Up Front

The effect of banning the bag

The states have moved to ban single-use plastic bags from retail outlets, but just how effective is the blanket ban on keeping plastic bags out of the waste stream?

For a thin film material that represents an approximate 0.1 per cent of waste to landfill, banning the plastic bag has been the subject of much debate over the years.

From Channel 10’s The Project joint petition with Clean Up Australia to get states to ban single-use plastic bags, to a 2017 Four Corners report: Oceans of Plastic, the plastic bag is one issue that has stirred uproar by consumers and environmental scientists alike.

But this 0.1 per cent of landfill waste estimated by MRA Consulting covers five billion single-use plastic bags used by Australians each year. The impact on marine life is a problem that cannot be ignored. CleanUp Australia estimates thousands of marine animals and seabirds die every year across the globe as a result of plastic litter. Moreover, plastic bags can last up to 1000 years in the litter stream.

So it’s only fitting that state governments across Australia have moved to ban single-use plastic bags from retail outlets. South Australia was the first state in Australia to ban single-use plastic bags in 2009, with the Northern Territory and Australian Capital Territory following suit in 2011 and Tasmania in 2013. The Queensland Government announced its decision to ban the bag last year, and its plan passed the parliament in September, while the Western Australian Government recently announced its own statewide ban and Victoria followed suit in October.

The bans vary from state to state. In the ACT, for example, these include lightweight polyethylene polymer plastic bags less than 35 microns in thickness. The ACT Government notes on its Environment, Planning and Sustainable Directorate that the ban has reduced plastic bag use, with shoppers encouraged to bring their own bags. However, while the ban applies to all retailers, it does not cover fruit and vegetable barrier bags. Supermarket checkouts have responded in the ACT by introducing compostable biodegradable bags that are thicker and sold to consumers at a fee.

South Australia, the Northern Territory and Tasmania’s ban applies to lightweight, checkout style bans.

Australia’s two supermarket giants Coles and Woolworths also announced a similar nationwide ban on single-use plastic bags to be introduced by mid-2018.


According to Planet Ark, only three per cent of Australia’s plastic bags are being recycled.

Consumer group Choice states there are four kinds of commonly sold bags: biodegradable, degradable, high-density polyethylene and low-density polyethylene. Biodegradable/compostable bags are made from starches that meets the Australian Standard for biodegradability, allowing them to break down or compost into carbon dioxide, methane, biomass and water. CleanUp Australia notes on its website that biodegradable bags can be used in composting, but may contribute to emissions if sent to landfill.

Retailers in the ACT and other states sell compostable biodegradable bags, while consumers also choose to bring their own reusable bags. Other bags such as barrier bags, reusable retail plastic bags and paper bags are also exempt from the ACT’s ban.

The lack of recyclability between products exempt from the ban has caused some issues in one state. In 2017, the Tasmanian Government launched a probe into the plastic bag ban after it was found retailers were giving away thicker, single-use plastic bags which were not in breach of their ban.

A spokesperson for the South Australian Government also tells Waste Management Review that the government is exploring options such as compostable bags in place of barrier bags, with a trial expected to commence in late 2017.

When it comes to a compostable biodegradable product, the key difference between this and a biodegradable item is that compostable biodegradable products break down fast under defined conditions into raw materials to improve soil quality and support plant growth. All plastics will biodegrade to a certain extent, but it could take years to do so.

Compostable biodegradable bags can also be made of starch-based materials, which enables them to break down faster.

Conversely, degradable bags are petroleum-based plastic which break down into small pieces when exposed to oxygen or sunlight.

High-density polyethylene are lightweight plastic that form the vast majority of single-use plastic bags, while low-density polyethylene are thicker plastic used to make customised boutique bags for higher-end shops.

Yet the question remains: how effective are plastic bag bans on reducing waste to landfill?


Some research has shown the ban to be effective at reducing plastic waste to landfill. According to the ACT Government’s 2014 Review of the Plastic Shopping Bags Ban, plastic waste to landfill reduced by 36 per cent in the two years after the ban from May to October 2013. Bags include single-use plastic bags, boutique bags, reusable bags and bin liners. A common problem identified in the bag ban is that the decision will lead to an increase in bin liner sales, offsetting any potential to reduce plastic bag waste through a retail ban. The ACT’s research showed an initial rise in bin liner sales after the ban, before reportedly returning to pre-ban levels at the time of the review in 2014. It determined that the high sale of boutique bags could indicate households are now substituting these for bin liners, with the survey showing most households hold between one, ten and 20 of these bags at home. The review argues the increased level of boutique bags sold and low numbers of retained in the home suggest they could be used as bin liners.

Other research overseas has been mixed. In Ireland, data from the Central Statistics Office showed that sales of plastic bags decreased to a record low of 85 million after the government introduced a plastic bag levy of 15 cents in 2002. By the end of 2006, it had risen to 130 million. A year later, the government responded to the rise by increasing the levy to 22 cents.

Gary Mortimer, Associate Professor at Queensland University of Technology’s School of Business, believes banning the bag is simply the first step to reducing its impact on landfill, litter and marine life.

