In December 2009, the Container Recycling Institute issued Understanding Economic and Environmental , a comprehensive white paper documenting the controversy with single-stream recycling. The impressive paper is well researched and worth the read for those concerned about the ultimate destination of good-hearted recycling efforts.
From the bottom of page 16, here is copy differentiating between recycling and downcycling:
It is important to understand that diversion from disposal is not recycling. Collection is not recycling. A product is not recycled until it is made into another product. Broken glass used as landfill cover is ―downcycled‖ into one use only. Closed-loop recycling occurs when a product can be made and remade infinitely, such as recycling containers back into aluminum cans and glass and PET bottles.
The two major contaminants in the recycling stream are organic matter and glass. From page 20, here is copy discussing glass in the recycling stream:
Historically, one of the greatest challenges in single-stream collection has been glass. It is virtually impossible to prevent glass from breaking as it goes to the curb, is dumped in the truck, gets compacted, gets dumped on the tipping floor of the MRF, is repeatedly driven over by forklifts, and is dumped on conveyor belts to be processed by the MRF. Therefore, it is highly unlikely that glass collected in single-stream systems will be used for its highest closed-loop application—glass bottles or fiberglass. Unless there is beneficiation capacity nearby, which can clean the glass to recyclers’ specifications, single-stream glass will be downcycled to a use that is far less desirable in terms of energy conservation, avoided emissions and other high-end benefits. The most likely end uses for mixed cullet from a MRF is sandblasting base, aggregate material, or Alternative Daily Cover (ADC) for landfills.
The ZWZ team is working on creating an economic model for separated glass recycling. Strong demand for the recycled glass and collection infrastructure are the two main challenges. Once a viable system is developed ZWZ participants who serve alcoholic beverages will be required to separate glass for recycling collection. Stay tuned for developments.