in the washer to permeate linens and garments that are being laundered.

    Before expanding on my statements, let me point out a significant commercially successful fact of ozone laundering. Ozone diffusion laundry systems (and ONLY ozone diffusion systems) have been approved by the United Kingdom’s Department of Health and the public health departments of the states of Missouri and New Hampshire for laundering with ozone and are operational in several thousand commercial laundering facilities in the UK and the USA. These approvals have been based on considerable third-party testing plus user satisfaction with their bubble diffuser laundry systems.

    According to Mr. Moore’s comments, which are based on mass transfer considerations alone, the use of bubble diffusers in a laundry washer is unsafe because excessive off-gassing of ozone MUST happen. But in commercial practice, properly designed and operated bubble diffusion laundry systems do not degas and pose potential threats to laundry workers. If Mr. Moores’ theory is that bubble diffusion cannot work without excessive ozone off-gassing, then his theory needs to be updated.

    Mr. Moore states that “The idea of the fine bubble diffusion injection method used in washing machines is borrowed from the bottled water industry.” Aside from the fact that “injection” is a process of dissolving ozone into water that is impossible to perform with a diffuser — that is why “injectors” are called “injectors” — bubble diffusion in laundry machines has nothing at all to do with bottled water or drinking water treatment with ozone. The objectives of adding ozone to a laundry washer sump by bubble diffusion are several-fold:

    1. to mix an effective amount of ozone with the water AND with the soiled laundry;
    2. to maintain an effective residual of ozone in the machine (in the water AND in the washer air) for the full processing step time;
    3. without allowing degassing of excess ozone into the laundry room where workers could be exposed to gaseous ozone.

    The driving characteristic that allows these three objectives to be attained is the ozone demand of the washer contents (water plus soiled laundry), NOT mass transfer considerations. Ozone-demand of washer contents is further affected by ozone solubility, ozone reactivity with various laundry chemicals and soils (different rates in water vs gas phases), agitation, and auto-decomposition of ozone (fast at high temperatures).

    DRINKING WATER TREATMENT WITH OZONE

    While it is certainly true that in large scale drinking water plants, tall (18-20 feet) ozone bubble diffusion contactors are employed, they must be this tall for reasons other than optimizing mass transfer. In drinking water treatment, ozone has been in commercial use since 1906 (starting in Nice, France) for disinfection. And for ozone (or chlorine for that matter) to be effective as a disinfectant, a minimum dissolved ozone concentration must be maintained in the water for a specified number of minutes. The French set the ozone parameters at 0.4 mg/L (ppm) to be maintained over four minutes.

    These requirements are based on determinations by French public health officials to be effective for the inactivation of polioviruses in a laboratory. French water treatment engineers added a safety factor of eight more minutes (total 12 minutes) of “contact time” in full scale plants for insurance. Since the solubility of ozone in water greater than 0.4 mg/L is difficult to attain by bubble diffusion without using additional energy (costs for Venturi injection are out of the question when considering millions of gallons of water per day), increasing the ozone contact time was and remains the best commercially practical approach.

    These ozone disinfection requirements for treating drinking water are still applied today, although they have been refined to include other microorganisms that have been found in raw drinking waters.

    The sidewater depth of a water column above a bubble diffuser in a municipal water treatment plant cannot be more than 17-19 feet. This is because ozone is produced in generators operating with influent air (today high purity oxygen) exiting the corona discharge (or plasma) ozone generator at a gas pressure sufficient to overcome water column heights of 17-19 feet. Water columns higher than 17-19 feet will flood the ozone generators and stop the process.

    In these bubble diffuser contactor designs, mass transfer considerations were entirely secondary, except for the aspect of maximizing efficiency (to lower costs). From a plant operation expense point of view, ozone costs money to generate, nothing to contact (by diffusion), but any excess ozone off-gas must be destroyed, which costs more money. Fortunately, the smaller the gas bubbles (that contain ozone) rising upward in a down-flowing (by gravity) water column, the slower the rate of rise of the bubbles, and the higher the efficiency of mass transfer of ozone — easily reaching 90-95%.

