Environmental Engineering Reference
In-Depth Information
speeds in what mechanical engineers would call a fully developed channel
flow. In a normal channel flow, the top surface and center of the water
channel has higher speed than that of water near the edges and the bottom.
That would make the machine inefficient.
In 1995 this box, UVWaterworks, was handbuilt by research technicians
at a national laboratory. It cost $1,000 to build, which means it would have
to be sold for about $5,000 if somebody were to take it on as a business. At
this point there was a socially responsible group of investors who came
together wanting to start a business and licensed this technology and the
design from Lawrence Berkeley National Laboratory. They promised to
raise the money to redesign this product from a research prototype that cost
$1,000 to build into a factory-manufacturable product which we can mass
produce cheaply. It took at least one day for our lab technicians to build one
research prototype. On the other hand, the box made by WaterHealth Inter-
national is built in 12 minutes. And they can sell it for about $700 with a
decent profit margin. Urminus Industries, the water-treatment company
that partially funded our first field trials in India, negotiated and obtained
the rights for the Indian market.
The design process took 2 years.We tested the early prototypes in India.
The final prototype has been tested in eleven different laboratories in five
different countries. We have ongoing field testing in South Africa, funded
by the US Department of Energy and by Lawrence Berkeley Laboratory.
Commercial production started in 1998.
Now, nothing works perfectly. Even this box does not work perfectly—
it is not a silver bullet to eliminate diarrheal waterborne diseases. In addi-
tion to making it available and affordable, you need to convince people that
they need to drink only safe water in order to avoid diarrheal diseases.They
need to scrub their hands after they to go to the toilet. They need to dis-
pose of human waste and animal waste in an appropriate manner. All of
these other actions and activities are needed so that they all work together
to eliminate diarrheal disease and save lives. Nevertheless, safe or clean
drinking water is a necessary condition for getting rid of diarrheal deaths.
Furthermore, UVWaterworks does not remove toxic chemicals or
Giardia
spores, and we still do not claim that it disables
Cryptosporidium,
or amoe-
bae. If these larger protozoan parasites are present in the water, they must
be removed by either a sand filter or a roughing filter. On the other hand,
if the raw water supply is obtained from a hand pump, then you do not
need to worry about
Giardia
and
Cryptosporidium
because the layers of soil
