Desalination in Egypt and the future application in supplementary irrigation

Irrigated agriculture in Egypt consumes about 80% of the Nile's water. Almost ail available conventional water resources have been exhausted. New development requires careful review of water allocations in order to raise efficiencies and protect against pollution. The integrated water policy in Egypt is based on three fundamentals: increase the natural Nile discharges at the upper sources, increase the water use efficiency in all sectors and prevent pollution, include non-conventional water sources, in this paper a general overview of Egypt's present and future water resources is presented. The use of non-conventional water resources is reviewed, with special emphasis on the reuse of drainage water, treated wastewater and possibly simple desalination processes as supplementary sources. An historical review of desalination in Egypt is given and present development status is indicated. Egypt's needs a breakthrough in research and development for irrigation using renewable energy (mainly solar and wind) by a desalination process. A simple integrated system of a solar still and drip irrigation is proposed. The solar still is a low-efficiency desalination process, and drip irrigation using salt-free water is a very high-efficiency irrigation system. Environmentally friendly systems in agriculture have gained high priority in arid and semi-arid countries. The paper proposes a system to be tested in areas where a saline water source is available, there is little rainfall, local land conditions are suitable and little attention for system operation and maintenance is needed. The techno-economic criteria are not the governing factors, but what really matters are the socio-economic aspects.