In 2009, the Container Recycling Institute undertook a study on the impacts of single-stream collection of residential recyclables, with a particular focus on the economic and environmental impacts of this collection method on the final material sent to end-markets for recycling.
The past decade has experienced a significant increase in packaging generation. At the same time, recycling collection systems have shifted from source-separated programs to single-stream collection models in which all recyclable materials are placed in the same receptacle.
Click here to see the study http://www.container-recycling.org/assets/pdfs/reports/2009-SingleStream.pdf
While these system changes have resulted in lower collection costs, they have also led to an increased level of contamination at Material Recovery Facilities (MRFs). Processed materials sold to recyclers also contain higher levels of contamination and require further processing. Bales of paper-based secondary material, for instance, contain more glass, metal and other contaminants, which lowers the economic value of the material and can impact recycling operations in terms of extra labor and capital requirements. Polyethylene terephthalate (PET) bottles collected through commingled collection systems usually require additional sorting by recyclers or are simply too contaminated for high-end uses.
To date, the impacts on various collection methods — source-separated curbside, commingled curbside, deposit/return—on the quality of materials destined for recycling have not been formally researched and documented. In fact, rarely is “material quality” or the “end-destination” of the material considered by government decision-makers when choosing an appropriate recycling system.
The following report provides information on the impact of single-stream collection systems on material quality with respect to recycling and its economic value. For municipalities that are being asked to consider a shift to a single-stream system from a curbside sort or a dual-stream (fiber and containers) system, this report attempts to highlight the economic and environmental impacts that this decision may have. Our goal is to provide guidance on what strategies to incorporate when considering a single-stream collection system for maximum efficiency and environmental effectiveness.
Research for this report was attained through a series of interviews with recyclers representing different material end-markets and MRF operators. In addition, CRI reviewed existing reports that address issues relating to material quality and related end-market applications. These resources are listed at the end of the report.