SODIS Roolz

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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Dr A Burns

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.

Richard S Courtney

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]

Legatus

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!

View from the Solent

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?

John M

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.

Curiousgeorge

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.

ldd

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!!

Michael Jankowski

But nasty chemicals will leach out of the plastic!

Speed

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.

Mrs Djike lives with her family in the Song-Mahop slum in Cameroon. She has been selling chilled water to neighbours and travellers for many years. In 2008, a SODIS campaign was conducted in her neighbourhood. A promoter also visited her home and explained the use of the method. Mrs Djike hesitated at first. Considering the poor water quality in her slum, the method appeared to be too easy to work. After placing PET bottles on her roof and testing the method herself, she became an active user of SODIS method. Since then, her family is drinking clean water and suffers far less from diarrhoeal diseases.
After her positive experience with the method, she also decided to offer her customers chilled SODIS water. The good quality of her water got around quickly in the neighbourhood. Today, she proudly says: “With the SODIS method, I already treat more than 40 bottles of water every day, which I chill and sell the next day. Thanks to the good water quality, I have acquired many new customers”. Since Mrs Djike also shows her customers how to use the SODIS method at home, she makes a significant contribution towards improving the living conditions in her neighbourhood.
http://www.sodis.ch/index_EN

In the beginning of the project we focused on the training of the households in the slums of Yaoundé, the capital city of Cameroun. Since 2009 we are working together with the medical faculty of the University of Yaoundé and have expanded our activities on other regions.

In the slums of Yaoundé the method is already well anchored. More than 50,000 people are using it daily to treat their drinking water.
http://www.sodis.ch/projekte/afrika/kamerun/index_EN

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)

Kyle Anders

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

Therapist1

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!

Therapist1

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.

James Sexton

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.

PaulH

Nice idea! Simple and effective.
And fortunately the “dangers” of BPA are pure junk science:
http://www.debunkosaurus.com/debunkosaurus/index.php/Bpa

Speed

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.

There has been some concern over the question whether plastic drinking containers can release chemicals or toxic components into water, a process possibly accelerated by heat. The Swiss Federal Laboratories for Materials Testing and Research have examined the diffusion of adipates and phthalates (DEHA and DEHP) from new and reused PET-bottles in the water during solar exposure. The levels of concentrations found in the water after a solar exposure of 17 hours in 60°C water were far below WHO guidelines for drinking water and in the same magnitude as the concentrations of phthalate and adipate generally found in high quality tap water.
Concerns about the general use of PET-bottles were also expressed after a report published by researchers from the University of Heidelberg on antimony being released from PET-bottles for soft drinks and mineral water stored over several months in supermarkets. However, the antimony concentrations found in the bottles are orders of magnitude below WHO and national guidelines for antimony concentrations in drinking water. Furthermore, SODIS water is not stored over such extended periods in the bottles.
http://en.wikipedia.org/wiki/Solar_water_disinfection

bob paglee

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?

Atomic Hairdryer

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?

Willis Eschenbach

Curiousgeorge says:
May 15, 2011 at 3:38 pm

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.

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.

Genghis

Is this method as good as filtration, like a Pur or Katydyn water filter?

Willis Eschenbach

James Sexton says:
May 15, 2011 at 4:10 pm

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.

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.

Willis Eschenbach

Kyle Anders says:
May 15, 2011 at 4:01 pm

… 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

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 …

Mindbuilder

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.

Jimbo

Anthony Watts says:
May 15, 2011 at 3:13 pm
No, no, no Willis…this is all wrong.

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)

Jimbo

Richard S Courtney says:
May 15, 2011 at 3:05 pm
Willis:
It is common practice in many hot countries.
Richard

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(

Jimbo

Kyle Anders says:
May 15, 2011 at 4:01 pm
… 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

Is a glass bottle OK?

Jimbo

Kyle Anders says:
May 15, 2011 at 4:01 pm

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.

Tom in Florida

“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.

Jimbo

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.

intrepid_wanders

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 😉

u.k.(us)

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.

Mike McMillan

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.

mike g

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.

