At - affordable technologies
AT-Affordable Technologies for Water Supply
A number of Affordable technologies, that are being introduced in various programs and projects by Arrakis and Institutions working in the same field as Arrakis, are described hereafter. It concerns:
- Hand rope pumps;
- Brick cement tanks;
- Siphon filters;
- The Baptist well drilling technology;
- Wind rope pumps;
- Low cost irrigation systems;
- Well recharge systems.
The technologies related to the needs.
The technologies introduced are instrumental in fulfilling the following basic needs of the population in rural areas at very low, affordable costs:
· The need of water for small-scale agriculture; · The need for clean drinking water; · The need of sufficient water in the wells.
· The need of water for small-scale agriculture;
· The need for clean drinking water;
· The need of sufficient water in the wells.
For making low cost tube wells, the Baptist drilling method is used which is a manual drilling technology developed and used in South America.
The hand pump type introduced is the hand rope pump, that has the advantage that it can be produced and maintained with locally available skills and materials.
AT irrigation systems
One of the simplest systems for small scale low cost irrigation is the satellite tank irrigation system.
For the need of clean drinking water, siphon ceramic filters are introduced, which can be used at the point of use.
Description of the AT-Affordable Technologies
Hand rope pumps.
The hand rope pump is a positive displacement pump, in which water is lifted by an endless rope with a chain of washers, that is driven by hand in a circular movement of a handle, instead of the up and down movement of a conventional hand pump. It is generally used to depths up to 35 m. It produces a constant output, unlike the pulsating flow of a conventional piston pump, and has a good efficiency.
Brick cement tanks for storing the pumped water are a low cost option compared to the usual heavy all-concrete tanks. They are built from bricks and cement using only simple steel wire for reinforcement around the outer rim. They vary in capacity between 2 and 10 m3 and have to be placed on a compact bottom.
Siphon filters A siphon filter is a treatment system at the point of use for water coming from contaminated sources, such as rivers, ponds, contaminated wells, etc. It consists of a high quality ceramic filtering element with a hose, bulb and a non-return valve. This combination produces 20 to 40 litres safe drinking water per day.
A siphon filter is a treatment system at the point of use for water coming from contaminated sources, such as rivers, ponds, contaminated wells, etc. It consists of a high quality ceramic filtering element with a hose, bulb and a non-return valve. This combination produces 20 to 40 litres safe drinking water per day.
SODIS stands for Solar Disinfection. It uses sunlight to inactivate harmful micro organisms in water almost completely. Transparent plastic (PET) or glass bottles filled with contaminated, but clear, water are exposed to the sun for 6 hours in sunny weather or two days in cloudy weather. If a temperature of 50 degrees Celsius is reached, an exposure time of one hour is sufficient. The initial costs are very low, since plastic bottles can be re-used.
The Baptist well drilling technology
The Baptist manual drilling technique has been developed by the missionary Terry Waller in Bolivia. It can drill in sand and compact clay layers up to a depth of 60 meters.
The wind rope pump
The wind rope pump has been developed in Nicaragua by Henk Holtslag and is produced and sold by the workshop Aerobombas de Mecate (AMEC) in Managua, which started production in the beginning of the nineties and until now, has delivered and installed about 400 systems.
Low cost irrigation systems
Irrigation by means of drip irrigation, where water is only applied to direct surroundings of the plant, is an efficient way of using water. Trials have shown that, depending on the crop, drip irrigation uses 10 times less water than flood irrigation.
Well recharge systems
Many wells in Africa dry up at the end of the dry season, because more water is taken out than is coming in by natural recharge. Problems with recharge are: compact topsoil layers, run off rain due to loss of vegetation, increasing erosion, etc.
There are many ways to increase the recharge of groundwater such as underground and above ground dams, planting trees or Vetiver grass that have long roots.
CWD was a Dutch organisation that developed and transferred the technology of wind pumps to developing countries. It was closed in 1990, but many CWD-innovations have been introduced in wind pumps worldwide.