Stinker: Your garbage is hastening climate change
That is, over and above the emission from legacy waste that has accumulated over the past decades, the garbage dumped at dumpsites emit 79 tonnes of methane every day.
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CHENNAI: It is easy to blame vehicles that spew out plumes of thick, dark smoke for climate change. But what about the banana peel or the leftover food that you threw into the bin yesterday? The garbage strewn over streets and dumped at Kodungaiyur and Perungudi dump yards are not merely eyesores and stinking up the area, they also emit tonnes of methane – a gas that is 25 times more potent than carbon dioxide in trapping heat in the atmosphere.
As per a study conducted by the Centre for Climate Change and Disaster Management (CCCDM), Anna University, for Tamil Nadu Pollution Control Board (TNPCB), biodegradable garbage dumped in Kodungaiyur and Perungudi every day has the potential to emit as much as 28,870 tonnes of methane every year.
Of the 7,663-tonne solid waste generated in the city every day, around 2,363 tonnes are processed at facilities like micro compost centres (MCC), onsite composting centres (OCC), windrow composting and bio-methanation. The rest, which works out to as much as 5,300 tonnes, are dumped at Kodungaiyur and Perungudi dumping yards every day.
That is, over and above the emission from legacy waste that has accumulated over the past decades, the garbage dumped at dumpsites emit 79 tonnes of methane every day.
Explaining that only biodegradable waste emits methane, Professor Dr Kurian Joseph, director, CCCDM, said the total methane emission has been estimated based on the present rate. “If the quantity of waste increases, the emission of methane will also increase,” he cautioned.
When asked about the methane emission from legacy waste, he said that legacy waste also comprises biodegradable waste. Legacy waste staying for a long time might have exhausted its emission, but recently dumped waste can continue to emit, he added.
Underlining how skewed waste generation is, the numbers reveal that Chennai alone accounts for 52 per cent of the total methane being emitted by solid waste in urban local bodies across the State.
Chennai’s single-day garbage generation is about 45 per cent of the total waste generated in the State, and also accounts for 52 per cent of total methane emitted by solid waste in urban local bodies across the State.
In total, Tamil Nadu generates 17,021 tonnes of garbage every day. Methane emissions from the other urban local bodies in different regions range from 600 tonnes of methane per year in the Vellore region to 3,779 tonnes of methane per year in the Tirupur region.
Suggesting the way forward, the study report titled ‘Baseline Study for Waste to Energy - A Pathway to Clean Power Generation’ recommended that methane emission from the disposal facilities can be avoided by enhancing source segregation and increasing biodegradable waste processing by additional facilities for composting and bio-methanation.
“Carbon dioxide emission from the vehicles used for transport of wastes to the disposal facility in Greater Chennai Corporation is 19 tonnes of carbon dioxide per year. This can be substantially reduced by enhancing the decentralised processing of composting and thus reducing the need for transport to centralised processing,” the report said.
Pointing out that the Chennai, Kancheepuram, Coimbatore, Salem and Madurai regions require waste-to-energy plants with a minimum total capacity of 500 tonnes per day, the report recommends carbon capturing technology to avoid emissions from the waste to energy plants. Also, the Greater Chennai Corporation has the potential to set up bio-CNG plants of 600 tonnes per day capacity in addition to the one plant of 100 tonnes per day capacity already in operation to process biodegradable waste.
