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Exploitation of geothermal water in agriculture (in Tunisia): Heating and irrigation of greenhouses

El Mandra, Tunisia

Abstract

Tunisia is a country in north Africa, has many sources of energy or they are well exploited in agriculture (solar, wind, geothermal…). Agriculture is important sectors for the economy of Tunisia, where it provides the main source of livelihoods for the majority of the poor.
The use of geothermal energy (> 80 °C) in Tunisia is limited to direct application because of the low enthalpy resources, which are localised mainly in the southern part of the country. In Gabes, most of the resources are utilised for irrigation of oases, heating greenhouses and used in bathing. Geothermal energy is also a prime source for heating greenhouses, soils, and water for fish farming. However, it is available 24 hours a day, 365 days a year making it more convenient to access than solar especially at higher latitudes that receive less daylight.
The geothermal water will heat the greenhouses in the cloud weather (day or night) until become 30 degrees Celsius or more, then poured into fish ponds that will be rich in nitrogen from fish waste, these waters will drain and irrigate the culture (tomatoes, cucumber, melon) to have a semi-closed circuit and zero waste of water. This commitment is based on the values of sustainable development of the three following axes: energy saving, water management, waste management.
The geothermal water is using too in bathing, and many of the geothermal manifestations in the country have the name of ‘‘hammam’’ or bath. So, near the greenhouses and fish ponds there are space for camping and relax in “hammam”.

Keywords: Fish ponds, geothermal water, greenhouses, sustainable development

Contact Address: Faouzia Smiti, El Mandra, Tunis, Tunisia, e-mail: mandra.ccfagmail.com