Wikipedia
SOLVATTEN is a combined portable water treatment and solar water heater system that has been designed for use at the household level in the developing world. The device uses natural UV radiation to treat water, and units are capable of rendering highly contaminated water drinkable (as defined by the WHO safe drinking water standards.) in a few hours, provided there is sufficient sunlight.
SOLVATTEN incorporates three water treatment processes: filtration, pasteurisation and UV sterilisation. Under optimal conditions, the device can eliminate all pathogenic material in 10-litres of water within 2 hours, allowing for multiple batches of water to be treated in a given day.
The device is typically used in situations where water resources are scarce and prone to contamination, but it has also been applied in disaster relief scenarios. The device and its inventor, Petra Wadström, have both achieved recognition through a series of national and international awards.