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Water Treatment System for Developing Countries

Updated on November 24, 2017
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Susette has a Masters degree in Sustainable Development. She leads her local Green Council and writes for The Sustainable Business Review.

Well developed countries have all kinds of ways of making dirty, disease-ridden, contaminated water drinkable. Some have governments that treat acres feet of water at once and distribute it for miles to individual homes and businesses, charging only a nominal fee. Some have treatment systems for sale that are individual, point-of-use units treating one particular location.

In a developed country, such high-tech treatments are readily available and most of us have the resources to purchase them, but all countries don't have these resources.

SODIS project in Indonesia. Local leaders are trained to spread the word and show how solar water disinfection works.
SODIS project in Indonesia. Local leaders are trained to spread the word and show how solar water disinfection works. | Source

Some countries have governments that keep most of the money the country makes and use it for themselves, instead of the people. Some have cities that are served, but countrysides that are poor and bereft. Some have water galore, but all of it diseased, and little product or money anywhere to clean it up. And some have no water, except what's deep in the ground. The Western system would not work for them, but there is a system for cleaning up water that's fairly simple, very inexpensive, carries its own risks, but can be utilized in many of these situations, especially in tropical countries.

Countries where the SODIS water disinfection method is utilized.
Countries where the SODIS water disinfection method is utilized. | Source

UV Bottled Water Treatment

Every country has a certain amount of sun, especially during that country's summer season. The ultraviolet (UV) rays produced by the sun will kill bacteria, viruses, and many parasites when the water has reached a certain temperature. In nature it happens all the time, but then the water is reinfected when it cools down and mixes with the soil again. However, if the disinfected water can be isolated, then it will stay disinfected and can be drunk without harm.

There are three ways in which solar radiation destroys these disease-causing (pathogenic) organisms:

  1. UV-A itself destroys the bacteria's cell structure.

  2. UV-A breaks up oxygen molecules dissolved in water, producing free radicals and hydrogen compounds that damage pathogens.

  3. Left in direct sun for at least six hours, water heated to 50ยบ C speeds up the disinfection process to help kill even the most resistent pathogen. On a very cloudy day without rain, it takes two days. The system will not work when it's raining.

SODIS System (SO=Solar + DIS=Disinfection)


The World Health Organization (WHO) lists the SODIS system as one of many viable, easy ways for villagers in tropical countries to make their drinking water healthier. Recipients are trained by the SODIS project or an affiliate nonprofit in what kinds of bottles to use, how to position them in the sun, and how long to leave them. If you live in the tropics and want to try it yourself, here is how the system works:

  1. Identify an area in your yard that gets at least five consecutive hours of direct sun per day.
  2. Purchase a number of 2 quart (2 liter) transparent PET bottles or you can reuse PET bottles made for soft drinks, as long as they are transparent with no cracks or scrapes.

  3. Fill each bottle with water. If the water is a little cloudy, you can add sea salt or ground legume seeds (peas, beans, lentils, peanuts) to help clean it up. If it's too muddy, it will have to be filtered first.
  4. Lay the bottles down on their sides in the sunny area of your yard. Transparent bottles let the UV rays go in after the pathogenic bacteria, but will only treat the surface if the water is too deep.
  5. Leave the bottles lying for six hours or more on a sunny day. If you want to increase the effectiveness of the sun or speed it up a little, place all your bottles on a reflective surface, like corrugated tin.
  6. When the time is up, either store your bottle in a cool, dark area, or transfer it to a larger container that is clean and store that in a cool, dark area (like a refrigerator). The smaller bottle can then be used right away to clean more water.

Look for this symbol on the bottom of the bottle. This indicates it was made from PET plastic (polyetheline teraphthalate).
Look for this symbol on the bottom of the bottle. This indicates it was made from PET plastic (polyetheline teraphthalate). | Source

Bottled Water & Health

Because of a very reasonable worry that the WHO was supporting a system that would leach pthalates or other plastic residues into the water while baking in the sun, different labs around the world experimented (and still are) to find out what really happens. They tested for antimony, adipates and pthalates, and aldehydes, among other things.

The results across the board seem to show that leaching is minimal - less than WHO's recommended limits for drinking water. There are also experimentations to develop safe PET bags that can be used in emergencies, like what Haiti experienced recently (and keeps experiencing).

Note that this method cleans up pathogens, but not chemical contaminants. If there is a factory upstream that dumps wastes in the water, or one nearby that dumps liquid wastes on the ground that sink down to contaminate the groundwater your well draws from, this disinfection method will not relieve you of either of those problems.

