.

  • Written by Jeff Seadon, Senior Lecturer, Auckland University of Technology

Recycling in Australia used to be fairly simple. Our older readers may remember bottle drives, paper and cardboard collections, and the trip to the scrap metal merchant to sell metals.

This is called, in recycling parlance, sorting the “streams”. It creates very clean recycling that requires little sorting at a plant.

But recycling got more complicated. As councils organised kerbside collection, it made less economic sense to sort at the kerb. Instead, trucks collected mixed recycling and took it to centralised sorting facilities.

The materials also changed, with glass often replaced by plastics. Plastics like the PET in drink bottles and HDPE in milk bottles were easy to separate and had a ready recycling market.

Then, when developing countries like China opened the floodgates to paper and plastics, there was no need to separate the seven categories of plastics. It was cheaper and easier for Australian companies to bundle it all up and send it to China for “recycling” – in 2017, some 600,000 tonnes.


Read more: Here's what happens to our plastic recycling when it goes offshore


When China found they were the world’s dumping ground they shut the door and demanded only clean, separated plastics – and then only the ones that had a secondary market in China.

Suddenly Australia was expected to separate more carefully – and this cost money. Now the federal government has pledged A$20 million to boost Australia’s recycling industry.

But what is Australia’s recycling industry?

Right now, there are 193 material recovery facilities in Australia. Most are hand-sorted; nine are semi-automated, and nine are fully automated. These are nowhere near sufficient to sort Australia’s annual recycling.

There are two basic ways to sort recycling: mechanical-biological treatment plants, which sort mixed waste into low-grade recycling, and material recovery facilities, which have a stronger focus on extracting reusable stuff.

Here’s how they work.

Mechanical-biological treatment

MBT plants are in various stages of development in Perth, Melbourne, and Sydney. These plants take the rubbish we generate every day and inject it into a rotary drum (a bioreactor) that spins and is heated to 60–70℃.

The process shreds the waste and the organic wastes are stabilised and homogenised. Most of the water evaporates through a fermentation process in which microorganisms break down the organic material and release heat – much like a composting system.


Read more: Why can't all plastic waste be recycled?


The material then leaves the reactor and passes over a screen that separates the organic waste. The organic waste then fermented and composted, then separated again using a smaller mesh screen. The smallest particles are sent back to the bioreactor drum to provide the microorganisms.

Meanwhile, the larger material from the first screening is sent to a wind separator where the lightweight material, like plastics, are blown the furthest, medium-weight materials, such as textiles, fall in the middle and the heaviest, like metal, glass and stone, fall immediately. The heaviest fraction is sent along a conveyor and metals are separated by a magnetic separator.

The remaining material is sent to another wind separator, along with any remaining material from the other fractions that cannot be separated, which separates combustibles and debris.

The debris (about 10% of the original waste) goes to landfill, and combustibles are sent to a facility that compresses the material into blocks for industrial fuel.


Read more: We can't recycle our way to 'zero waste'


Material recovery facilities

Material recovery facilities accept mixed recycling. The first step is putting recyclables on a conveyor belt where they are carried up to a sorting line.

In the more mechanical processes, people line up along the belt and rip open bags and remove contaminants such as non-recyclable plastic, used nappies and other rubbish, which then goes to landfill.

In the more automated systems, ripping open the bags can be done by machines and the sorting is done in the next stage.



The material then goes onto a scalping screen that sorts out the small foreign objects before passing over a screen in which flat materials such as cardboard pass over and the others drop down. The paper and cardboard go off to storage. Meanwhile, the material that has dropped through hits another screen that breaks any glass, which drops through the screen and is taken by conveyor belt to a recovery bin.

The leftover material goes to fibre quality-control stations where the fibre materials (such as paper) pass by operators who pick off any contaminants before the paper goes into another bin for baling and recycling.

This leaves the cans and plastic containers. Passing this stream over a magnet means any steel cans will be removed from the stream and collected.

Next, any fibre that has made it through the process is removed manually and the plastics are then sorted manually into individual types. The bottles are perforated mechanically so they do not explode when compressed.

With the plastic containers removed, the next step is to divert the aluminium. Powerful magnetic fields created by an eddy current separator throws non-iron metals, like aluminium, forward from the belt into a product bin and non-metals fall off the belt into a separate bin. Finally most of the materials are compressed and baled for efficient transport.

Automated sorting systems

The nine more modern facilities in Australia use optical sorting systems to take out the manual and mechanical sorting. The optical sorters detect anywhere between three and eight varieties of material.

