UV Water Purification
In many areas around the world, waterborne diseases such as typhoid fever, gastroenteritis, cholera, dysentery, and infectious hepatitis would kill several hundreds of children each and every hour of the day. In addition to this horror, billions of work productivity hours are lost each year.
In many developing countries, the luxury of tap water is not an option. About 2 thirds of humans on earth get drinking water from outside their dwelling.
To address this health and energy issue, an effort was set upon by Lawrence Berkeley National Laboratory Indoor Environment Program to introduce a UV water purifier that would work in developing countries.
The device to provide a durable and inexpensive unit that can be setup locally and maintained easily. The result: UV Waterworks.
Another unit with a twist, to Ultra Violet Purification.
This Ultra Violet Waterworks would be able to disinfect drinking water for a relatively low price, including the cost of electricity used for the UV system, and the annualized capital cost of the UV WaterWorks System. The original cost would be approximately Three Hundred Dollars, the UV System would use 40 watts of electricity, and would provide 4 gallons of UV Purified drinking water per minute.
The UV Purifier disinfection process is energy-efficient and uses approx 20k times less energy than the standard alternative: Distilling (a.k.a. Boiling) drinking water over a stove.
How the system purifies drinking water
The UV WaterWorks technology uses UV (ultraviolet) light to kill or disable waterborne pathogens (such as bacteria, molds and viruses) found in the water supply. Ultra Violet light is classified by three wave length ranges.
This unit uses UV-C. This is a germicidal ultraviolet light system that is widely used to kill micro organisms found in air, water, and other liquids. The most effective wavelength of UV light is 253.7nm and it would disable microorganisms found in the different environments mentioned. UV Germicidal system applications include but are not limited to drinking water sterilization, UV Ultraviolet Light air cleaning, among many others.
The germicidal UV destroys and inactivates the DNA of the microorganisms and therefore they loose their ability to reproduce. Light with a wavelength of 253.7 nm gives the highest germicidal efficacy in the Ultra Violet range.
Since the UV operates at the wavelength at which a mercury lamp emits roughly ninety percent of its light, standard fluorescent technology can be used in the Water Works UV system.
Are you aware that the glass light fixtures used in fluorescent lamps which can be found today in many offices and homes, are coated with a phosphor that is there simply to absorb Ultra Violet light and give off visible light. The UV lamp in the UV water disinfection device is similar to standard fluorescent lights, but the glass tube is NOT coated with a phosphor, and it is also constructed with a special glass that is transparent to UV light. This Germicidal variety of lamps are available through many manufacturers that produce standard fluorescent bulbs.
The one-time capital cost of Ultra Violet Waterworks includes the material, fittings, and labor. According to the designers, life of the UV Base metal unit is expected to run approx. Fifteen years, the Ultra Violet Bulbs need replacement every now and then. Assuming the UV system operates for 12 hours per day and you pay for electricity 8 cents per kWh, the annual cost for electricity while operating a UV Water Purification system would be approximately Fourteen Dollars.
In addition to this one may consider the cost of Bulbs, ballasts, and starters for the Ultra Violet Water Purification system. These can be purchased off the shelf, at many sources online and offline.
It still needs to be taken into consideration the total annualized cost of the 35-watt Ultra Violet Bulb, ballast, UV metal chamber, and the actual cost for electric. In a developing village or town, the customers would provide their own pump (by Hand) for groundwater or storage tanks and a sand filter to remove particles etc. The raw materials for those are available and not too expensive either.
If the UV disinfection water system operates for 12 hours a day, 4,000 tons (4 million liters) of water can be disinfected each and every year. Using a per-ca-pita pure drinking water requirement of 10 liters per day, a single UV WaterWorks system might be able to provide enough water for approximately 1000 people.
More on the UV WaterWorks can be found here