Chemical and bacteriological composition of treated wastewaters for grapevine drip irrigation–first results

Abstract

Nowadays, treated wastewater is considered in a lot of countries as a growing alternative resource of water. Although the wastewater reuse remains currently a very limited practice in France, its development in region like Languedoc-Roussillon submitted to high water stress appears to be essential to secure and make sustainable regional agriculture such as viticulture.

Within this context, a cooperative research project ‘Irri-Alt’Eau’ has been launched in 2013 to develop a rational, competitive and sustainable practice of drip irrigation on grapevine with treated wastewater where the quantity and quality have been controlled.The expected results are to demonstrate the harmless of treated wastewater on grapevine, vine and environment, the performance of the implemented process and the benefits on the grapevine production. To conclude, the results should enable to deploy the validated technology and contribute in the development of wastewater reuse in France. Therefore, a tertiary pilot of treatment with prefiltration, UV disinfection and chlorination has been connected at the outlet of a wastewater treatment plant located in Narbonne Plage in order to irrigate two experimental vineyards on INRA Pech Rouge in Gruissan, France. An analytical survey was carried out on treated wastewaters during two irrigation campaigns (2013 and 2014) as well as a detailed monitoring on vineyards irrigated with agricultural water and drinking water.

With treated wastewater, the results showed the compliance with French standard (NOR: AFSP1410752A) for all physicochemical parameters, Escherichia coli and Enterococci fecal, the absence of both disinfection byproducts and metallic micropollutant and very small quantities of pharmaceutical pollutants. Microbiological analysis with PCR has permitted to evaluate the impact of wastewater transport, in comparison with water quality outlet pilot. No bacterial regrowth was observed between the pilot outlet and the vineyard and no human pathogens were detected in produced vine.