question about calcium hypochlorite

[phantom power]

I've been researching the use of powdered calcium hypochlorite as a concentrated, portable source of chlorine for emergency water purification.

It's the active ingredient in most pool chlorine, but in that form it seems to come with about 30% "other stuff", mostly stabilizers. I'm hoping some knowledgeable person can straighten me out:

1) Where can I get pure calcium hypochlorite? (as in, from a chemical supply catalog, preferably on line)

2) Is that 30% other-stuff harmful if ingested (at the relatively low concentrations for water purification, not pure!)

[Dogmudgeon]

1. The other stuff

It's mainly potassium phosphate and calcium carbonate (chalk), IIRC. It's not harmful.

Used for water purification, it's fine. You just want to avoid drinking water with high concentrations of it for more than a couple of weeks -- chlorine in those concentrations can be rough on the innards over time.

If anyone knows better -- please post!

--p!

[phantom power]

2. I've read the preferred technique is to let the chlorine gas off.

Let it purify the water, then allow it to dissipate. That takes time, but I figure it's possible to set up a pipeline process, where some water is purifying and some is ready to drink.

And, hopefully I'd never need it for more than a few weeks at a time. Hopefully.

[Dr.Phool]

3. Chlorine bleach is effective

8 drops per gallon of water. I do it every year at this time for hurricane preparedness.

[phantom power]

4. Definitely, but you can purify a LOT more water...

with a quart-jar of powerdered sodium hypochlorite, than with a quart jar of liquid bleach.

I realize that's sort of overkill, for a couple weeks, but I figure it wouldn't hurt to be prepared for a much longer period, if it's reasonably easy.

As bad as Katrina was, I think we're all going to live to see worse. Maybe much, much worse.

[phantom power]

5. Interesting, the resources I found suggest 10 drops per quart.

(of typical 5% houseold bleach)

[benburch]

6. Read the MSDS before you try getting the pure stuff.

http://ptcl.chem.ox.ac.uk/MSDS/CA/calcium_hypochlorite.html

You are better off with bleach!!!

[NNadir]

7. I would personally go with the bleach.

Cheaper, simpler, cleaner, and easier to use. It is also pretty much the commercial product used in public water systems.

Bleach/chlorine is thought to be slightly carcinogenic and many public systems may replace bleach with onzonolysis.

I have no idea what the "other ingredients" are, and probably they are proprietary and vary from brand to brand. Silicon dioxide (sand) is possibly one filler/binder, since it's common in a lot of these kinds of formulations. Sodium carbonate would probably be another, since it is basic, and would tend to slow the decomposition of the bleach. Bleach is made by passing chlorine gas through basic solution, causing it to disproportionate into hypochlorite (bleach) and chloride. Sometimes bleach can be stabilized by some organic peroxides as well. Some of these are relatively harmless in low doses.

Of course, bleach wouldn't help very much with the water in New Orleans, which is not merely contaminated by also effectively poisoned as well. Also there is a limit to what bleach can do. My own emergency kit includes household bleach, but I also have bottled water. It has been a problem in some public swimming pools that some fecal bacteria have substantial resistance to chlorine. One cannot in general, chlorinate raw sewage and make it potable either. Ozone is actually a more effective decontaminating agent, since it is one of the strongest oxidizing agents known. On the other hand, the water needs to be aerated well after use to drive off the (toxic) ozone.

(Maybe you could get a giant solar cell and an ozonolysis device.
:evilgrin:)

I also have in my emergency kit a camp latern (propane), extra food, the usual batteries, matches, can opener and a wrench to turn off the gas to my house. I also keep a substantial quantity of split, ready to use wood in winter, but I don't think you'll need that in Phoenix. I kind of wonder, too, where you would get the water to purify.

[phantom power]

9. For H20, we happen to have a pool. We could live off that for a while.

There are also various "lakes" that people tend to build in developments.

As you say, disinfecting doesn't deal with poisons, but you do what you can :-) In a pinch, the body can deal with some toxins, over the short term. But cholera can kill quickly.

I've been thinking quite a bit about nasty disaster scenarios lately. And one conclusion I've reached is that beyond a certain point, you're just completely hosed, and there's nothing you can do about that.

But I'm going to die with a bottle of bleach in my cold dead hands!

[NNadir]

10. Your pool water may be more saline than you think.

You add sodium hypochlorite regularly when you chlorinate your pool. In contact with organics (bacteria, skin, etc) the hypochlorite is reduced to chlorine gas. Some of this gas leaches out of the pool of course - it's what you smell. But some of that chlorine is reduced further to chloride.

Over long periods, sodium hypochlorite is reduced to mixture of sodium chloride and sodium bicarbonate, and the water can, over extended periods, become quite saline, especially is there is no regular outlet other than what splashes out of the pool.

If I lived in your area, and I were thinking of the use of my swimming pool as a water reserve, I would seriously think about a type of solar powered still, if you are in a position to afford such a thing.

[phantom power]

11. Good to know. I could backflush it more often.

Or get a solar still. Or better yet, leave town.

