Working group "Waste Process Engineering"

The working group "Waste Process Engineering" deals with interconnected recycling and recovery processes to achieve higher recycling rates for non-hazardous mixed waste. This is carried out by an intensive combination of scientific and practical work on the following relevant sub-areas:

Circular economy through recycling and energy recovery

Europe wants to become a modern and sustainable recycling economy and there is currently a lot of dynamics towards this. One of the most significant developments is the European Circular Economy Package, which sets concrete recycling quotas for municipal waste, packaging waste, etc. until 2035 and beyond. In the working group, these aspects are of course considered and practical investigations are carried out together with our project partners to increase the characterization, sorting and recycling quotas from mixed waste. In this context, not only the quantity is an essential criterion, but rather the quality of the recovered fractions for subsequent recycling.

Recyclability

Increasing recyclability is a key element in meeting the goals of the circular economy package. This is because only recyclable products can actually be characterized, sorted out and recycled in the subsequent waste stream. The rejection of certain material fractions will change the remaining waste streams that are sent for thermal treatment. These future waste streams (FWS) will be investigated concerning their composition, including the search for potentially new recycling routes. Thus, the working group deals with theoretical considerations and an experimental approach through practical trials to increase the real recyclability.

Substitute fuels and co-processing

Mixed municipal and commercial waste is often processed into solid recovered fuels (SRF) and used in the cement industry. In this process, which is referred to as co-processing, the mineral residues (SRF ashes) are incorporated into the clinker simultaneously with the energy recovery and, from a technical point of view, are recycled. The working group is therefore intensively involved in the composition of SRF for thermal utilization, SRF ashes and their material utilization in the cement industry. Furthermore, an international ISO EN standard for the recycling of SRF in co-processing (R-index) is being developed. The current status is available at https://www.iso.org/standard/79886.html.

Valuable materials (recyclables), impurities and pollutants

The proportions of valuable, interfering and harmful substances in waste streams are significant for waste treatment in many respects. Their detection and removal represent an important lever for optimizing the treatment process and maximizing economic and ecological benefits. Sorting out recyclables and feeding them for recycling generates ecological and economic value, while contaminant removal can prevent downtime and plant damage. The removal of impurities and pollutant carriers additionally enables the production of e.g. a substitute fuel or a recyclate of high quality. This SRF can subsequently be used to substitute primary fuels while recyclate can be used to substitute primary raw materials. One of the goals is to find the optimal range in which the largest possible amount of recyclables can be sorted out for recycling without reducing the quality of the produced SRF. Furthermore, suitable treatment routes are to be found for rejected impurities and pollutant fractions.

Online and Ontime Quality Assurance

Quality assurance is becoming increasingly important in waste management. For example, when SRF - produced from household and commercial waste - is used in co-incineration plants (e.g. cement industry), legally defined and contractually agreed quality criteria (e.g. calorific value, chlorine content, heavy metal content, etc.) between SRF producers and utilizers, have to be met. Since this quality assurance is currently mainly performed "offline" and is only available with a longer delay (i.e. via sampling and laboratory analysis), research activities are directed here towards particle-specific characterization, real-time analysis and/or online/on-time quality assurance. In the working group, databases are built up, sensor-based technologies are used and data analysis methods are applied, among other things.

Method development for the evaluation of machine and plant performance

Strong variations in the composition of waste streams, different treatment steps in treatment plants and different types of machines make for a non-comparable representation of machine or plant performance. To be able to compare these with each other nevertheless, work is being done on the development of standardized and internationally recognized methods, whereby the entire process is to be considered, from the taking of the sample, via the possible treatment, up to the actual treatment in the respective aggregate.

Sensor technology, smart machines and plants

Our research vision is the "Smart Waste Factory" (SWF) or the plant of the future. This describes a plant in which it should be possible to actively intervene in processes through intelligent, digital networking of machines and sensor technology. Based on material data of the waste streams and combined information from sensor data ("sensor fusion") in combination with suitable algorithms, various actuators in the plant are to be controlled to optimize the output streams of the plant to specific requirements. In addition, new methods for material characterization will be developed, also focusing on artificial intelligence approaches. Individual components in the plant (shredding units, screens, sorting machines, etc.) are to be equipped with additional sensors for material flow and machine monitoring to obtain data for controlling the plant. Furthermore, real-time measurements are to be used to obtain information about the machine performance at the current point in time, in order to optimize the individual machines on the one hand and the entire process on the other. This in turn supports the further development of a machine or plant into a cyber-physical system.

Digital platform

An overarching digital platform is being developed so that data from different software and technology providers can be shared. This is to be understood as the infrastructure of a manufacturer-independent overall plant monitoring, control and optimization and, based on online and on-time communication between waste quality and machine performance, will enable treatment efficiency, recycling and recovery rates from mixed material streams to be increased and greenhouse gas emissions from the overall waste treatment system to be reduced.

Data tools

Enhanced process understanding represents a key lever for improving process engineering operations, including waste treatment. The challenges posed by waste heterogeneity lead to a focus on empirical modelling methods from statistics and machine learning. These are applied both at the bulk level and at the particle level. In parallel, physical modelling of waste engineering processes, considering specific challenges due to waste heterogeneity, is pushed to deepen process understanding. Finally, both approaches complement each other in the form of hybrid models.

Ongoing projects of the WG

• Recycling-oriented collaborative waste sorting by continual learning
  Short title: RecAlcle // Project start: 2023
  
  
• Recycling and recovery of waste for future
  Short title: ReWaste F // Project start: 2021

Completed projects of the WG (in the laste 2 years)

• Recycling and recovery of waste4.0
  Short title: ReWaste4.0 // Project period: 2017 - 2021

Group members of the WG

Leader of the WG

Dr. Renato Sarc
Hazardous Waste, Refuse Derived Fuels and Waste Management

Assistants

Dipl.-Ing. Julian Aberger
Chemical & Process Engineering and Machine Learning Applications

Dipl.-Ing. Maximilian Enengel
Intelligent Waste Treatment and Waste Management

 Dipl.-Ing. Lisa Kandlbauer
Digitalisation, Sensor-based Characterisation and Intelligent Waste Treatment

Dr. Karim Khodier
Empirical Modeling and Large-Scale Experimentation

Student employees

• Jakub Belzár
• Lena Brensberger
• Alexander Egarter
• Harald Grantner
• Jonas Gwandner
• Katharina Kargl
• Anna-Lena Krabichler-Mark
• Nina Nowak
• Alisa Rizvan
• Lukas Schiester
• Katharina Schwaiger
• Yuliya Varsh
• Michael Weinlechner

External employees

Dipl.-Ing. Tatjana Lasch
Chair of Process Technology and Industrial Environmental Protection

With the following form you can directly contact the leader of the working group Mister Dr. Renato Sarc.