In the sun-scorched heel of Italy's boot, the coastal town of Gallipoli has become an unlikely laboratory for a continent-wide struggle against a hidden threat: the pharmaceutical and chemical residues that survive conventional wastewater treatment. Here, under an EU-funded initiative called ECO FLOW, scientists are testing how to rid treated water of substances that have slipped under the regulatory radar for decades.
The choice of Puglia is no accident. Danilo Spasiano, a professor and researcher at the Polytechnic University of Bari, explains that the region's geography makes it a perfect stress test. "Puglia is a unique region, above all because of its geographical location," he says. "It is characterised by a semi-arid climate. There are no mountains, no rivers, no lakes. The only water resources available in Puglia are the scarce aquifers, but they are being rapidly depleted, especially in the Salento area."
As coastal aquifers become increasingly brackish, the water that reaches farms and homes is altering soil chemistry and threatening agriculture. "The water that is currently used, especially in coastal areas, is increasingly brackish, which can have important consequences for agriculture and the environment," Spasiano notes. The region's dependence on a dwindling resource makes it an ideal proving ground for a circular approach to water management.
Two goals, one project
ECO FLOW pursues twin objectives. The first is behavioural: convincing farmers and residents that treated wastewater from municipal plants can be a safe, reliable alternative to overstretched aquifers. "We are trying to convince farmers and citizens that the reuse of effluents from a treatment plant can constitute an alternative source of water supply," Spasiano says.
The second is technical: eliminating so-called emerging or recalcitrant pollutants. These are the residues of modern life—drugs, endocrine disruptors, cosmetics, non-stick coatings, pesticides, and microplastics—that began appearing in water samples around the turn of the millennium. Conventional treatment plants were never designed to catch them, and they now pose a growing risk to ecosystems and human health.
Spasiano points to a regulatory driver: Directive 2024/3019 of the European Union, which mandates that these pollutants be removed from treatment plant effluents, even when the water is not reused for agriculture but discharged directly into the environment. The directive names specific compounds, including diclofenac, an anti-inflammatory; carbamazepine, used to treat epilepsy and bipolar disorder; and various antibiotics.
"Science and research must anticipate the coming regulations and, above all, collaborate with the bodies in charge of developing them," Spasiano insists. The project is designed to generate the evidence that policymakers will need as they turn the directive into national law across the EU's twenty-seven member states.
The challenge is formidable. These pollutants are present in minute concentrations, often at parts per billion, yet they can disrupt hormonal systems and contribute to antibiotic resistance. Removing them requires advanced oxidation processes, activated carbon filtration, or membrane technologies—methods that are energy-intensive and costly. The ECO FLOW team is testing a combination of approaches, tailored to the semi-arid conditions of southern Italy.
Gallipoli's role is symbolic as well as practical. The town, known for its baroque architecture and turquoise waters, draws thousands of tourists each summer, putting extra strain on its water infrastructure. If the project succeeds here, it could offer a blueprint for other Mediterranean regions—from Spain's Costa del Sol to Greece's islands—that face similar water scarcity and pollution pressures.
The stakes extend beyond Puglia. As climate change intensifies droughts across southern Europe, the reuse of treated wastewater will become an increasingly vital part of the water supply. The EU's rain gardens may help manage floods, but for arid zones, the answer lies in closing the loop on every drop.
For now, the researchers are focused on the science. But they are also aware that public acceptance is as crucial as technical efficacy. "We need to show that this water is safe, not just in the lab but in practice," Spasiano says. The project includes demonstration sites and outreach to local farmers, who are often sceptical of treated effluent.
If ECO FLOW meets its goals, it could help shape the EU's approach to water reuse for years to come. And Gallipoli, a town more famous for its beaches than its laboratories, would have earned a place in the history of European environmental policy.
