Use biodegradable bags, avoid polythene ones: Experts

Hyderabad: Many bags claiming to be environment friendly, carrying prints such as ‘I am not a plastic bag’ or ‘100% compostable’, are in the market, leaving consumers unclear on the difference between them.

Biodegradable objects are products, such as papers, boxes and bags, which can break down completely.

Dr K. Veera Brahmam of the Defence Research and Development Organisation (DRDO), explaining the difference between biodegradables and compostables, highlighted the hazards of polythene bags.

Dr Brahmam said, “Polyethylene bags, which are made from petroleum, take more than 200-300 years to degrade in the soil, whereas biodegradable bags do within 90-120 days. In the open, the microbial activity starts in 60-80 days, which degrades these bags into microscopic pieces of, say, two microns 1,000 microns make a millimetre —  and they gets absorbed without leaving any toxicity.”

“At DRDO we make compostable bags that turn into manure after around 120 days. These are made up of polybutylene adipate terephthalate (PBAT) — one of the biopolymers and corn starch and additives, which turn into manure and serve nutrition to the soil after composting,” he said.

Dr Brahmam stressed that it was crucial to look for a substitute for polythene bags and that biodegradable bags could serve as a sustainable and eco-friendly alternative.

He said, “We chose corn starch as one of the main ingredients in making the compostable bags as corn is abundantly available in India. We have added fillers and additives to add strength to the bag, but we have also given a shelf life of 90-120 days to the bags for one time use and easy degradation. Even if these bags are consumed by animals or enter water bodies, they will not cause any harm.”

Md Azahar Moinuddin, CEO of a city-based company that manufactures compostable bags, said, “We make 100 per cent compostables from natural ingredients and corn starch. It means that these bags break down into small particles within 60 days and mix with the soil. It does not need any processing. Such bags are manufactured in the green industry category. These bags come with the ‘I am not a plastic bag’ tag and also specifies 100% compostable with the IS0 17088 certification, indicating that the bag is eco-friendly and will not produce any microplastic.”

Biodegradable:

The American Society for Testing and Materials, an international standards organisation, defines biodegradables as “anything that undergoes degradation resulting from the action of naturally occurring microorganisms such as bacteria, fungi, and algae.”

Compostable:

ASTM defines compostables as “anything that undergoes degradation by biological processes during composting to yield water, inorganic compounds and biomass at a rate consistent with other compostable materials and leaves no visible, distinguishable or toxic residue.”

Testing:

There are two preliminary tests which can be conducted to identify if a bag is biodegradable. The first is the burn test, in which biodegradable bags leave behind ash as residue, and the second is the dichloromethane test, as it dissolves biodegradable bags.