Small scale desalination pilots powered by renewable energy sources: case studies

In Tunisia, water resources are very limited and have high salinities. Domestic water in rural communities has TDS reaching 2750 ppm. Inhabitants of these areas are scattered and lack proper infrastructure for the implementation of conventional desalination plants. However, these regions have an important potential of renewable energy (RE), especially solar energy where sunshine in southern regions can reach 2500 h per year. RE can be harnessed to power small-scale desalination plants in order to produce the fresh water necessary to cover the basic requirements (drinking and cooking). This paper aims to identify the potential of renewable energies, mainly solar and geothermal. It illustrates the quality of distributed water in rural communities. It presents several studies that were carried out, including solar multiple effects distillation, reverse osmosis driven by photovoltaic panels, and lately membrane distillation using a geothermal resource. The experimental results show technical promise. However, more investigations will need to optimise the operating parameters and improve economic feasibility.