- Sludge recovery, Wastewater
Castres (Tarn)
Castres: a benchmark for ecological innovation in the Adour-Garonne region
In 2023, SPL Eaux de Castres Burlats awarded Stereau the contract to methanize sludge from the Castres Melou wastewater treatment plant. Innovative solutions have been developed to meet the local authority’s sustainability and energy efficiency challenges. By building a methanization digester at the Castres Melou wastewater treatment plant, Stereau is converting sludge into biogas, thereby producing renewable energy. This initiative marks a new stage in the region’s transition to a greener, more circular economy.
The challenges
- To treat and valorize sludge resulting from wastewater treatment into biogas, which, after filtration, is transformed into injectable biomethane in the GrDF network.
- Controlling the energy and carbon performance of the Castres wastewater treatment plant to support the local authority’s climate-energy strategy.
- A modern, robust and environmentally-friendly facility capable of recovering effluent from 130,000 population equivalents over the next 30 years.
Our solutions
The methanization system designed by Stereau converts sludge from wastewater treatment into biogas, providing a renewable energy source and contributing to more sustainable management of local resources.
Made from duplex stainless steel, a material renowned for its strength and durability, the digester incorporates 60% recycled materials, reinforcing the plant’s commitment to the circular economy. This robust design ensures a longer service life than conventional concrete structures, reducing maintenance costs and environmental impact. The 2,400 m³ digester is equipped with a system for preparing and stabilizing the incoming flow, guaranteeing optimal digestion. Complementary infrastructures, such as an insulated slab and storage annexes for the tanks, ensure safe and efficient management of by-products. Modernized electrical equipment and automation system ensure precise control and high performance.
Benefits
- Reduced wastewater treatment costs thanks to energy recovery from sludge.
- Reducing the site’s environmental impact.
- Improved reliability and performance thanks to the use of a metal digester.
- Adoption of sustainable practices that support the local circular economy.
Other achievements
