The Kochi landfill site around Brahmapuram that caught fire is a stark reminder that Indian cities need to be prepared for more such incidents as summer approaches.
What are landfills?
A landfill is an area of land that is used to dump garbage, either directly on the ground (landraising) or filling an unwanted hole in the ground (landfilling).
Types of Landfills
- Municipal Solid waste (MSW) Landfills:
- MSW landfills are the most common types of landfills and is where Household Waste is disposed.
Industrial waste Landfills:
- These landfills dispose of commercial and institutional waste.
- Hazardous Waste Landfills:
- These facilities receive specialty waste that needs to be carefully handled because it has the potential to be harmful if not disposed properly.
Waste generation in India:
- Every year, 2.01 billion tonnes of municipal waste is generated.
- India produces 277 million tonnes of municipal solid waste every year.
- In India, 77% of waste is disposed of in open dumps, 18% is composted and just 5% is recycled.
- A significant 34% of all waste is generated by just 16% per cent of the world’s population, largely from high-income countries, but more than one-third of this waste is recovered through recycling and composting.
- In low-income countries the problem is of waste mismanagement — over 90% of waste is not disposed of correctly, leading to higher emissions and risk of disaster
How do landfills catch fire?
Waste collection in India:
- India’s municipalities have been collecting more than 95% of the waste generated in cities but the efficiency of waste-processing is 30-40% at best.
- Municipal solid waste consists of about 60% biodegradable material, 25% non-biodegradable material and 15% inert materials, like silt and stone.
- Municipalities are expected to process the wet and dry waste separately and to have the recovered by-products recycled.
Slow rate of processing:
- The rate of processing in India’s cities is far lower than the rate of waste generation, so unprocessed waste remains in open landfills for long periods of time.
- This openly disposed waste includes flammable material like low-quality plastics, which have a relatively higher calorific value and rags and clothes.
- In summer, the biodegradable fraction composts much faster, increasing the temperature of the heap to beyond 70-80°C.
- A higher temperature coupled with flammable materials is the perfect situation for a landfill to catch fire.
- Some fires go on for months.
- There are two possible permanent solutions to manage landfill fires:
- The first solution is to completely cap the material using soil, and close landfills in a scientific manner.
- This solution is unsuitable in the Indian context, as the land can’t be used again for other purposes.
- Closed landfills have specific standard operating procedures, including managing the methane emissions.
- The second solution is to clear the piles of waste through bioremediation.
- It implies to excavate old waste and use automated sieving machines to segregate the flammable refuse-derived fuel (RDF) (plastics, rags, clothes, etc.) from biodegradable material.
- The recovered RDF can be sent to cement kilns as fuel, while the bio-soil can be distributed to farmers to enrich soil.
- The inert fraction will have to be landfilled.
- However, implementing a bioremediation project usually takes up to two or three years, necessitating a short-term solution for summertime landfill fires.
Some immediate measures:
Dividing waste into blocks:
- The first immediate action is to divide a site into blocks depending on the nature of the waste.
- The different blocks should ideally be separated using a drain or soil bund and a layer of soil should cap each block.
- This reduces the chance of fires spreading across blocks within the same landfill.
- The most vulnerable part of the landfill — the portion with lots of plastics and cloth — should be capped with soil.
- The fresh-waste block shouldn’t be capped but enough moisture should be provided by sprinkling water and the material should be turned regularly for aeration, which helps cool the waste heap.
Classifying the waste:
- Once a site has been divided into blocks, the landfill operator should classify incoming waste on arrival to the site, and dispose them in designated blocks rather than dumping mixed fractions.
Reduce accumulation of waste:
- Already segregated non-recyclable and non-biodegradable waste should be sent to cement kilns instead of being allowed to accumulate.
Removal of dry grass:
Dry grass material and dry trees from the site should also be cleared immediately.
The way forward
- Around 100 cities are set to be developed as smart cities.
- Civic bodies have to redraw long term vision in solid waste management and rework their strategies as per changing lifestyles.
- They should reinvent garbage management in cities so that we can process waste and not landfill it.
- To do this, households and institutions must segregate their waste at source so that it could be managed as a resource.
Recycling of waste:
- The Centre aims to do away with landfill sites in 20 major cities.
- There is no spare land for dumping garbage, the existing ones are in a critical state.
- It is reported that almost 80 per cent of the waste at Delhi landfill sites could be recycled provided civic bodies start allowing ragpickers to segregate waste at source and recycle it.
- Compost pits should be constructed in every locality to process organic waste.
- Community participation has a direct bearing on efficient waste management.
- Recovery of e-waste is abysmally low, we need to encourage recycling of e-waste on a very large scale level so that problem of e-waste disposal is contained.
SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB