Until recently, curbside recycling programs required residents to sort their materials into two categories or streams:  paper  and comingled containers:

• Paper includes cardboard, mail, catalogues, magazines and newspaper.
  
• Containers include plastic, glass, and metal food, beverage and household product containers. 

The two streams are kept segregated in the recycling truck and are transported to a Materials Recovery Facility (MRF) where they are sorted through a combination of manual and mechanical separation into separate streams of glass, ferrous metal (steel cans), non-ferrous metal (aluminum cans), plastics (according to resin types, such as #1 and #2).  Materials are then baled and sold to commodity markets for use in manufacturing new products.  

Single stream recycling made its debut on the west coast about ten years ago, but only arrived in Massachusetts in 2006.  

With single stream, residents place all recyclables (paper and containers) into one bin.  The mixed materials are then sent to a single stream MRF where sophisticated sorting technology separates the paper from the containers.  The container stream is then sorted into the separate commodity streams as with dual stream recycling. 

Approximately 30 Massachusetts municipalities (24 curbside and 7 drop-off) have converted to single stream recycling from dual stream in the past 12 months, and more are planning the conversion. 

Another industry trend emerging in Massachusetts is automated or semi-automated collection of trash and/or recyclables in curbside programs.

Automated collection refers to the process where residents are provided with specially designed carts that are emptied by an automated vehicle.  This vehicle uses a mechanical arm to pick up the cart and dump the contents. Carts range in size from 32 to 95 gallons, with most communities using 64 or 95 gallon carts.  In a semi-automated collection program, the driver or attendant manually positions the cart for the lift-arm and pulls a lever to tip the cart.  

Some communities in Massachusetts have converted to a two-cart system; one for trash and one for mixed (single stream) recyclables.  Others are using a cart system for single stream recyclables only, while residents use traditional trash cans for waste.  And in some, trash is collected in a cart, and recyclables in the traditional dual stream method with curbside "blue bins." 

Some materials never enter the waste stream, but are taken by their generators directly to a facility that sends them to be recycled.  For example, as a result of a five cent deposit that we pay for each bottle and can containing a carbonated drink, many people return their empty bottles and cans to stores or to "redemption centers" that in turn send the collected bottles and cans to facilities that recycle them into other materials. 

Between July 1, 2006, and June 30, 2007, the deposits on nearly 1.5 billion (66 percent) of the 2.2 billion redeemable containers sold were returned for recycling.  Deposits on the remaining 750 million containers were not redeemed (some of these containers may have been recycled through municipal recycling programs; others were discarded in trash).  The unredeemed deposits that had been paid when the containers were purchased contributed $37.8 million to the Massachusetts General Fund during this period.