A new facility in New South Wales can detect eight different types of material: aluminium, cardboard, glass, HDPE plastic, mixed paper, newspaper, PET plastic, and steel. The combined stream passes through a light beam which then instructs a set of high pressure air jets to direct the material to one of eight collection bins.


Read more: Australian recycling plants have no incentive to improve


As worldwide demand for high quality, clean recycling material increases, Australia must upgrade its technology. Incentives and financial help for recycling companies may be necessary to see Australia develop a viable domestic recycling industry.

Jeff Seadon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Authors: Jeff Seadon, Senior Lecturer, Auckland University of Technology

Read more http://theconversation.com/how-recycling-is-actually-sorted-and-why-australia-is-quite-bad-at-it-121120

Private health premium increases might be the lowest in years, but that doesn't mean they're justified

Those facing large price increases might drop or downgrade their cover. Wayhome studio/ShutterstockEvery year private health insurers raise premiums and every year we rue the hit to our hip pocket. Th...

Nathan Kettlewell, Chancellor's Postdoctoral Research Fellow, Economics Discipline Group, University of Technology Sydney - avatar Nathan Kettlewell, Chancellor's Postdoctoral Research Fellow, Economics Discipline Group, University of Technology Sydney

So your kid's finished their first year of school. Here's what they should have learnt

Every child progresses at different levels, just like everyone learns to talk and walk at different times. from shutterstock.comIt’s the end of the first year of school for many children and pro...

Jenny Johnston, Lecturer in Primary Education, Southern Cross University - avatar Jenny Johnston, Lecturer in Primary Education, Southern Cross University

5 human rights issues that defined 2019

One of this year’s most refreshing developments was the youth-led action on climate change. AAP Image/Dan PeledAs we approach the last days of the decade, it’s important to reflect on the ...

Elaine Pearson, Adjunct Lecturer in Law, UNSW - avatar Elaine Pearson, Adjunct Lecturer in Law, UNSW

As heat strikes, here's one way to help fight disease-carrying and nuisance mosquitoes

Although yellow fever does not currently exist in Australia, the species Aedes aegypti - which can transmit the disease - is found widely across northern Queensland. The virus remains a global health ...

Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney - avatar Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney

Don't blame the Murray-Darling Basin Plan. It's climate and economic change driving farmers out

For the thousand or so farmers in Canberra in the past week venting their anger at the federal government, it’s the Murray-Darling Basin Plan to blame for destroying their livelihoods and forcin...

Sarah Ann Wheeler, Professor in Water Economics, University of Adelaide - avatar Sarah Ann Wheeler, Professor in Water Economics, University of Adelaide

Expect family talks about climate change this Christmas? Take tips from Greta Thunberg

Swedish climate activist Greta Thunberg is a master of staying on topic. AAP/Julian SmithAs bushfires rage and our cities lie shrouded in smoke, climate change is shaping as a likely topic of conversa...

Peter Ellerton, Lecturer in Critical Thinking; Curriculum Director, UQ Critical Thinking Project, The University of Queensland - avatar Peter Ellerton, Lecturer in Critical Thinking; Curriculum Director, UQ Critical Thinking Project, The University of Queensland

Climate explained: seven reasons to be wary of waste-to-energy proposals

Many developed countries already have significant waste-to-energy operations and therefore less material going to landfill. CC BY-ND Climate Explained is a collaboration bet...

Jeff Seadon, Senior Lecturer, Auckland University of Technology - avatar Jeff Seadon, Senior Lecturer, Auckland University of Technology

In our time of climate crisis, the exhibition Water is a subtly crafted plea

Olafur Eliasson, Denmark, b.1967 Riverbed 2014 (detail) Site specific installation. Pictured: The Louisiana Museum of Modern Art, Humlebæk, DenmarkCourtesy of the artist; neugerriemschneider, B...

Chari Larsson, Lecturer of art history, Griffith University - avatar Chari Larsson, Lecturer of art history, Griffith University

We're still fighting city freeways after half a century

Demonstrations against freeway construction in Melbourne included a street barricade erected in protest at the F19 extension of the Eastern Freeway. Barricade! – the resident fight against the...

Andrew Butt, Associate Professor in Sustainability and Urban Planning, RMIT University - avatar Andrew Butt, Associate Professor in Sustainability and Urban Planning, RMIT University

Why were tourists allowed on White Island?

The volcanic alert level on Whakaari/White Island remains at three, one rung higher than it was when the eruption took place. AAP/GNS Science, CC BY-NDThe official death toll remains at six, and eight...

