Techno-economic assessment of central sorting at material recovery facilities:the case of lightweight packaging waste

摘要

Simulation of technical and economic performance for materials recovery facilities (MRFs) is a basic requirement for planning new, or evaluating existing, separate waste collection and recycling systems. This study mitigates the current pervasive scarcity of data on process efficiency and costs by documenting typical steps taken in a techno-economic assessment of MRFs, using the specific example of lightweight packaging waste (LWP) sorting in Germany. Thus, the study followed the steps of dimensioning of buildings and equipment, calculation of processing costs and projections of revenues from material sales and sorting residues disposal costs. Material flows through the plants were simulated considering both optimal process conditions and real or typical conditions characterised by downtime and frequent operation at overcapacity.By modelling four plants of progressively higher capacity (size) and technological level, the analysis revealed the cost impact of economies of scale, as well as complementary relations linking capacity, technology and process efficiency. Hence, within a fourfold increase in capacity (from 25,000 to 100,000 tonnes per year), the total capital investment was shown to triple from 7 to 21 million EUR and the yearly operational expenditure grew by a factor of 2.4 from 2 to 4.7 million EUR. As a result, specific unit processing cost decreased from 110 to 70 EUR/tonne. Material sales and disposal costs summed to between a net cost of 25 EUR/tonne and net revenue of 50 EUR/tonne. Measured as total materials recovery, the difference between optimal and typical operation was approximately 15% points. The complex nature of LWP waste combined with challenging processing conditions were identified as important factors explaining the relatively low overall recovery efficiencies achieved in these plants.