New CDE recycling plant for Sodextra SA

French waste-management firm recovers 70% of inert waste with CDE wet processing equipment

WASTE specialists Sodextra SA have invested in a bespoke construction, demolition and excavation (CD&E) recycling plant from CDE, marking a first venture into the wet processing of materials and allowing the recovery of up to 70% of incoming inert waste materials.

Based along the Plateau de Saclay, 15km south of Paris, Sodextra operate a major waste recycling treatment facility that supports local construction firms to deposit and process waste and rubble in the Paris region.

Established in 1975, the waste-management firm has, for over 45 years, facilitated the diversion of significant tonnages of CD&E waste from landfill, assisting in the recovery of a variety of high-value construction materials, including recycled sand and aggregate products, and returning them to the sector for use in major public works and infrastructure projects.

Currently, the third-generation family business recovers one million tonnes of waste materials per annum – a substantial volume it hopes to increase further as a result of its latest investment in CDE technology which is allowing the recovery of inert soil.

For Sodextra, the new 135 tonnes/h CDE waste-recycling plant is producing six sand and aggregate products, and more importantly from a commercial standpoint, opening up new markets for the French recycled aggregates supplier.

Sacha Bottemanne, managing director of Sodextra, said the company’s biggest challenge was treating highly variable waste coming into the facility. ‘We used to screen [inert] soil and recover around 20% of the pebbles which were reused in our crushing plant,’ he commented.

‘The remaining 80% was dumped. We realized that in this 80% there were still materials with high added-value which today, with the CDE installation, we can recover.’

Based on the soil analysis from the Saclay plateau, Marc Sopransi, business development manager at CDE, quickly understood the challenge posed by the processing of the very heterogeneous and heavily clay-bound material.

‘Sodextra approached us to find out how to further recover their inert soil, to find a way to recover more sand and gravel and turn them into high value-added construction materials,’ said Mr Soprasi.

To demonstrate the potential for CDE technology in supporting Sodextra to recover high-grade and high-value products from their waste stream, Sacha Bottemanne and his team were invited to a CDE reference site in Germany to see how the wet processing plant worked.

Mr Bottemanne recalled: ‘We saw the materials that went into these installations, which were of very poor quality, very sticky and full of diverse contaminants such as plastics or roots…[But] we then saw the process and the quality of the materials coming out. That’s why we decided to go with CDE.’

The new CD&E recycling plant incorporates a combination of CDE signature modular technologies, including the AggMax modular logwasher for scrubbing and sizing.

Also supplied is CDE’s flagship EvoWash sand classification and dewatering systems with integrated patented technologies, including the company’s Infinity screen and counter-flow classification unit (CFCU) for density separation, which efficiently separates materials of differing specific gravity to maximize the quality and value of feed stock.

Marc Sopransi said the sand treatment solution engineered for Sodextra is unique. ‘It consists of a first cyclone pass, attrition cells, a second cyclone pass, a hydraulic classifier, and a third cyclone pass with two major classification points placed at 250 microns and 2mm,’ he explained.

‘This sand treatment provides a dynamic response to a dynamic problem. And the type of sand treatment in this application is a first in Europe.’

The solution developed for Sodextra not only allows for the recycling of CD&E waste, but it also maximizes water efficiency with CDE’s AquaCycle – a highly efficient water-management solution that minimizes costly water consumption by ensuring up to 90% of process water is recycled for immediate recirculation.

Designed to maximize profitability at Sodextra, the new CDE waste-recycling plant is processing material that was once destined for landfill and producing a range of products, including three different sands: a fine sand (0–250 um); a 0–2mm; and a 0-4mm; as well as three different aggregate products: 4–10mm, 10–20mm and +20mm, all ready for use in construction projects in the Paris region.

A filter cake product created by an integrated CDE filter press can also be reused as a waterproofing layer or for pipe bedding and landfill capping.

‘Today, the CDE installation allows us to recover 70% of the waste and to create new materials that are reused in construction sites throughout Greater Paris,’ said Sacha Bottemanne.

‘The CDE plant produces high-quality aggregates that we now call ‘eco-gravel’ or ‘eco-sand’. These are very high-quality materials that are similar to natural materials.’