Desalination Projects in Tunisia: Fresh Water at What Cost?
Introduction: A Nation Running Dry
Pressure to find sustainable solutions is mounting in Tunisia, where the average annual water consumption per person has dropped to its lowest rate. One of the country’s most ambitious responses is the construction of desalination plants, designed to convert seawater into potable water. But while these plants promise relief for water-scarce regions, they come with steep economic, environmental, and social costs.
A Solution for Djerba: Balancing Tradition and Technology
On the southern Tunisian island of Djerba, a seawater desalination plant currently produces 50,000 cubic metres/day with plans to increase this capacity to 75,000 cubic metres/day, aiming to cover the entire water needs of the island. The plant is a crucial part of Tunisia’s comprehensive water management strategy and has alleviated the severe water deficit that south-eastern governorates have experienced in recent years, where water outages are frequent and costly for the region’s residents.
Faten, a 50-year-old housewife from the region of Ghizen, shares her perspective on the plant’s impact. “It has increased water pressure and reduced summer water cuts,” she says. Yet, despite these improvements, Faten still relies on her traditional fasqiya (a rainwater cistern) for drinking water, using tap water only for cooking. On Djerba, traditional fasqiya water cisterns have ensured a supply of water during the island’s dry summers for hundreds of years, with evidence that they evolved from Roman water management strategies. The fasqiya collect rainwater from roofs and courtyards that have been whitewashed with quicklime and channel the water into large underground cisterns. The fasqiya play an essential role in the supply of water , providing a reliable resource during times of droughts and water scarcity.
For Faten, desalination did not replace the fasqiya but works in conjunction with traditional approach.
Desalination Technologies: A Nostrum for Tunisia’s Water Needs?
Tunisia is betting on desalination projects to revive its scarce water resources, which have been severely impacted by the combined and water-related challenges like climate change, urbanization, poor water management and water-intensive agriculture.
These factors have plunged the country into severe water stress as the average annual water consumption of water by person has dropped to 460 cubic meters, below the global water poverty threshold of 1,000 cubic meters with around 70% of its population living near the Mediterranean but struggling with diminishing freshwater supplies.
Recent years have seen the Tunisian government ramp up desalination efforts. Two new seawater desalination plants have been inaugurated this year. The first, Zarrat, is in a city on the southern coast producing approximately 50,000 cubic metres/day for the southern governorates of Gabes, Mednine and Tataouine, as well as 100,000 cubic metres/day directed towards Sfax. A second plant is in Sfax and is expected to open before the end of the year and will have a production capacity of 50,000 cubic metres/day.
The Zarrat project, which will benefit some 1.1 million residents in the south, is part of the broader strategy of Tunisia’s National Water Exploitation and Distribution Company, which seeks to ‘strengthen water resources in the southeast and secure their supply by the year 2035’.
Tunisia’s desalination strategy developed slowly over the years. In 1983, a model plant was constructed on the island of Kerkennah, followed by a groundwater desalination plant in the city of Gabes in 1995. However, it wasn’t until May 2018 that widely available desalinated water became a reality, with the opening of a plant on Djerba at a cost of approximately 200 million dinars.
Despite Tunisia’s slow uptake of modern desalination technologies it has a long history of experimenting with solar desalination techniques. In 1927, a device was designed to desalinate water using solar evaporation and two devices supplied potable water to French military forces.
A chief reason for Tunisia’s slow adoption of desalination technologies is the high iron content of its groundwater resources in much of the country. This increases costs, reduces efficiency and requires more complex desalination technologies.
After years of political skepticism around the economic and technical viability of desalination projects, the Tunisian Water Exploitation and Distribution Company recently concluded that desalination “ is the only solution today in the Middle East and North Africa region to secure new water resources”.
Tunisia’s seawater desalination plants, along with 15 other groundwater plants, now contribute to around six percent of the country’s total potable water supply. The Tunisian government aims to increase this contribution to 30 percent by 2030.
However, Tunisia’s decision to prioritise its desalination strategy over other water storage, transportation and saving strategies may overlook practical and locally-based solutions to water scarcity. Alaa Marzouki, an expert at the Tunisian Water Observatory, notes that improving network maintenance, encouraging household water saving strategies and the rationalising consumption in the agricultural and industrial sectors could effectively address Tunisia’s water crisis and reduce reliance on expensive, imported desalination technologies.
The Hidden Costs: Energy, Economy, and Ecology
Economic Strain
The current cost of desalinating one cubic metre of water is three Tunisian dinars, equivalent to one dollar. This is three times the cost of a cubic metre of water from Tunisia’s reservoirs. Behind these already significant economic costs lie a series of social, political and ecological costs and considerations.
Historically, the Tunisian Water Exploitation and Distribution Company has shielded Tunisian citizens from the true cost of water. The Company sells to the consumer at 200 millimes per cubic metre (about 70 cents), while the state has traditionally subsidised the difference through its compensation budget. However, in recent years, this compensation has been less forthcoming leading to financial deficits for the Company that now exceed 860 million dinars. Following regular demands from the Company to review water prices, in March 2024, the Tunisian government raised drinking water prices by up to 16 percent. The increases were justified in terms of the country’s past five years of drought.
Energy-Intensive Technology
Desalination technologies require substantial energy; currently energy costs account for around 40 percent of the expense associated with producing a cubic metre of drinking water in Tunisia. While desalination plants globally supply less than 1 percent of the world’s water needs, they account for a quarter of energy use in the global water industry.
