SODIS solar water disinfection. (for drinkwater)

[778 neighbour of some guy]

First pre filter the water to get sediment out, a t shirt will do fine, the uv light (sunlight) will take care of the disinfection, just like a Steripen does.


SODIS is an alternative water treatment method designed for use at the household level. the technology is simple in terms of the procedure yet effective in eliminating water borne related pathogens,it is very affordable and utilizes locally available material.

SODIS STEPS:
1. Prepare empty PET bottles- transparent plastic bottles from softdrinks and bottled water(1.5 to 2 liter). Wash PET bottles including the cap using soap with soft material like cloth. Rinse

2.Fully pour PET bottles with water

3.Place prepared SODIS bottles horizontally under direct sunlight for a minimum of six hours (termination of water borne related pathogens). you can place it anywhere, as long as there is enough sunlight.

4. Harvest the SODIS water, set aside to cool.drink

Source: https://youtube.com/watch?v=UsIj96cHvHU

Source: https://youtube.com/watch?v=FnjO-y8-Crw

[Bob]

Solar Disinfection - Being in Colorado with the intense flooding - just a simple technical question. Maybe somebody can answer this for me. Pure water is obviously on everyone's mind in Colorado front range these days.

Solar UV question: the disinfection wavelengths are about 250 nano meters in wavelength to about 180 nanometers. If I look at what wavelengths are used to disinfect. (googlie searching).

Plastic soda bottles block 254 nanometer wavelengths.

Atmosphere is supposed to block 254-180 nanometer wavelengths (which are good for disinfection).

How does the solar energy that disinfects get through the atmosphere and through the plastic bottles?

I must be missing something?

[778 neighbour of some guy]

Posted by Bobd (here)
Solar Disinfection - Being in Colorado with the intense flooding - just a simple technical question. Maybe somebody can answer this for me. Pure water is obviously on everyone's mind in Colorado front range these days.

Solar UV question: the disinfection wavelengths are about 250 nano meters in wavelength to about 180 nanometers. If I look at what wavelengths are used to disinfect. (googlie searching).

Plastic soda bottles block 254 nanometer wavelengths.

Atmosphere is supposed to block 254-180 nanometer wavelengths (which are good for disinfection).

How does the solar energy that disinfects get through the atmosphere and through the plastic bottles?

I must be missing something?

Not sure how to answer that question or even what the correct answer would be and or if you or me are missing something here but UV is also used in many hospitals to disinfect water, it is also used by the military and in many expeditions, for that reason I have besides means of (filtering water, not the same as purification) also a Steripen ( model Freedom, that can be charged of solar charger by mini usb), the Steripen also uses UV light to disinfect water, the Steripen is however, held INTO the water and it has to be agitated for particulates in the water will block the penetration by UV, so to "get around" the particulates have to be moved out of the way in the water to bust the assumed present contaminants.

So, UV light that has to pass through a transparent container before it eliminates the contaminants must lose some its properties, but somehow it still seems to work fine going from the stories of third world countries who apparently are having great success with this method, its a mystery to me as well, because how come I don't get a sunburn then when I am behind a clear window if UV light penetrates transparent materials, refraction of the waves perhaps or does the size of the exposed biological materials make the difference here?

[Bob]

Posted by 778 neighbour of some guy (here)

Posted by Bobd (here)
Solar Disinfection - Being in Colorado with the intense flooding - just a simple technical question. Maybe somebody can answer this for me. Pure water is obviously on everyone's mind in Colorado front range these days.

Solar UV question: the disinfection wavelengths are about 250 nano meters in wavelength to about 180 nanometers. If I look at what wavelengths are used to disinfect. (googlie searching).

Plastic soda bottles block 254 nanometer wavelengths.

Atmosphere is supposed to block 254-180 nanometer wavelengths (which are good for disinfection).

How does the solar energy that disinfects get through the atmosphere and through the plastic bottles?

I must be missing something?

Not sure how to answer that question or even what the correct answer would be and or if you or me are missing something here but UV is also used in many hospitals to disinfect water,

it is also used by the military and in many expeditions, for that reason I have besides means of (filtering water, not the same as purification) also a Steripen

( model Freedom, that can be charged of solar charger by mini usb), the Steripen also uses UV light to disinfect water, the Steripen is however, held INTO the water and it has to be agitated for particulates in the water will block the penetration by UV, so to "get around" the particulates have to be moved out of the way in the water to bust the assumed present contaminants.

So, UV light that has to pass through a transparent container before it eliminates the contaminants must lose some its properties, but somehow it still seems to work fine going from the stories of third world countries who apparently are having great success with this method, its a mystery to me as well, because how come I don't get a sunburn then when I am behind a clear window if UV light penetrates transparent materials, refraction of the waves perhaps or does the size of the exposed biological materials make the difference here?

