Single-stream recycling, also called "fully commingled" or "single-sort" recycling, is a system where all recyclable materials—such as paper, plastic, metal, and glass—are mixed together in a collection truck. This is different from the dual-stream system, where people separate recyclables into different categories (like paper, plastic, and glass) and place them in separate containers for collection. In dual-stream recycling, some materials like glass, plastic, and metal are grouped together in one stream, while paper products are in another stream.

Single-stream recycling is easier for people to use because they do not need to sort materials before placing them in a bin. However, this system has some drawbacks. It often results in lower quality plastic and paper being sent to recyclers. These materials require more processing later in the recycling process. The increase in lower-quality recyclables from Europe and North America, partly caused by single-stream recycling, contributed to China’s decision to start its Operation National Sword policy. This policy aimed to address the challenges of handling lower-quality recyclable materials.

Advantages

Supporters of single-stream recycling highlight several benefits:

• Less sorting by residents may lead to more recyclable materials being placed at the curb and increased participation in recycling programs.
• Lower collection costs can result from using single-compartment trucks, which are less expensive to buy and operate. Collection processes can be automated, and routes can be managed more efficiently. Single-stream recycling also reduces the time drivers spend collecting recyclables, decreasing the amount of time spent on the road.
• Greater flexibility in vehicle use allows single-compartment trucks to collect recyclables, reducing the need for extra reserve vehicles. To help customers identify recycling trucks, a large sign or banner is sometimes used to show when a refuse truck is collecting recyclables instead of garbage.
• Fewer worker injuries may occur because switching to single-stream recycling often involves replacing bins with carts for collection.
• Changing to single-stream recycling can create an opportunity to improve collection and processing systems and include additional materials in the list of accepted recyclables.
• More types of paper, such as junk mail, telephone books, and mixed residential paper, may be collected.

Disadvantages

Potential disadvantages of single-stream recycling may include:

• The first cost includes buying new carts, different trucks for collecting, and improving the place where materials are sorted.
• Sorting costs might be higher than in systems that separate materials first. On average, single-stream recycling costs about $3 more per ton than dual-stream.
• More items that shouldn't be recycled might end up in the bin. This could lower the value of recycled paper or plastic.
• High-quality paper fibers might be used for lower-quality products like boxboard if there are too many unwanted items mixed in.
• More glass might break during sorting, leading to more waste that can't be recycled.
• If more recyclables end up in landfills due to contamination or if materials can't be sold, people might lose trust in the recycling program.

Single-stream system

A single-stream system is a complicated system of machines that mixes newer and older technologies to separate materials for recycling, such as PET, HDPE, aluminum, tin cans, cardboard, and paper.

List of equipment used in a single-stream system:

• Back Scraping Drum: moves materials onto a conveyor belt.
• OCC Screen: separates cardboard and old corrugated containers (OCC). Cardboard is sent to the Single Ram Baler to be compressed.
• Fines Screen: all materials except cardboard pass through this screen. It separates glass and small pieces less than five centimeters long. Glass is sent to the Glass Cleanup System for further sorting.
• News Screen: separates newspaper from other recyclable materials.
• Elliptical Separator: separates flat items (2D) from three-dimensional items (3D).
• Ferrous Magnet: pulls magnetic metals, such as tin cans and steel, toward the magnet.
• Optical Sorter: identifies PET plastic containers.
• Eddy Current Separator: removes aluminum and non-ferrous materials.
• Two-Ram Baler: compresses all materials except cardboard and clear film.
• Glass Cleanup System: cleans glass by removing light materials after it passes through the Fines Screen.
• Closed Door Baler: compresses clear film plastic.
• Motion Floor: stores corrugated cardboard and mixed paper in moving floor storage areas.
• Single Ram Baler: compresses all corrugated materials.

By country

Phoenix, Arizona, started looking into single-stream recycling in 1989. In 1992, a contract was given to CRCInc, and their MRF, the first large-scale recycling center in North America to handle mixed materials, opened in 1993. Later, many cities and towns across the United States began single-stream recycling programs. By 2012, there were 248 MRFs operating in the U.S. In 2013, 100 million Americans had access to single-stream recycling programs.