5.3 m³/h
Sludge dewatering capacity at 1 cycle/h
Quarries & Aggregates
Limestone
Belgium
Carrière de Leffe (Holcim Belgium)
Integration of a sludge-dewatering system to replace natural drying, reduce freshwater demand and support closed-loop water management in a protected natural area.
10.6 m³/h
Sludge dewatering capacity at 2 cycles/h
15.9 m³/h
Sludge dewatering capacity at 3 cycles/h
Carrière de Leffe (Holcim): modern quarrying in a protected natural area
Carrière de Leffe is one of Holcim’s main quarrying operations in Belgium, producing limestone for aggregates and building materials. The site is undergoing a major expansion and modernisation programme aimed at reaching an annual output of 2 million tonnes and securing operations for the next 40 years. Alongside production, Holcim is investing in technologies and operating practices intended to improve energy efficiency and reduce environmental impact. Because the quarry lies within a protected natural area, the company works closely with local stakeholders to combine extraction with progressive site restoration, converting disused areas into natural or recreational spaces with particular attention to biodiversity.
The project challenges
Sludge treatment
The sludge-dewatering stage had to be integrated into the new plant layout, replacing the previous system in which thickened sludge was discharged to external settling basins that had reached capacity.
Climate constraints
Natural sludge drying had become inefficient and difficult to predict under Belgian weather conditions, creating operational and cost constraints that had to be addressed.
Water recovery
A key objective was to reduce freshwater demand through continuous recovery, treatment and reuse of process water in a closed loop.
Tecnoidea's process-engineering approach
Site layout
To meet the environmental constraints of the protected area and the limited space available, the component layout was developed around the available footprint. This made it possible to integrate a large filter press and its sludge tank into a compact structure while maintaining access for operation and maintenance in accordance with the applicable site requirements.
Feed adaptability
The plant was configured on the basis of laboratory testing of multiple sludge samples. The results were used to define the operating parameters and accommodate the natural variability in feed-sludge characteristics.
Remote operation
Because the plant is located away from the client’s management offices, the facility was engineered for remote monitoring and control. A Tosi-box system provides authorised access to the control interface from Holcim management devices.
Results
Flexible dewatering capacity
Depending on sludge characteristics, the plant provides a dewatering capacity from 5.3 m³/h at one cycle/h up to 15.9 m³/h at three cycles/h, with higher throughput for less clay-rich material.
Remote monitoring and diagnostics
Remote assistance allows Tecnoidea technicians to monitor process parameters in real time and intervene in the control software when required, supporting troubleshooting without the need for an immediate on-site visit.
Environmental integration
Replacing lagoon-based sludge drying with mechanical dewatering reduced reliance on external settling basins and supported the site’s water-reduction objectives, while integrating the treatment process into Holcim’s broader environmental and site-restoration strategy.