For PreZero the Sollenau project is a strategic investment aimed at strengthening Austria’s regional recycling infrastructure. Its location was selected to fill a geographic gap, enabling shorter transport routes, reduced emissions, and more efficient waste management. Designed to process 104,500 tonnes annually across two modules, the facility combines innovation and scalability to help Austria achieve its sustainability ambitions.
The project’s delivery required technical expertise and precise coordination across multiple teams and phases. With many trades working simultaneously and installation beginning before the construction of the halls was complete, the complexity of execution was unusually high. Stadler’s ability to navigate these conditions was crucial to delivering the turnkey facility on schedule, with commissioning finalised by late summer 2025.
At the core of the Sollenau facility is a highly integrated and automated sorting system capable of processing lightweight household packaging as well as plastic bottles and lightweight packaging waste from commercial streams. The process begins with fully automated extraction of the input material from deep bunkers using an overhead gantry crane. After a size reduction stage, the material is sorted into different grain sizes.
A total of 35 Near-infrared (NIR) sorters from Steinert are used throughout the process. Film materials are separated from the bulk stream using NIR sorters with air separation, then pass through four redundant sorting stages with further NIR sorters. Ferrous and non-ferrous metals, as well as beverage cartons, are removed during dedicated sorting stages, while the 3D material stream is sorted into several final product fractions across multiple NIR sorting stages. Each sorting line includes recovery NIR units from Steinert that recirculate misclassified materials back to the start of the process, closing the loop and ensuring very high sorting accuracy and optimal material recovery rates.
The system also incorporates the advanced AI-based BatterySort system, which enables early detection and safe removal of hazardous batteries.
To ensure smooth operation, the plant features intermediate buffering systems, redundant sorting lines, and fully automated baler control for the final output of up to 20 material fractions. It was designed to operate continuously.
What makes the Sollenau plant especially distinctive is the high level of intelligent automation throughout the entire process. Fourteen volumetric flow sensors developed in-house by Stadler continuously monitor material throughput, enabling real-time adjustments to maintain a stable, balanced feed to each sorting line.
The plant operates as a fully automated system that dynamically adapts to changing material compositions. This allows for optimal use of capacity while maintaining consistently high sorting quality. By minimising manual intervention, the system increases efficiency, reduces downtime, and enables 24/7 operation.
