Outlining a comprehensive techno-economic approach to evaluate the performance of an advanced sorting plant for plastic waste recovery

Mixed plastics from municipal solid waste are usually recycled in suitable Material Recovery Facilities (MRFs) following separate collection. These plants allow the sorting of individual plastics with variable performance depending on the technologies adopted. The evaluation of the performance of MRFs is also conducted with different approaches, even in terms of timescales, making the results difficult to compare. In this context, this study presents a comprehensive techno-economic approach to evaluate the performance of a MRF for plastic waste recovery. As a support, the Molfetta MRF case study (Southern Italy) was considered with an inlet plastic amount of about 19,000 t/year. The methodological proposal was based on the analysis of the quantity and composition of the different incoming waste streams, calculation of the Purity Index (PI) and Recovery Index (RI), quantification of the mass balance as well as accurate economic assessment. PI and RI assess the technical performance of the facility. They achieved the highest values (>95 %) for manual and optical sorting indeed they reached good values (70–80 %) for dimensional one; the economic analysis showed a specific gain of 12.58 €/t of sorted waste. The comparison of the obtained results with those of a similar MRF in Northern Italy had corroborated the suitability of the proposed approach suggesting its application, although with the due exceptions referred to the economic part, to other world contexts

Assessing the Sorting Efficiency of Plastic Packaging Waste in an Italian Material Recovery Facility: Current and Upgraded Configuration

The first step in reintroducing plastic waste into the recycling cycle is to use material recovery facilities (MRFs). However, while the composition and types of plastic waste are changing over time, the layout of MRFs does not always adapt to this change. In this paper, an existing MRF in Southern Italy was chosen as a reference to evaluate its current performance and to estimate possible improvements in sorting through a specific upgrade. First, an analysis of the amount, composition, and sources (in terms of type of waste and distance from the MRF) of the input waste was conducted. The composition of the input waste was then compared with the amount of selected output waste streams in order to calculate the current sorting efficiency of each stream and compare it with the values obtained from the upgrade. Lastly, the current performance of the plant was compared with a previous assessment of the same MRF in order to highlight possible variation. Results showed how the incoming waste was mainly composed of packaging plastic waste, and that some plastic waste not yet selected by the plant ended up in specific output streams. Therefore, the current performance of the MRF resulted high for PET and PE bottles (80.2% and 92.8%, respectively), in contrast to mixed or flexible packaging, where the efficiency achieved lower values (55–50%). These values were caused by a weakness in the 2D flow sorting line, which the upgrade mostly addressed. The upgraded configuration increased the production of recyclable waste from 34.32% to 50.39%, especially due to the recovery of small flexible packaging films in PE and biopolymers