French authority Syndicat Mixte pour l’Aménagement Hydraulique (SIAH) for the Croult and Petit Rosne valley region inaugurated the Bonneuil-en-France wastewater treatment plant (WWTP), which treats wastewater from 35 municipalities in the eastern district of the Val d’Oise department. Veolia, via its subsidiary OTV, led a consortium responsible for designing and carrying out the works, and will operate and maintain the plant until 2027.
Worth a total of €199.4m excluding taxes, this decade-long contract has reportedly increased the plant’s treatment capacity from 350,000 to 500,000 population equivalent (PE). By increasing the plant’s treatment capacity and performance, the work will enable wastewater to be used to produce green energy locally. The priority given to reusing existing structures such as biological basins and pretreatment buildings has helped reduce both the construction’s carbon footprint and dependence on fossil fuels, and preserve sensitive natural areas.
The sludge generated by the purification process is used to produce biogas, which is purified using the MemGas process developed by Biothane — a Veolia subsidiary — before being injected into the existing gas network. This renewable green energy source reportedly corresponds to the annual gas consumption of 1,750 new homes heated with gas. The heat produced by the treated water is also recovered using the Energido process to heat the administrative buildings. After treatment, some of the wastewater is reused as industrial water, reducing the pressure on water resources and helping to mitigate the effects of climate change.
The treatment system installed is at its heart the Hybas biological process developed by AnoxKaldnes, another Veolia subsidiary. This process combines moving bed biofilm reactor (MBBR) technology with activated sludge in a single tank, providing a compact solution for eliminating organic matter and nitrogen. This is a worldwide concern since it causes eutrophication of water which is responsible for the proliferation of algae and the deterioration of aquatic ecosystems. The Morée river will be given a new lease of life by improving water quality and restoring its landscape.
Anne Le Guennec, senior executive vice-president, worldwide water technologies at Veolia, said: “Veolia expertise in water technologies [and] energy management transform what was once considered a waste product into a value-creating resource. From wastewater and sewage sludge, we produce biomethane, a local, renewable and affordable energy source — that is the ecology of solutions.”
Veolia has designed a number of wastewater treatment plants that recover wastewater as a source of energy and heat. In France, the Aeris plant at Cagnes-sur-Mer in the Alpes-Maritimes region, in operation since 2021, was said to be the first positive-energy WWTP. The MAERA and SIVAL plants, under construction in Montpellier and Valenton, will also produce biogas to provide 10,000 residents with energy and heat.
