Full or empty water tank in tropical temperatures

[S/V Illusion]

Originally Posted by a64pilot

12% is about as strong as is easily sourced, directions say to use three times as much as 35% of course.

So, .5 gl of 30% per 100 gls, is 1.5 gls of 12% per 100 gls.
Cost is about $35 per gallon, for my 150 gl tank it would take 2 gls of 12% or $70 of hydrogen peroxide.

Hydrogen peroxide is of course rocket fuel among other things and is extremely reactive at higher concentrations. Assumption is 30% is safe of course, but will likely pretty quickly degrade so it’s not something to store for a long time before use.

$70 of hydrogen peroxide vs literally a few cents of bleach is a no brainer unless your hyper concerned about corrosion.
I am, but $70, plus difficult to source, plus short shelf life is tough to overcome.

Considering the effective ‘half life’ in solution is 10 times that of chlorine, it’s a false economy to compare prices based on unit volume.

Also, the extrapolation for lower concentration peroxide isn’t linear. You can’t apportion treatment volume simply based on concentration charges. For those chemical engineers who understand molar ratio, it’s simple to calculate but I suspect most here wouldn’t want to know.

Suffice it to say don’t simply assume.

[Singularity]

Originally Posted by a64pilot

12% is about as strong as is easily sourced, directions say to use three times as much as 35% of course.

So, .5 gl of 30% per 100 gls, is 1.5 gls of 12% per 100 gls.
Cost is about $35 per gallon, for my 150 gl tank it would take 2 gls of 12% or $70 of hydrogen peroxide.

In addition to re-apportioning the calculation change from 35% to 12%, remember that you're just trying to sanitize the tank. If you can drain the tank down to 5-10 gallons, and if that 5 or 10 gallons will slosh all over the inside of the tank (on a sail or something), then you only need to "concentrate" a small amount of water.

At the same time, I guess I hadn't considered the corrosive action of peroxide in a stainless tank...not sure about that...

[sailorboy1]

It doesn't corrode, in a way it's just fancy super air so it's only corrosive as far as the oxygen transfer maybe

face it, for most people bleach works best and if you want to get fancy a bromide family type of treatment is next

[a64pilot]

Originally Posted by S/V Illusion

Considering the effective ‘half life’ in solution is 10 times that of chlorine, it’s a false economy to compare prices based on unit volume.

Also, the extrapolation for lower concentration peroxide isn’t linear. You can’t apportion treatment volume simply based on concentration charges. For those chemical engineers who understand molar ratio, it’s simple to calculate but I suspect most here wouldn’t want to know.

Suffice it to say don’t simply assume.

The solution half life is irrelevant, except for storage, which is the point of the thread.
However for those that want or need to occasionally “shock” their tank and water to clear up an existing bio growth, how long it stays in suspension isn’t relevant.

But yes, chlorine off gasses rather quickly, reason if you have ever had a pool that you have to add chlorine often.

I don’t store my boat, but if I did it would be tank full with the expectation of having to shock the tank and pump it out when I put the boat back onto use.

I did often store our RV and I think the chlorine in city water must have been enough, cause over years we never had a smelly water problem with it.


So how about you telling me how much Hydrogen Peroxide is needed to disinfect 150 gls of water and the container?

[sailorboy1]

Originally Posted by a64pilot

DOE

So how about you telling me how much Hydrogen Peroxide is needed to disinfect 150 gls of water and the container?

It will take enough to do the BOD of whatever is in the tank and then enough to have 1 ppm of H2O2 left over.


People keep expecting this is a given dose number but the only real number in the answer is a residual and everything else is just fancy guesswork

[a64pilot]

So your saying dose rate is dependent on the amount of bio growth there is as the bio growth neutralizes the H2O2?

[sailorboy1]

Yes and the same applies to “bleach”

[S/V Illusion]

Originally Posted by a64pilot

So how about you telling me how much Hydrogen Peroxide is needed to disinfect 150 gls of water and the container?

I can’t without knowing the peroxide concentration you want to use. That’s what I was explaining previously.

Additionally, the effective residence time is relevant as that is what the OP asked in his question regarding a 6 month layup. Peroxide won’t last 6 months but it will be more effective over a longer term than would hypochlorite.

And while residual level is important, without continuous treatment, maintaining that level is impracticable so it irrelevant for purpose of this discussion.

Disinfection efficacy is a function of contact time, not instantaneous concentration or instantaneous residual level. Peroxides “last longer”.

[Singularity]

Originally Posted by a64pilot

So how about you telling me how much Hydrogen Peroxide is needed to disinfect 150 gls of water and the container?

FWIW I don't buy the BOD concept in this application...I mean the tank isn't a swamp to begin with, but anyhow:

Supposing 5 gallons 30% H2O2 sanitizes 1,000 gallons water...
Probably screwing it up weight v volume, but...

1 gallon is 3785ml
30% H2O2 contains .3g H2O2 per 1ml
.3g x 3785ml = 1.135kg H2O2 per gallon of 30% solution

It's given that 5 gallons 30% H2O2 (which contains 5 x 1.135kg = 5.68kg H2O2) sanitizes 1000 gallons....5.68kg H2O2 needed for 1,000 gallons

So 150 gallons is 15% of 1,000 gallons.
So 15% of 5.68kg H2O2 is 852grams H2O2...we need 852g H2O2 to treat 150 gallons water

12% H2O2 contains .12g H2O2 per 1ml
A gallon is 3785ml, so
1 gallon 12% H2O2 contains .12g x 3785ml = 454g H2O2....but we need 852g.....so we need just under 2 gallons of 12% to treat 150 gallons water.

There's something to be said about a career pilot's typically superlative ability to synesthetically shoot math accurately from the hip.

[thinwater]

Originally Posted by a64pilot

I have looked a lot to try to determine the dosage rate for Hydrogen Peroxide.

I can’t find an official source that uses it for water disinfection, I can find many sources on how it’s used to treat water for iron content, but not disinfection.

If anyone has a link, I’d appreciate it.

There are multiple protocols for using peroxide for disinfection. However, to my knowledge, there is no US protecol for treating drinking water; if there is enough to render the water safe, there is too much to drink.


I would LOVE to be wrong about this. PLEASE post any US health department rule that accepts H2O2 or any source of peroxide for drinking water treatment. I know that there have been petitions for certain products, but I am not aware that any passed.

[Singularity]

So I need to correct a very incorrect statements that I made, generalizations that I made, and perhaps the statements of another:
1) BOD should be checked for peroxide use to be meaningful unless super-high concentrations are used
2) the "5 gallons 30% to treat 1,000 gallons" must be to treat something very specific....it's otherwise way way too dilute for general use

[But again, if one only fogged the tank instead of sanitizing the water too...one could get by with much less H2O2]

I googled the heck out of this before, but only now found a good source, CDC. On the one hand I don't doubt that a strong concentration will kill anything...and one could rinse out the bathwater when done and use the tank...(or drink the effluent after it was aired out for an extended time...but that'd be impractical). It's minimally worth mentioning that hydrogen peroxide used to be used to make people vomit, but getting peroxide and/or stomach contents into the lungs can be life ending (though my vet recommended it for my dog once).

From CDC on hydrogen peroxide; I'm cut/pasting the HP reference, but the page otherwise lists other chemical agents:

Microbicidal Activity.

Hydrogen peroxide is active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores 78, 654. A 0.5% accelerated hydrogen peroxide demonstrated bactericidal and virucidal activity in 1 minute and mycobactericidal and fungicidal activity in 5 minutes 656. Bactericidal effectiveness and stability of hydrogen peroxide in urine has been demonstrated against a variety of health-care–associated pathogens; organisms with high cellular catalase activity (e.g., S. aureus, S. marcescens, and Proteus mirabilis) required 30–60 minutes of exposure to 0.6% hydrogen peroxide for a 108 reduction in cell counts, whereas organisms with lower catalase activity (e.g., E. coli, Streptococcus species, and Pseudomonas species) required only 15 minutes’ exposure 657. In an investigation of 3%, 10%, and 15% hydrogen peroxide for reducing spacecraft bacterial populations, a complete kill of 106 spores (i.e., Bacillus species) occurred with a 10% concentration and a 60-minute exposure time. A 3% concentration for 150 minutes killed 106 spores in six of seven exposure trials 658. A 10% hydrogen peroxide solution resulted in a 103 decrease in B. atrophaeus spores, and a ≥105 decrease when tested against 13 other pathogens in 30 minutes at 20°C 659, 660. A 3.0% hydrogen peroxide solution was ineffective against VRE after 3 and 10 minutes exposure times 661 and caused only a 2-log10 reduction in the number of Acanthamoeba cysts in approximately 2 hours 662. A 7% stabilized hydrogen peroxide proved to be sporicidal (6 hours of exposure), mycobactericidal (20 minutes), fungicidal (5 minutes) at full strength, virucidal (5 minutes) and bactericidal (3 minutes) at a 1:16 dilution when a quantitative carrier test was used 655. The 7% solution of hydrogen peroxide, tested after 14 days of stress (in the form of germ-loaded carriers and respiratory therapy equipment), was sporicidal (>7 log10 reduction in 6 hours), mycobactericidal (>6.5 log10 reduction in 25 minutes), fungicidal (>5 log10 reduction in 20 minutes), bactericidal (>6 log10 reduction in 5 minutes) and virucidal (5 log10 reduction in 5 minutes) 663. Synergistic sporicidal effects were observed when spores were exposed to a combination of hydrogen peroxide (5.9%–23.6%) and peracetic acid 664. Other studies demonstrated the antiviral activity of hydrogen peroxide against rhinovirus 665. The time required for inactivating three serotypes of rhinovirus using a 3% hydrogen peroxide solution was 6–8 minutes; this time increased with decreasing concentrations (18-20 minutes at 1.5%, 50–60 minutes at 0.75%).
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Concentrations of hydrogen peroxide from 6% to 25% show promise as chemical sterilants. The product marketed as a sterilant is a premixed, ready-to-use chemical that contains 7.5% hydrogen peroxide and 0.85% phosphoric acid (to maintain a low pH) 69. The mycobactericidal activity of 7.5% hydrogen peroxide has been corroborated in a study showing the inactivation of >105 multidrug-resistant M. tuberculosis after a 10-minute exposure 666. Thirty minutes were required for >99.9% inactivation of poliovirus and HAV 667. Three percent and 6% hydrogen peroxide were unable to inactivate HAV in 1 minute in a carrier test 58. When the effectiveness of 7.5% hydrogen peroxide at 10 minutes was compared with 2% alkaline glutaraldehyde at 20 minutes in manual disinfection of endoscopes, no significant difference in germicidal activity was observed 668. ). No complaints were received from the nursing or medical staff regarding odor or toxicity. In one study, 6% hydrogen peroxide (unused product was 7.5%) was more effective in the high-level disinfection of flexible endoscopes than was the 2% glutaraldehyde solution 456. A new, rapid-acting 13.4% hydrogen peroxide formulation (that is not yet FDA-cleared) has demonstrated sporicidal, mycobactericidal, fungicidal, and virucidal efficacy. Manufacturer data demonstrate that this solution sterilizes in 30 minutes and provides high-level disinfection in 5 minutes669. This product has not been used long enough to evaluate material compatibility to endoscopes and other semicritical devices, and further assessment by instrument manufacturers is needed.
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Under normal conditions, hydrogen peroxide is extremely stable when properly stored (e.g., in dark containers). The decomposition or loss of potency in small containers is less than 2% per year at ambient temperatures 670.
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Uses.