In the Western world we would not reuse these bottles, but in the tropics where clean water is less available, the tradeoff makes it worthwhile.
In the Western world we would not reuse these bottles, but in the tropics where clean water is less available, the tradeoff makes it worthwhile. | Source

Developing Country Water Projects

The SODIS project includes promotional demonstrations at technical expos, as well as introductions to kids in elementary schools - training the next generation. The team also sets up turnkey projects, training local leaders in the specifics, the potential dangers, and how to make sure villagers are following the guidelines for safe water. There are nine laboratories around the world currently studying these projects, coordinated by the Royal College of Surgeons in Ireland. They are taking statistics and looking for ways to improve the program.

The SODIS team has projects in 24 countries around the world, as shown in the following map. In each country there is a partnering nonprofit that keeps the program going and spreading. In Bolivia the government is involved too, all working together to provide pathogen-free water for the Bolivian population.

More than 5 million people around the world now clean their drinking water using the SODIS method. There are another 1 billion people who still don't have access to clean drinking water, and who have to deal with bacterial diseases every day. Below the map is a video of a project in Cambodia.

SODIS Project in Cambodia

How to Get Started

If you are in a location where clean water is lacking and all around you children are getting sick and dying from diarrhea and dysentary, check the SODIS website for more information. You will find contact information in the lower left hand column on each page.


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    • watergeek profile image

      watergeek 5 years ago from Pasadena CA

      LadyLola I just looked at the link you sent me and it's awesome! I've been wanting to write something derogatory about the bottled water industry (lol) but this link shows me a way I can just help it to become more environmentally safe. When I write my hub, I'll link the hemp part to one of yours. Thanks for the tip.

    • watergeek profile image

      watergeek 5 years ago from Pasadena CA

      I agree Leah. And Shara, I've been thinking that same thing. Have you guys ever heard of Ted Talks? They're a great resource for innovative technologies like this. They find them and put them on videos online. Here is the url, in case you're interested -

    • leahlefler profile image

      Leah Lefler 5 years ago from Western New York

      Wow - I had never heard of SODIS bottles but this is a GREAT idea. It is inexpensive and simple - what a great way to prevent infectious and parasitic diseases in tropical regions! I love ingenuity that finds a simple solution to a seemingly difficult problem!

    • shara63 profile image

      Farhat 5 years ago from Delhi

      i salute those budding scientists of the scarcity.....what we can do to help them out, is to promote them more & more through our resources ie. blogs, email, twitter etc. that they can get due recognition for their huministic work for the downtrodden and neglected circle of the society!...and i've done this by twitting it recently!

      congrats for your wonderful work..keep it up !

    • watergeek profile image

      watergeek 5 years ago from Pasadena CA

      OK LadyLola - I'll have to look more closely at your hubs. I have a thing for hemp too, although I don't write about it . . . just letters to Congress (lol).

      Jennyjenny - I agree, this technique would be great for anyone learning survival techniques. Thanks for sharing it on FB.

      Shara63 - I kept thinking about the people I knew in Botswana when I was a Peace Corps volunteer years ago, and how well SODIS would have worked there. There are so many simple techniques being discovered for and by the "third world" now, it's amazing.

      In Thailand, for example, this guy is making light bulbs from plastic bottles filled with water and a touch of bleach. He cuts a hole in his roof, inserts and caulks the bottle in, and the sun makes it glow - as brightly as a regular lightbulb. The technique is spreading all over Thailand.

    • shara63 profile image

      Farhat 5 years ago from Delhi

      A very informative hub...SODIS way of cleaning water sounds really gud and i think, it shud be promoted widely specially for the remote instead of all the advancements, about 2/3rd population is still under threat of water born diseases, generated by bacteria. This method seems to be really cheaper and effective enough in problem solving easily!

      watergeek, thankyou for sharing this wonderful information out here!

    • jennyjenny profile image

      jennyjenny 5 years ago from Somewhere in Michigan

      Very cool! Thank you for sharing. This is a great tool for scout leaders to use to teach an important survival technique. Can't wait to pass this on! Shared on Facebook for my scouting friends and families. Thanks! :)

    • LadyLola profile image

      Lanie Robinson 5 years ago from Canada

      I read about a guy who is making hemp plastic water bottles at I wonder if this product could be useful for the SODIS method? (Your thing is water, mine happens to be hemp. Don't worry I never met this guy, I just happen to like what he's doing.)