What happens to recycling: 4 materials through the UK system
SaveYour recycling leaves the kerb and heads to a materials recovery facility, where conveyor belts, magnets, optical scanners and human sorters split it by type. Clean, correctly sorted material gets baled and sent to reprocessors who turn it into new products; contaminated loads risk rejection and incineration. Ecomojo traces paper, plastic, glass and metal through collection, sorting and reprocessing to show why preparation at home determines what actually gets a second life.
Collection and first sorting
Most UK households use either single-stream recycling, where everything goes in one bin, or dual-stream, which separates paper and card from containers. Collection lorries compress the load to fit more per trip. At the depot, vehicles tip their contents onto a concrete floor, and a front-loader pushes material onto the first conveyor.
Single-stream systems rely entirely on mechanical and manual sorting at the facility. Dual-stream collection lightens that load by keeping fibres separate from containers, which reduces contamination of paper with food residue and makes the whole process faster.
Mechanical separation at the MRF
A materials recovery facility runs several sorting stages in sequence. The first screen is a trommel—a rotating drum with holes—that lets small items and fragments fall through while larger pieces travel onward. Magnets pull out steel cans. An eddy-current separator then repels aluminium using a rotating magnetic field, flinging tins and foil trays onto a separate belt.
Optical sorters shine infrared light at the remaining stream. Different plastics absorb and reflect infrared in distinct patterns, so the machine identifies PET, HDPE and PP, then fires jets of air to push each type into its own chute. Glass, which does not respond to the scanner, drops through to a lower belt. Paper and card, already separated in dual-stream systems or picked out by hand in single-stream ones, bypass most of this machinery.
Manual quality control
Human sorters stand at picking stations along the line, pulling out contaminants the machines missed: crisp packets, black plastic trays that infrared cannot read, textiles, nappies and food waste. They also remove items placed in recycling by mistake—batteries, cables, handbags—and improve the purity of each sorted stream by catching misidentified pieces.
This stage is repetitive and fast-paced. The cleaner your recycling arrives, the less the sorters handle, and the more the facility can process per shift without sending material to residual waste.
Baling and dispatch
Each sorted material is compressed into bales weighing several hundred kilograms and bound with wire or strapping. Paper bales go to paper mills, plastic bales to polymer reprocessors, glass to bottle plants, and metal to smelters. Some reprocessing happens in the UK; much is exported, particularly plastic, which often travels to Europe or Southeast Asia.
A bale rejected for contamination—too much food residue on card, non-target plastics mixed in—can be sent for incineration with energy recovery or, in the worst cases, landfill. Rejection rates vary by facility and by the standards of the end buyer.
Reprocessing: what each material becomes
Paper and card are pulped in water, which breaks the fibres apart. Contaminants such as staples, sticky tape and plastic windows sink or float and are skimmed off. The pulp is cleaned, sometimes bleached, then formed into new sheets. Fibres shorten with each cycle, so most paper is recycled four to six times before it becomes too weak and is mixed with virgin fibre or composted.
Glass is crushed into cullet, washed, and melted at high temperature. It can be recycled indefinitely without losing quality. Colour sorting matters: clear glass for clear bottles, green for green, brown for brown. Mixed cullet is used in aggregate for roads or construction.
Steel is melted in a furnace and reformed into new steel products—cans, car parts, construction beams. The process uses less energy than making steel from iron ore. Aluminium follows a similar path but requires even higher temperatures and yields significant energy savings compared to primary production.
Plastic is shredded, washed to remove labels and residue, then melted and extruded into pellets. PET becomes new bottles, trays or polyester fibre. HDPE is moulded into detergent bottles, drainage pipes or plastic lumber. Each polymer type must be processed separately; contamination with other plastics degrades the batch.
| Material | Main UK use after reprocessing | Contamination risk |
|---|---|---|
| Paper and card | Newspapers, packaging, tissue | Food residue, plastic film |
| Glass | New bottles, aggregate | Heat-resistant glass, ceramics |
| Steel | Cans, construction, vehicles | Non-magnetic metals in the same load |
| Aluminium | Cans, foil, vehicle parts | Steel caps, labels left on |
| PET plastic | Bottles, trays, clothing fibre | Other plastics, caps, sleeves |
| HDPE plastic | Bottles, pipes, outdoor furniture | PVC, polystyrene, coloured HDPE in clear streams |
Why preparation at home matters
Rinsing containers removes food and liquid that would otherwise contaminate paper in a single-stream system or foul the sorting machinery. A yoghurt pot with dried residue can spoil an entire bale of plastic if it is not caught at the picking station. Removing lids and separating materials—metal lids from glass jars, plastic windows from envelopes—keeps each stream pure.
