MRFs: Magical or Mysterious?

A few months ago we covered the journey that recyclables go on when they leave a curbside, multi-family building, or depot. Let’s take a closer look at the material recovery facility, or MRF, one of the key steps in that journey.

A MRF (pronounced “merf”) is a facility where materials are dropped off by trucks after they have been collected from curbside and multi-family buildings. Most depot materials are already sorted and can be baled without having to travel through the maze of machinery within a MRF.

After materials collected from residents’ at curbside, or from multi-family buildings, are dropped off, they ride up a conveyor belt so that people tasked with hand sorting can remove any obvious non-recyclables or items that will hinder the recyclability of other items (loose plastic bags are a great example of this). Common non-recyclables that these sorters see include recyclables tied into bags (they cannot open these bags for safety reasons), garbage and organics, and electronics. Common non-recyclables shift with the seasons. For example, at this time of year, the hand sorters often find yard trimmings and paint cans. The materials rush by quickly, and hand sorters can’t get to everything, and the items that slip by can spoil the recyclability of other materials (as is the case with garbage and organics) or wreak havoc with machinery (as is the case with plastic bags), which is why we ask that residents only set out items that are accepted in the program.

Next, items travel through a series of machines that separate the different kinds of plastic containers from metal containers from paper containers and cartons and from paper and cardboard. Each machine has a different purpose (for example, magnetic currents separate different kinds of metal containers and optical sorters separate different types of plastic containers) and is tasked with identifying a specific material type.

Materials continue through the machines until they are separated into compartments containing single types of material.  For example, imagine a giant pile of milk jugs, laundry detergent bottles and other containers made from high-density polyethylene (HDPE) that have been separated from other recyclables. The compartments are emptied and the materials are squished together into square bales for transport to recycling remanufacturers. Once at recycling remanufacturers, the materials are processed so that they can be used to make new products or packaging.

For a visual and a video of these steps, visit