Every drop of water counts in the desert
Posted on June, 21st 2016.
Two treatment plants in Abu Dhabi treat the Emirate’s growing amount of wastewater and recycle it for agricultural and industrial purposes.
The United Arab Emirates has one of the most dynamic economies in the world. Growth, which accelerated in the 1990s, has been accompanied by a population boom and a dazzling amount of urban development. In the Abu Dhabi Emirate, which covers 90% of the territory, the population is expected to reach somewhere between 3 and 5 million by 2030.
How can all this development be achieved either without any water or with so little? How can the people be supplied and the needs of agriculture and industry be met while also pursuing a sustainable development objective ?
In order to not only survive but also thrive in the desert, people have always had to adapt - they create oases. But now they build environmentally friendly cities and futuristic installations among the sand dunes. The ISTP2 (Independent Sewage Treatment Plant) project, in which Veolia is major partner and stakeholder, is a good example of this tremendous adaptability.
Developed under a BOOT (Build – Own - Operate - Transfer) contract, the ISTP2 includes two treatment plants with a combined processing capacity of 430,000 m3 of wastewater per day, built in the Abu Dhabi Emirate: the Al Wathba plant, located 40 km southeast of the capital, and the Al Hamah plant, near Al Ain.
The project has two objectives: to process the increasing volume of wastewater from the two cities, and reuse 100% of the treated water for agricultural and industrial purposes, thus covering some of the needs currently being met by desalinated water - which is very expensive to produce and requires large amounts of energy.
The wastewater takes a complex route. It first undergoes pre-treatment, which involves getting rid of the bulky waste as well as any sand, gravel, and fat. Then comes the primary treatment, which removes most of the suspended solids using the MULTIFLO ™ method developed by Veolia.
Secondary treatment substantially reduces the amount of BOD5 and ammonia, two organic pollutants; it includes an activated sludge method (aerobic purification system) and a clarification process. Finally, a third treatment, which includes filtration and disinfection, meets the regulatory standards for recycled water quality.
This process, optimized at every step to reduce its carbon footprint, not only produces water for irrigating fields, parks and forests, but also sewage sludge or "biosolids" (up to 22,000 tonnes per year), which is used as an organic amendment to improve the quality of agricultural soils. Using this sludge - naturally rich in organic matter - as fertilizer (nitrogen, phosphorus, potassium) reduces both the need for irrigation and the use of chemical fertilizers.
Every drop of water, even "used", counts in the desert, and people continue to innovate in order to maintain and improve the oases around which life is organized. Just like in the Al Wathba and Al Hamah plants.
Main picture: Phototheque VEOLIA - Stephane Lavoue