New Sludge Cake Transfer Facility in Garmerwolde: Integrated Mechanica
At the Garmerwolde wastewater treatment plant, Waterboard Noorderzijlvest processes large volumes of sludge cake every day. This residue of the dewatering process is demanding to store and transport due to its sticky and irregular texture
At the Garmerwolde wastewater treatment plant, Waterboard Noorderzijlvest processes large amounts of sludge cake every day. This residue of the dewatering process is challenging to store and transport because of its sticky and irregular texture. In 2024 the entire transfer facility was renewed. Jansen&Heuning acted as main contractor and delivered a turnkey solution that included both the temporary bypass and the permanent installation. The core of this project lies in mechanical conveying, integrating shaftless screw conveyors, a belt conveyor and high-capacity silos with a built-in weighbridge.
Ensuring Continuity with a Temporary Bypass
Because the plant must operate without interruption, sludge handling could not be stopped during construction. Jansen&Heuning therefore designed a temporary facility that went into operation in April 2024. Two shaftless screw conveyors, connected directly to the filter presses via new collection hoppers, ensured stable transfer of the sludge cake. This setup allowed two trailers to be loaded simultaneously while the old installation was dismantled. The bypass created a safe transition to the new system without capacity loss and will remain available as an emergency backup.
The Permanent Installation
The second phase, executed between May and September 2024, involved construction of the new transfer station. Four filter presses discharge into collection hoppers from which several screw conveyors transport the material to silos and a belt conveyor. The silos are elevated to save ground space and enable direct trailer loading from above. Underneath, a new weighbridge has been integrated into a weighbridge hall with stair tower and platforms. This setup not only speeds up logistics but also ensures precise truck loading.
A key part of the installation is the extraction system with filters. It reduces emissions and prevents odour problems in the surrounding area. In combination with the closed conveying lines, it creates a safe and hygienic work environment.
Technical Focus: Mechanical Conveying
The decision to use shaftless screw conveyors is crucial for the installation’s performance. Sludge cake is difficult to move with conventional equipment due to its variable and viscous texture. Shaftless conveyors prevent clogging around a central shaft and guarantee a continuous, reliable flow with minimal maintenance.
In addition, a belt conveyor is applied for horizontal transfer inside the weighbridge hall. While screw conveyors take care of vertical or inclined conveying, the belt conveyor ensures dependable horizontal movement. Together they form a fully integrated conveying chain where each system has its own role.
The silos form the heart of the transfer facility. By using vertical storage and direct trailer discharge, logistics flows are streamlined. The weighbridge underneath makes it possible to load and weigh trucks in a single operation, reducing transport movements and improving efficiency.
Efficiency, Sustainability and Safety
The installation achieves about 30% energy savings compared with the previous system. This is the result of optimized bulk flows, gravity-assisted conveying and closed transport lines. The vertical arrangement with silos also leads to significant space savings and a more compact site layout.
Safety and environmental performance have improved as well. Closed conveying minimizes direct operator exposure to sludge cake, while the extraction system with filters reduces emissions and controls odours. In addition, the modular design made it possible to reuse parts of the old installation, supporting circularity and resource efficiency.
Collaboration and the Role of Jansen&Heuning
In this project Jansen&Heuning acted as main contractor and system integrator. We were responsible for the design, engineering, supply and installation of the complete facility, working closely with Utibo (steel construction) and Batenburg (automation). With our extensive expertise in bulk handling we supplied the key components: shaftless screw conveyors, the belt conveyor, collection hoppers and elevated silos with integrated weighbridge. Combined into one system, they provide a technically advanced solution that fully meets the requirements of the waterboard.
Conclusion
The Garmerwolde project shows how mechanical conveying performs under demanding conditions. By combining several conveying principles into one integrated facility, a robust and sustainable system has been created that delivers both operational and ecological benefits. The sludge cake transfer station illustrates how Jansen&Heuning applies bulk handling expertise to make complex material flows manageable and efficient.