Commercially available 3% hydrogen peroxide is a stable and effective disinfectant when used on inanimate surfaces. It has been used in concentrations from 3% to 6% for disinfecting soft contact lenses (e.g., 3% for 2–3 hrs) 653, 671, 672, tonometer biprisms 513, ventilators 673, fabrics 397, and endoscopes 456. Hydrogen peroxide was effective in spot-disinfecting fabrics in patients’ rooms 397. Corneal damage from a hydrogen peroxide-soaked tonometer tip that was not properly rinsed has been reported 674. Hydrogen peroxide also has been instilled into urinary drainage bags in an attempt to eliminate the bag as a source of bladder bacteriuria and environmental contamination 675. Although the instillation of hydrogen peroxide into the bag reduced microbial contamination of the bag, this procedure did not reduce the incidence of catheter-associated bacteriuria 675.
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A chemical irritation resembling pseudomembranous colitis caused by either 3% hydrogen peroxide or a 2% glutaraldehyde has been reported 621. An epidemic of pseudomembrane-like enteritis and colitis in seven patients in a gastrointestinal endoscopy unit also has been associated with inadequate rinsing of 3% hydrogen peroxide from the endoscope 676.
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As with other chemical sterilants, dilution of the hydrogen peroxide must be monitored by regularly testing the minimum effective concentration (i.e., 7.5%–6.0%). Compatibility testing by Olympus America of the 7.5% hydrogen peroxide found both cosmetic changes (e.g., discoloration of black anodized metal finishes) 69 and functional changes with the tested endoscopes (Olympus, written communication, October 15, 1999).

[sck5]

DONT LEAVE BLEACH IN ALUMINUM TANKS!!!!!!!! It is OK to shock aluminum tanks with chlorine and then rinse them out but if you leave bleach in there you are asking for pitting, corrosion and leaks down the road.

I left my boat on the hard in various Eastern Caribbean islands. Always emptied the water tanks before leaving. Always shocked them with a healthy dose of chlorine when recommissioning. Never had a problem.

FWIW I always left the diesel full and never had a problem with that either.

[Michaele]

I always try to keep my water tanks absolutely full to the brim particularly when I leave the boat in some hot clime for the hurricane season. If there is no air in the tank or very little then the water does not stagnate.

Sailing in the tropics and elsewhere as well as European waters this has always worked for me.

The same thing applies to your diesel tank - try to leave the boat with it full

[abarrow]

I don't worry about full or empty, I just leave it as it is. At the beginning of the season, I fill them, add half a cup of bleach, run the faucets and pumps, drain everything. Fill again, drain. Fill again. Water tastes good and clean.

[a64pilot]

Originally Posted by thinwater

There are multiple protocols for using peroxide for disinfection. However, to my knowledge, there is no US protecol for treating drinking water; if there is enough to render the water safe, there is too much to drink.


I would LOVE to be wrong about this. PLEASE post any US health department rule that accepts H2O2 or any source of peroxide for drinking water treatment. I know that there have been petitions for certain products, but I am not aware that any passed.

That is what I keep finding as well, not the fact that the required amount is unsafe to drink, but that would make sense why I cannot find a recommended way to use H2O2 to disinfect drinking water, not a sanctioned way anyway, not some survivalist blog.