    BOTTLED WATER TREATMENT WITH OZONE

    When the U.S. Food & Drug Administration approved the use of ozone for treating bottled water in the early 1980s, the approval was based on using ozone for disinfection of water that already meets EPA drinking water standards. Consequently, the FDA required a minimum ozone residual of 0.3 mg/L over a minimum of FOUR minutes. This meant that the height of bottled water diffuser contactors did NOT have to be 17-19 feet. I have visited bottled water plant (large and small) in which the height of bubble diffusers are on the order of four to six feet tall. However, some very large bottled water plants may indeed process sufficiently large volumes of water to warrant the use of bubble diffusers of greater height.

    I am sorry to have taken all this space to discuss the mass transfer argument, which never should have been raised in discussing laundry applications of ozone because it has almost NOTHING to do with laundry systems. And talking about it partially, without presenting the complete discussion, really is pointless.

    SIGNIFICANTLY APPLICABLE OZONE LAUNDRY CONSIDERATIONS

    As mentioned earlier, what is most important in laundry applications is the ozone demand of the washer contents — meaning water and soiled laundry. The higher the ozone demand of the washer contents (meaning the greater the degree of soiling), the more ozone (or any other laundry chemical whose purpose is disinfection and/or oxidation) will be required to result in the desired degree of cleansing. Since municipal water supplies usually are used to charge laundry washers, the ozone demand of this water will be quite low, especially when compared to the ozone demand of the soiled laundry to be washed.

    The next most significant factor is the location of the ozone-demanding materials — obviously very little is in the water — the lion’s share is in or on the soiled laundry itself. And “in or on” the laundry makes a big difference to an ozone molecule — because at best, ozone is only a partially soluble gas in water. It does not ionize and dissolve in water as does something like table salt. Instead, it hangs around in solution until one of four things happens:

    1. It finds something to react with ( =ozone-demanding soils or impurities),
    2. During agitation, the ozone molecule finds itself at the water/air interface, and escapes to the air,
    3. It auto-decomposes — it simply reverts back to oxygen from which it was generated originally — and the higher the temperature, the faster ozone auto-decomposes,
    4. It reacts with one or more laundry chemicals that may be present (peroxide destroys ozone almost instantaneously, for example).

    The trick with ozone is to get it to the ozone-demanding soils in/on the laundry, and this can be accomplished by applying BOTH the aqueous and gaseous phases of ozone — both of which exist in a laundry washer regardless of how the ozone contacting is done initially. More on this later.

    Nature of Soils and Microorganisms

    Soils and microorganisms that are present on the surfaces of linens will be exposed to dissolved ozone and be attacked by the ozone. If the concentration of dissolved ozone is sufficient to complete the oxidations or disinfections, all well and good. But if the concentration of dissolved ozone falls too low to be effective, then the soils and microorganisms can escape being laundered/disinfected.

    On the other hand, if soils and microorganisms are located inside the soiled cloths, or (worse) in the interstices of the fibers, it may be much more difficult for dissolved ozone to reach those impurities before being lost to degassing or decomposition. Fortunately, as long as some gas-phase ozone is present in the washer water (much of it in the form of fine bubbles that have coalesced and aggregated into larger bubbles) these pockets of gas phase ozone can find their way into places where aqueous ozone (of very much lower ozone concentration than in the gas phase) and provide an additional bang for the ozone buck.

    TYPES OF OZONE CONTACTING SYSTEMS

    With these laundering mechanisms considered, the specifics of Venturi injection vs fine bubble diffusion systems now become significant.

    There is no question that either method of contacting ozone in commercial laundry systems provides a better way to launder than by conventional (thermal) techniques. No knowledgeable laundry professional should argue this point, because ozone’s advantages have been and are being proved every day. The argument raised by Mr. Moore is only that he believes that Venturi injection is better, more effective and safer (from the points of view that he raises) than fine bubble diffusion. His argument is that bubble diffusion cannot be safe because of the off-gassing potential. If that were the case, there would few commercially operating bubble diffusion ozone laundering systems.

    But instead, ozone fine bubble diffusion laundry systems and ONLY ozone fine bubble diffusion laundering systems have been approved by the United Kingdom’s Department of Health and by the States of Missouri and New Hampshire. It seems to me that instead of bashing bubble diffusion with reason why it should not work, Mr. Moore might be wiser to ask himself, “why do ozone bubble diffusion systems work?”

