Stadler completes lightweight packaging sorting plant for PreZero in Austria

The LVP sorting facility in Sollenau. Image: STADLER

STADLER, the globally active German company specialised in the planning, production, and assembly of turnkey sorting plants, has completed and commissioned a groundbreaking lightweight packaging (LVP) sorting facility for PreZero Sorting Austria GmbH in Sollenau. The plant represents a major advance in automation, safety, and performance – and stands as the most complex and largest facility STADLER has built to date.

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 tonnes annually across two modules, the facility combines innovation and scalability to help Austria achieve its sustainability ambitions.

Tackling the challenge with innovation and precision

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.

“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 also emphasized STADLER’s strong partnership approach and technical expertise throughout the process, as Marya Brandt, Project Manager at PreZero, pointed out: “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.”

Intelligent automation and circularity at scale

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. This is a vital innovation for fire prevention and better material recovery that PreZero highlighted as a standout feature 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: “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.

A benchmark for the future of waste management

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.

Julia Stadler, Co-CEO of STADLER, explained: “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.”

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. This is thanks to the comprehensive, deeply integrated automation logic that provides a robust and stable system foundation.

PreZero has already observed the impact of these innovations in the plant’s 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.