Thanks for your reply. I am curious how folks can obtain sterilization from wavelengths that aren't sterilization wavelenghts. UV light is a broad term. There are three bands of UV light. Only 1 of them is a sterilization band.

The "known" sterilization wavelengths are 254 nanometers in wavelength (UV C and shorter). 180 nanometers UV light is used in water treatment systems, as you mentioned hospital air purifiers.

I do have a portable 180 nanometer portable battery operated UV device called "STERI-PEN" - - (www.steripen.com is where I got it from). I use it in the bush on warm stream water that has the mud removed. Warm is important as for some reason the very ice cold stream waters have issues with the SHORTWAVE UV steripen operation.

The Steri-Pen works, but it is using SHORTWAVE UV.

The wavelengths of SHORTWAVE UV does not reach the earth's surface, the atmosphere of the earth stops wavelengths shorter than 300 nm.

STERI-PEN uses wavelenghts SHORTER than 300 nanometers (the atmospheric solar cut-off). That's the issue, so we can't just say UV (in general coming from the SUN will sterilize, not by the known sterilization techniques).

Steri-Pen requires that the water be directly exposed, for the correct time period for the amount of liters of water being treated. One cannot use steripen THROUGH PLASTIC, cannot use it through the outside of one's water bottles. I think they may mention it on the brochure that came with the steripen.

I think it is important to explain as you do mention some unknowns exist as to how it could happen..

Here is some of the science and logics.

UV-B is the wavelength that gets one sunburned, and UV-A is what is in "black lights" that make day-glow things glow brightly.

But, Those LONGER wavelengths are not sterilization wavelengths.

That is why I was wondering about when you mentioned plastic bottles + sunlight will create sterilization, just HOW could that be happening.

Let's assume that some type of water treatment is happening, then HOW would that occur?

It can't be directly from the UV B or UV A as both wavelenghts just aren't noted as "sterilization" wavelengths.

UV-B then potentially has enough energy to make it through the plastic and do "something" - what is that something..

I did some further study to share with you and here is what I found.

UV-A will pass through plastics to an extent, UV-B will pass through thin plastic.

BUT the actual sterilization wavelengths is UV-C and shorter. OK UV-C is needed to sterilize as shown in the STERI-PEN, but SUN does not let UV-C hit the earth !

What happens with UV-B - the plastic breaks down.

UV-B is also the wavelength that damages Skin, and mutate body DNA too.

UV-B will create mutations. UV-B causes the DNA replication mechanism to add a TT code (thiamine thiamine) on the growing DNA strand during replication. This mutation can result in cancerous growths, and is known as a "classical C-T mutation".

Then if we are to assume then it is UV-B is somehow killing the pathogens while IN a plastic bottle exposed to the BRIGHT SUN - HOW is that happening.

We know UV-B could mutate pathogens - then we are having pathogens in our water that now are containing CANCERS in them and those pathogens die from their damaged DNA. How dead are they and are mutated pathogens healthy for one, like is drinking a cancerous protein healthy? I can't answer that, but it kinda freaks me out.

That is kinda scary to me, drinking cancerous proteins in my drinking water..

UV-B then if it is directly the UV-B getting through the plastic is leaving cancers in the water.

UV-B doesn't have enough energy to burn away with free oxygen or ozone those proteins - UV-C does have enough energy to burn away cancerous proteins, but UV-C is not in the water, cannot make it through plastic, and doesn't make it to earth from the sun..

What it seems to me is happening is UV-B could do is to cause the PLASTIC in the Soda Pop bottles to break down, most likely into a gas and free radicals.

That is the problem in some landfills and the ocean, this plastic doesn't completely rapidly degrade, it partially breaks down.

Do you remember the warnings we have had about using waterbottles made of plastic that contain BPA. HEAT and COLD, Solar exposure releases the mutagen BPA. (BisPhenol A).

Nasty stuff when the plastic water bottles break down. Mutations, female synthetic hormone mimic'er. Light plus plastic bottles, equals BPA is released in the minimum into the drinking water or beverage.

(Is your water bottle giving you cancer - http://desmogblog.com/your-water-bot...ng-bpa-dangers )

If there is "sterilization" happening in water stored in PLASTIC BOTTLES exposed to bright sunlight, the only logical thing happening would be free radicals form the plastic (toxic byproducts) and the BPA are doing the sterilization (and mutations). (OMG really)

It seems to me, if UV-B were the disinfection wavelength to directly kill virus' and bacteria, protozoa, companies would go for making more money by spending less money on equipping sterilizers with the more expensive UV-C SHORTWAVE lamps.

