Alexander Feil

Separate collection of plastic waste, better than technical sorting from municipal solid waste?

The politically preferred solution to fulfil legal recycling demands is often implementing separate collection systems. However, experience shows their limitations, particularly in urban centres with a high population density. In response to the European Union landfill directive, mechanical biological waste treatment plants have been installed all over Europe. This technology makes it possible to retrieve plastic waste from municipal solid waste. Operators of mechanical biological waste treatment plants, both in Germany and the Netherlands, have started to change their mechanical separation processes to additionally produce plastic pre-concentrates. Results from mechanical biological waste treatment and separate collection of post-consumer packaging waste will be presented and compared. They prove that both the yield and the quality of plastic waste provided as feedstock for the production of secondary plastic raw material are largely comparable. An economic assessment shows which conditions for a technical sorting plant are economically attractive in comparison to separate collection systems. It is, however, unlikely that plastic recycling will ever reach cost neutrality.

Fine grain separation for the production of biomass fuel from mixed municipal solid waste

The main goal of the project MARSS (Material Advanced Sustainable Systems) is to build a demonstration plant in order to recover a renewable biomass fuel suitable for the use in biomass power plants out of mixed municipal solid waste (MMSW). The demonstration plant was constructed in Mertesdorf (Germany), working alongside an existing mechanical-biological treatment plant, where the MMSW is biological dried under aerobe conditions in rotting boxes. The focus of the presented sorting campaign was set on the processing of fine grain particles minor than 11.5mm which have the highest mass content and biogenic energy potential of the utilized grain size fractions. The objective was to produce a biomass fuel with a high calorific value and a low content of fossil (plastic, synthetic) materials while maximizing the mass recovery. Therefore, the biogenic components of the dried MMSW are separated from inert and fossil components through various classification and sifting processes. In three experimental process setups of different processing depths, the grain size fraction 4-11.5mm was sifted by the use of air sifters and air tables.

A methodical approach for the assessment of waste sorting plants.

A techno-economical evaluation of the processing result of waste sorting plants should at least provide a realistic assessment of the recovery yields of valuable materials and of the qualities of the obtained products. This practical data is generated by weighing all the output products and sampling these products. Due to the technological complexity of sorting plants, for example, lightweight packaging waste treatments plants and the high expenditures concerning time and costs of sampling with subsequent manual sorting for quality determination, usually only final products undergo such an investigation. Thereby, the transferability of the results depends decisively on the boundary conditions (extent, throughput of the plant, process parameterization). Given that the process is too complex, not all relevant information of the process steps can be determined by sampling. By model calculations and/or adjustment of reasonable assumptions, information concerning weak points in the process can be identified, which can be used for further plant optimization. For the example of the recovery of beverage cartons from co-collected and mechanically recovered mixtures of lightweight packaging waste, a methodical approach for the assessment of processing results will be presented.

Efficiency of recycling post-consumer plastic packages

The recycling of packaging waste is an important part of the EU circular economy package, with a political focus on raising the recycling targets for post-consumer plastic packaging waste (PPW). The recycling of PPW involves at least three steps; collection, sorting and mechanical recycling. In contrast to the first two steps, mechanical recycling is poorly documented, as it is considered a free market activity. In order to provide a complete chain description the mechanical recycling yields were determined. The recovery of mass was determined for the main plastic sorting products from both major collection systems: separate collection (SC) and mechanical recovery (MR) from municipal solid waste. This technical assessment was conducted with a laboratory set-up for a standard mechanical recycling process. This analysis showed that there is a substantial sample-to-sample variation in polymeric composition between similar feedstocks and this variation is also observed in recovered masses. Next, the mechanica...

Aufbereitung fester Abfallstoffe

Die in der Aufbereitung fester Abfallstoffe eingesetzten Technologien sind mit wenigen Ausnahmen der mechanischen Verfahrenstechnik zuzuordnen. Aus dem Abfallgemisch werden durch Trennprozesse einzelne Stoffgruppen soweit angereichert, dass sie als Wertstoffkonzentrat fur Folgeprozesse verwendet werden konnen. Recyclingprozesse sind in der Regel mehrstufig aufgebaut, wobei die mechanische Aufbereitung sehr haufig die Eingangsstufe bildet. Gegenstand der Aufbereitungstechnik beim Wertstoffrecycling ist die Erzeugung von Zwischen- oder Endprodukten aus Abfallgemischen mittels physikalischer und/oder untergeordnet biologischer oder chemischer Prozesse. Alle Prozesse, auch Verfahren genannt, bestehen aus Kombinationen einzelner Prozessstufen, die auch als Grundoperationen bezeichnet werden. Im vorliegenden Lehrbuch werden die hierzu in der betrieblichen Praxis zum Einsatz kommenden Zerkleinerungs-, Klassier- sowie Sortieraggregate beschrieben und in Bezug gesetzt zu den stofflichen Eigenschaften von Abfallgemischen, da diese vielfach die Auswahl an Technik masgeblich beeinflussen.