Solar Disinfection, or SODIS for short, is the process of using the sun's energy to disinfect water. Sunlight has two components that make this happen: ultraviolet and infrared radiation. These two types of radiation work together in synergy to kill up to 99.9% of microorganisms. Some pathogens take longer exposure to kill than others. Research has shown the effectiveness of SODIS and it is well documented.
Ultraviolet-A rays (UV-A, 320 - 400 nm) will inactivate harmful bacteria, parasites, and viruses in water, given enough exposure to the sun. UV-A radiation interacts at the molecular level of the pathogens and leads to cell death.
Infrared radiation is absorbed by the water and increases the temperature. Microorganisms are sensitive to heat and can be inactivated by this alone. Water does not have to be boiled to kill microorganisms. Heating the water to an elevated temperature over a long period of time (50-60°C for one hour) has the same effect as boiling.
SODIS is dependent on the amount of sunlight available. Radiation from the sun varies in intensity from one geographical location to another depending on season and time of day.
Niger is one of the hottest countries in the world. It consists of three climate zones: the Saharan, the Sudan, and the Sahel. The Saharan zone is part of the Saharan desert and is located to the northern region of the country. The intense heat of the desert often causes rain to evaporate before it hits the ground in this zone. The Sahel zone is in the southern part of the country and this is where the capital city of Niamey is located. The Sudan zone is located in the southwest corner of the country.
Of the land of Niger, 20% is a semi-arid climate and 80% is a desert climate. Ninety percent of the population lives in the semi-arid climate zone. The average daily temperature for the capital city is 31° C (88° F ) to 41° C (106° F ). It gets much hotter the further north you travel. For the most part, the sun is always shining.
The Wayna Hina Project
'Wayna Hina" translates from the Zerma language as "the sun can" or "the sun has the ability to". A perfect name for a solar disinfection program because the sun has the ability to change the lives of millions of people in this region.
One of the things we try very hard to do at Fofo Hari is use resources that are readily available. The biggest resource in this part of the world is the sun. Over 80% (14 million people), don't have access to proper sanitation in Niger. Nearly 50% (8 million people), don't have access to safe drinking water. Solar disinfection is a simple, affordable, and sustainable way to make your water safe to drink in this part of the world.
The First of Many
Deep in the bush, outside of the village of Toure, a small community of families was equipped with the resources they needed to start their own solar disinfection system. We had this idea where we would buy local materials in the market and set up a simple solar disinfection system for a small group of people and train them on how to use it. Then, periodically, Mark would check back in with them to see how it was performing. We spent a total of US $12 on materials that included sixteen 1.5 Liter clear plastic bottles for $1.50, one funnel for $1.00, five bricks for $4.00, one 4’ x 4’ sheet of reflective metal for $3.50, and two 25-Liter water containers for water fetching and storage for $2.00. By buying local materials, we helped 5 different small businesses. But the ability to empower a group of individuals with education and materials to perform their own solar disinfection proved priceless. Seeing the look on the face of Mounkayla as we taught him how to treat his own water with the very images we’ve been using in our research was so exciting. He immediately understood and taught it back to us. He was so thrilled that he now had the ability to treat his own water. He was empowered.