title: Analysis of material recovery facilities for use in life-cycle assessment.
abstract: Insights derived from life-cycle assessment of solid waste management strategies depend critically on assumptions, data, and modeling at the unit process level. Based on new primary data, a process model was developed to estimate the cost and energy use associated with material recovery facilities (MRFs), which are responsible for sorting recyclables into saleable streams and as such represent a key piece of recycling infrastructure. The model includes four modules, each with a different process flow, for separation of single-stream, dual-stream, pre-sorted recyclables, and mixed-waste. Each MRF type has a distinct combination of equipment and default input waste composition. Model results for total amortized costs from each MRF type ranged from $19.8 to $24.9 per Mg (1Mg=1 metric ton) of waste input. Electricity use ranged from 4.7 to 7.8kWh per Mg of waste input. In a single-stream MRF, equipment required for glass separation consumes 28% of total facility electricity consumption, while all other pieces of material recovery equipment consume less than 10% of total electricity. The dual-stream and mixed-waste MRFs have similar electricity consumption to a single-stream MRF. Glass separation contributes a much larger fraction of electricity consumption in a pre-sorted MRF, due to lower overall facility electricity consumption. Parametric analysis revealed that reducing separation efficiency for each piece of equipment by 25% altered total facility electricity consumption by less than 4% in each case. When model results were compared with actual data for an existing single-stream MRF, the model estimated the facility's electricity consumption within 2%. The results from this study can be integrated into LCAs of solid waste management with system boundaries that extend from the curb through final disposal.
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, NC State University, 2501 Stinson Drive, Raleigh, NC 27695, USA. Electronic address: pnpressl@ncsu.edu.
authors.forename: Phillip N
authors.initials: PN
authors.lastname: Pressley
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, NC State University, 2501 Stinson Drive, Raleigh, NC 27695, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Levis
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljøvej, 2800 Kongens Lyngby, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Damgaard
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, NC State University, 2501 Stinson Drive, Raleigh, NC 27695, USA.
authors.forename: Morton A
authors.initials: MA
authors.lastname: Barlaz
authors.affiliation: Department of Civil, Construction, and Environmental Engineering, NC State University, 2501 Stinson Drive, Raleigh, NC 27695, USA.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: DeCarolis
mesh_terms: D003365:Costs and Cost Analysis; D004560:Electricity; D018803:Models, Economic; D008962:Models, Theoretical; D059027:Recycling / Q000191:economics; D012037:Refuse Disposal / Q000191:economics* / Q000379:methods*; D062611:Solid Waste
chemical_list: D062611:Solid Waste
keywords: Life-cycle assessment; Material recovery facility; Municipal solid waste; Recycling