IBM Award for Sustainable Development
SWS Filtration Ltd
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, Africa, 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, Africa, 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.
See also Nigeria Resources