Conversion from dual stream to single stream recycling results in nuanced effects on revenues and waste stream amounts and composition

Single stream recyclables collection (residents set out all recyclables in one container without sorting them further) has become the dominant means of curbside recycling in the United States. Proponents claim it motivates residents to set out more materials for recovery because it is more convenient than other collection strategies; others claim it may also lead to poorer quality materials sent to market. Here we report on a conversion on Long Island (New York) from dual stream collection (paper and container recyclables collected in separate passes) to single stream collection. No other major change was made to the waste program, unlike other documented switches from single stream to dual stream, which means changes we document appear to be due solely to the collection processes change. Waste composition studies before and after the conversion added important information. We found significant (25%) increases in set outs for recycling, but also more inclusion of non-recyclable items in the recycling bins. Residents increased their separation rates of targeted recyclable materials, but because waste composition changed from 2012 to 2014, the increased separation rates resulted in about the same amount of recyclable materials being set aside. However, we estimate that the residual waste stream contained much less recyclable material concurrent with the change to single stream recycling, primarily due to the changes to the waste stream composition and size.