It’s all getting quite confusing to those who are looking for safer and better alternatives to traditional plastic bags to store and dispose of their waste. But are these so-called alternatives truly safe?
But before we discuss their merits and demerits, let’s understand what and how different they are from each other when it comes to degradability. The following scientific facts have emerged out of the American Society for Testing and Materials (ASTM):
- Degradable: That undergoes significant changes in its chemical structure when subjected to various specific environmental conditions, resulting in a loss of properties that can be measured by standard methods, in a given period of time.
- Biodegradable: That undergoes degradation resulting from the action of naturally occurring microorganisms such as bacteria, fungi and algae. There is no reference to the amount of time needed for degradation or the type of physical and chemical quality attributes of the end product.
- Compostable: That undergoes degradation by biological processes during composting to yield CO2, water, inorganic compounds and biomass at a rate consistent with other compostable materials and leaves no visible, distinguishable or toxic residue.
That explains the process. Now, let’s discuss different types and forms they are available in:
Various terms are being used to describe this particular type of plastic: Biodegradable, photodegradable, oxydegradable, etc. Please note: They are all the same. These are regular petrochemical-based plastics and may take decades or even centuries to break down. Moreover, when they finally degrade, they will leave behind toxic residues.
In this case, the regular plastic is woven, rather than blow-moulded, so that they form a net and will simply penetrate the soil and get depolymerised into smaller fractions due to UV light and biodegradable additives. They have the same negative impact on Nature just as the regular plastic in terms of carbon footprint. The degree of the damage may vary a bit.
Bio-compostable plastic does exist. They are manufactured mainly in Germany, some other parts of Europe and the US. Says Dr Manoj of Pelican Biotech: “Compostable plastic becomes humus, CO2 and water. However the time taken will vary from 3 to 6 months and they don’t carry any EC (no polyphenols) and hence, can be disposed at will.”
Back in 2012-13, I ran a trial run of bio-compostable bags involving 10 more residents in our community and realised that they were not a magic-bullet solution as promised. They remained intact for nearly 6-8 months. Only the overall size shrunk a bit but there was no disintegration as such. Imagine composting 100s of such bags in a day! You will end up with another pile which will take six months or even more to compost (just one batch).
Apart from biodegradable and bio-compostable, you might have also come across discussions on the safety of using bioplastics. It’s quite important to understand this category of plastic as these jargons can get mind-boggling.
Bioplastics are made from natural materials, predominantly corn starch and whole cereal grains. They look very much like traditional plastic bags. But unlike the latter and also biodegradable plastics, bioplastics generally do not produce a net increase in CO2 when they break down. Moreover, some bioplastics are compostable as they break down, decay and blend with soil.
However, there’s a big BUT lurking around here. Not all bioplastics can be harmlessly composted. While some can be, “others leave toxic residues or plastic fragments behind, making them unsuitable for composting if your compost is being used to grow food”.
According to one source, certain bioplastics degrade only when placed in a commercial or industrial composter. In other words, it may not be suitable for your household or community level composting system where the process goes on at lower temperatures.
With already 13 different types bioplastic being manufactured globally, it will be hell of a task to pick and choose the safest one for each one of us, educated or not. For an uninformed consumer, these many categories are too much to handle. This particular anomaly must be viewed with greater concern especially in India where industrial norms to protect environmental ethics can be torn asunder anytime.
No matter which one you opt for, none of them offers you a practical solution. Certain types of bio-compostable bags take too long to compost. Even if you are ready to put up with this mess, you will be burdened by the longer turnaround time of your compost batches. You will also face odour issues as these bags can lump up and cause anaerobic microbial proliferation inside the compost pile.
Segregating them into different categories is nearly impossible for pourakarmikas or your own housekeepers. When thrown around at will, which is usually the case, they can choke the drains and animals might even chew on them. When they enter a landfill, they produce methane, especially the biodegradable ones. Above all, if any unscrupulous manufacturer labels a biodegradable bag as a bio-compostable one, the consumer is the one who stands to lose on all fronts.
Poverty of philosophy
In a country where a sizeable population goes hungry every single day, using such bags made from edible food material just for the sake of one-time convenience amounts to poverty of philosophy. Setting aside huge tracts of land to grow these bags is not something a country like ours can afford.
When we opt for bio-compostable bags, apart from convenience, we are only looking at its eventual degradability. We must spare a thought over its embedded carbon footprint right from growing the edible raw material using water, seeds (GMO or otherwise), nutrients, chemical fertilisers, pesticides, labour, etc., to shipping it to manufacturing units and from there the end product to distribution centres, retail outlets and finally, to your home. It has to travel these many miles only to serve its purpose of lining your bin for a day or two!
If this is not rank arrogance, what is?
(Sources: American Society for Testing and Materials, Mother Nature Network, Bag to Earth, Green Living Online, Explain That Stuff, Alternet.org.)