RP-01638

Conclusions
In an era of rapid development and population expansion, the challenge to
improve environmental health confronts every nation. In the Third World, this
problem is made more acute by limited resources. Provision of adequate, safe water
supplies to rural populations by 1990, an official target of the International
Drinking Water Supply and Sanitation Decade, means that an estimated 20 million
or more new handpumps may be needed by the year 2000 if the goal of bringing
potable water to the millions of rural inhabitants of the World is to be achieved.
These pumps must be able to withstand the use and abuse of the many who depend
upon their proper functioning for their daily water supply.
When a handpump breaks down and remains out of service, the economic loss is
considerable. The replacement parts, and the possibility of vandalism and disappearance
of parts if the pump is out of operation for more than a few days, result
in considerable cost and loss of financial investment, not to mention the hardship
and inconvenience to those who have to walk long distances to obtain water. One
solution to this problem is to focus efforts on the development of locally fabricated
handpumps that are inexpensive to manufacture and can be easily repaired at the
village level with a minimum amount of expertise.
The Waterloo design, developed in 1976, does just this. The piston and foot valve
are produced from polyvinyl chloride (PVC), a material that is readily available in
most developing countries. Their design is such that the piston and foot valve are
interchangeable, i.e., the piston can be used as a foot valve and vice versa.
This greatly reduces the number of spare parts needed for repair or replacement
purposes. Another advantage of the Waterloo design is that it incorporates polyethylene
piston rings, similar in design to those in an automobile engine. These can
be replaced easily when worn. Finally, the design takes advantage of a PVC pipe as
the riser pipe and the cylinder section, the place where the piston slides up and
down, is the riser pipe itself. If this section becomes worn, the piston can simply be
moved to a new position in the riser pipe. A smaller diameter PVC pipe is used for
the piston rod. The above-ground components are of local design, utilizing locally
available materials. These designs vary from the direct-action type demonstrated
by the Sri Lankan project to more complex steel lever-action arrangements
demonstrated by the Thai project. Inexpensive concrete pedestals were used by the
Philippine project, a concept that deserves further investigation.
The technology developed and tested with support from the International
Development Research Centre (IDRC) through these projects clearly indicates
that no universal design will function adequately under all conditions with all user
groups. Moreover, it was not the intent of this research to find such a design.
Although the basic principle of the pump remained the same with all four projects,
there were individual variations and modifications. The results of this research
have brought to light the Tact that this technology, or any other handpump
technology, must first be tested under local conditions and modified according to
the needs and opinions of the user group, environmental conditions, available
materials, and level of expertise of those expected to adopt it and maintain it.
Without this testing, the technology cannot be expected to meet the needs of the
target group and will most probably fail.
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