The White Paper below is an overview I started when flying to a 5 star resort in Hawaii with positive Legionella to address as many questions as possible from the administration, stakeholders, management and regulators. Moral to the story? After 4 days treatment, no more positive Legionella hits!
Also included for your planning and information is the latest from the CDC on Legionella; we designed this chlorine dioxide generator as a cost effective, efficient way to absolutely minimize your risk using the most effective mechanism, single chemical, gas stripped, electrochemically generated ClO2!
"So there I was", tales from the front lines... check back to see how the story ends, updates every Monday
So there I was, downtown New Orleans, with a severely fouled Thermal Energy Storage System (TES) and miles and miles of distribution piping that had been underwater, post-Katrina for >four months with large amounts of biofilm, rust/corrosion and dissolved iron in the water. The piping ran from the TES facility to many of the downtown business towers and two hospitals.
The group that was responsible for the treatment on that system they had been adding large quantities of non-oxidizing biocides with little improvement. After my presentation and with all of their excitement with chlorine dioxide and its potential for a solution, in the several weeks between when the decision was made and the generator was delivered, rather than wait a decision was made to bring in totes of 3000 ppm chlorine dioxide from another vendor. As the general manager told me at the end of this experience, "I wished I'd listened to you... we'd never done that" but that part of the story is a tale for another day.
We started treatment and after several weeks, no ClO2 residual was noted in the water. Folks were starting to wonder if the molecule was really going to get the job done as there was no evidence of progress. However we kept our heads down and dosed moderate amounts of chlorine dioxide in an attempt to minimize the amount of sloughing of biofilm and debris that would be occurring at any one given time.
After seven – eight weeks of treatment we started to see improvements in turbidity and micro counts. We stayed with the program, and at six months (with new floors and buildings still opening and new biofilm and debris still being added to the loop at times) it was obvious that we were on the right track. Water still had a bit of a red tint indicating dissolved iron oxide that was much reduced from previous samples. The copper heat exchange surfaces went from corroded/ green to clean/ copper colored. Micro counts were in the acceptable range. Another six months and water turbidity was nonexistent, absolutely clear and micro counts were minimal to nonexistent. Distribution piping and heat exchange surfaces were clean with the iron, copper and aluminum oxides all removed, leaving clean the exchange surfaces and an efficient process.
Fast-forward to 10 years post-Katrina, I called the general manager who I'd originally set this up with for a progress report on what things look like now. It took him a minute to think back then he said "you're right, we still have that system in and we use it; we turn it on just one time per year, that's all it takes to maintain a chlorine dioxide residual in the distribution loop."
They obviously have a nice tight system without a lot of makeup or corrosion but we have definitely used my favorite molecule to turn a sow's ear into a silk purse!
I love it when a plan comes together, and it certainly did here!
Mold is one of the original forms of life on the planet and a worthy adversary... So anyway, there I was, at a very large yogurt processing plant that had high environmental mold counts in the finished product. In a case like this with many interconnected rooms, with receiving, processing areas, packaging rooms and cold storage, the first questions is where to begin?
Mold by itself is tricky enough, a very resilient foe that is made up of three components, the surface mold that you usually see, the roots that go down into a surface so it can remain attached and spores that are released into the air at different times. The typical solution is simply washing or wiping it down with high concentration of chlorine; this is not very effective as you are only addressing one of the three problems, the surface mold. The spores are still in the air and the roots are still attached to the surface. The mold may even still be alive, all you did when you cleaned it with that high concentration chlorine was bleach the color out, the mold lives!
This is where chlorine dioxide has significant advantage over our old friend chlorine. Where chlorine is quickly degraded by organic material such as food soils and yes, mold, it is difficult to get needed concentrations to where the actual organisms exist. Chlorine dioxide has that affinity for cellular material, specifically the disulfide linkages that exist in the cell walls themselves. Chlorine dioxide will quickly find the living mold because it is a small molecule, actually a gas in solution, it will penetrate the cell wall and change the permeability of components inside the cell such as the mitochondria and the nuclei. The cell quickly dies. And that problem that chlorine has with organic material and reducing levels of effect because of it? Not a problem for ClO2 as our new favorite molecule ignores most organic material, focusing on those disulfide linkages to find the target, allowing it to be consumed only where needed; in only the living cellular organisms.
