The Doraleh desalination plant is now operating at full capacity. Tedagua, in consortium with the French company Eiffage Génie Civil, completed the design, construction and commissioning of this seawater desalination facility with the capacity to produce 22,500 m3 of drinking water per day. A five-year operation and maintenance stage for the new facility, built over a five-year period, has now commenced.
This plant is part of the EU PEPER (Producing Safe Drinking Water with Renewable Energy) initiative, which in turn forms part of the “Sustainable Energy for All (SE4All)” initiative of the United Nations General Assembly’s 2030 Agenda for Sustainable Development. The project had a budget of 46 million euros, of which 40.5 million euros was provided by the European Union and 5.5 million euros by the state of Djibouti.
The National Office of Water and Sanitation of Djibouti (ONEAD) was responsible for the execution of the project. The contract also includes the management, operation and maintenance of the facilities constructed for a period of five years.
Djibouti, capital of the state of the same name, has a population of over half a million. Located between Eritrea, Somalia and Ethiopia, in the Horn of Africa, it has a desert climate with very low annual rainfall. The country’s strategic location and its status as a free trade zone give it a special importance in the region. The desalination plant, located on the outskirts of Djibouti, the country’s capital, provides the supply system with a new drinking water resource capable of supplying around 2,500,000 people. The new facility will serve to stimulate development and quality of life in the city.
At full capacity, the plant can produce 22,500 m3/d of drinking water, but the construction work has been carried out in such a way as to enable production capacity to be doubled in a future expansion. All designs have been made with this future expansion in mind, meaning that when it is executed, plant output will not be interrupted.
The plant takes water from the Gulf of Tadjoura through an open intake tower located 425 meters from the shore at a depth of 18 metres. The raw water is piped through a 1400 mm diameter high-density polyethylene (HDPE) pipeline to a pumping station equipped with three submersible pumps. The pumping station is protected by self-cleaning screens with a mesh size of 6 mm.
The plant’s design seeks to optimize energy consumption at all times, so that once the water is pumped at the head of the plant, it does not lose pressure until remineralisation, thus eliminating the need for intermediate pumping. In addition, all the energy required for the operation of the desalination plant will be supplied by a wind farm built nearby, which will reduce energy costs and, consequently, the price of water for households.
Published in: #81 FuturENVIRO June – July 2021