Michael Lueck, Professor of Tourism, Auckland University of Technology - avatar Michael Lueck, Professor of Tourism, Auckland University of Technology

Curious Kids: why do we get bruises?

From red, to blue, to purple, to yellow and even green – why do our bruises change colour? From shutterstock.com How and why do we get bruises? – Francesca, aged 8. Hi Francesca, thank...

Abishek Santhakumar, Senior Lecturer in Haematology, Charles Sturt University - avatar Abishek Santhakumar, Senior Lecturer in Haematology, Charles Sturt University

To save koalas from fire, we need to start putting their genetic material on ice

Over the coming months, koalas will depend on wildlife hospitals to recover from the effects of unprecedented bushfires. Lachlan G. Howell , Author providedThousands of koalas may have died in fires ...

Ryan R. Witt, Conjoint Lecturer | Conservation Biology Research Group, University of Newcastle - avatar Ryan R. Witt, Conjoint Lecturer | Conservation Biology Research Group, University of Newcastle

(Almost) everyone's a winner? Art is meant to break rules and prizes must adapt

British artists (L-R) Oscar Murillo, Lawrence Abu Hamdan, Helen Cammock and Tai Shani celebrate after being announced as the joint winners of Turner Prize 2019. Vickie Flores/EPALast week Britain&rsq...

Lachlan Warner, Australian Catholic University - avatar Lachlan Warner, Australian Catholic University

Unlawful metadata access is easy when we’re flogging a dead law

After watching this year’s media raids and the prosecution of lawyers and whistleblowers, it’s not hard to see why Australians wonder about excessive police power and dwindling journalisti...

Genna Churches, PhD Candidate, UNSW - avatar Genna Churches, PhD Candidate, UNSW

Why the profit motive fails in education

The disastrous experience of vocational education and training in Australia holds many lessons about trying to fit education into a for-profit market model. www.shutterstock.comThe Morrison government...

John Quiggin, Professor, School of Economics, The University of Queensland - avatar John Quiggin, Professor, School of Economics, The University of Queensland

The X17 factor: a particle new to physics might solve the dark matter mystery

Anomalies in nuclear physics experiments may show signs of a new force. ShutterstockA team of scientists in Hungary recently published a paper that hints at the existence of a previously unknown subat...

Celine Boehm, Head of School for Physics, University of Sydney - avatar Celine Boehm, Head of School for Physics, University of Sydney

The water crisis has plunged the Nats into a world of pain. But they reap what they sow

Angry farmers are pressuring the Nationals to tear up the Murray Darling Basin Plan. Lukas Coch/AAPWhen farmers descended on Parliament House in Canberra this month to demand the Murray Darling Basin ...

Daniel Connell, Research Fellow, Crawford School of Public Policy, Australian National University - avatar Daniel Connell, Research Fellow, Crawford School of Public Policy, Australian National University

8 Factors to Consider When Buying a Standby Diesel Generator

Diesel generators play a vital role in different home and business applications. However, they are commonly known for providing backup power, especially during the mains outage or blackout. Though...

News Company - avatar News Company

2019 was a year of global unrest, spurred by anger at rising inequality – and 2020 is likely to be worse

2019 may well go down as the most disrupted year in global politics since the fall of the Berlin wall in 1989 and the subsequent implosion of the former Soviet Union. However, the likelihood is that ...

Tony Walker, Adjunct Professor, School of Communications, La Trobe University - avatar Tony Walker, Adjunct Professor, School of Communications, La Trobe University

Sick and Tired of Your Dead End Job? Try Teaching!

Tired of the same old grind at the office? Want an opportunity to impact lives both in your community and around the world? Do you love to travel and have new experiences? Teaching English is the perfect job for you! All you need is a willingness to ...

News Company - avatar News Company

The Impact of an Aging Population in Australia

There’s an issue on the horizon that Australia needs to prepare for. The portion of elderly citizens that make up the country’s overall population is increasing, and we might not have the infrastructure in place to support this. Australians h...

News Company - avatar News Company

LifeStyle

Latest Wednesday Lotto Results

Wednesday Lotto draw 3917 Lucky numbers for this draw were 43 followed by 25. The rest of the...

Ways Love and Relationships Benefit Body and Mind

Being in a happy relationship is great. You always have someone to greet you when you come home ...

The Importance of Smiling: How You Can Smile More

Happiness is something we all strive for and is often just out of reach. Of course, it’s impos...

5 Things to Do On Your Wedding Morning

After months of meticulous planning, wedding mornings usually find the bride excited but stressed ...