I pulled up some reference pages that explain the different wavelengths - its pretty simple to get the understanding between the different wavelengths..
http://www.layfieldenvironmental.com...s.aspx?id=5030

Here is a picture of the UV Visible and Infra-Red spectrum laid out graphically -



Note that UV stops at 300 nanometers for the Earth's surface irradiance. The sterlization wavelenths (254 nm-180 nm) are showing up as virtually ZERO intensity.

But it is noted that there is sufficient UV-B and UV-A in the solar radiation to reach the ground. OK so only 2 UV wavelengths make it to the ground, and UV-A doesn't have enough energy to do bond breaking, or Ozone generation, assuming that OXYGEN/OZONE would be important for sterilization).

What could then be in the bottles is BPA (Dangerous mutagen), and the breakdown components from the plastic bottle, not direct UV-C sterilization wavelengths.

I just think one should know what one is drinking. Plastic plus sunlight it seems to me is not a healthy combination..

peace

I just think folks want to be safe.

[Operator]

Ok, maybe there is an easier and more reliable way: the water cone or similar
solutions.



I am currently investigating solar water distillation as a means to be self-sufficient in drinking water.

Perhaps we will try the cone here. But we're actually looking for a more 'bulky' solution.

[778 neighbour of some guy]

Thanks for your serious reply Bob, in your reply you said, see below

That is why I was wondering about when you mentioned plastic bottles + sunlight will create sterilization, just HOW could that be happening.

The Sodis steps are a copy and paste job that belonged to the video it selve on Youtube, anyway its seems to be working for the people using it, and the benefits of drinking water in the short term must heavily outweigh the disadvantage of bpa poisoning that will only show in the longer term.

If a plastic bottle would be the only one I had, I'd use it, religiously, that would be no time to be picky.

[778 neighbour of some guy]

Posted by Operator (here)
Ok, maybe there is an easier and more reliable way: the water cone or similar
solutions.



I am currently investigating solar water distillation as a means to be self-sufficient in drinking water.

Perhaps we will try the cone here. But we're actually looking for a more 'bulky' solution.

Op Curacao?

[CD7]

Also plastic bottles and sunlight heat up all the yummy chemicals in the plastic and go straight into your drinking water. This seems more like a problem then a solution.

[Bob]

I think some type of innovative solar still would be the safest way. I've seen Nigeria and metal is obtainable, and of course plastic more than anyone wants. India, all over, plastic water bottles. In the sun. If we can get a simple way to make solar still, get them everywhere.. The one's I have seen use clear plastic that the water condenses on. So the same plastic leaching its chemicals into the evaporated water.

I actually would like to see a massive aid program started that builds AIR WELLS (basically rock type of pyramid structures that capture moisture out of the air, and condense it on the rocks inside.. the temperature gradient constantly pumps the excess water out of the air.

This is a wonderful thread we need clean water, I am just afraid of the toxins from plastics harming us when they leech out.

I appreciate your post and thoughts very much

Bob

[778 neighbour of some guy]

Posted by CD7 (here)
Also plastic bottles and sunlight heat up all the yummy chemicals in the plastic and go straight into your drinking water. This seems more like a problem then a solution.

Correct, but I doubt they can be that picky there, dehydrate and/or get seriously ill/ die in 3 days, or get lethally poisoned in a couple of years, by accumulating BPA's, I'd drink from the bottle if that was my only option, if they had any other option they would prolly just do that.

[Ammit]

That's exactly what was going through my mind CD7.
I have a Webtex Surviva-Pure and also a survival straw. These are use after filtration through an army filtration bag ( if the water is muddy etc ).

I am not sure about the SODIS system......

[778 neighbour of some guy]

Posted by Ammit (here)
That's exactly what was going through my mind CD7.
I have a Webtex Surviva-Pure and also a survival straw. These are use after filtration through an army filtration bag ( if the water is muddy etc ).

I am not sure about the SODIS system......

Filtering water is not the same as disinfecting/purifying it, not all water filters can take out all the biological, bacterial and viral contaminants, I own two Sawyer water filters ( Squeeze)for filtering they are good for 1 million gallons each and very small and portable, disinfection by UV is a entirely different process , for that I have a Steri- Pen Freedom, other methods are for instance water purification tabs ( I have the oasis brand)if it can be done with glass containers that would obviously be better than with PET bottles, no questions there, they work with what is available and what seems to work, and that appears to be PET.

[Operator]

The problem with sunlight is that if you don't do the things at the right temperature and the right times
you will get algae BECAUSE of the sunlight ...

So distillation is a much safer way to get rid of ALL (i.e. bacteria, viruses unwanted minerals) contamination.
If it is stored for a longer period it should be kept cool, in the dark and constantly moving.

