SOLVATTEN combines water pasteurization with SODIS. We have seen from our research that the synergetic effect of direct solar radiation and heat has a great impact on the purification results of the water. To allow the short wavelength of UV come through into the Solvatten container to work on the DNA in the cells as well as to be used as heat. The exposure time at for 3 hours is important. When we compared the same water heated in the laboratory (no sun light) during a long time the purifying effect was reached as you mention at temperatures over 60°C but the same water was tested parallel in the Solvatten and the effect of the UV light together with heat was obvious. The same water was also exposed in PET bottles but the temperature never reached the same level as in the Solvatten and th