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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How about a crude one meter diameter parabolic mirror made of aluminum foil and cardboard to bring water to a boil? It could work for cooking as well.
No, no, no Anthony…this is all wrong. There is no money to be made from it.
And I live in a Third World country. By the way I don’t need to shake bottle and put it out in the sun. I drink directly from the tap. ;O)
Not in mine. This is new to me and I live in a hot country. I guess I should have used my common sense about UV. :O(
Is a glass bottle OK?
I have both glass and plastic bottles. You have a good point that is why I pointed out glass. The above solution by Willis is still valid.
“Six hours in the sun and the oxygen plus the solar UV kills diarrhea.”
Sorry but diarrhea is a result not a cause. Which bacteria/virus does this method kill? Is it effective on bacteria/virus that would cause problems other than diarrhea? What if the used water bottle mouth is contaminated? Perhaps one could also sterilize urine and really help reduce water consumption.
Willis,
I find that many people who have never ‘seen’ the world they tend to have a skewed view of things (TV, magazines, etsc). Many assume that most Africans are starving – this is not the case. Many assume that the Pacific island atolls are sinking – this is not the case. Your travels and experience are invaluable. Keep up the good work.
Jimbo,
I do believe that glass would not be as effective due to the UV absorptive/reflective nature of the silicon dioxide material. One does not sunburn in a auto with the windows up 😉
5 people watching someone place water bottles of undetermined origin, upon a rack to be sterilized by sunlight.
While billions are spent to mitigate global warming.
Does somebody have a guilty conscience ??
Or is guilt the the driver, behind this newest of business plans.
Willis Eschenbach says: May 15, 2011 at 4:35 pm
. . .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 . . .
Clorox is a 6% solution of sodium hypochlorite and 90% advertising. Cheaper to buy a couple pounds of sodium hypochlorite and mix up your own.
Willis said, “… 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 …”
Not yet. I suspect that is BHO’s goal, though. At least, it appears to be his policy.
At 3:20 pm, responding to Dr A, Dr. Leif provides a quote (no attribution) regarding bread and cake – and all-in-all makes a good point.
The history of this quote or statement may not be known by readers, or more likely, know erroneously. Have a look:
http://en.wikipedia.org/wiki/Let_them_eat_cake
~~~~~~~~~~~~~~~~~~~~~
Another thought about clear versus clean water:
Our water, from 64 feet down, comes with ‘reduced’ iron and sometimes other undesirable things. Getting the iron out involves interesting science and technology. After 22 years the first system failed and was replaced last year. During the re-install we added 4 filters under the sink in the kitchen and a new ‘drinking water’ tap. If the new equipment lasts for another 22 years I will be pleased.
The clear plastic bottle “shake & shine” technology would likely also oxidize the iron and produce a drinkable but uninviting product and after two or three uses the bottle would gain an unsightly interior coating. Still, it sounds better than diarrhea. The photo for the post shows exceptionally clear water in plastic bottles. I wonder about that?
Oh, oh! The bedwetter greenies will not like this idea as they all know that there will be lethal amounts of chemicals (even at kilograms per bottle!) leached from the plastic under these conditions. The drinkers of this polluted, deadly water will not have diarrhea but will become hungry human-eating zombies, not unlike the more devout vegetarian-carnivore tree-huggers. This is common knowledge to the alarmists. Imagine coming up with a good use for plastic bottles; it’s just not possible for something invented by free market capitalism to come up with anything good. 😉
The Abstract is a bit vague to me……
“Higher motivation” ? This may mean an awareness to promote better hand to mouth hygiene and this factor more than drinking water may have reduced dystentery in this group. But I would need a definition.
Unfortunately the full text is behind a paywall.
I reviewed some of the referenced literature at the SODIS site. As expected, disinfection of micro-organisms is easiest when they are “free-floating” or in their “vegetative” state. When micro-organisms protect themselves by forming spores or cysts, they can become very difficult to inactivate. Another concern is re-growth after disinfection, as the SODIS process does not provide for any bactericidal effect after treatment.
Here are selected quotes:
Boyle, et al. 2008:
Gómez-Couso, et al. 2009:
Heaselgrave, et al. 2006:
In conclusion, it would appear that SODIS can be a very effective disinfection method. However, turbidity removal prior to SODIS treatment is very important. More critical is the fact that SODIS is ineffective against amoebas, due to the fact that temperatures above 45°C are rarely reached (Boyle, et al. 2008) and that no SODIS-induced reduction in viability was observed below temperatures of 45°C (Gómez-Couse, et al. 2009). SODIS mentions this serious limitation by stating:
However, from McGuigan et al. 2005:
If clean food-grade bottles (such as used soft-drink bottles originally bottled by multi-nationals) were used as SODIS reactors, then concerns about chemicals leaching out into the water would already have been addressed by the multi-national corporations as they would generally have to meet first-world standards for all of their packaging. I would also submit that perfectionism is the enemy of improvement in this case. Indeed, the marginal risk of leaching of chemicals from plastic bottles, assuming that clean food-grade bottles are used, is so completely masked by the far greater risks of disease and chemical contamination already present in the source waters that it is essentially zero.
