Biodegradation & Composting Trends

Can Bioplastics Save Us From Drowning In Our Own Waste?

Alternatives like paper, cloth, biodegradable plastics, glass, etc have relative merits and no single alternative can be the solution to what is essentially a crisis caused by human behaviour.

Ever since Prime Minister Narendra Modi called out against the use of single-use plastics (SUPs) in his 73rd Independence Day speech, stakeholders have been holding their breath waiting for the other shoe to drop.

Approximately 25,940 tonnes per day (TPD) of plastic waste is generated in India, according to the Central Pollution Control Board’s (CPCB) 2015 report on assessment and quantification of plastics waste generation in major cities.

Of this, around 15,600 TPD (60 per cent) gets recycled, still leaving behind nearly 10,000 tonnes of it.

Additionally, plastic packaging consumption in India is about 4.3 kilogramme per capita and the industry uses about 45 per cent of its total plastic demand to create products that are consumed and discarded within just a few minutes of its first use.

Most of this plastic may be SUPs, but that does not mean it is easily disposable. When discarded in landfills or in the environment, plastic can take up to a thousand years to decompose.

In a bid to get rid of SUPs in the country, an impulsive ban against these plastics may have unprecedented repercussions: One of which is opening the floodgates for ‘bioplastics’ in India.

The bioplastics industry has slowly gained momentum as economies move towards responsible sourcing and leave their oil stained past behind.

With the ever increasing demand for greener innovations, the global bioplastic market value is estimated to reach $35.5 million by 2022.

As we brace ourselves for the incoming onslaught of ‘green’ and ‘eco-friendly’ plastic, we need to first recognise if we have hit the jackpot yet again (of wonder materials) or if is it just another hoax.

Bioplastics — the new wonder material?

Bioplastics is a term that broadly includes bio (mass)-derived plastics and biodegradable plastics. Being sourced from carbohydrate rich biomass, they align with sustainable development and provide the option of quick-fixing our waste problem.

Thus, these plastics are projected as a good alternative to indestructible, fossil derived plastics.

However, a common misconception associated with bioplastics is their biodegradability.

The biodegradability of a polymer is dependent on its chemical structure, not on its source of origin — all biodegradable plastics are bioplastics, but all bioplastics are not biodegradable.

These plastics are not new in India. Supermarkets, online platforms and take-aways offer a mix of alternatives with contentious catch phrases like “this product is not plastic” or “this product is made of corn starch” or “oxo-biodegradable” or “biodegradable” or “compostable”.

For the unskilled consumer, these tags more or less mean the same. They all sound green. But the fact is, these terms cannot be used interchangeably in the lexicon of plastics.

For example, oxo-biodegradables, a greenwashed alternative to plastics, are essentially oil-derived plastics containing additives that accelerate their degradation on exposure to ultraviolet, heat, oxygen, etc.

These are considered to contribute to microplastics and a ban on these plastics is set to take effect in the European Union (EU) by 2021.

Biodegradable is a vague term, if you think about it. It has no defined time frame under which the material will breakdown. Given enough time, all matter will eventually biodegrade say, 500 years for conventional plastics.

In contrast, compostable plastics are designed to completely biodegrade under controlled conditions within 180 days. Their quality and claims are regulated by a set of standards and certifications such as ASTM International, European Norms, DIN Certo etc.

According to Plastic Waste Management (PMW) Rules, 2016, the manufacturers or sellers of compostable plastic carry bags or products are required to obtain a certificate from the CPCB before marketing or selling compostable carry bags or products.

Such compostable plastics are specified by IS/ISO 17088 under the Bureau of Indian Standards (BIS) in India.

Can they live up to the hype?

Bioplastics arguably have a lower carbon footprint than conventional plastics due to their reliance on biomass and their potential to ‘close the loop’. However, the current use of carbohydrate rich crops as feedstock and possible pesticide/fertiliser contamination has been a bone of contention amongst critics.

According to them, bioplastics have a potential to compete for arable land and aggravate food insecurity. This burden on land can be reduced drastically by commercialising innovative secondary and tertiary feedstocks such as seaweed, organic waste, sunlight and microbes etc.

Such innovative sourcing can validate agri-residues and waste.

Despite these benefits, one major limitation against their feasibility in India is their unique disposal requirements.

Compostable bioplastics require controlled conditions (pH, temperature, humidity, etc) that can only be found in industrial composting facilities.

Moreover, these materials take longer to break down as compared to the preferred compost feed (organic waste) and may add toxicity to the resulting compost.

High rate of contamination of these compostable plastic waste streams by conventional plastics further diminish their credibility.

The ambiguity in labelling alongside existing waste management systems increases their risk of leaking into natural environment. The environmental impact, in such scenarios, can be as bad as normal plastics.

Mixing of these plastics with their traditional counterparts can affect the economic viability of the resulting recyclates and damage established recycling streams. In landfills, they will behave like normal plastics, if not worse.

Studies suggest that polylactic acid (PLA, the most common bioplastic) either remain fossilised or undergo anaerobic biodegradation and emit methane.

The latter indicates the potential of PLAs to contribute to global warming if disposed incorrectly, since methane is a greenhouse gas that is 28 times more potent than carbon dioxide.

In the case of littering (and assuming they get buried over time), a study shows that compostable plastics, although no longer functional, remain intact when buried in soil over three years.

Even in the marine environment, biodegradable plastics may not fare any better than conventional plastics and only compound marine plastic pollution.

A step in the only direction

The anticipated policy framework against SUPs may accelerate the influx of biodegradable alternatives into the market, which will invariably, given the present waste management systems in the country, add to the plastic conundrum.

It is imperative for India to strengthen existing policies and improve management systems to streamline their flow from production to disposal before looking towards trendier alternatives.

In order to fully realise the benefits of bioplastics and at the same time mitigate the negative impacts from leakage, we need to invest in R&D.

In addition to the conditions laid out for compostable plastics in the Plastic Waste Management Rules, 2016, the CPCB needs to include a robust identification system for all compostable plastic products and not just for carry bags, revoke the extended producer responsibility exemption enjoyed by certified manufacturers/sellers of these plastics and formulate a comprehensive system to certify and filter out the greenwashed alternatives.

The limitations attached to these alternatives can be a blessing in disguise. It should nudge legislators, businesses and consumers to approach plastic alternatives with caution.

As various life cycle assessment studies have shown, each alternative (paper, cloth, biodegradable plastics, plastics, glass etc) has its relative merits and no single alternative can be the solution to what is essentially a crisis caused by human behaviour.

This should direct us to adopt prudent utilisation of available materials and allocate the right materials for the right applications.

Ultimately, we urgently need to address our throwaway culture, circularise our consumption and production patterns, reduce what we discard and abide by the waste hierarchy.

Cutting down on our consumption and waste is the need of the hour, without it, we would just be creating a different kind of waste altogether.


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Can bioplastics save us from drowning in our own waste?

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