This being a large plant with an urgent need, it made no sense to treat thousands upon thousands of square feet of production area, so an airborne air sampler was brought in and samples taken in each of the areas. After culturing overnight it was obvious that we had definite problems in certain areas and minimal problems in others. The job at this point was to determine why we had issues in the hot areas.
On inspection and using a piece of tissue attached to a stick (high tech!) we were able to determine and map the predominant airflow leading to the problem areas. Using this method it appeared that the main contributor to airborne counts was a dumpster inside the building near where returns and old stock were disposed of.
So now we have the source identified (and removed); the job now is to get the airborne and surface counts down to their normal levels. There are typically several options for environmental foaming and fogging, these typically include quaternary ammonia and peracetic acid. Both of these have their weaknesses in that the peracetic and quaternary concentrations need to be significant to be effective, a task made more difficult by the handling hazards and corrosiveness of the peracetic (low pH is needed for efficacy) and the health hazards of fogged quaternary ammonia, airborne, as they are significant. Whereas the two biocides require significantly high concentrations for efficacy, ClO2 outperforms both of those at a concentration of 40 ppm for foam, a fraction of that needed for our old school standbys. Simply mix the chlorine dioxide concentrate with an anionc surfactant (ask your chemical supplier) and then foam merrily away (PPE is recommended). The foam will keep the chlorine dioxide entrained in the bubbles, giving the molecule time to penetrate the mold on the surface and the roots beneath them. They all have disulfide linkages and ClO2 will find them! The key is here that all we are doing is giving the chlorine dioxide time to penetrate the mold as once it is inside cells, "the fox is in the henhouse'. What happens next is irreversible, the cells die.
So to resolve the plantwide mold issue, we cleaned as much as we could, as best we could and chlorine dioxide foamed and fogged all areas. We did it again the following weekend just to be sure and subsequent air sampling showed mold counts had been reduced to less than normal levels. Gosh, how I love it when a plan comes together!
Tough duty, hanging out on the beach in Aruba, right? No; four 10 story towers, under construction, no working elevators and the window manufacturer goes bankrupt. What does the contractor do after stating that Aruba never gets hurricanes? That's right, while waiting for the windows, hang the drywall... you see where this is going?
Yes, we're going there. The drywall is hung in 100+ rooms and Aruba gets a hurricane, with no windows protecting the building from the torrential rain and wind. Flooding on the ground floor up to 3 feet deep and just about every room in the complex with an ocean view seeing anywhere from some damage to quite a bit; most of them with at least some mold on maybe 40% of the surfaces, sometimes more. First job was to mobilize, we need to get materials on the way... these included goodly amounts of two-part chlorine dioxide powder to generate the ClO2 solution we will use to kill the mold. As mentioned previously there are three components to mold, the surface mold that we all see, the roots and the spores that we don't. All three must be killed for control. Many decisions needed to be quickly made as the amount of drywall to be demoed was determined, blowers and heaters brought on-site to start the drying process, sprayers, PPE and other application equipment shipped.
Once on-site I got my crew of 10 or so temporary workers got together and formulated a plan, first order of business was safety training and familiarization with the concentrated chlorine dioxide solution that we will be working with. The importance of PPE is going to be stressed hard because we are using chlorine dioxide near the limit of solubility in both the liquid and gas forms, so activated charcoal gas respirators were required. Once everybody understood how to mix and apply the concentrated chlorine dioxide, we got to work. First job was to remove the drywall that had been submerged in water. There's no way to dry the inside of a wall so any drywall that was had flooded was simply removed. Next job was to dry those formerly wet and soaked surfaces; the 80-90° temperatures did not hurt the drying process but the >60% humidity didn't help that much either!
