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We challenge you to use your TRIZ skills and your knowledge to help solve a
humanitarian or social problem. We hope that you will submit your results for
publication in the TRIZ journal. Every few months we will set a new challenge -
but that does not mean that you cannot continue to work on previous challenges,
indeed you may have chosen to work on this for your project or coursework.
Send your results, ideas, comments and suggestions for future challenges to
challenge@triz-journal.com.
This month's challenge is an engineering challenge with a humanitarian
aspect. How can you purify water for drinking in a subsistence environment in a
developing country such as Zimbabwe?
More than a billion people lack access to clean drinking water, and millions
die every year from water related diseases.
Filters can remove insects, larvae, worm eggs and cysts but allow bacteria
and viruses through. Membranes rely on you being able to keep the clean side
sterilised and are delicate. Chlorinating requires chemical additives and does
not kill all bacteria (look what lives in your swimming pool). Heating uses fuel
and far from killing them, can cause some viruses to accelerate their growth.
Can you devise a cheap and portable method to 'clean-up' water to make it fit
for drinking. The method needs to be simple to operate and cheap so that no-one
is excluded from using the method.
Can you think of a method that could be used in conjunction with
last month's challenge (a water pump for the
developing world) such that a proportion of the pumped water is suitable for
drinking.
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Trevor Baylis (the inventor of the combined wind-up and solar radio) has
applied his mind to this. His company produces a device that you pull up a rope,
which is secured to a tree, this winds up the mechanism and as the mechanism
falls a voltage is produced that is conducted from the rope through the water to
the bucket. If there is no natural salt in the water this is added (a few
grains), the chlorine from the salt and the hydrogen from the electrolysis
sterilise the water. The disadvantages are: initial cost; may need to purchase
salt; some organisms can survive the process (admittedly not many); and you need
a tree or tall structure (you don't want to wind it, otherwise the current flows
to ground through you). The advantage is that it is quick (2 minutes) and 99%
effective.
The WHO (World Health Organisation) and UNICEF are promoting a scheme that
uses discarded clear PET bottles (such as you might buy a couple of litres of
lemonade in). The bottle is filled with water and placed on a black surface in
the sun for most of the day (they suggest around 5 hours). The temperature rises
in the bottle (the water and bottle form a lens to heat the black surface and
the water), the ultraviolet radiation from the sun kills the viruses in the
water. Advantage is that cost is effectively zero. Disadvantage is that not all
pathogens are killed (typically less than 1% survive), particularly if
harbouring in the cap or the moulding of the base. The bottle cannot get too hot
otherwise the plastic deforms and the bottle splits.
At present this is probably the best, cost effective solution. Can you
improve on it?
In Mediterranean countries, a beach barbecue can be cooked using flexible
silver film (like Aluminium foil) that forms a parabolic cooker and folds up
smaller than a bikini when finished. This can get food very hot very quickly.
Could this simple technology be utilised to pasteurise the water without
destroying the container?
Wateraid
http://www.wateraid.org.uk/ describe on their website
http://www.watermatters.org.uk/html.html describe the problems that we face
in providing safe water for the entire world (something most of us take for
granted).
Oxfam's
http://www.oxfam.org.uk/ latest campaign (see their web site:
http://www.oxfam.org.uk)
is the establishment of water supplies in Goma. The aim is to provide 15 litres
of clean water per day per person.
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