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Single Stream FAQ's

Why Recycle?

The single stream process involves multiple sorting steps utilizing state of the art sorting technology.  This video highlights the sorting steps in our Des Moines facility.

  • Entry - Material is dumped onto the “tipping floor” where it is loaded into the hopper.
  • Presort - Bulky items are removed (trash is taken to a compactor and plastic and metal are sorted into containers).
  • Rolling discs - Cardboard is removed from the stream while other items drop to the next conveyor.
  • Screens - sort fibers (paper) and containers (bottles, etc.) into separate components
  • Screens and air drums - separate fibers into types (newspaper, cardboard)
  • Magnets - pull steel (cans) from the stream
  • Optical Sorters - identify plastic bottles and use air to separate them
  • Manual Sorting - HDPE (colored and natural plastic containers) are usually removed by hand sorting, but can also be optically sorted.
  • Eddy current magnets - use reverse polarity to separate aluminum cans
  • Residue recovery - Manual removes any material that has bypassed the sorting process including plastic bottles & aluminum.
  • Mixed Paper recovery - Manual sorting removes any fiber material to be sorted and sold as “mixed paper” (multiple grades).
  • Residue - Any remaining material falls off the end of the conveyor into a roll off container that is taken to the landfill where the material is disposed of.
  • Baling – Material is compressed in a chamber to create bales and secured with an automatic wire tier.  Bales can weight from 1,200 to 2,100 pounds and allow for easy handling and shipping.

I know that single stream is convenient, but does the use of sorting equipment create a negative environmental impact?

  • The convenience of single stream greatly increases participation rates, resulting in more recycling tons.  This increase creates a larger positive environmental impact while also providing local green jobs.

  • Here is an interesting quote from Popular Mechanics on the merits of single stream recycling: “Such state-of-the-art facilities now feature magnets to attract steel, eddy currents to deflect aluminum, infrared spectrometers to identify different types of plastics, and a host of other sorting technologies. These plants are expensive, so they only make sense if 100 to 200 tons of recyclables are being processed daily, and they still require some human sorters to oversee the process. But the collection costs of picking up a single bin, rather than multiple ones, are much lower--and because it's easy for homeowners, the recycling rates are higher--so the overall economics of mechanized sorting pays off.

Click here to download PDF version

Recycled materials are delivered to the nearest Greenstar single stream recycling facility and are processed into categories (paper, plastic, aluminum, etc.).  Then, they are shipped to end users (i.e. paper mills) who use the items to create new products. 

  • What do my recycled items turn into?

    • Each recycling stream finds new life in various forms.  A great example of this is plastic bottles, which can be used as carpet, fabric, and water bottles.  This process can take as little as 60 days for aluminum cans, which are used to make new cans.
  • What are the most commonly recycled materials?

    • Aluminum (cans, bottles, foil), paper (newspaper, magazines, office paper), plastic (bottles, colored and natural containers) and cardboard.
Accepted Materials Not Accepted Materials
  • Aluminum cans
  • Clear and colored plastic containers (HDPE)
  • Plastic bottles (PET)
  • Paper (mixed, newspaper, office, magazines)
  • Cardboard
  • Aseptic cartons (gable top liquid containers)
  • Plastic bags
  • Wire clothes hangers
  • Batteries and electronics
  • Soiled food containers, napkins, and food waste
  • Styrofoam
  • Bathroom waste
  • Clothing

Does single stream accept plastic bags?

  • Plastic bags easily get caught in sorting equipment.  Knotting bags or bagging recyclables in plastic bags can also cause problems.  To recycle plastic bags, take them to your nearest grocery store or search the Earth911 directory for the nearest plastic bag recycler.

Are cartons recyclable?

  • Cartons are recyclable in many, but not all areas.  We have implemented carton recycling in several of our markets and are working with the Carton Council of America to have cartons designated as a recyclable item.

Aren’t aseptic packages and milk cartons coated with wax?

  • No. The coating on these types of packages is actually a sprayed on plastic coating and the industry has made accommodations to separate the materials to recover the fiber, which is most widely used in the production of tissue paper.

Should I leave the caps on my bottles when I recycle them?

  • Our typical position on bottle caps is to please remove the caps whenever possible. The caps are small and if they come off the bottles in transit they fall through our sorting screens and contaminate other materials.

How can I get recycling?

How do I calculate my recycling rate and how can single stream increase it?

  • Your recycling rate is the amount of recycling divided by the amount of total waste generated (trash + recycling).  Single stream can increase this percentage by eliminating the need to sort your materials, making recycling easier and more convenient.

How much of Greenstar’s materials are exported in relationship to those sold domestic?

  • Greenstar Recycling maintains a diverse portfolio of supplier agreements, including mills both domestic and foreign. Our diversity allows us to maintain supplier agreements through a variety of market conditions and helps stabilize the demand for our recovered commodities.

As a green company, what is Greenstar doing to help the environment?

  • In addition to removing over 2 million tons of recyclables from the waste stream annually, Greenstar participates in waste-to-energy and recyclable upgrading initiatives.  We are also actively involved in the community, participating in tree planting, Earth Day, and other community events.  Our goal is to become a zero landfill company, and we are aggressively pursuing options to achieve this goal.


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