Project design and construction has been awarded to a consortium headed by OTV France Nord, a Veolia Water subsidiary. The consortium comprises Norpac, Demathieu & Bard, Amodiag, Bonnard & Gardel and ALH (Alain Le Houedec, architect). Work will begin in mid-October and will last approximately four years. Operation of the plant will start on 1 January 2011 and Veolia Water will be the operator under a contract of almost six years.

The new plant will have the capacity to treat wastewater from an equivalent population of 620,000. It will have two separate treatment trains, one for wastewater (2.8 m³/second) and one for stormwater (5.3 m³/second). Proven technical solutions will be used, such as the Multiflo and Actiflo settling processes and Hybas biological treatment. OTV’s Exelys thermal hydrolysis process will be used for sludge treatment. It will reduce the quantity of sludge produced by 20-40% and increase the production of biogas by 15-30% compared to a standard digestion. After being dried and stored, half of the sludge will be used in agriculture and the other half in a cement works. Veolia Water’s offer includes full control over odour emissions their treatment and monitoring.

The reconstructed plant is part of a programme to evolve toward sustainable development solutions, and its carbon balance has been established with the ‘Carbone 4’ design bureau. The balance is based on three points: reduce the use of fossil fuels, generate energy and respect Veolia Environnement’s environmental commitments through OTV’s Ecolia 21 plan.