In Tunisia, the energy balance related to desalination is expected to worsen due to Tunisia’s severe energy deficit crisis. A study conducted by a group of Tunisian researchers found that electricity consumption by the seawater desalination plant in Djerba represents around 14 percent of the total energy consumption in the region. Moreover, Zarrat’s seawater desalination plant employs reverse osmosis technology, a notoriously energy intensive technology that uses filtration to remove impurities from water as it passes through a membrane at pressure. Currently, reverse osmosis plants consume more than 13 kWh for every thousand gallons produced. The requirement for water pretreatment, along with the use of specialized equipment and membranes, raises these energy costs even more.
In response, the Water Exploitation and Distribution Company is currently exploring alternative energy sources, particularly solar, in an effort to reduce energy costs.
Environmental Concerns
In addition to the significant economic and energy costs associated with desalination, there are also concerning effects on coastal marine environments. According to a 2019 United Nations Global study on the desalination industry, 1.5 litres of brine are produced for every liter of fresh water, and it is estimated that the Djerba desalination plant alone expels 58 tons of saline solution per day. Despite pressing issues, there are worryingly few studies on the impact of desalination projects on Tunisia’s coastal ecology.
Tunisia is grappling with a long-standing waste management and marine pollution crisis as desalination plants could further accelerate the ecological collapse of its fragile coastal ecosystems, including its globally significant sabkha, or mudflats. Without comprehensive environmental impact assessments on desalination projects in Tunisia, ecological damage wrought by desalination may go unnoticed and unreported.
Environmental activists in Tunisia have called for the monitoring of desalination effluence and legal protections to safeguard the marine environment. Additionally,there have been suggestions to repurpose the byproducts of desalination (such as sodium, magnesium, calcium, and potassium) into valuable inputs for industrial and agricultural processes instead of discharging them into the sea. For instance, in the UAE, scientists have successfully conducted experiments using brine to grow halophytes (salt-loving plants) on both coastal and inland demonstration farms, showing evidence of improved yields.
Although there are a number of environmental NGOs and associations operating in the region, research on tourism and environmental health in Djerba has shown that environmental monitoring pertaining to conservation issues is still insufficient. This is concerning because Djerba features important ecological niches, such as wetlands colonized by a rare species of the Mediterranean clam called Pinna nobilis and frequented by pink flamingos, as well as relic zones of Posedonia meadows that serve as habitat for grey cranes.
Hydrogen: A Hidden Driver of Desalination?
In October 2023, the Tunisian government released its national green hydrogen strategy, developed in partnership with Germany’s development agency, GIZ. The strategy consists of four key pillars: produce 8.3 million tonnes of hydrogen per year by 2050; modernize Tunisia’s energy infrastructure; promote the use of green hydrogen in industrial sectors; and increase green hydrogen’s use in the transport sector and electricity production.
As noted by environmental activists and development experts, Tunisia’s hydrogen strategy is strongly export-oriented, with hydrogen packaged as a means to fulfill Europe’s energy needs. At the same time, hydrogen production requires extensive amounts of both land and water resources, such as land for large solar farms and water to split into hydrogen. Environmental campaigners in Tunisia have posited that the country’s decision to ramp up its desalination production is not primarily driven by domestic needs; instead, it’s a response to the anticipated significant water requirements of large-scale hydrogen production.
It is estimated that desalination plants with a throughput of 160 million cubic metres per year will be needed to quench the water needs of Tunisia’s hydrogen production. This is equivalent to the annual consumption of 400,000 Tunisians. All that being said, experts agree that given Tunisia’s acute water crisis it will be forced to pursue its desalination strategy regardless of whether its hydrogen agreements with Europe come to fruition.
Lessons from the Past: Combining Old and New
To ensure that desalination projects benefit the local community, it is important to ensure best practices at every stage of the desalination chain, including its inputs, processes, and outputs. First, Energy inputs must be thoroughly assessed and there should be a move towards green energy sources to power the desalination process. However, this transition must not compromise the energy needs of local populations. Second, the location of desalination plants and how they will impact the local environment, societies and livelihoods must be properly assessed.
Third, and As Hamza Elfil, the head of the Laboratory of Nature Water Treatment (Lab TEN)), recommended, waste outputs, including brine and chemical additives, must be properly tested and Tunisia must implement disposal methods that protect its coastal ecology.
Moreover, desalination processes cannot be primarily oriented towards Tunisia’s hydrogen industry. This is likely to lead to an extractive relationship with resources, degrade local environments and leave Tunisians disenfranchised from water resources and their conservation.
Finally, desalination technologies should be viewed as complementary rather than a replacement for older water management strategies and technologies. Tunisia possesses a rich history of water infrastructure that can be modernized and integrated with desalination plants, from ancient household water storage systems to the dam-building initiatives established under Habib Bourguiba.
Conclusion: The Road Ahead
Desalination technology has become standard across much of West Asia and North Africa and is widely seen as the most viable means of navigating the region’s severe water stress. Tunisia has been a relatively late adopter of desalination and with this comes both benefits and risks.
The benefits include the technology now being low risk, low cost and with proven viability in other states that were earlier adopters. However, this creates the risk that Tunisia becomes a dumping ground for poor quality and environmentally destructive desalination technology and practices as multinational companies seek to make a cheap profit.
Therefore, to ensure these projects serve the nation’s needs, they must be rooted in sustainable practices, prioritizing local communities and ecosystems over short-term profits or international hydrogen deals.
As Tunisia navigates its water crisis, the country must draw on its rich history of water management while embracing innovative technologies. By balancing tradition with modernity, Tunisia can build a resilient water future that quenches the needs of its people and protects its fragile environment.