Guest Post by Willis Eschenbach
One of the joys of writing for this blog is that I can promote good ideas. Here’s one I just came across, thanks to a commenter on another post of mine. The idea is solar disinfection of water, or SODIS. Follow the link, lots of good info.
Figure 1. The SODIS method in graphical form.
The idea is bozo simple. Put water into a clear plastic bottle. Shake it up well to oxygenate it. Put it out in the sun. Six hours in the sun and the oxygen plus the solar UV kills diarrhea.
I mean, how great is that? Now that’s solar tech I can get behind 100% … plus it uses up old water bottles. And doesn’t require any chemicals. Brilliant. Get the word out. Kids’ lives are at stake.
w.
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Just how effective is it ? Is it equivalent to 5 minutes boiling for example ?
That is truly simple and I have not doubt effective. However since few will make money on it I suspect less then well advertised.
Willis:
It is common practice in many hot countries.
Richard
No, no, no Willis…this is all wrong.
1. You need a peer reviewed study to prove the method works.
2. You need a deployment grant.
3. You need supervisors and field techs.
4. You need environmental impact studies.
5. You need education and training in the field (after all these people can’t do this themselves).
6. You need to have Greenpeace provide a permanent advisor for the village with a permanent stipend.
7. You have to setup a recycling program for the bottles.
Sheesh – what were you thinking? /sarc
Dr A Burns says:
May 15, 2011 at 2:45 pm
Just how effective is it ? Is it equivalent to 5 minutes boiling for example ?
“If they don’t have any bread, let them cake instead”.
Boiling requires firewood [or dung] which is in short supply [and creates CO2 and ugly smoke, uhuh]
Conclusion, throwing away our old water bottles is wastefull, we should save them and ship them to those who need them. It won’t even cost much to ship empty bottles.
Personally I think that, after haveing spend billions of dollors over here to make clean, safe tap water, that bottled water is a scam (which show how really gullible people are today). Now, however, it turns out that the bottle is, in fact, usefull in and of itself. We should continue to make the bottles, just ship them to people who need them. We just don’t need to go to the time and expends of putting anything in them, or shipping them when they are full.
And by scam, I personally like the bottled water labeled “Corpus Christy municipal water supply”, tap water, and they pay extra for this stuff! http://www.youtube.com/watch?v=XfPAjUvvnIc
Finally, a USE for this scam!
Dr A Burns says:
May 15, 2011 at 2:45 pm
Just how effective is it ? Is it equivalent to 5 minutes boiling for example ?
—————————————————————————
No, but. Follow the link and see http://pubs.acs.org/doi/abs/10.1021/es103328j
Apparently, if done correctly it achieves a 75% reduction in infection. At zero cost of fuel, fuel being a major expense in those societies where the technique will be useful.
Perfection is expensive. A vast improvement is cheap.
Which is preferable?
I’m sure some environmentalist will try to ban the procedure since it probably leaches a few parts per trillion of chemicals out of the plastic.
Have we now accepted our global pre-industrial fate? Have you resigned yourself to slow, cold, and dim? Are we to be conditioned to accept this kind of 3rd world poverty even here by WUWT? I expected better from you. A man 30 years my senior, once offered some good advice many years ago: “Live as well as possible for as long as possible”. I intend to do so.
This kind of abject minimalism does not offer much hope of a brighter future.
What a great idea.
In places with warmer/hot climates they have their ‘hot water’ tanks on their roofs.
The sun heats that water up very well.
We use the sun to our advantage as well.
Small bungalow home. Have good windows all round, but specifically in dining area where they are numerous and facing east to SE, making a semi-circle wall of windows. The sun in winter heats this area of the house up to 27-28c (even if it’s -20c outside) as the sun shines in the windows directly up to 11:am or so, sometimes have to crack a window in the kitchen especially if the wood stove downstairs is still glowing. An air venting system carries this warm air all over the home. In summer not a problem, as the sun is higher so not directly in windows much past 8 am.
I admire who ever designed and built this place.. even have a point system in the basement.
