A technology that uses the UV-B rays from the sun to create safe drinking water is revolutionising lives.

Water and energy are connected. Over two billion people lack access to water at home, and as a result 200 million hours are spent by women and girls collecting water; even more time is used collecting firewood. These are girls that should be in school and instead are walking miles in the bush, vulnerable to male violence and snake bites.

Additionally, 43% of energy is used for water heating. The fuel is generally charcoal, made by felling four million hectares of African forest, losing trees that are invaluable for shade, and home to bats that remove mosquitos.

Making drinking water safe with sunlight

Solvatten is a combined portable water treatment and water heating system that has been designed for off-grid household use in the developing world. It was the brainchild of Swedish inventor Petra Wadström, who saw the potential of using sunlight to create water containers that would clean contaminated water.

The container is a large Jerry Can that opens in half in the same way a book does. The material heats with the sun to 75°C. The ultraviolet (UV) rays produced by sunlight destroy the formation of DNA linkages in microorganisms, preventing them from reproducing and rendering them harmless. When the water is good to use a green smile appears.

The product is targeted at families with children under five years old, and lasts 7-10 years. It is also supplied to midwives to provide water for washing mothers and babies.

The Solvatten solar heater warms the water so it reduces the energy required for cooking; it can be mixed with nutrient powder to create a safe porridge for young children; and improves hygiene by enabling hand washing before cooking and eating.