A Guide To Solar Disinfection (SODIS)

A Guide To Solar Disinfection (SODIS)

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In this blog post, we'll briefly discuss the growing phenomenon behind the SODIS water purification method. It's quick and easy and can be used as a water disinfectant. By the end of this article, you'll have enough knowledge to know how to make and utilize the SODIS method to your advantage.

Types Of Solar Disinfection And Purification

Here are the types of Solar Disinfection :


SODIS is one of the more popular choices on this list. It allows the user to remove the bacteria that's located inside of their water. How so? Through sunlight. Sunlight has UV-rays that can enter the DNA molecules of the bacteria and kill the bacteria within a few hours by destroying their DNA.

SODIS Bacteria Killing

Since SODIS is inexpensive, it's received widespread usage. Remember, SODIS is only able to remove bacteria that's stored in water. If you are looking for something that's a bit more in-depth, there are a few alternatives that are available.

Solar Powered Demineralization

This method is used to remove salt from seawater. It uses reflective film in its solar energy generators to remove more than just salt located inside your water. Solar Power Demineralization can be used to remove selenium and ferrous metals found inside your water. Most people in the agriculture industry use this method to ensure that their water is suitable for farming and crop growth.

Solar Demineralization of Water

Photochemical Oxidation

Also known as APO, photochemical oxidation is used to treat contaminated solids located inside your water. Understand that while SODIS is used to remove bacteria, you'll need more methods used to remove any excessive amount of chemicals stored inside of your water container.

Photochemical Oxidation APO

We like this method because it adds another sense of security when purifying water. Use a mixture of all three methods listed above to ensure that you have the best quality water at your disposal. Throughout the duration of this article, we'll discuss how SODIS is a primary method used to keep your water clean.

What Is SODIS?

SODIS stands for solar disinfection. It is the most popular method used for solar disinfection and can be used in various settings.

For instance, many developing countries such as India use SODIS. SODIS provides an inexpensive and quick way to disinfect water that might have been contaminated. Because of this, it's gained popularity and is proven to be a natural way to purify your water.

Here's a quick history lesson. SODIS started in the 1980s as a cheap, yet effective way to decontaminate water that's used for oral rehydration solutions (Example: water fountains, water bottles, etc.).

By 1991, the Swiss Federal Institute of Environmental Science and Technology started to use the SODIS method as a means to prevent diarrhea in developing countries. As a result, SODIS began to gain scientific data that proves that it's an effective method of water purification.

SODIS in Developing Countries

SODIS is scientifically verified and proven to combat the viruses, protozoa, and bacteria that's known to cause diarrheal disease. Lab Studies have shown that the use of SODIS reduces the instances of diarrheal disease by up to 9.86%. Also, field data reports that the use of SODIS improves the quality of water in developing regions in the world.

How It Works

SODIS works by through these three steps.

  • Fill plastic bottle with low turbidity water
  • Shake the water bottles (Oxygenation)
  • Place bottle in areas rich of UV-rays

SODIS uses a simple method to purify contaminated water. First, users must fill .3-2.0 liter of plastic bottles with low turbidity water. Turbidity stands for how cloudy or transparent your water bottle can be. It's caused by colored material and particles that are located on the water.

Turbidity in Water

Having a high turbidity is dangerous because it's harder to purify and has a cloudy like appearance. This means that your water is more likely to be contaminated; which increases the chances of a user becoming sick. Make sure to test your turbidity levels to ensure that it stays as low and transparent as it can be.

After that, you want to shake the water bottles to allow them to oxygenate. Oxygenation plays an important role in water decontamination because of a process called photo-oxidative destruction. This means that the water uses oxygen to remove the harmful materials, viruses, and bacteria that is usually found in contaminated water.

UV Damage to DNA

Next, you'll want to place the water bottles into an area where it can receive direct sunlight. Sunlight is the main key in decontaminated water in this method, as it allows the UV rays to eliminate the pesticides found within the bottle. Place it on the roof for 6 hours when the sunlight is out to remove the harmful chemicals inside of your water fully.

If the weather is too cloudy, then you can place your bottles outside for a span of 2 days. This process will take longer because fewer UV rays are being emitted. After keeping your water out in the sun, you'll realize that it's completely decontaminated.

SODIS combines photo-oxidative destruction, UV light DNA damage and thermal inactivation to destroy harmful organisms that live in your water. These organisms have the ability to pass through the liquid and potentially harm you if not purified correctly. Make sure to use the SODIS method to ensure that you are safe from such virus inducing bacteria that could live in your water.

Build Your SODIS

To build your SODIS, you need a few things:

  • Plastic Bottle or Water Container
  • Low Turbidity – Water
  • Sunlight

As we've stated above, you'll want to place the water bottle in an area where it can receive sunlight. Shake your water bottles at first to shake up the DNA particles inside of that contains bacteria. This makes it easier for the sun to decontaminate the water.

A common question that's asked is "What temperature kills bacteria and viruses"? You'll want to keep it at least 80-120 degrees Fahrenheit or 26-35 degrees Celsius. This ensures that your water will remain free from bacteria while keeping it at an acceptable temperature that won't destroy the bottle.

Keep the water out in the sun for a maximum of 6 hours. Solar water disinfection needs a bit of time for it to work properly. This is because the UV rays from the sun need to be at the right level to kill off the bacteria inside of it.

Making your SODIS is easy. Just remember to have a water bottle that's sturdy enough to undergo this procedure. Solar water purification requires time, sunlight, and a good water body to ensure that the bacteria is thoroughly removed from the container.

Why SODIS Is Great For Developing Countries

A common question that's asked amongst newcomers to SODIS is "Does sunlight kill bacteria?".

And the correct answer is "Yes."

There are over 2 million people around the world that use the sodis method for water treatment and purification. It's a powerful method that's accessible through almost anywhere.

SODIS is great for developing countries because it allows them to purify water with sunlight; which helps to lower the costs for water decontamination.

Countries such as Latin America have over 100,000 people using the SODIS method to improve water quality. It's ideal for developing countries because it's a virtually free method. All you need is a plastic bottle and sunlight for the method to work properly.

Developing countries SODIS


To conclude, SODIS is ideal for removing bacteria inside of your water. It's a simple, and effective method that's been proven correct and valid through multiple science reports. You'll want to use this method to ensure that your water is safe, clean, and is ready to drink.

As technology improves, we'll start to see more efficient ways to disinfect water. Developed countries will start to create innovative products and methods that can improve the quality of what they drink. Ultimately, SODIS is the main method of quick water purification and will only continue to enhance the lives of others shortly

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