Sanitizers

[257WbyMag]

This thread is all about satisfying my curiosity and by no means should indicate that I am looking for something else.

Those of us who have been on TFP for a while understand that there are really only three EPA approved sanitizers that are suitable for widespread use in swimming pools, these being chlorine, bromine, and baquacil. This got me to thinking about why that is and what else has been tried in the past.

Now, I am no chemist, but I know that the first two, chlorine and bromine, are both halogens and both can be used for bleaching purposes. But what about iodine and fluorine though? Both of these elements can be classed as halogens. Iodine has long been used in the medical and pharmaceutical industry due to its antimicrobial properties. Additionally, iodine has historically had a place in making non-potable water into potable water. I'm not so sure about fluorine though. Aside from what I remember about from chemistry in college, I think that the reactivity of fluorine would make it a not-so-good choice for sanitizing water.

What else has been tried in the past for water sanitation and what would preclude the use of iodine-based or even fluorine-based products in doing the job?

 

[JasonLion]

A huge number of things have been tried, most notably copper, silver, zinc, ozone, UV, iodine, biological filters, hydrogen peroxide, chloramine, radiation, magnets, and prayers to name a few. The problems with the various choices fall into a couple of categories. Many choices are too slow. They kill everything off eventually, but leave too long a window of opportunity where person to person transmission can occur. Other substances pose risks to swimmers. Some are too expensive, or dissipate too quickly.

 

[duraleigh]

Well, I'm not sure it's fair to lump magnets into that category of failures.

My magnets have worked fine with just a small side effect........They pull the tin foil hat off the top of my head and then I can no longer receive the alien transmissions through the fillings in my teeth.

 

[257WbyMag]

Thanks for moving this thread to the proper place. I forgot about "The Deep End".

Yes, I am familiar with the minerals and I completely understand the shortfalls associated with those. I slo see the limitations of radiation as the effect of it is limited only to that given volume of water that is currently being irradiated and that it isn't doing anything for the volume of pool water receiving a bolus of urine from the 5 year old on the other side of the pool.

So, iodine for example...why isn't it used? Jason mentions it on the list of those tried. What was the failure point? I have my suspicions which include price, toxicity, and convenience. My suspicion is that chlorine is the greatest because it may be the cheapest, it may be the easiest to use, it may be the safest, and it may just work better than all of the rest. But I don't know.

Oh, and duraleigh, tin foil hats are so "cold war" era. My suggestion is to keep your magnets and upgrade to an aluminum foil hat. The magnets won't affect it, it is much lighter, cheaper, and you can throw it in with your empty cans come recycling day.

 

[chem geek]

The chemistry of chlorine and bromine are such that they are very effective sanitizers, and they are oxidizers to boot so you get a 2-fer. Look at the chemical structure of hypochlorous acid and compare that with water and you will see that they are fairly similar. Hypochlorous acid is a neutral molecule that looks a lot like water so is able to get into cells fairly easily. It's a reasonably strong, though selective, oxidizer. It mostly attaches to reduced nitrogen sites in molecules and there's plenty of those in most critical organic compounds in cells, including amino acids, proteins, DNA, etc. So it can pretty much wreck havoc and thus not be something where resistance would be developed since, unlike antibiotics, it does not have only one method of action. And, as noted, it can oxidize bather waste (mostly urea and ammonia from sweat and urine).

Bromine (hypobromous acid) is somewhat similar to chlorine and most of the above applies to bromine as well, though bromine is a weaker oxidizer than chlorine, but doesn't get moderated by CYA so on balance may be roughly comparable in disinfection.

The main problem with the halogen-based sanitizers is that they can create disinfection by-products, some of which increase the risk to health at higher concentrations. Since these come from organic precursors, using supplemental oxidation (ozone, UV, non-chlorine shock) in higher bather-load situations can help reduce this problem.

The only other compound that has good properties of disinfection and oxidation and doesn't produce as many disinfection by-products is chlorine dioxide, but it is unstable at higher concentrations so usually needs to be generated on-site and that can be tricky to avoid producing too much chlorate. It also breaks down in sunlight, but does not combine with CYA.

Iodine is basically an effective sanitizer, but it does not control algae and it does not effectively oxidize organic matter.

As Jason noted above, metal ions do not kill pathogens quickly enough to be used (by themselves) in commercial/public pools since they may not be able to prevent person-to-person transmission. When the FC is around 10% of the CYA level, most common heterotrophic bacteria are killed by chlorine in under one minute (for a 99% kill). It takes silver ion around 10-20 minutes and copper ion around 40 minutes for an equivalent kill rate. Also, metal ions are not effective (at pool concentrations) at inactivating viruses. For example, this paper shows that copper ions do a 90% inactivation of Herpes Simplex Virus in 30 minutes at 100-200 ppm, but that is far, far higher in concentration than found in pools (copper is usually < 0.3 ppm in pools). This paper shows that silver ions have virtually no effect on vacciniavirus, adenovirus, VSV, poliovirus, HVJ, but that with herpes simplex virus there is a 5-log kill in 60 minutes (roughly a 90% kill in about 5 minutes), but at over 3200 ppb compared to the usual limit of 20 ppb to prevent silver staining.