Flattening boxes and bottles reduces the volume your bin holds, so the lorry collects more per trip and the facility processes a denser load. Keeping non-recyclables out—crisp packets, polystyrene, film—prevents sorting delays and equipment jams. The goal is not perfection but consistency: clean, dry, correctly sorted material that reprocessors will accept without penalty.
Steps to improve what you send
- Check your council's list of accepted items and follow it exactly, because facilities differ in what they can handle.
- Rinse food containers under the tap after washing up, when the water is already running.
- Remove lids and caps, and put them in the recycling separately if they are accepted.
- Flatten cardboard boxes and squash plastic bottles to save space in the bin and the lorry.
- Keep a small container beside the sink for items that need a second check—tear off and bin plastic windows from envelopes, peel labels from jars if they do not rinse away.
Common points of failure
Wishcycling—putting something in the recycling bin in the hope it will be sorted—creates work for pickers and increases contamination. Black plastic trays, often used for ready meals, cannot be read by optical sorters and end up in residual waste even when the polymer itself is recyclable. Film and flexible plastics tangle in machinery and usually belong in supermarket collection points, not kerbside bins.
Small items fall through the trommel screen and are lost. Bottle caps, shredded paper and torn card end up mixed with fragments and are harder to recover. Keeping paper whole and caps attached or placed loose in a larger container improves capture rates.
Where your material goes next
Some councils publish annual reports showing tonnages collected, rejection rates and end destinations for each material. Others provide less detail. A circular economy depends on closing the loop—buying products made from recycled content so there is a market for what you send. Recycled paper, glass bottles marked with recycled-content percentages, and clothing made from recycled polyester all signal demand to reprocessors.
Export is not inherently wasteful, but it adds transport emissions and depends on the importing country's standards. The UK has tightened rules on exporting contaminated plastic waste, yet enforcement varies. Choosing to reduce and reuse before you recycle lowers the volume entering the system and the burden on sorting facilities.
Verification and tracking
Some reprocessors offer facility tours or publish video walkthroughs of their plants. Industry bodies such as the Recycling Association maintain directories of UK sites. Packaging marked with the On-Pack Recycling Label tells you whether an item is widely collected, but the final decision rests with your council's contractor and the buyer at the other end.
Related approaches
Reducing packaging at the point of purchase cuts what you need to recycle. Reusable covers and refillable cleaning products lower the flow of single-use containers. Composting food waste at home removes one of the main contaminants from recycling bins and turns scraps into soil conditioner.
Where council services accept food waste separately, using that bin keeps recycling cleaner and reduces methane emissions from landfill. Pairing good recycling habits with waste reduction gives reprocessors better raw material and lowers the total volume the system must handle.
#Recycling #Plastic-free #Circular economy
Download PDF: Recycling prep checklist: 10 steps before the bin PDF, 29 KB
Further reading
Frequently asked questions
How long does it take for recycling to be sorted after collection?
Most materials recovery facilities process and bale recyclables within a few days of collection, though the time from kerbside to reprocessing depends on transport schedules and the end buyer's location.
What happens if I put the wrong thing in my recycling bin?
Sorters at the facility remove obvious contaminants by hand or machine, but items that slip through can spoil a bale and cause rejection by the reprocessor, sending the load to incineration or landfill instead.
Can black plastic be recycled in the UK?
Most kerbside systems cannot recycle black plastic trays because optical sorters rely on infrared light, which the carbon black pigment absorbs, making the material invisible to the scanner.
Where does UK recycling go after it is sorted?
Paper, glass and metal are often reprocessed in the UK or Europe, while plastic is frequently exported to facilities in Europe or Asia, depending on market demand and the material's quality.
Why does my council reject recycling that other areas accept?
Each council contracts with a different materials recovery facility, and those facilities have varying equipment and end buyers, so what can be processed economically differs by area.
Is it better to recycle or reduce packaging in the first place?
Reducing packaging avoids the energy and resources needed for collection, sorting and reprocessing, so buying loose, unpackaged goods or choosing reusable containers has a lower environmental cost than recycling single-use items.