    Mr. Moore’s situation is akin to the status of winged supersonic aircraft in the mid-1950s. At that time I was a chemist working in an aerospace plant where the B-58 bomber was being produced for the U.S. Air Force. During my indoctrination into the mechanics of flight I was advised that according to aerodynamic theories then prevalent, the bumble bee cannot fly. Impossible. But fly it does. So aerodynamic engineers looked up from their text books, considered that theoretical discrepancy, and promptly developed better theories — and better aircraft, as a result.

    Venturi Injectors

    With Venturi injectors, ozone is added to water BEFORE it is sent to the washing machine. Excess ozone in the contacting system is degassed and destroyed so that there is no undissolved ozone in the water sent to the washer. Happily, a relatively large amount of dissolved ozone (Mr. Moore’s last graphic shows a little over 1.6 mg/L) is present in this (ozone demand-free) water when it is sent to the washer. This represents a real initial advantage for ozone by Venturi injection.

    However, this is the LAST ozone that laundry in that specific laundering step will see until that washer is drained and a new ozone-containing water charge is added for the next laundering step. Some part of the ozone demand of the laundry will be satisfied. If more ozone demand exists than is available from the dissolved ozone, the ozone residual level in the water will drop.

    As soon as the washer agitator starts agitating, some of the dissolved ozone will degas. If the degassing ozone bubbles work their way through fabrics, the ozone gas contained therein can be available to work on entrapped impurities. So much the better for ozone. But the total ozone concentration HAS to decrease over time — by satisfying ozone demand of the laundry, by degassing, and by decomposition (either auto- or by reacting with one or more laundry chemicals).

    Fine Bubble Diffusers

    These contactors allow ozone addition to water IN THE WASHER. They are designed to provide ozone addition throughout each washing step. The gas phase level of ozone can be monitored and controlled so as to stop the addition of ozone if and when the ozone demand has been satisfied, thus never allowing excessive ozone gas to escape to the laundry room. The advantage of this approach is that ozone is present in both the aqueous and gaseous phases throughout the total laundry processing step times. The “disadvantage” of the diffusion procedures is that lower concentrations of ozone are maintained in the washer water than are initially present by the Venturi procedure.

    Having made that statement, the question now becomes, “How much ozone is necessary in the washer — and how much is too little?”

    Only laundry practitioners can answer this question. Is ozone more effective at lower concentrations throughout each laundering step or at higher initial concentrations decreasing rapidly to zero? Remember — the rapidity of ozone loss is determined primarily by the amount of ozone-demanding soils on/in the laundry.

    OZONE ANALYSES

    The state-of-the-art with respect to the analysis of ozone in water is such that it is not prudent to monitor dissolved ozone in an operating laundry washer. This is because continuously monitoring dissolved ozone analyzers require probes in the water and these will foul quickly with lint and other debris. That leaves batch sampling, which is subject to the uncertainties of grab sampling at various points in the washer, and results are always uncertain because of sampling at different locations.

    Fortunately there are relationships between dissolved ozone and gas phase ozone above the water to allow accurate monitoring of gas phase ozone levels. The aqueous concentration of ozone is always some fraction of that in the gas phase, and accurate monitoring and control of gas phase ozone is a much simpler matter. In this manner, monitoring gas phase ozone concentrations can be used to control aqueous ozone concentrations — a technique widely used in large- and small-scale wastewater treatment plants using ozone.

    Speaking of analyzing for ozone, I cannot comment on the final graphic Mr. Moore shows in Part 2 of his discussion. Nowhere do I see how and where samples were taken, what analyses for ozone were used, what chemicals were added during the various laundering steps, nothing about agitation, temperature, etc. In fact, from the ozone facts I have discussed above, some of Mr. Moore’s results shown for both diffusion and for injection are quite puzzling.

    For example — the data given appear to be for dissolved ozone in washer water. For the bubble diffuser Mr. Moore shows very little ozone in the flush step, reasonable constancy of ozone in the wash and bleach steps, almost no ozone in Rinse 1 and 2, and plenty of ozone in the early part of the final rinse, but not in the later part. How is all this possible if ozone is added continually throughout each of the laundering steps? Did someone shut down or decrease the output of the ozone generator? If so, I would have expected Mr. Moore to jump on that point, saying, “See — told you so! Diffusion is not effective “. But no. So what really happened?