John F. Hultquist

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?

higley7

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. 😉

Keith Minto

The Abstract is a bit vague to me……

At baseline 62.4% of the study households had stored water which met World Health Organization guidelines for zero thermotolerant coliforms per 100 mL. Dysentery was recorded using a pictorial diary. Incidence of dysentery was significantly associated with higher motivation, defined as 75% or better completion of diarrhea data. Incidence rates were lower in those drinking solar disinfected water (incidence rate ratio 0.64, 95% CI 0.39−1.0, P = 0.071) but not statistically significant. Compared with the control, participants with higher motivation achieved a significant reduction in dysentery (incidence rate ratio 0.36, 95% CI 0.16−0.81, P = 0.014). However, there was no significant reduction in risk at lower levels of motivation. Solar disinfection was not significantly associated with nondysentery diarrhea risk overall (P = 0.419). A statistically significant reduction in dysentery was achieved only in households with higher motivation, showing that motivation is a significant determinant for measurable health gains. Failure of three-quarters of participants to achieve a significant reduction in dysentery suggests that research into effective implementation is required.

“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.

Phil

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:

…bacterial species which are spore forming may survive

Complete inactivation (i.e., reductions greater than 4 orders of magnitude (4 log units) and final population below the limit of detection, which is 17 CFU/ml) was achieved within 3 h of exposure to sunlight for all the species studied except B. subtilis endospores, which experienced a reduction of only approximately 0.5 log unit by the end of the first day’s exposure of eight consecutive hours. These B. subtilis samples were re-exposed on the following day. After a cumulative exposure time of 16 h of natural sunlight (Fig. 1b), the maximum reduction observed for the endospores of B. subtilis was 96.3% (standard error, 3.0%), which corresponds to a 1.3-log-unit reduction for a cumulative global received dose of 79.9 MJ m^-2. (CFU=Colony Forming Units) (parenthetical comment added)

In light of the well-documented resistance of B. subtilis to heat and pressure sterilization (23), it is remarkable that SODIS was able to inactivate as much as ~96% of the B. subtilis endospores at all. These results are supported by the recent findings of Mendez-Hermida et al., whose SODIS studies of the highly resistant oocysts of the protozoan pathogen Cryptosporidium parvum showed that exposures over two consecutive days of strong sunshine were typically required for their complete inactivation …

Gómez-Couso, et al. 2009:

However, SODIS field trials in different geographical regions, carried out by SANDEC, have shown that temperatures above 45°C are rarely reached.

A reduction in oocyst viability of approximately 50% points (from 91.60% to 40.70%) was detected in samples with a turbidity level of 0 NTU, whereas for highly turbid water samples (300 NTU) the reduction was very low (from 91.60% to 80.64%). (NTU=Nephelometric Turbidity Unit)(parenthetical comment added)

Laboratory experiments have shown that in water samples of turbidity higher than 200 NTU, less than 1% of the total incident ultraviolet light (UV) penetrates further than a depth of 2 cm from the surface (Joyce et al. 1996). It is therefore recommended that water destined for treatment by SODIS do not display turbidity levels above 30 NTU (EAWAG 2008).

…when the temperature of the water did not surpass 25°C, the decrease in the oocyst viability in water of 300 NTU was very low, independently of the time of exposure.

…after SODIS procedures, some bacteria may regrow, and therefore the EAWAG recommends that SODIS treated water should be consumed within 24 h after the treatment (EAWAG 2008).

Heaselgrave, et al. 2006:

No SODIS-induced reduction in (Acanthamoeba) polyphaga cyst viability was observed for sample temperatures below 45°C. (parenthetical comment added)

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:

Amoeba species (that cause) Amibiasis (are) (n)ot rendered inactive. Water temperature must be above 50 °C for at least 1h to render inactive!

However, from McGuigan et al. 2005:

Higher temperatures are usually only achieved if the reactor is fitted with either rear-foil reflectors or the rear surface is coated in a matt black substance (paint, mud, etc.).

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.

Ray

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.

NW Libertarian

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.

flyfisher

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.

Frank K.

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…

Nicodemus

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.

James Reid

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

crosspatch

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.

Geoff Sherrington

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.

Dave

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