How is Recycling Sorted?

How is Recycling Sorted?

What happens to your recycling once you have methodically washed and sorted it at home? Well, it needs to be sorted further, and contamination is removed, before materials can be made into either new materials or new products.

We are recycling more than ever, but for recycling to be effective, it needs to be sorted appropriately to maximise the amount of materials that can be recovered.

New technologies are being implemented constantly to improve the efficiency and effectiveness of the waste sorting process.

The recycling process

Once your rubbish has been collected, it will usually be taken to a Materials Recovery Facility (MRF). The waste bags are opened and the waste is put on to a conveyor belt and moved into a processing area. First, the waste will go into a pre-sort area, where any items that can’t be recycled are removed, and then the materials move into an area where they can be sorted automatically by machines, or manually by workers.

What happens to different materials?

• Glass, plastic, metal, card, and paper pass through trommels, which are screened cylinders or drums that separate materials by size. A 45mm trommel removes broken glass, and a 170mm trammel separates newspaper, paper, card, plastic, and metal from oversized options.
• Air classifiers separate lightweight materials, such as paper and cardboard, from heavier items.
• Plastic, metal, card, and paper are further sorted by ballistic separators. Plastics are then separated by an optical scanner and infrared sensors, which can identify different polymers and separate them by colour.
• Huge magnets sort steel cans, and an eddy current separator creates a strong magnetic field to disperse aluminium into a separate collection area.
• Paper and card are sorted into different grades.
• All materials are given a final check before they are dispatched.
• High quality recyclables are sold to be made into new products.
• Separated materials are rolled into bales and loaded on to lorries to be transported and reprocessed.

Where are the materials taken?

• Paper is taken to papermills where it is made into newspapers, magazines, tissues, toilet paper and cards.
• Card is turned into cardboard packaging.
• Food tins are sent to steelworks, where they are recycled into anything from paperclips to coat hangers or even vehicle parts.
• Aluminium cans are made into new drinks cans.
• Plastic bottles can be recycled into many different products, including garden furniture, road signs and fleece jackets.
• General household waste is taken to an Energy-from-Waste (EfW) plant, where it is incinerated and the heat energy that is recovered is used to produce steam which can be used to generate electricity for the national grid.

Recycling reforms 

Regulations have been introduced across the UK in an effort to increase recycling and reduce contamination. In England, Simpler Recycling reforms are being phased in, requiring workplaces to separate the core recyclable materials. It follows similar measures in Scotland and Wales. The UK has set a target to recycle 65% of municipal waste by 2035. This is one reason why recycling and sorting processes need to be as efficient and effective as possible.

Separation technologies

Most waste facilities use one or more of these methods to sort materials for recycling:

• Trommel separators/drum screens

This technology can separate materials according to their particle size. Waste is fed into a large drum which rotates. The drum is perforated with holes, and any material that is smaller than the holes will drop through, while the larger particles will stay inside the drum.

• Eddy current separator

This method is used for the separation of metals. An ‘eddy current’ is created when a conductor is exposed to a variable magnetic field. The magnetic field separates certain types of metals from others.

• Induction sorting

Material is sent along a conveyor belt which has sensors underneath. The sensors locate certain types of material then separate them using fast air jets.

• Near-infrared sensors (NIR)

When materials are illuminated they reflect light, and the infrared sensors can distinguish certain materials from others based on the way they reflect light.

• X-ray technology

X-rays can be used to distinguish between different types of materials based on their density.

• AI-assisted sorting 

High-speed optical sorters use sensors and cameras to identify different materials. In some modern recycling facilities, artificial intelligence helps to recognise objects, while robotic arms separate waste into different material streams.

Article updated June 30, 2026

Images courtesy of WRAP UK