Solid wastes generate greenhouse gases such as carbon dioxide, methane, and small amounts of nitrous oxide. The global warming potential of methane is 25 times as much and nitrous oxide, 298 times as much as that of carbon dioxide.
Disposal of mixed waste including biodegradable matter (sometimes as high as 60 per cent) in dumpsites across India provides a perfect anaerobic environment for generation of methane and leachate. One tonne of biodegradable waste releases 0.84 tonne of carbon dioxide equivalent emissions if left to decompose anaerobically (in the absence of oxygen when buried in deep pits).
The volume of waste sent to the landfill sites can be reduced if biodegradable waste is processed locally to produce compost. Compost helps store carbon back in the soil. Its usage reduces the need for chemical fertilisers which emit large quantities of nitrous oxide — both during production and in application— and thereby helps mitigate emissions. Compost also improves moisture retention in the soil. We are losing out on mitigation through composting because at most only two per cent of the municipal solid waste in India is composted.
Recycling of dry waste also helps reduce greenhouse gas emissions because the energy required to manufacture a product using virgin materials is higher than when using recycled materials. While India has had a tradition of recycling paper, glass, metals, etc with the engagement of the informal sector, lack of segregation comes in the way of realising the full potential of recycling.This is particularly true for paper that soils easily when waste is mixed. As a result, only 27 per cent of paper in India is recycled, compared with 60 per cent in Japan and 73 per cent in Germany. Recycling requires up to 50 per cent less energy compared to production of paper based on wood pulp, and it also saves trees from being cut.
Disposal of mixed waste including biodegradable matter (sometimes as high as 60 per cent) in dumpsites across India provides a perfect anaerobic environment for generation of methane and leachate. One tonne of biodegradable waste releases 0.84 tonne of carbon dioxide equivalent emissions if left to decompose anaerobically (in the absence of oxygen when buried in deep pits).
The volume of waste sent to the landfill sites can be reduced if biodegradable waste is processed locally to produce compost. Compost helps store carbon back in the soil. Its usage reduces the need for chemical fertilisers which emit large quantities of nitrous oxide — both during production and in application— and thereby helps mitigate emissions. Compost also improves moisture retention in the soil. We are losing out on mitigation through composting because at most only two per cent of the municipal solid waste in India is composted.
Recycling of dry waste also helps reduce greenhouse gas emissions because the energy required to manufacture a product using virgin materials is higher than when using recycled materials. While India has had a tradition of recycling paper, glass, metals, etc with the engagement of the informal sector, lack of segregation comes in the way of realising the full potential of recycling.This is particularly true for paper that soils easily when waste is mixed. As a result, only 27 per cent of paper in India is recycled, compared with 60 per cent in Japan and 73 per cent in Germany. Recycling requires up to 50 per cent less energy compared to production of paper based on wood pulp, and it also saves trees from being cut.
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