What can you actually put in your yellow recycling bin? An environmental scientist explains

Expert commentary by CQUniversity Science lecturer and environmental scientist Dr Emily Bryson.

Most of us want to recycle, but it can sometimes be hard to know exactly how.

Do jar lids and bottle caps go in the yellow bin? What kinds of plastic can be recycled?

And given that food residue can mess up the machines used to recycle waste, how clean do things need to be before they get recycled?

Much depends on where you live

The first thing to know is what’s accepted in your yellow-lidded kerbside bin depends on where you live and what your local material recovery facility can actually recycle.

Online search tools such as Recycling Near You and the Australasian Recycling Label’s “check locally” feature let you enter your postcode and look up how to dispose of specific items.

When in doubt, check for Australasian Recycling Labels on packaging before you bin it. A “chasing arrows” symbol indicates the item is accepted in more than 80% of kerbside recycling bins. However, not all packaging has these labels. Some carry multiple labels.

Aluminium

Aluminium is what soft drink cans are made from, and it’s a high value metal. It’s worth recycling, but size matters.

Aluminium doesn’t contain iron, so it’s not magnetic.

In other words, the magnets used in waste recycling facilities to separate metals from other recyclables won’t pick up aluminium cans or foil.

Instead, aluminium items are sorted using a process known as eddy current separation.

When items travel along a conveyor belt at a sorting facility, they move past a fast-spinning magnetic rotor at the end. This rotor creates a repelling force that flicks the aluminium items off the conveyor belt and into collection bins.

But this force isn’t strong enough to recover small items like jar lids and wine bottle caps.

When it comes to recycling metal jar lids and metal or plastic bottle caps, every recycling facility has different rules.

Some need the lids to be left on their containers. Others require lids larger than 5cm to be removed before placing them in your mixed recycling bin or dropped off at a collection site.

If you’re not sure, ask your local council or search Recycling Near You or the Australasian Recycling Label site.

Plastic

Recycling plastic is great, but only about 46% of collected plastic is processed domestically, with a lot sent overseas for processing.

Most plastic still ends up in landfill due to contamination and low recovery rates.

Packaging made from a single type of plastic, such as translucent high-density polyethylene (HDPE) milk bottles, are easiest to recycle into new products.

But only around 40% of these get collected for recycling through kerbside bins and dedicated drop-off locations; the rest don’t get collected at all.

Plastic caps and labels on HDPE bottles are often made from a different type of plastic (polypropylene), so they should be removed before recycling.

Rigid plastics, such as drink bottles, are easier to recycle than soft plastics, but their quality degrades with each recycling cycle.

Most single-use soft plastic packaging ends up in landfill.

Chemical recycling for soft plastics is a relatively new technology in Australia. However, it’s not widely available, is expensive and comes with environmental and health concerns.

Contamination

Recycling systems can only work effectively when packaging is clean and free from contaminants.

Food and liquid remnants, labels and small pieces of packaging can get tangled in machinery. Even small amounts of food residue can introduce germs and odours into recycling loads.

This is difficult and costly to remove, and ultimately reduces the quality of recycled materials, especially those intended for food packaging.

Packaging doesn’t need to be squeaky clean, but it should be rinsed and placed in the recycling bin dry.

Labels and seals on packaging are also an issue. Paper labels and water-soluble glues generally wash off during processing. However, tamper-proof seals – such as the ring around the base of a soft drink bottle lid – and plastic-coated labels don’t. These materials are hard to remove and can contaminate the recycling process.

Plastic-coated and polyvinyl chloride (PVC) labels – which you sometimes find on, for instance, a punnet of strawberries or milk bottle – are a challenge. They’re usually made from a different plastic than the container itself, which means they can’t be recycled together.

Removing them before disposal helps ensure a cleaner, more recyclable product.

Multi-layered packaging is another problem. Cardboard-like items such as long life milk cartons and potato chip tubes are made from layers of paper, plastic and sometimes metal foil – all laminated together.

Since these layers can’t be separated easily or efficiently, the packaging can’t be recycled through most kerbside bins. It usually ends up in landfill.

The bigger picture

Consumers still bear the burden of responsibility on knowing what can and can’t be recycled. At the end of the day, recycling infrastructure is still limited and too much is being landfilled.

We must redesign packaging for reuse and to work within the system we have.

This article is republished from The Conversation under a Creative Commons license. Republish via the original on The Conversation website.