Single-stream (also known as “fully commingled” or "single-sort") recycling refers to a system in which all paper fibers, plastics, metals, and other containers are mixed in a collection truck, instead of being sorted by the depositor into separate commodities (newspaper, paperboard, corrugated fiberboard, plastic, glass, etc.) and handled separately throughout the collection process. In single-stream, both the collection and processing systems are designed to handle this fully commingled mixture of recyclables, with materials being separated for reuse at a materials recovery facility.
The single-stream option replaces the dual-stream option, which is where people separate certain recyclable materials and place them in separate containers for collection. Typically, dual-stream has partial commingled materials such as glass, plastic and metals in one stream separated from paper products in the other stream. From an end consumer perspective, single-stream is easier to participate in. However, single-stream recycling has disadvantages, including the output of lower quality plastics and paper to recyclers. This lower quality material has to be processed more downstream. The increased flow of decreased quality recyclables from Europe and North America in part due to single-stream recycling was part of China's motivation for launching its Operation National Sword policy.
Proponents of single-stream recycling note several advantages:
Reduced sorting effort by residents may mean that more recyclables are moved to the curb and more residents may participate in recycling;
Reduced collection costs because single-compartment trucks are cheaper to purchase and operate, collection can be automated, and collection routes can be serviced more efficiently. Single-stream reduced the amount of time it takes for a driver to collect the recyclables, which reduces the driver time on the road.
Greater fleet flexibility, which allows single-compartment vehicles to be used to collect recycling, providing greater fleet flexibility and reducing the number of reserve vehicles needed.