STADLER completes lightweight packaging sorting plant for PreZero in Sollenau, Austria
STADLER, the German company specialising in the planning, production, and assembly of turnkey sorting plants, has completed and commissioned a lightweight packaging (LVP) sorting facility for PreZero Sorting Austria GmbH in Sollenau. The facility is the largest and most complex that STADLER has built to date, underlining the scale of the project.
For PreZero, the international environmental service provider of the Schwarz Group, 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 t/a across two modules, the facility aims to combine innovation and scalability to help Austria achieve its sustainability ambitions.
According to STADLER, the project’s delivery required technical expertise and precise coordination across multiple teams and phases: with several trades working simultaneously and installation starting before the construction of the halls was complete, the execution involved a high level of complexity. Commissioning was finalised by late summer 2025.
“This project was undertaken under a very tight schedule and required continuous coordination with all involved trades working in parallel,” said Benny Kalmbach, Project Manager at STADLER. “Despite the logistical challenges, we delivered a complex, high-performance facility on time through close collaboration with PreZero, STEINERT, and all on-site partners.”
Intelligent automation and circularity at scale
At the core of the Sollenau facility is an 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, to improve sorting accuracy and material recovery rates.
The system also incorporates the advanced AI-based BatterySort system, which enables early detection and safe removal of hazardous batteries. According to PreZero, this feature supports fire prevention and material recovery and was considered an important element of the plant.
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, a key requirement for PreZero’s high-throughput operation.
High level of automation
The Sollenau plant features a high level of 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. According to STADLER, this setup supports efficient use of capacity and consistent sorting quality. By reducing the need for manual intervention, the system is designed to improve efficiency, limit downtime, and enable continuous operation. The automation logic provides the technical framework for stable performance.