Most of these 'biodegradable' bags aren't doing what people believe: they do not disintegrate into organic material when thrown, like a fruit peel would.

Buying biodegradable garbage bags They may not be as eco-friendly as you thinkImage for representation
news Environment Friday, June 28, 2019 - 13:11

With many states including Karnataka, Tamil Nadu and Maharashtra urging residents to move away from using single-use plastics such as bags, many are looking for alternatives. Take garbage bags for example – they are basics in many households. And now, the market seems to have many options for biodegradable garbage bags, and many happy customers buying them under the impression that they are eco-friendly.

However, most of these biodegradable bags may not be doing what people believe. They do not disintegrate into organic matter and become one with the soil when thrown, like a fruit peel would.

The difference between biodegradable and compostable

The basic thing to understand is that almost everything is biodegradable – it’s just a matter of how much time it takes. While a cloth bag may take a few decades to break down and decompose completely, plastic would take hundreds of years; although microplastics are virtually non-biodegradable.

In contrast, something is compostable if it can completely break down into organic material. So, while an apple is both biodegradable and compostable, a plastic garbage bag being marketed as biodegradable may not be compostable.

The problem is that these words are being used interchangeably. “It’s companies taking advantage of semantics,” Suchismita Pai, Outreach Head at SWaCH, a Pune-based cooperative of self-employed waste collectors and other urban poor, points out.

Harshad Barde, General Secretary of Kagad Kach Patra Kashtakari Panchayat, a trade union of waste pickers, points out that most of the garbage bags being marketed as “biodegradable” are actually oxo-degradable. Oxo-degradable plastics, or oxo-fragmentable plastics as they are referred to in Ellen Macarthur Foundation’s The New Plastics, are those that have additives which trigger fragmentation of the plastic on exposure to heat or UV radiation. “This means that when exposed to these elements, the polymer chains in the bags won’t break down but the additions between them will,” Harshad explains.

Hence, oxo-degradable garbage bags will simply break into smaller pieces - microplastics and nanoplastics – in 45 days to six months, depending on the brand, and the environment.

Further, there are compostable garbage bags, which are made of natural materials like corn starch and should break down completely when put in a composting unit, at the same rate as the other organic waste in the unit, leaving no toxins behind. However, Harshad says that within compostable bags too, most have 5% to 10% of polymer content to make it stronger. “So, when these bags are put in compost units, they do leave behind some microplastics as residue, but it’s not visible.”

The completely compostable bags – which have zero polymer content and are truly biodegradable – generally do not have tensile strength and tend to tear easily, limiting their use.

While activists say that garbage bags marketed as 'oxo-biodegradable' are also oxo-fragmentable, Michael Stephen, Chairman of the Oxo-biodegradable Plastics Association, reveals that oxo-biodegradable bags are actually meant to be "environmental insurance, which automatically removes unwanted plastic if it becomes litter."

"Oxo-biodegradable plastic products are made from ordinary polyethylene or polypropylene. They are made in the same way as normal plastic, but the manufacturer adds a catalyst which accelerates a change in the molecular structure soon after its useful life has expired so that it ceases to be a plastic," Michael tells TNM. He further claimed that oxo-biodegradable plastics degrade into "harmless residues" within a few months to several years if they land up in land or aquatic environments. 

This, as opposed to oxo-degradable plastics, which does not cease to be plastic even when it degrades. It must also be noted this does not mean that oxo-biodegradable plactics are meant for composting. 

What happens to these bags?

A majority of “biodegradable” garbage bags just end up breaking into microplastics, explains Kripa Ramachandran, a Chennai-based independent researcher on waste management. “This is worse because the micro particles become one with the soil, enter water bodies and make their way into the food chain,” says Kripa. 

Harshad points out that the issue is exacerbated by the fact that there is no uniformity in the types of garbage bags in the market. “If there were, say, only compostable bags, people as well as the government could have a standard practice to dispose of them. There is no look and feel mechanism also to tell which bag is which. So, someone may end up putting an oxo-degradable bag into a composting pit or landfill.”  

If these bags end up in landfills, decomposition has little chance in absence of UV light. And in the absence of oxygen, when this bag breaks down, it will release methane which does much more harm to the environment than carbon dioxide.   

Do we even need garbage bags?

Experts say that that ideally, we shouldn’t be using garbage bags at all, and that waste segregation is non-negotiable.

“This system is derived from the West where the trash is not collected every day. I am still not recommending bin liners at all. But they have to collect the trash and store it until it’s collected. Here in India, garbage is collected every day,” Suchismita points out.

Given that people are segregating their waste into wet and dry, and also tend to rinse their dustbins, that is enough to maintain hygiene, removing the need for garbage bags in the first place. “Ideally, people should compost wet waste at home. Biohazardous and sanitary waste has to anyway be wrapped in a manner that it doesn’t have to be handled by hand. Just having your standard bins for wet and dry waste is enough,” Suchismita maintains.

While admitting that hotels and hospitality industries could probably find use for the garbage bags because of the amount of waste they produce, he adds that those producing bulk waste must anyway have composting units or arrange for the wet waste to be biodigested. They could also start using reusable bags made of cloth.

Are there alternatives?

Kripa agrees that segregation at source is the key to waste management. She also argues that there are ethical issues with using compostable trash bags made out of corn starch, tapioca etc. “To make something disposable out of something that is food for thousands of people is problematic,” Kripa says.

When asked if a policy shift would help, Suchismita says that policies such as the plastic ban, when unaccompanied by education, often result in further complications. For instance, non-woven polypropylene bags that became popular after the ban – they looked like they were made of cloth, fooling customers and allowing law enforcement to be hoodwinked. “There is no replacement for education. Without that policies often result in further problems, which mandate more policies,” Suchismita says.

However, if someone absolutely insists on using bin liners, she says that they can invest in thick newspaper bags. “Unless you’re planning to pour in liquids, a newspaper bag can hold wet waste. And for dry waste, a trash bag is anyway not needed. But I wouldn’t recommend bin liners of any kind,” she states.  

People can also look out for "100% compostable" or "organic" written on the packaging of the bags, Harshad offers, given that companies are being honest about it.  

Kripa suggests that one could use online tutorials to make their own compostable bag, and it would help if companies became more transparent about what sort of product they were selling. 

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