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INTRODUCTION
The Lille Metropolitan Area is in Northern France. It covers 61,000 hectares and has a population over one million. The old Marquette-Lez-Lille Wastewater Treatment Plant (WWTP), built in 1969, served local residents for more than 40 years but was no longer meeting current environmental standards, particularly in terms of nitrogen and phosphorus removal. Because of this, it became necessary to upgrade this facility in the area, in a sustainable and efficient manner.
Veolia Water was awarded the contract to reconstruct the Marquette-lez-Lille WWTP in 2010, including designing and building the plant, administration building, and landscaped areas, as well as 5.5 years of operation. The new treatment plant is built on the site of the previous one, which is now obsolete, and will meet the requirements of the European Water Framework Directive (Directive 2000/60/EC) on ‘good ecological status' of water.
There are two separate treatment trains in the water line in the new plant, one for wastewater (2.8 m3/s) and the other for stormwater (5.3 m3/s). Stormwater will be treated using the patented Actiflo® ballasted flocculation process, while the wastewater will be treated successively by a series of proven technical solutions:
Multiflo™, a lamella settler used as the primary treatment for suspended solids removal;
Hybas™, a biological treatment hybrid technology combining the best of two well- known technologies: activated sludge and AnoxKaldnes MBBR; and
Hydrotech Discfilters™ used as tertiary treatment to polish the effluent.
For sludge treatment, the implementation of Exelys™, a new thermal hydrolysis process (THP) from Veolia, will reduce the quantity of sludge produced by 20-40% and increase the production of biogas by 15-30%, compared to standard digestion. After being dried in a BioCon™ dryer and stored, half of the sludge will be used in agriculture and the other half in a cement works.
As the WWTP is located in a densely populated urban area, particular care has also been taken in dealing with odors. Full control over odor emissions, treatment, and monitoring is provided by the dedicated odor treatment lines to minimize nuisance.
By integrating the most compact solutions, reducing the use of fossil fuels and generating energy, a sustainable approach was achieved to turn waste to energy and reduce the plant's carbon footprint.
MARQUETTE-LEZ-LILLE WWTP
The new WWTP will have the...