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George Cansdale, who presented BBC TV’s first
zoo programme, ‘Looking at Animals’, devised a way
of obtaining clean seawater for a Skegness zoo by
drawing it through the sand in the beach. He
realised that this idea could be adapted to provide
clean water in developing countries. SWS
Filtration, a firm he set up with his son Richard,
began to make filters for this purpose.
Late in 1981, SWS, based at Hartburn near
Morpeth, sent stainless steel filters to Tim Rous,
a Church Missionary Society engineer, in East Zaire
where people get their water from hillside
springs.
The problem was to protect the spring water from
contamination. Rous devised a technique of digging
a trench up to a spring from the downhill side,
laying a pipe, placing a filter on the spring and
covering it in sand and gravel. Water collects in
the sand and gravel and flows through the filter
down the pipe, supplying on average about 35
people.
Rous established the principle that villagers
should do the work, so that they would see a water
scheme as theirs. The Cansdales insist that a
scheme must be socially acceptable; local customs
must be respected and women must be consulted. It
should also be integrated with better sanitation
and other development work.
Meanwhile, Richard Cansdale had produced an
improved version of the Rower pump, devised by a
Mennonite agency in Bangladesh. This pump, with
plastic body and stainless steel piston rod,
weighing only 4 kg, is designed for raising water
from shallow depths. It is set at an angle. The
operator raises the piston by pulling a handle
towards him. The pump offers a means of drawing
water through a filter when it cannot simply be
collected by gravity.
The pump also enables people to get water
without standing in it and running the risk of
infection with bilharzia parasites.
Cansdale lengthened the pump, making it easier
to use and reducing wear. He also introduced new
and better moulded plastic pistons and check
valves, and synthetic rather than leather seals.
The valves are now more reliable, longer-lasting
and easier to maintain, with no special tools
required to remove or replace them.
The pump’s simplicity makes it easy to explain
how it works and therefore how to maintain it. It
is one of few pumps that a villager appointed as
pump caretaker can maintain without outside help.
It is not especially robust but users can keep it
going because they can repair it.
The British embassy in Zaire,with British aid
funds, bought pumps for dry, savannah areas near
the copper-mining town of Lubumbashi. As a result,
waterborne diseases declined and, with fewer people
sick, farm output rose.
The first pumps were installed at Mtumbwe where
the Zairean water company, Regideso, also provided
two boreholes fitted with handpumps. The Regideso
pumps were harder to use and produced water with a
high mineral content. So, while these remained
idle, the villagers asked for more Rower pumps to
meet the needs of 500 new arrivals drawn to Mtumbwe
by the improved water supply.
Requests came in for filters and pumps from
neighbouring countries and even other continents.
Over 1,000 SWS Rower pumps have been installed in
Cental Africa.
A version of the pump has been developed for the
Blue Nile Health Project of Sudan’s Ministry of
Health. So far the SWS Rower pumps have been made
only in Britain. A workshop is now being set up to
make them in Zambia. Richard Cansdale says that
offering valves specially designed to fit into
standard PVC pipes should make it possible to
assemble pumps anywhere these pipes are made.
Ordering pumps in greater numbers should reduce the
cost of a pump to what a peasant farmer or small
community can afford.
On a World Bank project in Nigeria in 1982,
Cansdale introduced well-jetting as a way of
driving a pipe and filter into the sandy bed of a
dry river so that water can be pumped up from
beneath. A jet of water makes the sand fluid and
allows the pipe to go in. An agricultural scheme in
West Sudan is using well-jetting and Rower pumps to
win water from wadis. Local people dig wells in the
wadis but these fill with sand every year which
must be laboriously dug out again. Jetted wells
offer an alternative. Farmers can often recoup
their investment in a year.
The Rower pump and the well-jetting technique
provide better water cheaply and reliably without
unmanageable technology. They are a first step
towards a water supply of European standard.
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