In summary, SODIS would seem to have a very large benefit to cost ratio.
I am quite sure polyethylene terephthalate bottles absorb the UV rays in that area of the spectrum or if a little can go through it is surely not enough to do the job. I would however give more credence to heat and the presence of oxygen. One other possibility for this observed action is that some chemicals could be leaching from the plastic material and those combined with oxygen and heat could be the source for sanitizing the water from harmful bacteria.
One thing is certain, on the long run, the decomposition by-products of the plastic bottles will have a longer impact on their health. It might not be immediate as is the case for those bacteria giving diphtheria but it will certainly be more harmful and who knows what those chemicals will do to their genetics on the long run.
Willis,
In your Cold Equations you call Temperature a flow. But Temperature is a measure of Energy.
1 eV = 11,605 deg K.
You can look it up.
Glass bottles break & can then no longer hold water. If Enviro-Stewarts really cared about the ends not the politics, they would provide plastic bottles that bounce not break. That can later be used for this method, or other useful things. Glass takes much more energy to make, transport and more resources.
If you are going to give them something to filter water, instead of that whole complex bio-sands thing, why not Reverse osmosis run by human pumping or MSR Miniworks & give it to them. Then the best thing would be to help them build power plants, drill wells or harness other water sources & build treatment plants.
Genghis,
This method would not be nearly as safe as filtration. It wouldn’t get rid of giardia, cryptosporidium, ascaris eggs (a large roundworm that lives in the intestines in about 30% of the world’s population, over 90% in Africa alone). According to Katadyn’s specs it will filter down to 0.2 micron, good enough for just about all bacteria, but not common viruses that can cause diarrhea (rotovirus and norwalk). The sodis method seems to kill a large portion of the bacteria that can cause diarrhea.
Speed says:
May 15, 2011 at 3:56 pm
“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).”
And while people in third world countries die of disease, we give how many billions of dollars to the CAGW climate elites for “research”?
This is a great example of our grossly misplaced priorities…
Ray says:
May 15, 2011 at 7:16 pm
“One thing is certain, on the long run, the decomposition by-products of the plastic bottles will have a longer impact on their health. It might not be immediate as is the case for those bacteria giving diphtheria but it will certainly be more harmful and who knows what those chemicals will do to their genetics on the long run.”
Spoken like a true elite who has plenty of clean water to drink…I’m sure the sick and dying poor people really care about your unsubstantiated claims about plastic bottles…
Soil solarisation has been used by some horticulturalists for decades: cover damp soil with *clear* plastic sheet, and the heat and uv dispose of a high proportion of plant pathogens. I was involved with some research in this area, and it NEVER OCCURRED TO ME that it might work to disinfect water. Very humbling.
This little company in Australia has developed a very low cost solar desalination plant that works extremely well (won the inventor of the year a few years ago – I believe that Rotary International is funding distribution into “developing” countries);
http://www.fcubed.com.au/aspx/home.aspx
Add a drop of iodine and you can probably get rid of that last 25% and do a great dietary service for populations with a low iodine diet where goiter is common.
The good done by treating some bottles of water can be undone if untreated water is also consumed.
In a paper in preview, an incidental analagous situation is here quoted ananymously in part until publication: “In 1853-54 there was a serious outbreak of cholera in London’s Soho district….. Had Dr Snow derived only the average number of cholera-related deaths in each street in Central London he would not have been able to challenge the orthodox view. Snow instead showed how the incidence of cholera in the 1854 outbreak was closely correlated with the nature of the drinking water supplied by the Southwark and Vauxhall water company on the one hand, and the Lambeth company on the other, to individual houses on the same streets.”
So management as well as treatment of water is needed. The bottle idea is so simple that it is worth widespread trial, even if it saves fewer lives than anticipated. Nice find, Willis.
BTW, opposition to water treatment by fluoridation (government compulsory interfering with rights of people) is easily answered if you ask if chlorination should be stopped for the same reason. This program should not be stopped for fear of plastic leachates, the good far outweighs the harm – same logic.
Anthony.
There is nothing new under the sun!
In 1965 I left the UK to live in South Africa. I came across this same sterilization of dirty or suspect water then. The were using large empty clear glass wine bottles simply left out in the hot sunlight for a day or two. I realized at the time it wasn’t the temperature but probably the ultra violate that killed the bacterium, that lives in most water sources throughout Africa.
I believe this was not taught to the Native population but rather discovered by accident from simply storing the water in any container that was free/available and handy, after I found the water taste and clarity improved dramatically.
As for enough wine bottles there was and still is millions of them available. South Africa has always produced some of the best and cheapest wines under the sun and lots came in a one gallon bottles some of it was good drinkable domestic (dirt cheap) white wines from the Cape.
On a last note I never witnessed people sterilizing water in plastic bottles. I believe it was because of the plastic taste of water heated in pop bottle or container. This memory has stuck with me for over 45 years as a survivalist idea for drinking water.
REPLY: Note the author