How Waste Is Sorted

How household waste is collected

What happens to household recycling after collection depends on how it was collected. Before anything can be recycled, it has to be separated into clean, consistent streams that reprocessors will accept. Sorting is not the same as recycling. A sorting facility separates and prepares materials, and reprocessors then turn suitable outputs into usable raw materials.

Dry recycling is usually collected in one of three ways:

• Source-separated: households sort materials themselves, for example paper in one box, glass in another and cans in a third.
• Two-stream: paper and card are collected separately from other dry recyclables.
• Co-mingled: the dry recyclables accepted together by the council go into one bin or bag for sorting later. Glass may still be collected separately.

Councils also collect residual rubbish, which is the waste left after items have been separated for recycling and other dedicated collections. Source-separated material usually needs the least processing, because much of the separation has already happened at home or during collection.

In England, the Simpler Recycling reforms set a deadline of 31 March 2026 for councils to collect the specified recyclable streams from households, including weekly food waste. Some councils have agreed transitional arrangements for food waste. Plastic film packaging and bags have a later deadline of 31 March 2027. The reforms set out what must be collected, but councils can still use different bins and combine materials in different ways.

Inside a materials recovery facility

Co-mingled and two-stream recycling is normally taken to a materials recovery facility, or MRF. Machines handle much of the bulk separation. The exact setup varies between sites, but common stages include:

• Trommels and screens: rotating drums or vibrating decks with holes that separate items by size. Small pieces fall through while larger items such as cardboard carry on.
• Ballistic separators: angled, moving platforms that separate flat materials such as paper and card from three-dimensional items such as bottles and cans, which roll away. Small fragments are screened out at the same time.
• Air classifiers: currents of air that lift lighter materials, such as paper and plastic film, away from heavier ones.
• Magnets: overhead magnets that pull out steel cans and other ferrous metals.
• Eddy current separators: a rapidly changing magnetic field induces currents in aluminium and other non-ferrous metals, producing a force that throws them off the belt.
• Optical sorters: sensors, often using near-infrared light, that identify different plastics or paper grades and use short bursts of air to push them into the right channel.

Manual sorting usually involves workers removing selected materials or contaminants from a conveyor belt. People can spot items that machines miss, so many automated facilities keep staff on picking lines for quality control. Both manual and mechanical sorting need proper safety controls for sharp objects, dust, moving machinery and fires.

Paper, card, plastics and cans are often baled for transport. Glass is generally handled separately as loose or crushed material, because broken glass can contaminate paper and damage equipment.

The quality of the output depends on what goes in. Food residue, liquids and items your council does not accept can lower the value of whole loads or get them rejected. Recycling should normally go in loose, since bagged material can obstruct sorting. Empty containers, rinse them where needed, and follow local instructions.

Some contamination is dangerous. Batteries, electrical items and gas canisters can cause fires in collection vehicles and sorting plants. They should never go in household recycling or rubbish bins. Use your council's dedicated collections or retailer take-back services instead.

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Food and garden waste

Separately collected food waste is commonly treated by anaerobic digestion, which breaks waste down without oxygen and produces biogas that can be used for energy. Garden waste usually goes for composting. Because these materials are collected separately, the resulting compost or digestate can be produced to quality-assured standards.

Residual waste and mechanical biological treatment

Some residual rubbish goes through mechanical biological treatment, or MBT. MBT combines mechanical separation with biological treatment, although the sequence and outputs vary. Plants may recover metals and some other materials, stabilise biodegradable waste, or dry waste to help produce a fuel.

Material recovered from residual waste is usually of lower quality than material separated at home, because it has been mixed with food and other contaminants. Any compost-like output or digestate from mixed waste is not equivalent to quality-assured products made from separately collected food and garden waste, and its uses are restricted.

Material not recovered for recycling may be used to produce fuel, sent to energy-from-waste facilities or landfilled. Some is exported as refuse-derived fuel. The balance varies across the UK.