Context:
The Kochi landfill site around Brahmapuram that caught fire earlier this month is a stark reminder that Indian cities need to be prepared for more such incidents as summer approaches.
Relevance:
GS III: Environment and Ecology
Dimensions of the Article:
- What are Landfills?
- How do landfills catch fire?
- Managing Landfill Fires: Permanent Solutions
- Immediate Measures for Landfill Management
What are Landfills?
- Landfills are designated areas where waste materials are buried and left to decompose over time.
- They are essentially large pits or excavated areas in the ground that are lined with a protective layer to prevent contamination of the soil and groundwater.
- The waste materials are then deposited in the landfill and compacted to reduce the volume of the waste and make space for additional waste.
- Once a section of the landfill is full, it is covered with a layer of soil or other materials to prevent odors and litter.
How do landfills catch fire?
- 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.
- Unfortunately, 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 of about 2,500-3,000 kcal/kg, 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.
Managing Landfill Fires: Permanent Solutions
There are two possible permanent solutions for managing landfill fires:
Complete Capping and Closure
- This solution involves capping the landfill material using soil and closing the landfill in a scientific manner.
- However, this approach may not be suitable in the Indian context as the land cannot be used again for other purposes.
- Closed landfills have specific standard operating procedures, including managing methane emissions.
Bioremediation
- The second solution involves clearing piles of waste through bioremediation.
- This process involves excavating old waste and using automated sieving machines to segregate flammable refuse-derived fuel (RDF) from biodegradable material.
- The 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, which necessitates a short-term solution for summertime landfill fires.
Immediate Measures for Landfill Management
When faced with the challenge of managing landfill sites, there are immediate measures that can be taken to mitigate the risk of fires. These measures include:
Dividing the site into Blocks
- Divide the landfill site into blocks based on the nature of the waste.
- Separate fresh waste blocks from blocks with flammable material, and those that have already been capped with soil.
Cap Vulnerable Portions with Soil
- Cap vulnerable portions of the landfill, such as areas with lots of plastics and cloth, with soil.
- Provide enough moisture to the fresh-waste block by sprinkling water, and turn the material regularly for aeration to cool the waste heap.
Classify Incoming Waste and Dispose of in Designated Blocks
- Classify incoming waste upon arrival and dispose of it in designated blocks instead of dumping mixed fractions.
- Send already segregated non-recyclable and non-biodegradable waste to cement kilns instead of allowing it to accumulate.
Clear Dry Grass Material and Trees
- Clear dry grass material and dry trees from the site immediately.
While these measures can help reduce the damage caused by fires, they are not long-term solutions. The permanent solution is to ensure cities have a systematic waste-processing system where wet and dry waste are processed separately, and their byproducts treated accordingly.
Source: Indian Express
