SITA Nord is a subsidiary of Suez Environnement. It has 1,000 employees and its headquarters is in Valenciennes, France(59). Facing the challenges of scarcity of natural resources, the company naturally accelerates its growth course in the business of collecting, sorting and waste recycling and puts sustainable development as a major element of its policies and activities.
SITA NORD – SUEZ ENVIRONNEMENT produces electricity from waste
Energy / Greenhouse Gases (GHG)
- Create a maximum amount of value from waste, including final waste: if it is not recyclable, it can be a source of energy.
- Help reduce the environmental impacts of the site by treating the lixiviats (waste water) by cogeneration, and limiting travel by road tankers
Residual waste disposal at the Installations for Non-Hazardous Waste Storage (ISDND) corresponds to household or business waste remaining after recycling at the source or non-recyclables rejected by recycling centers(refused).
This waste is stored in watertight compartments divided into cells.
The gas from the fermentation of waste (biogas) is recovered through a network of pipes and wells that power the engines. Humidity contained in the biogas is trapped to protect the motors. A compressor is used to direct biogas to the engine operating on the internal combustion engine principle. Each engine is coupled to an electric generator. A transformer then raises the voltage to 20 kV in order to evacuate the production on the local power grid. The export of production on the local distribution network (ERDF) is provided 24 hours a day 7 days a week, for the needs of consumers. On all installations of SITA North and Pas de Calais, biogas is recovered as electricity.
In addition, each cell has a network of drains to collect water (lixiviats) that has percolated into the waste mass in order to be purified. Lixiviats are collected and pumped to a sealed storage basin to be analyzed to be then sent by truck to the external processor.
On the site of Lewarde, SITA Biovalix is developing a new process for lixiviats treatment. It allows the use of the heat produced by the biogas recovery engines for the treatment of lixiviats on the site. All energies are captured and reused by cogeneration. Since July 2011, the leachates have been treated on the Lewarde site and are no longer sent to an external treatment plant.
CONTRIBUTION TO COMPANY PERFORMANCE
- On-site treatment of lixiviats reduces truck transports (less CO2 emissions and inconvenience for local residents). It also secures the treatment system. SITA is autonomous and does not depend on external networks.
- 5 sites produce the equivalent of the consumption of 24,000 residents (a city like Armentières)
Or 4,181,877 teq of less CO2 emissions for 2009
- Treatment of leachates at Lewarde : 500 fewer trucks on the road/year (forecasted)
- On the site of Lewarde (annual forecast) : Electricity produced : 13,980,130 kWe