Olive trees irrigated with treated wastewater, a pilot project to combat drought

In southern Italy's Adriatic basin, water scarcity has become an increasingly pressing issue exacerbated by climate change and the spread of the bacterium Xylella fastidiosa, which has decimated olive groves. The European project ECO FLOW aims to address this problem by exploring the use of treated wastewater for irrigation. Originating from Greek and Italian experts, ECO FLOW focuses on treating wastewater from Gallipoli to remove emerging contaminants, such as chemicals, materials, and biological substances created by human activities.

These substances often infiltrate urban and hospital wastewater, before being reused for irrigation.

The experiment is being conducted in a field adjacent to the Gallipoli water treatment station, where three rows of bacteria-resistant olive trees are being irrigated using three distinct methods: traditional irrigation with water from a well, water treated at the purification station, and water subjected to a specialized treatment designed to reduce the amount of polluting substances.

Rocco Protopapa, of the Regional Agency for Irrigation and Forestry Activities (ARIF) in Puglia, explains that the project's objectives also include comparing the plants irrigated with well water, treated water, and treated water with hydrogen peroxide.

At the Gallipoli purification station, the wastewater destined for ECO FLOW undergoes additional disinfection using a patented technology called RE-WATER. This technique combines hydrogen peroxide with ultraviolet radiation generated by a lamp, resulting in an extremely reactive molecule capable of degrading pollutants. This innovative process was necessary, as such equipment was not previously available on the market.

The reactor where water is treated with this method is thermally insulated to maintain consistent temperatures and maximize the formation of reactive molecules.

ECO FLOW's budget exceeds one and a half million euros, with 75% funded by European cohesion policy and the remaining 25% sourced from Greece and Italy. In Greece, researchers worked on a physical membrane to enhance wastewater treatment and filtration, while in Italy, the emphasis was on developing a chemical solution to address the contamination issues.

The laboratory of the Polytechnic University of Bari is providing technical and scientific support to Acquedotto Pugliese, the project's primary partner in the ECO FLOW experiments. Danilo Spasiano, a professor and researcher at the university, explains that monitoring of the pilot project has recently begun. Their research focuses on water and plant development, as well as soil characteristics and the accumulation of contaminants in the soil where two Xylella-resistant olive varieties, Favolosa and Lecciana, are grown.

Antonio Astuto, owner of the Francesca Stajano farm, produces over sixty tons of olives annually. He irrigates part of his production with water from his well and another younger olive grove with treated water from the Gallipoli purification station. Astuto has observed differences in the growth and productivity of his olive trees, noting that the plants irrigated with treated water have grown faster than those using well water.

Consequently, Astuto is pleased with the results and believes the specialized treatment may contribute to the improved growth of his olive trees.