[Tesha]

12. Don't laugh! (Some) ozone generatorsshould work fine off solar.

> (Maybe you could get a giant solar cell and an ozonolysis device.
:evilgrin:)

Don't laugh -- this may actually be a better idea than you think! One
kind of ozone generator used for pools and hot tubs uses a high-voltage
corona discharge mechanism tomake the ozone, but the electronics inside
the box runs off a relatively low dc voltage, say 12V at an amp or so.
A solar panel culd easily crank this out and keep making clean water
for the several-year service lifetime of the gadget.

Now, somene needs to figure out how much water the produced ozone
could decontaminate in a reasonable amount of time, but it's probably
a useable amount; one of these generators keeps a 500 gallon (or so)
hot tub nicely free of nasties.

'Might be handy in post-apocalyptic America!

Tesha

[freethought]

8. I am not sure what the other stuff is but

but I do have some knowledge of its purpose. I used to work with hazardous chemicals of all sorts. Calcium hypochorite is not very stable, it gives off chorine gas at a pretty good rate. For example, you remember the pool stuff advertised on TV some time ago called 'HTH', that was calcium hypochlorite. If you were around a fresh batch of the stuff you could really smell that chlorine being given off. Breath in too much and you could die of chlorine gas poisoning.

The stablizers are added to do two things. First, slow down the degradation of the hypochlorite and Second, to keep the hypochorite in a usable shape, usually an oversized tablet of some sort. Calcium Hypochlorite by itself is a loose dry powder. Expose it to open air for awhile and it degrades to some sort of calcium salt, calcium chloride perhaps. Most pool chlorinators these days are made with bromine or Hydrobromic acid or someother bromine based chemical. I am not sure what the advantage is over hypochlorite. It could be any number of reasons

Pure calcium hypochlorite can probably be gotten in a lab quantity, 1-2 lb jars or something similar. Merck, Fisher Scientific, produce the stuff. The problem is that Calcium Hypochlorite is a hazardous material and is subject to HAZMAT transport regulations. The D.O.T. considers hypochorite to be a hazardous oxidizer-meaning that it gives of oxygen in contact with organic materials causing them to burn even in an oxygen lax atmosphere. Spill pure hypochlorite or a concentrated solution on your skin and you will definitely get burned.

I am not entirely sure if an individual consumer could by technical grade calcium hypochlorite, at least without some sort of permit or documentation. This may be something that would raise flags to "Big Brother". You might want to try a web search for "scientific supply/chemicals" but be warned.

If you are talking water purfication, hypochorite is a disinfectant. It kills microorgansims, bacteria, etc, and likely destroys certain organic chemicals but likely won't get rid off something like heavy metals. One bet is visit websites that sell camping,hiking,military, and survival gear. They might have chlorine tablets for the purpose of disinfecting water. Worth a try.

[Tesha]

13. Direct UV decontamination

In another eply, I mentioned a hypothetical solar-powered ozone
decontaminator.

It might also be worth thinking about direct shortwave UV
(ultraviolet) decontamination. Aquarists use these to kill off
algae andother nasties in their tanks/ponds, and I'd imagine
they'd also do good things for drinking water. They'd be
pretty easy to solar-power as well, althoughyou'd probably
need an inverter.

Tesha

[NNadir]

15. UV is not as good a solution as ozone.

UV is effective at killing most - but not all - organisms, but its ability to affect chemical contamination is limited by the absorption bands of the chemical in question. Many toxic compounds, including many found in oil are only effectively destroyed by very short UV radiation that is not very easily transmitted, or for that matter generated.

Ozone is much better at oxidizing chemical contamination. A caveat is that ozone is reasonably against most - but not all organic compounds. It will do nothing to remove heavy metal contamination (neither will UV). In some cases, ozone can be deleterious. For instance, if water is contaminated by chromium, lower valent chromium can be oxidized to chromium (VII). All chromium (VII) compounds are carcinogenic. Similarly, manganese, a constiutent of all living things, is oxidized to permanganate.

[Tesha]

18. Thanks! (NT)

[hunter]

14. I have a ceramic filter with activated carbon for drinking water...

...the kind backpackers and the military use. You can find them at almost any camping store.

We have a large spa that may or may not survive a huge earthquake, and a pond with fish in it, and a large fountain. The spa can be kept clean with the spa chemicals I keep on hand anyways (stirred in with a stick if I have to) and one of my next projects will be to install enough solar capacity to keep everything aerated in a prolonged power failure.

Filtered pond water could be used for drinking when we run out of bottled water, and the spa and fountain water could be used for washing.

I think our dog lives entirely off water she drinks from the pond, so I know it can't be too deadly. (Our dog hates water out of the tap; she would rather drink from the toilet.) The fish all seem to be happy, and the herons don't mind eating them every once and a while.

We'll just have to see how we handle the anarchy and chaos of a disaster. A surprising number of my neighbors have lived in some pretty rough places so I like to think we'll all stick together.

[NNadir]

16. Carbon filters work well.

[dwckabal]

17. Yes, don't forget filtration

Giardia Lamblia is notoriuously difficult to kill, but is removed easily through filtration (this applies mainly to surface waters that can easily come in contact with animal and human feces).