Solar Water Disinfection

We know that water is an important element in our life. Our lives are survived by water. Indeed, our body contains huge amount of water. Purified water can save our life. On the other hand, germ infected water can destroy our life. So, we need to drink water which is disinfected. We can make our water disinfected by utilizing various systems. Solar Water Disinfection is one of the significant system to make our water disinfected.

Solar Water Disinfection is a system which utilizes solar energy to remove biological agents like bacteria, protozoa, viruses and worms from water and makes it disinfection. There are three types of method to disinfect water by solar energy. They are as below:
  • Method-1: Utilizing the effects of electric current produced by solar photovoltaic module.
  • Method-2: Solar thermal water disinfection.
  • Method-3: Disinfecting water by utilizing solar ultraviolet.

In the first method, solar photovoltaic modules are used to produce electric current which provides electrolytic processes in order to disinfect water.

In the second method, heat energy from sun is utilized to heat water for a small period of time. Here, solar heat collectors use reflectors and changing levels of insulation. Some solar thermal water disinfection processes are batch based and others are through flow based. During full sun shine, through flow based process operates almost continuously.

In the third method, sunlight and plastic PET bottles are used to disinfect water. It is a free and effective method for decentralized water treatment. This method is known as Solar Ultraviolet (UV) Water Disinfection and familiar as SODIS. Typically, it is used in household level.

In the SODIS method, contaminated water is filled in a transparent PET bottles and exposed to the sun for 6 hours. During this period, UV radiation of the sun kills diarrhea causing bacteria pathogens. It has been observed by researchers that UV-A solar radiation can easily destroy micro organisms situated in water. If you would like to observe whether the water is clear enough for the SODIS method to function appropriately, then you can proceed the newspaper test. In this test, filled bottles are placed upright on top of the newspaper headline. Now, it is required to look down through the bottle opening. If you observe that letters of the headline of newspaper are readable, then you can use the water for the SODIS method. If the letters are not readable, then you must treat the water before applying to the SODIS method.This method contributes to prevent diarrhea as well as save lives of people. This is a very significant method for us. Because, every day children die from the consequences of diarrhea.


  1. And use Foil to reflect more sun on it. This does not give you the poisons that are in plastic.

  2. Thanks Edward for your comment.


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