The quick answer
- A materials recovery facility (MRF, often said “murf”) is a recycling sorting plant. It takes in recyclables, separates them by material and gets them ready to sell.
- It is where your curbside recycling goes after the truck picks it up, unless your area sends it to a transfer station first.
- Machines and people do the sorting. Screens, magnets, eddy currents, optical scanners and hand sorters split paper, cardboard, metal, plastic and glass.
- The output is bales and loads of single materials that are sold to paper mills, metal and plastic processors and glass plants.
- The wrong items cause real trouble. Plastic bags and hoses wrap around equipment, and batteries can start fires.
What a materials recovery facility does
An EPA handbook on these plants describes a MRF as a central operation where recyclables, mixed together or already separated, are processed by machine or by hand so they meet the specifications buyers set. In plain terms, it turns a truckload of jumbled bottles, cans, boxes and paper into clean piles of one material each, because a paper mill only wants paper and an aluminum plant only wants aluminum.
The name varies. You may see material recovery facility, materials recycling facility or just recycling center. Some MRFs are run by a city or county and others by private hauling companies under contract.
Clean MRFs, dirty MRFs and single-stream
- Clean MRF. Accepts only recyclables that households and businesses have already kept separate from trash. Most curbside recycling programs feed this kind of plant.
- Dirty MRF, or mixed-waste processing. Takes regular garbage and pulls out recyclables from it. Material recovered this way is usually more contaminated, and the setup is less common.
- Single-stream. All recyclables go in one cart, and the MRF separates paper from containers. Many curbside programs use this setup.
- Dual-stream. Paper and cardboard go in one bin and bottles and cans in another, so the plant starts with cleaner paper.
Which system your area uses decides what goes in which bin, so always follow your local hauler’s list over a general one.
How a MRF sorts recycling, step by step
Every plant is laid out differently, but most single-stream MRFs follow the same basic order:
- Tipping floor. Collection trucks dump their loads inside a large building. A loader pushes the pile onto a conveyor at a steady rate.
- Presort. Workers along the first belt pull out things that should never have been there, such as plastic bags, hoses, cords, large chunks of scrap and bags of trash.
- Cardboard screen. Rows of spinning discs let small items drop between them while big flat cardboard rides over the top and off to its own pile.
- Paper screens. More disc screens separate flat paper, which rides up, from round and heavy containers, which roll or fall away.
- Glass. Glass usually breaks along the way. The pieces fall through screens and are cleaned up as a separate stream.
- Magnets. An overhead magnet lifts steel and tin cans off the belt.
- Optical sorters. Scanners that read plastics by how they reflect light spot bottles and tubs by resin type, then puffs of air shoot them into the right chute.
- Eddy current separator. A spinning magnetic field pushes aluminum cans off the end of the belt, away from everything else.
- Quality control. People along the last belts pick out anything the machines missed.
- Baling. Each sorted material is pressed into dense bales and stored until it ships to a buyer.
What jams a MRF or starts fires
Most of the problems at a MRF come from items that look recyclable or that people hope are recyclable.
- Plastic bags and film. They wrap around the spinning disc screens. Crews have to stop the line and cut them free, which is why most curbside programs ask you to keep bags out of the cart. Some grocery and retail stores take clean plastic bags back for separate recycling.
- Tanglers. Garden hoses, extension cords, holiday lights, rope and chains wrap equipment the same way bags do.
- Batteries. Lithium-ion batteries in phones, vapes, power tools and toys can catch fire when they are crushed or punctured. A 2021 EPA analysis found 245 fires caused or likely caused by lithium batteries at 64 waste facilities from 2013 through 2020, and said MRFs bore the worst of the impacts. Take batteries to a battery or electronics drop-off instead; see where to recycle batteries.
- Propane cylinders and pressurized tanks. These can burst in a truck or on the line. Many household hazardous waste programs accept them; see where to dispose of propane tanks.
- Food and liquid. Leftover food and drinks soak into paper and cardboard and lower what buyers will pay for it. A quick rinse and an empty container help.
- Trash in the recycling. Diapers, clothes, electronics and bagged garbage all have to be pulled by hand or end up as residue. Electronics in particular belong in their own program; see where to dump electronics.
What happens to the leftovers
No plant catches everything. The material that is not recyclable, or that the line misses, is called residue. It is usually hauled to a landfill or, in some areas, to a waste-to-energy plant. That is one reason dumping trash in the recycling cart does not help: it costs the program money to sort out and still ends up buried. For what happens once it reaches a landfill, see what leachate is.
MRF vs transfer station vs landfill
- MRF: sorts recyclables into sellable materials. Little or nothing is buried there.
- Transfer station: a short stop where trucks unload trash or recycling so it can be consolidated into bigger loads and shipped onward. Some transfer stations share a site with a MRF.
- Landfill: the final stop where waste is buried in lined cells.
More on the last two in transfer station vs landfill.
Can you take recycling to a MRF yourself?
Sometimes. Many MRFs are built only for collection trucks and do not take loads from the public. Others have a public drop-off area for recyclables, and some sit next to a transfer station or county drop-off center that does take self-haul loads. Before you drive out:
- Call ahead or check the operator’s website to see if residents can drop off and what they take.
- Sort before you go. Drop-off areas often have separate bins for cardboard, paper, metal, plastic and glass.
- Keep trash out. Staff may turn away a load with garbage mixed in; see why staff inspect loads.
- Find nearby options on the Dumpmapper map or the dump near me page, and check what you can take to the dump for the items a recycling drop-off will not handle.
Materials recovery facility FAQ
What does MRF stand for?
MRF stands for materials recovery facility, sometimes written material recovery facility or materials recycling facility. People in the industry usually pronounce it murf.
What happens at a materials recovery facility?
Recyclables are dumped on a tipping floor, fed onto conveyors and separated by screens, magnets, eddy current separators, optical sorters and workers. Each material is then baled and sold to a manufacturer or processor.
What is the difference between a clean MRF and a dirty MRF?
A clean MRF takes only recyclables that were kept separate from trash. A dirty MRF, also called mixed-waste processing, pulls recyclables out of regular garbage, and its output is usually more contaminated.
Why can't plastic bags go in the recycling cart?
Bags and plastic film wrap around the spinning screens that separate paper from containers, so crews have to stop the line and cut them off. Some stores collect clean plastic bags for separate recycling.
Can I take my recycling directly to a MRF?
Some MRFs have a public drop-off area, but many only accept collection trucks. Call the operator first, or look for a nearby county drop-off center or transfer station that takes recyclables.
What happens to items a MRF cannot recycle?
Material that cannot be sold, along with items the line misses, becomes residue. It is usually hauled to a landfill or, in some areas, to a waste-to-energy plant.
The bottom line
A materials recovery facility is the plant that turns a cart of mixed recycling into bales of paper, cardboard, metal and plastic that manufacturers can use. It works best when what arrives is actually recyclable: no bags, hoses or batteries, and as little food and trash as possible. If you want to drop off recycling yourself, call first, because many MRFs only accept truck deliveries.