    Without more facts relating to this graphic, I cannot judge the validity of these data.

    Similarly, the data given for the Venturi injector system —

    Why does the level of ozone in the early part of the flush step decrease to zero shortly after addition? More significantly, why does the ozone level in the wash step stay at a measureable level throughout the laundering step? This is the step with the highest ozone-demanding constituents. That says to me that since no ozone can be added after the initial ozone-containing charge has been made, the ozone demand of the washer load has been satisfied. If that were not so, then there would be no measureable ozone residual — as seen in rinse steps 1 and 2, and the final rinse step.

    Again, without more facts about how these data were determined, there is no way to comment sensibly on the validity of the data presented.

    CLOSING COMMENTS

    To repeat an opening statement, I applaud the concept of the Laundry Forum. I also applaud the stated intent of Mr. Moore to write a series of “educational” articles separating Facts and Fallacies involved with ozone as applied to laundry applications.

    But I do not applaud the vindictiveness of the attacks on a tried, proven, economical, and moreover formally approved technology by the United Kingdom and at least two states in the USA (Missouri and New Hampshire).

    Both approaches to adding ozone to laundry waters provide excellent laundering results. However, as with all technologies, improvements can and should be expected constantly. Before crowing about why something “new” cannot work, it is better to wait, figure out why it does work, and then make statements.

    Thanks to the Laundry Forum for the opportunity to respond. Apologies for having to take so much space refuting an argument that has such little relationship to ozone laundering in the first place.

    QUALIFICATIONS OF RIP G. RICE TO COMMENTS ABOUT OZONE AND ITS APPLICATIONS

    I have been involved as a Consultant in Ozone Technologies since the early 1970s and have been making my living advising interested people coming to ozone for the first time what ozone is, what it is not, and particularly how ozone can be used effectively in specific applications. Thirty-eight years in the ozone industry makes me an expert in ozone, but it does NOT automatically make me an expert in laundry systems. In this respect, I am learning about what laundry systems are all about. Hopefully, laundry professionals will make the same effort to understand what ozone is all about.

    My Ph.D. degree is in organic chemistry, minor in physical chemistry (University of Maryland, 1957). In 1971 I became involved with ozone technology, specifically for treating municipal wastewaters, which were being disinfected with chlorine and causing large negative impacts on receiving rivers, lakes, streams, etc., into which they were discharged. Very rapidly, I became steeped in the technologies of generating and applying ozone, primarily to aqueous solutions for various applications — including wastewater, drinking water, bottled water, swimming pools, cooling towers, processing and storage of foods, and ultimately laundry systems.

    In 1974, I co-founded of the International Ozone Institute, now the International Ozone Association. In 1977 I was the ozone advisor on a scientific and engineering team of experts funded by the U.S. EPA to survey European and Canadian use of ozone and chlorine dioxide for treating drinking waters. In the late 1980s through the early 2000s, I represented multiple clients with ozone interests to the U.S. EPA during which time EPA’s Office of Groundwater and Drinking Water was developing new regulatory requirements for disinfection and disinfection by-products — all of which involved the then-coming-to-the-States use of ozone, both as a disinfectant and as a chemical oxidizing agent.

    I have edited many of the technical proceedings of the International Ozone Association, have written several books on various aspects of ozone technologies, and have over 100 peer-reviewed and published scientific papers dealing with various aspects of ozone technologies. Since 2005, I have been actively involved with the application of ozone into laundering machines, have written several peer-reviewed papers on the use of ozone in laundering which have appeared in the prestigious journal of the IOA, Ozone: Science & Engineering. A culmination of my ozone-laundry efforts is The Ozone Laundry Handbook, a publication that is in print, scheduled to be available from Amazon.com on or about April 6, 2011, and for which I am Editor-in Chief.

    If someone Googles me, be sure to include my middle initial — Rip G. Rice — there is a professional tennis player named Rip Rice, and one will find numerous references to tennis, which is not my bag, unless the “G.” is included.

    Contact me at RGRice4ozone@aol.com.

    Confucius say: “Better to keep one’s mouth closed and be thought a fool than to open it and remove all doubt.”

  • Aaron Cena said,

    As an ozone system designer for the past 17 years, and Director of Engineering for ArtiClean Ozone Systems, I feel compelled to respond with my two cents.