“I think there’s two elements at play. One is a genuine interest to remove plastic bags out of the environment, but we also can’t escape the other which would be a cost saving to retailers to remove that line cost out of their expenses.”

Gary notes that a report presented to the South Australian parliament in 2013 showed that while single-use plastic bags decreased by 45 per cent after the government’s ban, the sale of bin liners increased by 65 per cent, as 80 per cent of consumers purchased the bags. At the same time, the supermarket bans generally don’t include plastic bags for the deli, bakery and produce departments, he adds.

“Getting rid of plastic single-use bags out of our supermarkets is seen as a good corporate social responsibility practice, but I think it’s only the tip of the iceberg,” Gary says.

He says that consumers become conditioned to spending money on plastic bags as part of their overall supermarket purchase, as evidenced by Ireland’s data from the Central Statistics Office.

“There needs to be some form of consumer education, certainly around reminding consumers to bring their bags back.

“If retailers are going to sell a plastic bag for 15 cents and it costs them nine cents, some of it needs to be directed into community education schemes such as Clean Up Australia to remove litter out of waterways.”

He says another common problem is consumers leaving their plastic bags at home or in the car and purchasing new ones as a result.

“A fix to this would be a situation where supermarkets, department and convenience stores have a shared bag area where you can actually bring your plastic bags back to the supermarket and leave them for everybody else to use.”



Geoff Johnston, Managing Director of Biobag World, the idea of a shared bag area raises some concerns.

“The issue is you can no longer rely on the bag being food grade. People may have contaminated their bag,” he says.

“Taking the plastic back to the supermarket to be processed by their recycling company could be a good idea.”

He notes that bags need to be biodegradable compostable in order for the ban to be effective. 

BioBag’s products range from bin liners, to kitchen caddies and produce bags and are used by hundreds of councils and major organisations across Australia, including CSIRO. Geoff explains Biobags are made from corn starch and break down in compost to become plant food, and will begin to do so even by being exposed to sunlight in the home.

“The bags will start breaking down in a wheelie bin at home. For example, the bag of food waste in my green waste bin – by the time the truck comes around it’s pretty well gone,” Geoff says.

“So you’re dealing with a substance, that as a replacement to plastic will break down in relatively short periods of time. In compost, by eight or nine weeks it has become plant food.”

Plastics are made from hydrocarbons, which include hydrogen and carbon. Thicker plastic bags are made from longer chains of molecules to withstand greater impact. Geoff says the same process was used in developing the Biobag, which is built to withstand the same impact, but also compostable.

Geoff estimates that in Adelaide, 400,000 households are using a kitchen caddy for their food waste. One of its caddies the Max Air 2, uses an aerobic system that is estimated to reduce the weight of organic food waste transported by council by around 20 per cent. Currently councils are looking at trialling compostable in supermarkets in the south-west of Adelaide. The company continues to grow its customer base in New Zealand, Australia and parts of South East Asia.

Ryan Collins, Recycling Programs Manager at Planet Ark, says biodegradable bags used by the supermarkets should be included in the ban, due to their impact on emissions in landfill.

He adds that when littered, they will still persist in marine ecosystems for long enough to do damage, even if they do break down quicker than synthetic bags.

“Supermarkets should be promoting bring your own bag or those boomerang bags that get re-used and then returned to store. Those heavier bags are pretty much single-use bags,” he says.   

When looking at the potential for bags to create emissions in landfill, Geoff notes most major landfills will have methane capture systems, reducing any negative effect on the environment.

While reducing plastic bag generation may help keep it out of landfill, the organics industry has indicated potential exists to increase the recyclability of plastic bags. Martin Tower, Executive Director of the Australian Organics Recycling Association, says that with the states and supermarkets moving to biodegradable bags, momentum will be created to slowly increase the low recycling rates of plastic bags.

“Nationally, if we are going to divert organics out of landfill, then we need to change the infrastructure that’s been in place and been developed over the last 200 years and that includes the public’s perception of what we do with that surplus material.

“Very few are in existence or licenced because of the challenges of environmental emissions into the local community. An environmentally controlled building will cost between 12 and 20 million dollars, and if a council is releasing contracts for three years for collection and management service, then it really doesn’t work from a financial perspective.”

He says more councils need to take the lead and procure composting services in their local area. The benefits range from improving soil health to power generation and biodiesel manufacturing.

“We would seek the use of compostable plastics wherever practical to ensure that when it does come into the organic waste stream it can still be composted.

“Implementing national policies such as banning supermarket plastic bags is all well and good, but what we really need is to start at the other end and commit to recycling this material.”

He notes the Federal Government’s National Food Waste Strategy should hopefully drive change, with a working group established with input from industry stakeholders.

“If enough people feel we need to make that change, then I’m sure the politicians will get behind that. It’s not a top of mind issue at the end of the day.”

Planet Ark’s Ryan also agrees that more councils and state governments need to take the lead by introducing policies surrounding compulsory recycled content.

“Shopping bags can be converted into outdoor furniture, bollards, flooring and fencing, so councils would be a main target market for that product.”

Coles did not respond to a request for comment.

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