All surfaces were sprayed with high concentration chlorine dioxide, at these high concentrations the black color of the mold is bleached out nicely, unlike chlorine dioxide at lower concentrations where the color typically remains. One of the nice things about chlorine dioxide compared to other oxidizing biocides is that it doesn't react with organic material, such as the paper on the surface of drywall! Have you ever put a pair of jeans in the wash and then poured bleach in the washer on top of the jeans? Those holes are created by the oxidizing action of chlorine. If you had used chlorine dioxide instead of chlorine, because chlorine dioxide does not react with organic material, the jeans would still be bleached, just with no holes. Same thing if you spray chlorine dioxide onto organic materials, no breakdown; we see the same thing when using chlorine dioxide as an antimicrobial on fruits and vegetables, low counts with no surface oxidation or "mushiness" that is seen with chlorine or peracetic acid.
Another item that I brought out with me was an impaction air sampler that would sample a known quantity of air, depositing the contents of that air onto an agar, Jell-O like surface. These sample plates were allowed to grow and results reviewed for efficacy. Samples were also taken from neighboring resorts to use as a baseline. Obviously the samples that we took initially pre-cleaning were significantly high. The samples from neighboring resorts were lower but due to the humid environment in Aruba, mold was still found. One of the difficult things of being a hotelier in Aruba apparently is dealing with the moldy smells and resulting complaints that sometimes appear during the humid times. Oh, the problems of life in paradise... by the way, we had a workable treatment for that smell as well.
Inspections were done with maps of the floors and rooms and a battle plan drawn as to where to start treatment and where we were as to the state of completion. All affected areas were sprayed, cleaned and re-sprayed again, chlorine dioxide fog was pushed through communications and wiring tunnels along with the other enclosed areas to ensure the that the airborne and surface mold was eliminated. Hallways and rooms were blocked off with plastic sheeting to get the concentrations up to the targeted values with humidity tracked to ensure efficacy. Then we did the whole thing again to make sure we got as much as possible. End result? Mold down to or below the values at neighboring resorts, visible mold elimnated and the resort was able to get repairs done in time to be open for the profitable Christmas season!
Now me, well those 10 floors, no elevators and my already beat up knee, I got scheduled for a knee replacement. As I've said before, that is another story!
White grape juice, clear glass bottles, multiple shipping containers of product already on their way to Japan and a chlorine resistant mold growing "mold balls" in the QC retain samples... You how the hard chargers of the world say bigger, stronger, faster? It's a good goal but some of the realists of the world might say bigger, more expensive...mistakes! With global distribution networks and customers tens of thousands of miles away from manufacturing facilities, the control part of "quality control" borders on tenuous. The customer here made a beautiful white grape juice, packing it in a clear glass bottle to show off the clarity and color of the product, really, very nice!
Problems arose however when the quality control retain samples started to develop fuzzy "mold balls" suspended in the liquid and were right there for everyone to see. Worse yet, shipping containers packed with product were en route to the notorious picky Japanese market where poor product quality would definitely cause some "loss of face" as well as an expensive logistical issue with product that needed to be intercepted and replacement product packaged and shipped as soon as possible. First however, this mold needed to be isolated and a reliable control method developed.
Surface samples were taken from the large storage tanks and exposed to varying levels of chlorine (the biocide historically used to sanitize these tanks). It was determined that the mold had developed a level of chlorine resistance!
Molds have been with us since almost the dawn of time, probably one of the first living organisms on this planet. They have survived due to their ability to adapt to all the various stressors that have come their way; heat, acidity, salt and sugar are all used as control mechanisms to minimize microbial growth in food. In this case, the grape juice has a level of acidity that makes it naturally bacteriostatic to a degree and the sugar content occupies some of the free moisture; the combination of these two factors make it difficult for most organisms grow in the grape juice. Historically, so long as these parameters have been maintained, the organisms have been kept under control. However much like cells in human bodies, where some mutate and become cancerous, others simply mutate to some degree and don't become cancerous. It isn't always due to outside variables either, non-smokers get lung cancer and very unfortunately, young children get cancers as well...with everybody asking, WHY?
