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Old 5 August 2017, 11:30
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Water Purification - SODIS method

So you're grid-down, no filtration available, and water is available but you suspect it's loaded with viruses and bacteria. What to do?

Try the SODIS method.

Put your water into CLEAR plastic bottles that are made of PET. This can be identified by the triangular recycle symbol on the bottom with a '1' in it. Green or other colors won't do... it must be clear.

Lay the bottles in the sun, preferably on a sheet of corrugated metal, if available, for at least six hours. The ultraviolet light in the sunlight will kill all the nasties that are cruising around in the water in six or so hours.

Looks to me like this method is pretty reliable, low-impact, and can go a long way toward keeping you healthy when you're in GrubbyTimes.
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Old 5 August 2017, 21:53
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Quote:
Originally Posted by B 2/75 View Post
So you're grid-down, no filtration available, and water is available but you suspect it's loaded with viruses and bacteria. What to do?

Try the SODIS method.

Put your water into CLEAR plastic bottles that are made of PET. This can be identified by the triangular recycle symbol on the bottom with a '1' in it. Green or other colors won't do... it must be clear.

Lay the bottles in the sun, preferably on a sheet of corrugated metal, if available, for at least six hours. The ultraviolet light in the sunlight will kill all the nasties that are cruising around in the water in six or so hours.

Looks to me like this method is pretty reliable, low-impact, and can go a long way toward keeping you healthy when you're in GrubbyTimes.
Ahhhhhhhhhh...... Grubby times indeed!
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Old 5 August 2017, 22:44
DaveP DaveP is offline
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Always thought of chlorine as an end-default method, esp for larger volumes if/when needed, but it's not a pleasant taste even when the treated water is used for rehydration of dried foods, etc; and from the linked manual ver. 1, it apparently doesn't eliminate Giardia, crypto, or some ova - didn't know that.

Some specifics from the tech section (2) of the manual include inverse efficacy with turbidity (allowing settling or gross filters pre-'cook' would be helpful); ambient temp and degree of cloud cover dictate duration required even with reflector use (pasteurization-dependent); and pre-shaking increases available O2 for free-rad and peroxide formation, but mixing during sunlight exposure not advised.
The socio-economics parts of the lit were pretty interesting, too. Time-, resource-, labor-savings in third-world settings. For survival or E and E, avoiding production of smoke, smell, residue from a fire would be a bonus.

Cool link. Thanks.
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Old 12 August 2017, 06:01
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I haven't seen that on Dual Survival. Ha. Good to know though.
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Old 12 August 2017, 14:57
maim maim is offline
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Used it in Mali, taught the locals about it, appears to work well.
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Old 14 August 2017, 04:51
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Thanks for the great info!
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Old 17 August 2017, 16:15
foxcolt13 foxcolt13 is offline
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yeah thats good info to have. thanks
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Old 17 August 2017, 16:25
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Noted. Thanks!
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Old 17 August 2017, 17:50
Long Walk Long Walk is offline
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Thanks for the link.

It looks like this is more for killing organisms than for removing suspended particles. The manual suggested sand filtration as a possible method. Is that the most reliable, least technology intensive solution?
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Old 17 August 2017, 21:09
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That's correct... water having high turbidity (suspended mud particles) will not sterilize anywhere near as rapidly as clear water will.

I guess the implied but not stated task is to run your contaminated water through some kind of filtration first, to reduce the amount of UFOs in the water prior to bottling and sunning.

A cheap 55 gallon plastic rain barrel from home improvement box store is perfect; it's already got the plumbing you need. Put about ten or 20 old t-shirts in the bottom of the drum, completely covering the drain on the inside. Then fill it halfway with clean sand.

Each day your kids are charged with putting 20 (or however much you'll need in a day) gallons of dirty water in it, and an hour later they drain it out into clean clear 2 litre bottles and lay them down on the sun reflector.

This is a daily task: tomorrow's water is filtered and sunned today.
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