Vines irrigated using waste water from tourists

he Irri-Alt'Eau project is upping the ante. After a test phase at INRAe Pech Rouge, 80 hectares of vines will be irrigated with wastewater and reprocessed water from the Narbonne-Plage wastewater treatment plant this summer. “Everything is ready at Pech Rouge’s 45-hectare vineyard”, says research engineer Hernan Ojeda, who has been overseeing experiments since 2013. Members of the Gruissan and Coursan co-operative wineries now have to connect the main pipes to their vineyards and install the drip irrigation systems.

After initial trials this summer, the project’s partners will be fully operational in 2022. The treatment facility next to the Narbonne-Plage plant will not be able to supply a larger area. “It can treat 50 m3/h. We had initially considered reusing water from the larger Gruissan plant, but its salinity level would have required additional treatment”, adds Ojeda. Before reaching the vineyards, the water passes through a 50-micron mechanical filter, then is disinfected with UV and chlorinated with bleach. Since 2013, the partners have carried out numerous chemical and bacteriological analyses to ensure that the water comes out of the process with a minimum quality of level C, required for irrigation.

“We found that we often obtained a better sanitary quality than for agricultural water, which is not regulated”, says Ojeda, adding that the technique also entails significant cost-cutting on fertilisers.

The technicians have checked that the process is harmless for the end wines, both their physical and chemical composition and their taste profile. The winegrowers who use the system will pay about 0.70 euro cents per cubic metre of water. “The price is halfway between agricultural water, to which we do not have access, and drinking water”, concludes Ojeda.