Stadler Anlagenbau GmbH has completed and commissioned a lightweight packaging (LVP) sorting plant for PreZero Sorting Austria GmbH in Sollenau. Designed for 104,500 tonnes per year across two modules, the facility combines high levels of automation, AI-based safety functions and a scalable layout intended to strengthen Austria’s regional recycling infrastructure. The location was selected to close a geographic gap, enabling shorter transport routes, reduced emissions and more efficient waste management. The installation is described by Stadler as the most complex and largest facility the company has built to date.
Project execution required technical coordination across multiple trades and phases, with installation starting before the construction of the halls was complete. Stadler delivered the turnkey project on schedule, with commissioning 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."
PreZero highlighted the partnership approach and technical expertise throughout implementation. "Stadler successfully overcame challenges like integrating the AI-based fire protection system, ensuring high automation, and meeting strict safety and environmental standards. Their tailored approach enabled the smooth implementation of a complex, future-ready facility," said Marya Brandt, Project Manager at PreZero.
The plant processes lightweight household packaging, plastic bottles and lightweight packaging waste from commercial streams. It is configured for continuous operation, supported by redundant sorting lines, intermediate buffering and fully automated baler control for up to 20 material fractions. The layout and control strategy target high availability and operational flexibility, with built-in redundancy to minimize downtime during servicing.
Process design and automation
The process begins with fully automated extraction of input material from deep bunkers via an overhead gantry crane. After a reduction stage, the material is sorted into different grain sizes. A total of 35 near-infrared (NIR) sorters from Steinert are installed across the line. Film materials are separated from the bulk stream using NIR sorters with air separation, then pass through four redundant sorting stages with further NIR units. Ferrous and non-ferrous metals, as well as beverage cartons, are removed in dedicated stages, while the 3D material stream is split into several final product fractions across multiple NIR stages. Each sorting line includes recovery NIR units that return misclassified materials to the start of the process, closing the loop to secure high sorting accuracy and optimal recovery rates.
The system incorporates the AI-based BatterySort system to enable early detection and safe removal of hazardous batteries. This function supports fire prevention and improves downstream material quality. "One of our priorities in this project was to design a system architecture that ensures maximum availability and operational flexibility," said Julius Henn, Project Manager at Stadler. "By integrating redundant sorting lines, intermediate buffering, and fully automated systems, we created a facility that can operate continuously, even during maintenance." "This built-in redundancy ensures continuous plant availability, minimizes downtime and maintains high throughput even during technical servicing. It makes a real difference by increasing operational efficiency and reliability," added Tristan Merk, Project Manager at PreZero.
Operational control and system stability
Fourteen volumetric flow sensors developed in-house by Stadler continuously monitor material throughput to maintain a stable, balanced feed to each sorting line. "Volume flow sensors ensure a consistent and balanced material flow throughout the entire plant. For instance, our patented screen-cut-control solution enables precise distribution across multiple sorting lines, forming the basis for automated operation and long-term process stability," said Julia Stadler, Co-CEO of Stadler.
The plant operates as a fully automated system that dynamically adapts to changing material compositions. This allows optimal use of capacity while maintaining consistently high sorting quality. By reducing manual intervention, the automation increases efficiency, reduces downtime and enables 24/7 operation. "PreZero is very satisfied with the facility’s performance. It meets high standards in safety, efficiency, and material recovery, making it a key contributor to regional recycling and sustainability goals," said Marya Brandt.
Contribution to regional circularity
According to PreZero, the Sollenau plant is expected to support regional recycling rates through improved sorting precision and recovery. "PreZero tasked Stadler with delivering a highly automated, safe, and efficient sorting system tailored to complex recycling needs," concluded Tristan Merk. "Stadler exceeded these expectations by designing and implementing a cutting-edge facility that integrates AI-based safety and meets the highest standards in sustainability and performance." The installation is presented as a model of scalable, intelligent and safe recycling infrastructure aligned with Austria’s long-term sustainability objectives.
