What is Pasteurization
Pasteurization is the process of disinfecting food or liquids by heat or radiation. Disinfection means the destruction of disease-causing microorganisms.
The word “pasteurization” was named after the French doctor Louis Pasteur, the father of modern medicine. In 1864, Pasteur demonstrated that diseases are caused by microorganisms that can be killed by heating to 55ºC/131ºF for several minutes. Applied to wine, beer and milk, this process, called "pasteurization", soon came into use throughout the world.
Pasteur’s research proved that sufficiently heating a substance destroys all disease-causing germs. Pasteurization has been accepted as completely safe for more than 134 years! Today, throughout the world, beverages such as milk, fruit juice, beer and wine are disinfected through pasteurization. Consumers are familiar with and trust the process of pasteurization.
Pasteurization is a function of time and temperature. If heat is applied for a long period of time, disinfection will occur at a lower temperature. At higher temperatures, disinfection occurs in a shorter period of time.
SOLAR WATER PASTEURIZATION BY SAFE WATER SYSTEMS
Safe Water Systems uses the time-honored technique of pasteurization to disinfect water that is microbiologically contaminated.
Laboratory testing of SWS solar water pasteurizers confirms an effectiveness of 99.999% in disinfecting water that contains disease-causing micro-organisms, including bacteria, viruses, worms and protozoa. The effectiveness of SWS pasteurizers is superior to chlorine, slow sand filtration, ceramic filters, roughing filters, and UV radiation.***
The SunRay 30, after heating the water for 1½ to 2 hours, achieves effective pasteurization at 68ºC/143ºF. The SunRay 1000 is our flow-through solar water pasteurizer. Since the water spends only a short time in the system, the thermal control valve is designed to open at a higher temperature of 80ºC/175ºF before the water is released from the solar collector.
DISADVANTAGES OF BOILING WATER
In many countries, firewood, charcoal and other fuels are used to boil water. The burning of fossil fuels has been linked to air pollution, ozone damage, deforestation, soil erosion, and flooding. Families in developing nations spend up to 25-30% of income on firewood or water purchases. Many families gather wood or other fossil fuels because they cannot afford to purchase them. It can take 6-8 hours or more for women or children to gather enough fuel to cook the daily meal and boil the water.
ADVANTAGES OF SOLAR WATER PASTEURIZATION
- 99.999% effective in destroying water-borne pathogens
- Destroys disease-causing bacteria, viruses, protozoa and worms
- Uses only the heat of the sun; does not use electricity, chemicals or fossil fuels
- Prevents air pollution, ozone damage, deforestation, and soil erosion
Excellent for use during emergencies and natural disasters; guarantee that your family will always have safe drinking water
- Superior alternative to chlorine treatment, which is rated “poor” at destroying worms & protozoa, may be bad for one’s health, and gives water a bad taste.***
- Low maintenance and no replacement parts costs
- Large unit (SunRay-1000 model) can become a new business in developing countries: the owner can be a “water seller” in his/her community
LIMITATIONS OF SOLAR WATER PASTEURIZATION
Requires sunny weather
Cannot operate in freezing conditions
Does not remove chemical pollutants from water.
Does not remove minerals or salt from water (does not desalinate water)
***These statements are taken from a report by the National Renewable Energy Laboratory, a national laboratory of the US Dept. of Energy, entitled “An Overview of Water Disinfection in Developing Countries and the Potential for Solar Thermal Water Pasteurization,” Jay Burch & Karen E. Thomas, January 1998, Appendix J., pp. J-1, J-2.
SAFE WATER SYSTEMS
2518 Tantalus Drive, Honolulu, HI 96813
Phone: 808-949-3123 Fax: 808-949-3103