Material Recovery Facilities
This is footage from a WM Recycle America facility in Elkridge, MD.
The recyclables picked up from homes and businesses are taken to material recovery facilities (or MRF --rhymes with nerf) to be processed. The MRF is a facility that receives, separates and prepares recyclable materials for marketing to manufacturers. Recyclable material is sorted to specifications, then baled, shredded, crushed, compacted, or otherwise prepared for shipment to market.
There are several types of MRFs. The simplest is one that takes source separated material. This material is separated at the point of collection, often a drop-off program. For example, cans, bottles and paper are put into separate bins. Although some processing may be necessary to sort the materials further and remove any foreign material, it is minimal. The sorted material is prepared for market by crushing, flattening and baling according to the manufacturer’s specifications.
- Dual-stream MRFs accept materials that are recovered in two streams, usually fiber as one stream and packaging as the other stream. A combination of manual and automated sorting equipment is used for separation followed by baling or crushing similar to a source-separated MRF.
- Single-stream MRFs, which are becoming more common, require a more intensive separation process than dual-stream – processing as many as 35 or more different material types.
- Last, mixed-waste MRFs accept unsegregated solid waste and separates out the recyclable materials, with the balance of the material sent to a disposal facility such as a landfill or waste conversion facility.
As of 2013, there are 563 multi-material (“residential style”) MRFs in the U.S., according to Governmental Advisory Associates, which publishes a database of MRFs.
Local MRFs are a resource for their communities. The MRF operators are often willing (and eager) to give tours of their facilities to community members and schools. Contact your local MRF for tour scheduling. They’re very interesting facilities!
Discover how MRFs are moving recycling into the future
State-of-the-art MRF’s are filled with complex technologies that largely automate the process of sorting and separating commingled recyclables. Improved sorting technology allows for cleaner sorting and lets less foreign material in (known as contamination), which yields commodities that bring premiums from manufacturers and re-processors, and thereby makes recycling more economically viable for more communities. These sorting technologies include:
Inclined screens are used to separate fiber such as paper and paper board from containers. Disk screens can be used to separate different grades of paper or from other contaminants.
Optical sorting technology has become faster and more precise in recent years. A MRF may have a number of programmable units capable of identifying plastic by their resin type and sorting these different plastics by blowing them off the line into the appropriate bunker or conveyor. Modern scanners have higher resolution than their predecessors and can identify smaller pieces of plastic.
Magnets and Eddy Currents
Magnets and eddy currents are used to separate out steel and aluminum containers. The eddy current works by charging an aluminum container with a field of electrons, which attach themselves to the cans and give them a negative electrical charge. A conveyor can then carry the cans across a negatively charged magnet, which repels the negatively charged aluminum container up and into a bunker. Similarly, magnets remove tin and steel cans from the recycling stream.