Solar Disinfection

Solar Disinfection

A very simple and inexpensive solar disinfection process consists of simply filling clear plastic bottles with source water. The bottles are then placed on a sunlight-reflecting surface such as aluminum or corrugated iron sheets, possibly on a roof. These bottles are exposed to direct sunlight for anywhere from one hour to two days, depending on the conditions. The Sun’s rays work to kill microorganisms in water by irradiation with ultraviolet (UV)-A rays and also by raising water temperature to 50 degrees Celsius or higher.

Solar disinfection, does not, of course, treat chemical water quality problems such as arsenic, heavy metals, pesticides, etc. It also requires relatively clear water, because suspended materials and the natural color in water block the UV rays. Bottles larger than one or two liters should not be used, which limits the quantity of water that can be treated. And it is not recommended for days of continuous rainfall. However, it has potential to greatly reduce incidences of diarrhea and dysentery, and to minimize the terrible public health toll that they exact worldwide.

http://www.drinking-water.org/html/en/Treatment/Membrane-Processes-technologies.html#tech1