So if cancer isn't always due an outside stressor, what is the source of these cancers and new forms of mold? Cellular mutations; a kind of evolution that can have negative consequences. These oftentimes happen with cells that are replicating (duplicating) and for some reason a switch gets flipped and it not only replicates but to a form that is not benefical to the host (us)! We see the same thing in the fermentation of various foods, most often beer to save some money as when you use a pound of yeast to ferment the beer, you wind up with several pounds of perfectly good yeast at the bottom of the fermentation tank that can be reused. This yeast can be acid washed, which easily kills the mutated cells, as they are essentially a new form of life with little resistance. The Mother yeast strain is especially durable, much the same way sourdough starter outcompetes the spoilage strains in bread; don't get me started there however. The acid kills only the newly formed yeast cells, leaving the mother strain untouched. Now chlorine dioxide is used to wash yeast as well, as it is a selective antimicrbial, but that is yet one more discussion for another day.
The problem is that with each generation of yeast that is reused a very small number of mutations occur. These mutated forms of yeast are extremely similar to their older brothers and sisters; the only problem being is that they consume the sugars in the yeast without creating alcohol... freeloaders, I say, because creating alcohol is what they are there to do!
Now I know you're going to be surprised, but our new friend chlorine dioxide, to the rescue! Chlorine dioxide is a gas in solution, actually a true gas in solution in that it does not hydrolyze with water; let's compare and contrast how this is different than our old friend chlorine. For example when you add chlorine to water, the chlorine is first absorbed by any organic material present... dirty water or organics in the process severely degrade the concentration and antimicrobial performance of chlorine. Now if your water is of reasonable quality, depending upon the pH, it will form one of several chlorinated compounds. If the pH is below eight, the predominant chlorinated compound is hypochlorous acid, the actual sanitizing component of chlorine. If the pH is above eight, it forms hypochlorite, no hypochlorous acid with little antimicrobial effect; this is the form of chlorine that is typically used in alkaline cleaners, not as a sanitizer but to denature protein which assists in cleaning! Now if the pH is below three, CHLORINE GAS is created and being a large molecule, quickly comes out of solution creating a very hazardous atmospheric environment.
So long as the pH is between 4 and 8, hypochlorous acid will be created, the cell walls oxidized and the organisms killed. Normally.
What appears to have happened in this case is that the cell wall has developed a tolerance or resistance for low levels of chlorine; they want to survive, right? So after multiple mutations and persisting, the cells managed to adapt with maybe a thicker cell wall...now if that large chlorine molecule can't penetrate the cell wall, the bacteria or mold will persist. And that means we have a problem. Fortunately we have an antimicrobial that has both a small molecular size, doesn't react with organic material and is able to penetrate cell walls in aerobic/anaerobic organsms, biofilms and viruses.. The ClO2 seeks a common concentration on both sides of the cell wall and once inside, it changes the permeability of components inside the cell, such as the nuclei, mitochondria, etc. the cell quickly dies based on a time and concentration relationship. Each organism has a TC (Time, Concentration) value but that's yet another conversation for another time, see, we have lots to talk about!
As luck would have it, the manufacturer had a sales guy (could have been me) that had said something about how he had a non-corrosive, broad spectrum antimicrobial and how well it worked on tough to kill organisms at low concentrations with no effect on flavor. I brought some chlorine dioxide solution into the lab and we made up some known concentrations, treating tank surfaces at various concentrations versus a control... and... Success! The tanks were cleaned and sanitized, the juice was run and packaged, containerized and sent to Japan in those beautiful bottles for our picky customers to purchase and enjoy!
And I still love it when a plan comes together... just so you don't think this is going to be the "ClO2 cheering section", soon there will be a few, just a few sagas where for one reason or another, ClO2 didn't perform as we expected, but as I say, That Is A Story For Another Day!
New research on mutation; interesting! https://www.nytimes.com/2017/08/02/science/gene-editing-human-embryos.html
Tanker loads of peach puree were having viscosity breakdown between the manufacturing facility on the West coast and the packaging plant in the East... The question is why? This is a tricky one with a surprise ending...
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