How green is that? 😉
Works too, as a broken hot water tank proved recently…
Our town recycles… endless supply of clear plastic bottles… Count me in!!
But nasty chemicals will leach out of the plastic!
Dennis Nikols said,
That is truly simple and I have not doubt effective. However since few will make money on it I suspect less then well advertised.
Two success stories, the first a for-profit.
According to the World Health Organization, more than two million people per year die of water-borne diseases, and one billion people lack access to a source of improved drinking water. (Wikipedia)
Uhh… I wouldn’t assume this is a good idea over the long term, and yeah, some studies might be in order. Although letting plastic bottles filled with water bake out in the sun for ours may be effective at decontaminating the water, you’re also introducing unintended consequences, namely creating ‘plastic tea’ through the release of numerous petrochemical compounds from the plastic that leach into the water much more readily under high temperatures. BPA is one example, with several others to be concerned about depending on the grade of plastic. Yes, in a life or death situation such concerns are foolish, however for long-term, practical solutions in developing countries, there are much healthier and humane ways of decontaminating drinking water than scorching it in plastic. Here is just one example: http://www.enviro-stewards.com/?page_id=155
I work with a Haitian doctor who routinely returns to the island to treat people and bring supplies. I told him about this as well to easily get good drinking water. It is a fantastic idea!
I forgot. It also helps to try and filter the water through some cloth to get the large solids that make it cloudy. Cloudy water does not disinfect nearly as well and will get you sick.
I like the idea, but I’d still favor a cap full of Clorox/quart. I don’t have the effectiveness numbers handy, but is sufficed for the U.S. Army while I was in, so probably quite a bit more effective than the SODIS method, but I agree, you can’t beat the cost. If this is the only method available, it sure beats nothing.
Nice idea! Simple and effective.
And fortunately the “dangers” of BPA are pure junk science:
http://www.debunkosaurus.com/debunkosaurus/index.php/Bpa
Kyle Anders said, Although letting plastic bottles filled with water bake out in the sun for ours may be effective at decontaminating the water, you’re also introducing unintended consequences, namely creating ‘plastic tea’ through the release of numerous petrochemical compounds from the plastic that leach into the water much more readily under high temperatures.
Do the bottles need to be green in color (like ginger ale’s), or clear, like carbonated water’s? Carbonated —? Horrors!
So will the green bottles be politically correct while use of those clear bottles be taxed in compliance with the political “cap and trade” anti-carbon religious decree being promoted?
Re Kyle
Don’t worry too much about stuff leaching out. That may already have happened in the time between bottling and consumption of the original acid rich contents. It’s an interesting comparison of Western concerns, ie potential BPA contamination versus more pragmatic concerns over access to potable water which much of the world’s population doesn’t have. If this is really a way to provide safer drinking water, then it seems a far better use of our cast-off/recyled bottles. How do we get our bottles to those that could use them though?
Curiousgeorge says:
May 15, 2011 at 3:38 pm
George, if this method is adapted widely, it will save the lives of millions of children. In my world, that is hardly “minimalism” to be disparaged …
w.
Is this method as good as filtration, like a Pur or Katydyn water filter?
James Sexton says:
May 15, 2011 at 4:10 pm
That would be my vote as well … but then a full bottle of Chlorox doesn’t represent say five days wages for me, as it does for far too many folks on the planet …
w.
Kyle Anders says:
May 15, 2011 at 4:01 pm
What you say is true, but only in theory. And when we get out of the “life-and-death” situation, those ideas may help … although I have grave doubts about the Enviro-Stewards proposal for “biofilters in Southern Sudan”, sounds like parachute aid to me.
But for now, for many people it’s a choice of a) possible minimal effect from leached chemicals or b) probable sickness and death for the kids.
Not too hard a choice where I come from … of course, in the long run clean piped water is the solution, whether biofiltered or industrially cleaned in some way. But for now, we have to have solutions for the world in which we find ourselves.
w.
* Parachute Aid— a term of art in the world of village level development. Refers to experts who “parachute” in a package of technologies, and the leave and then expect the technological stuff to continue working …