    The first ozone system was installed in the USA before anyone reading this post was born, but it has only seen widespread use for the last three decades. As a result, potential customers are usually not in a position to be able to judge the “good” systems from the “bad” systems. In my years in the industry, I have encountered an abundance of organizations who (with undoubtedly good intentions) offer ozone systems for sale, but which lack a solid understanding of the underlying principles of safe and effective ozone application.

    The comments originally posted in response to Part I of the Ozone: Fact vs. Fallacy article by Mr. Moore, and the lengthy reply to Part II, trouble me because both imply a sound scientific basis for what is an inherently unsafe method of applying ozone in a laundry application…namely, using a bubble diffuser to inject ozone directly into the un-sealed sump of a commercial washer.

    First, I want to make it clear that I do not dispute that the bubble-diffuser systems work. They’re just unsafe.

    The problem is that by injecting ozone into the un-sealed sump, it is a GUARANTEE that ozone gas will escape the un-sealed sump and enter the air in the workplace. This is an inherently unsafe method of ozone injection, which is not excused simply because the system works.

    I have designed many hundreds of ozone systems for industries including laundry, bottled water, household water, swimming pools, spas, aquatic life-support, food-processing, and the list goes on. None of these systems utilized bubble diffusers to inject ozone gas into open containers, despite how much simpler and less expensive they would have been. Why? Because it is unsafe.

    The replies to Part I and Part II, particularly an article that was linked to Part I, might cause people believe that ozone levels in a “bubble diffuser system” laundry can be safely “controlled” by an ozone monitor. It even hints that a bubble diffusion system is safer than “charge” (i.e. venturi injector) systems because of this monitor.

    If this were true, it would seem vitally important that these monitors not only work reliably, but are designed to function as an ozone control device in human-occupied environments.

    Unfortunately, this isn’t true of the monitors I have seen used on bubble diffuser based systems.

    First, the ozone monitors in question do not directly measure ozone, and are NOT ACCEPTED by the EPA for ozone monitoring. Why? Because they do not directly measure ozone gas. These monitors are based on electro-chemical or HMOS sensors, both of which have a finite lifespan. Just like a battery, the sensors will simply stop working at some point. Will the average laundry worker be able to tell when the monitor stops measuring ozone?

    The laundry environment itself is also extremely hostile to the sensors…lint in the air will either blind the sensor (preventing ozone from reaching the sensor), or cause a decrease in life-span (HMOS sensors are hot, and are pitted if they contact dust or lint). If the sensor does not work, there is nothing in place to prevent unsafe levels of ozone from entering the workplace.

    Second, these monitors are designed to be a fail-safe device, kind of like a last-ditch emergency shutoff in the event that a leak develops in the ozone system. I am not aware of a single ozone monitor manufacturer that will tell you that their monitors are designed to regulate ozone levels in human-occupied spaces.

    My suggestion to anyone thinking of using a bubble diffuser based system in an ozone laundry application is to make a phone call to the manufacturer of the ozone monitor (the actual sensor manufactuer, not just the company who puts the sensor in a box). Tell them that you plan to inject ozone into the un-sealed sump of a washing machine, in the presence of laundry workers. Ask them if they endorse the use of their monitor to maintain ambient ozone at safe, allowable levels.

  • Bob Halpin said,

    I knew when I read I read Dr. Rice’s article that there would obviously be a rebuttal. What I didn’t expect was a general statement that if it isn’t done the authors way, it’s completetly unsafe, irresponsible, and negligent.

    The use of scare tactics to sell equipment has no place on this forum. I have seen and installed both types of systems and frankly, they both work as long the buyer and seller work closely with the chemical rep to achieve and maintain success.

    Scare tactics will set the industry as whole back years. It will further confuse a group of laundry people who are generally interested in a wonderful process. With the great success’s both systems currently have in the field and many features and benefits to be used in a sales
    presentation, there’s no place for the vitriol I read in the last comment.

  • laundryman said,

    I agree Bob, think enough has been said. Don’t want it to get anymore out of hand. We’re all in this laundry business together.
    Steve

  • laundryman said,

    To follow more of this conversation click:

    http://www.thelaundryforum.com/forums/ozone-f72/

    Thanks