UV, ozone, "active oxygen" and other systems that work via circulation do not provide a residual disinfectant in the bulk pool water so they are primarily used as supplemental oxidizers.

 

[257WbyMag]

Thanks for that explanation. Just what I was looking for.

 

[polyvue]

I found nothing in chem geek's (excellent) survey of sanitizers/oxidizers that was new to me, but it took several years and lots of reading to enable this familiarity. Those short paragraphs are all what most members need to understand this subject. Someday I hope it will find its way into Pool School.

 

[257WbyMag]

This paper[/url] shows that silver ions have virtually no effect on vacciniavirus, adenovirus, VSV, poliovirus, HVJ, but that with herpes simplex virus there is a 5-log kill in 60 minutes (roughly a 90% kill in about 5 minutes), but at over 3200 ppb compared to the usual limit of 20 ppb to prevent silver staining.

Not related to pools here, but this makes me wonder about the effectiveness of the Ag ion cycle in our front loading washer. By selecting this choice, it adds 30 minutes to a wash cycle to allow the Ag ions enough time to exert their effect. What I don't know is what the concentration of silver is in the water at that time. Hmmm.

 

[Raiken3712]

I've been recently looking into this and basically found out what Chem Geek said on Iodine. I'm wondering if it could be used in combination with Chlorine or Non Chlorine shock for a decent set up.

I like the idea of using Iodine because I've recently read some books on it and how many people are in a very deficient state due to Bromine dominance. Bromine from various sources such as brominated flour, flame retardants in furniture and various other places displace Iodine in the cell receptors.

If there is enough Iodine in the system Bromine doesn't do this, but if someone isn't getting enough Iodine than the Bromine takes up those receptors and Iodine can't do its job. The books Iodine, The Iodine Crisis, and Stop the Thyroid Madness were all very informative on this issue.

It all made a great deal of sense to me, but as of yet I haven't noticed benefits from taking Iodine. With everything I've read on it I think its mainly a time issue. It takes time for the Iodine to build up and to remove the toxins and such.

I've read quite a few great success stories on Iodine and am committed to sticking with it as although I haven't noticed any great positives as of yet I haven't had any major negatives either.

Anyway...veered a bit off topic..but anyway as to the sanitizer thing I think it could work with the right set up, but I'm not sure if its feasible to get the right amount and I'm not sure what form would work best.

I've heard Iodine is tightly regulated because it can be used in the manufacture of Meth...and since the United States has the retarded drug war...it may not be something you could do anyway...sadly

I suppose taking Iodine separately works fine, but I liked the idea of my family getting some much needed Iodine through the pool since getting them to take supplements is like pulling teeth.

 

[chem geek]

Well, it's the devil you know vs. the devil you don't. There is a ton of research on chlorine because it's been used in water disinfection for so long. That is not the case for iodine so there may be issues with it that we are not yet aware of. It's an interesting notion, but as you point out you'd have to have an ozonator or something to oxidize the bather waste that would otherwise accumulate over time.

I should also note that there are some who propose having ozone be the primary disinfectant, not just a secondary one in the circulation system. They propose maintaining 0.05 ppm ozone in the pool. So that should be added to the list in my earlier post. The main reasons this isn't done are:

• it requires a very powerful and efficient ozonator, usually with 6% or more concentration of ozone in air and a 90% transfer efficiency into the water (i.e. 90% of the ozone in the injected air/ozone bubbles gets transferred into the bulk water). The risk is of outgassing, both from the air/ozone bubbles that do not get fully dissolved and from general outgassing from the bulk pool water. In practice, the amount outgassed is low, but may exceed the 70 ppb EPA air ozone standard, especially right at the pool surface. More ozone would likely be outgassed from churning of the water as well.[/*:m:1j9g2xl4]
• the ozone half-life in water is around 30 minutes so one would have to run the ozonator 24/7 to protect the water at all times unless one was only to do so when bathers were present (and presumably shortly before they got into the water)[/*:m:1j9g2xl4]
• circulation has to be very good to get ozone everywhere evenly, especially in larger commercial/public pools[/*:m:1j9g2xl4]

 

[chem geek]

Updating this thread regarding iodine by referring to this thread where I describe how iodine was used in pools in the 1960's but since that time a lot more was learned about various disinfection by-products and the ones produced from iodine are the worst, followed by bromine, with the least toxic being those formed by chlorine.