Small scale desalination Madagascar

Primarily, the potential application of this desalination system is as stand-alone unit in small and remote villages. Especially coastal communities often face problems with high salinity levels of their drinking water sources. Once further developed, it can be expected that the system can also work for larger schemes as an alternative for large and expensive reverse osmosis units.

Goals overview

To make small scale desalination feasible for rural communities, new options need to be considered as the existing options are just too expensive. To achieve this goal, PRACTICA has started working on a small scale cyclic evaporation unit that uses solar hear to convert saline water in safe drinking water. PRACTICA wants to further develop this concept and test a prototype in Ambazoa, Madagascar.

Current status

Lack of rainfall, deep groundwater and climate disruption are just some of the causes of water shortages in Southern Madagascar: Large parts of the population in the South does not have access to safe drinking water. And even where there is access to water, the water is often too saline for human consumption (in the Ambazoa area, conductivity levels average around 8.000 μs/cm with 3.000 μs/cm being the upper limit for drinking water in Madagascar). However, as there are hardly any alternatives, people have no other choice than to drink this water.
Technology options to desalinate the water are costly in both investment as recurrent costs and are thus out of the scope of the rural communities. It is for this reason that PRACTICA has started working on small scale and low cost options for desalination of water.

Project plan

Already 12 years ago PRACTICA has done some conceptual work on developing a small scale cyclic evaporation and condensation desalination system that uses air as a carrier to extract fresh water from saline water. The heat needed for evaporation of the water is generated by solar panels. The big advantage of this system is that the solar heat used for evaporation of the water is regenerated and fed back into the system. This results in a smaller solar collector surface needed to add heat to the system, making the whole system much smaller and more economic than traditional solar still systems.
The cyclic evaporation and condensation system has the big advantage that the expected water production is 5-10 times more than conventional solar still systems. This reduces the size and the costs of the system. Also the system requires less maintenance and less specialized technical knowledge than common reverse osmosis systems.

The major problem with the new desalination system is that there is no good information about the feasibility. First step within the process is to develop a theoretical model, to conduct full laboratory testing and to come with recommendations about the feasibility of the system. PRACTICA wants to employ a research student to conduct the work. This can be scheduled for the first half of 2009. The research work should include:
- A desk study to find out the state of art of different desalination systems;
- Developing a theoretical model to confirm the feasibility of the concept and to learn the physical constraints;
- Building a prototype of the system on laboratory scale;
- Conducting basic tests on the system to confirm the theoretical model;
- Conducting extensive tests on the system to predict practical applicability in field situations;
- Start field testing with the unit;
- Expand field testing and/or implementation in the South of Madagascar if feasible.

Expected outcomes

• Get proof of concept of the small scale desalination device
• Build a prototype and lab-test the prototype in Papendrecht
• Install and test the prototype(s) in Madagascar
• If feasible, install another 4 systems in South Madagascar
• Have the concept ready for large scale implementation

Sustainability of the programme is directly related to the results of the prototype testing and field testing. If feasible, PRACTICA will put effort in publication and further distribution of the results to make sure the technology is known and available for all. Besides, PRACTICA will seek additional funding to continue implement desalination devices in Madagascar and other countries.
All the technologies PRACTICA develops are in the open domain, which means that the technologies are open to use for anybody who wants to serve the same goal as PRACTICA: to reduce poverty by improving the technical means.