Water & Wastewater Treatment Magazine
Issue link: https://read.utilityweek.co.uk/i/801555
Project focus Water treatment An innovative solution to the metaldehyde challenge Project focus I t will be well known to readers of this magazine that the issue of micropollutants and the challenges of drug residues in water are regularly in the news. The toxic effect of these persistent compounds on the environment, even in low concentrations, and the contamination of underground water resources, is becoming a key issue for water operators to solve. health concerns, drove Saur Group - the international utility group which operates a wastewater treatment plant in Glasgow for Scottish Water - to push hard to deliver an innovative solution which met both the regulatory limits and client concerns. The resultant CarboPlus technology has been introduced in over 20 sites, providing excellent quality of water while meeting rising needs. The most recent installation is at one of Saur's largest drinking water sites at Basse-Goulaine, near Nantes in France. The site, operated by Saur since 1952, currently handles 72,000 m 3 /day running continuously to provide drinking water to 405,000 inhabitants. The raw water pumping station at the plant is positioned on a tributary of the Loire river and the catchment area contains significant areas of intensively farmed land. As seen in many similar catchments, evolution and changes in agricultural practices has seen increased levels of pesticides entering the ageing plant. The surface water is also characterised by low organic matter, and high concentration of metals. The scope of the project at Basse-Goulaine was to achieve new tightened limits of individual pesticides and of total pesticides, while increasing water production to supply the growing population in the area. Seamless Installation Basse-Goulaine is a significant water plant in the region and while a key project objective is to reduce pollution for local drinking water, continuity of operation is an equally critical requirement for the client due to the constant water demands. This presented the project team with the challenge to install and commission the CarboPlus technology without compromising the running of the plant. Work started in January 2014, with the site clearance and earthworks for the installation of seven CarboPlus tanks, each with a capacity of 500 Following improved ability to detect trace compounds, regulation in the form of the October 2015 European Commission directive 98/83/EC has tightened water quality standards. The updated list of monitored substances in the directive defined a limit concentration on drinking water of 0.1 µg/L for individual pesticides and of 0.5 µg/L for total pesticides. This, together with increasing public The Saur plant at Basse-Goulaine under construction ● CarboPlus filter technology installed at treatment plant near Nantes ● Removal hits tightened European limits on pesticides ● Seven tanks installed and flow increased in new process stream FrederIc carbonnIer Plant DiRECtoR SauR GlaSGow www.wwtonline.co.uk | wwt | aPRil 2017 | 27 ● Tightened consents of 0.1 µg/L for individual pesticides and of 0.5 µg/L for total pesticides ● Intensive farming practices meant seasonal peaks of metaldehyde use ● Water production needed to increase to supply a growing population • Drivers