More than 400 children in the developing countries world wide, as mentioned in the original article, die every hour from waterborne diseases such as cholera, typhoid fever, gastro interitis, depentery and infectious hepatitis. Every year, besides the loss of lives, billions of hours of worker productivity are also lost. The pathogenic microorganisms that cause these diseases can be identified using a compound light microscope. The principal reason is that in many developing countries tap water is not readily available, so that in many households, two out of three people have to fetch water away from homes. These increase the probability of bacteria infecting unsterilized water.
As rain falls, it washes down raw sewage and contaminates the wells and surface water. Disinfection by boiling water over cookstoves entails much time of gathering of firewood by women and children that may otherwise be spent in other productivity activities. In 1993 a cholera outbreak in India, Thailand, and Bangladesh, people in Bihar, will gastrointestinal diseases caused the death of around 300 infants daily in the state of Orissa alone. The causative agent of this disease could be identified using a compound light microscope.
The original text talks about a purification system using ultraviolet light went under way in media, Mexico and South Africa. It was durable, easy to use and inexpensive to construct and maintain. It was called UV waterworks.
Cost-wise the devise can disinfect water for 2¢ per ton, inclusive of cost of electricity and annual capital cost with the initial cost of $300 per unit, using only 40 watts of electricity, it provides four gallons of disinfected water per minute. The process uses less primary energy at 20,000 times less than using ordinary cookstove to foil water and kill bacteria and other microorganisms that can be seen under a compound light microscope.
By and large, the devices serving a community of 1,000 people for 15 years has averted the death of 15 children under age 5 and avoid stunted growth of 150 children. It can increase life savings and improve quality of life especially of women and children by reducing their workload in gathering fuelwood, and by decreasing the number of children lost to diseases whose causative microorganism can be studied with the use of a compound light microscope.
How it works
UV waterworks uses ultraviolet (UV) light to kill water-borne pathogens (visible under a compound light microscope) in water supply and can be classified into three wavelengths. One is germicidal that kills bacteria, viruses and other pothogens. Light having a wavelength of25A nm is more efficient because it is in this range that mercury vapor lamp emits 90% of its light which is used in this system.
The UV light system uses lamp similar to conventional fluorescent lamp except that the tube is not coated with phosphor and the glass is transparent to UV light.
The total cost of UV units id $300 and the metal unit has an expected life of 15 years. It is assumed that potable water is ensured to a village of 1000 people at a year round cost of 5¢ per villager. Original article