There may be desirable minerals in there too. But there seems to be a consensus that it's better to get them
through vegetables anyway ...

[CD7]

Posted by 778 neighbour of some guy (here)

Posted by CD7 (here)
Also plastic bottles and sunlight heat up all the yummy chemicals in the plastic and go straight into your drinking water. This seems more like a problem then a solution.

Correct, but I doubt they can be that picky there, dehydrate and/or get seriously ill/ die in 3 days, or get lethally poisoned in a couple of years, by accumulating BPA's, I'd drink from the bottle if that was my only option, if they had any other option they would prolly just do that.

Yes I agree with you...and I actually was going to add...but if I was dying of thirst I may drink it! But then again id probably drink anything!!

[Bob]

Posted by Operator (here)
The problem with sunlight is that if you don't do the things at the right temperature and the right times
you will get algae BECAUSE of the sunlight ...

So distillation is a much safer way to get rid of ALL (i.e. bacteria, viruses unwanted minerals) contamination.
If it is stored for a longer period it should be kept cool, in the dark and constantly moving.

There may be desirable minerals in there too. But there seems to be a consensus that it's better to get them
through vegetables anyway ...

So I am hearing SOLAR STILL at the right temperature, some way to NOT have aluminum in the circuit, no plastic, something to prevent algae..

This would be a GREAT public service project, as the bottle concept with leeching plastic (start of the thread) is what a LOT of people are doing. I just know how dangerous BPA is and if there are other toxins leeching out of the plastic, the cancer risk, is too high for me to gamble. I do bring my Steri-Pen whenever I travel personally, but folks who don't have that are reaching - if we all could come up with a way to help them - (good education goes a long way and a lot of grace comes back from that IMHO) just thinkin out loud

[Bob]

Posted by 778 neighbour of some guy (here)

Posted by Ammit (here)
That's exactly what was going through my mind CD7.
I have a Webtex Surviva-Pure and also a survival straw. These are use after filtration through an army filtration bag ( if the water is muddy etc ).

I am not sure about the SODIS system......

Filtering water is not the same as disinfecting/purifying it, not all water filters can take out all the biological, bacterial and viral contaminants, I own two Sawyer water filters ( Squeeze)for filtering they are good for 1 million gallons each and very small and portable, disinfection by UV is a entirely different process , for that I have a Steri- Pen Freedom, other methods are for instance water purification tabs ( I have the oasis brand)if it can be done with glass containers that would obviously be better than with PET bottles, no questions there, they work with what is available and what seems to work, and that appears to be PET.

I know there are catalytic metals which if they are in the PAN (lets call it a glass pan or tray) and the metal is in it, it will create hydrogen peroxide (free oxygen will be present), which is what the sterilizers are supposed to do. Just that such metal isnt available (no commercial use of this please, it MUST BE A GIFT if used)... People need the help and something that is locally available.

Thing about the dehydration, they drink out of the solar irradiated bottles for YEARS not just a few critical days during dehydration - its a staple way of life. BTW, I noticed in LAGOS town, opening the tap one got OIL out of it with the water.. From the OIL SPILLS everywhere. In DELTA state and BAYELSIA state it is so bad I find it impossible for people to have any tap water, or tap water treated by the sun to be acceptable cause the oil is not removed by the sunlight, if anything the sunlight would accentuate the oil plus water plus plastic bottle. They so desperately need education that helps them get solutions. SODIS bottle water is all over the internet, and it isn't the best thing IMHO.. peace..

[ThePythonicCow]

Posted by Operator (here)
So distillation is a much safer way to get rid of ALL (i.e. bacteria, viruses unwanted minerals) contamination.
If it is stored for a longer period it should be kept cool, in the dark and constantly moving.

I would expect more volatile hydrocarbons, with a boiling point near to that of water or lower, to not be reliably filtered by distillation. Carbon filters handle that well however.

"constantly moving" ... can you say more how that helps, and have you any practical clue how to do that?

[778 neighbour of some guy]

"constantly moving" ... can you say more how that helps, and have you any practical clue how to do that?

Allow me to answer that, I think one of those very cheap pond pumps with a small solar panel can take care of that part, I have seen them priced at our local garden centre from 20 euro's and up, they offer a large variety of these pumps, you need to live in a overall sunny area of course but one can always use a battery on the cloudy days, perhaps you need a second pump, for that, I can even see how a few simple 5 euro aquarium pumps with some air stones ( they use very little power) can have the same effect if its just the agitation your are looking for, how the air will affect the water and the microscopics in it I don't know, but keeping it in a cool dark place should reduce the grows of just about anything ( like in a fridge). Once cleaned, sterilized and disinfected one could always give it a second run through a filter to be on the safe side.