What Is Single-Stream Recycling?
Single-stream recycling (also called co-mingled or fully commingled recycling) allows residents to put all recyclables — paper, cardboard, glass, plastics, and metals — in one bin, unsorted. A materials recovery facility then sorts everything automatically.
Single-stream was developed in the late 1990s and spread rapidly through the 2000s. By making recycling as easy as throwing things away, participation rates increased significantly — often by 30–50% compared to multi-stream programs.
What Is Multi-Stream Recycling?
Multi-stream programs require residents to separate recyclables into two or more containers — typically one for paper and cardboard, one for glass, and one for everything else. Some programs require more granular sorting.
The additional effort reduces participation but dramatically improves material quality. Paper separated from glass doesn't get contaminated with broken glass slivers; glass kept separate doesn't get crushed into fragments mixed with paper.
The Contamination Problem with Single-Stream
Single-stream convenience comes at a cost. When everything is mixed, problems multiply: glass breaks and contaminates paper, making it unrecyclable. Plastic bags wrap around sorting machinery. Small items fall through screens and end up in residue. Food residue from unrinsed containers spreads to paper.
Contamination rates in single-stream programs often run 10–25%, meaning that portion of collected material still goes to landfill — just after additional processing cost.
The Trend: Cleaner Single-Stream
The industry is moving toward improving single-stream quality rather than reverting to multi-stream. More sophisticated optical sorters, AI-assisted robotics, and better public education (particularly about plastic bags) are reducing contamination rates.
Some communities have eliminated glass from single-stream due to contamination problems, instead offering separate glass drop-off programs. This hybrid approach preserves convenience while protecting paper quality.