Impacts of a Change from Dual Stream to Single Stream Recycling Lori Clark David J. Tonjes, Omkar Aphale, Krista L. Thyberg Department of Technology and Society Stony Brook University

Using Recycled Materials in Manufacturing Reduces Carbon Emissions

The Big Debate: Evaluating Recycling Methods Dual Stream Higher quality Higher collection cost Set out confusion Simpler MRF Single Stream Increased quantity Less collection cost Contaminated fibers (glass) More residues Lower quality

Town of Brookhaven Switch-over: 2014 Three Districts Studied Economic and Logistical Changes 1. Collection from alternating weeks to weekly 2. MRF company and equipment change 3. Pricing regime change Disposal cost: $80/ton + $20/ton L&T -Dual Stream: $20/ton processing fee, 80% revenues to town -Single Stream $20/ton paid to town

Tons Recycled Were Declining

Recycling Rates Increased Significantly p< 0.05 Significant p< 0.05

Revenue Stabilized

Disposal Rates Continued to Decline

Three towns Waste sort MSW Recyclables

Recyclables and their Contaminants Increased * = Significant p< 0.05 Weissberger et al. PLOS Biology 13(4):e100228

Reported Residue Declined

The Total Waste Stream Changed: Recyclable Material Declined * = Significant p< 0.05

Non-recyclables in Total Waste Stream Increased

Source Separation Rates (Compliance) is Mixed * = Significant p< 0.05

Although Less Recyclables are Available, Set Outs Remain Constant

Observations Single stream increases curbside source separation Mostly through inappropriate materials No apparent operational impact Continuing changes in the waste stream but single stream seems to have “created” wastes Maintaining recycling rates requires ever increasing separation efficiency Still – fewer recyclables in the discards stream

Which method of collecting recyclables is better? Dual Stream better quality costs more (2 pass) set-out confusion (alternate set-outs) simpler MRF capital, operating costs Single Stream greater quantity costs less fibers contamination (glass!) more residues poorer quality set-outs Green = data supports; red = data rejects; blue = did not test; gray = maybe …

lori. clark@stonybrook. edu david. tonjes@stonybrook. edu www lori.clark@stonybrook.edu david.tonjes@stonybrook.edu www.stonybrook.edu/est