The risk of algal pollution of water in and beyond the River Seine will be substantially reduced starting next year when a new nitrate-removal system starts up in a Paris wastewater plant, one of Europe’s largest.
Costing nearly $500 million, the project still will eliminate only 30% of total nitrogen from the vast Seine Aval plant. Even in reduced form, the system is one of the world’s largest of its type, according to OTV France, part of Veolia Water Solutions and Technologies (VWST), Paris. OTV leads a turnkey joint venture, nearing the end of a 30-month construction phase, requiring up to 1,200 workers, says VWST’s CEO, Jean-Michel Herrewyn.
Rated at 2.1 million cu m per day, the plant accounts for about 80% of the treatment capacity owned by the Greater Paris wastewater authority, Syndicat Interdépartemental pour l’Assainissement de l’Agglomération Parisienne (SIAAP). Its upgrade is part of a long-term plan, of which one goal is 100% nitrogen removal by 2015.
Short of funds, SIAAP failed to install treatment capacity required by European Union law and was forced by the EU’s Court of Justice to comply, says Maurice Ouzoulias, president.
The new plant will treat up to 45 cu m per sec of flow from the existing unit in two phases. Biological oxidation of ammoniacal nitrogen in the nitrification phase, forming nitrates, will be applied to all the flow. Then, denitrification will remove 30% of the nitrogen.
Nitrification will use VWST’s biofilm technology, which holds bacteria on 55,000 cu m of tiny polystyrene balls in 84 filter beds. Denitrification will use a clay medium system, owned by Degremont S.A. Normally rivals, OTV and Degremont are partners in the joint venture. It includes Vinci Group and Eiffage Group on civil work.