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India produces 277 million tonnes of municipal solid waste annually, according to a 2016 estimate. This amount is equal to 13% of the global waste. At present, India only has 1604 solid waste treatment plants to treat this waste. They too, are not operating at their maximum capacity. So on an average, India recycles only 20-25% of the waste generated. The remaining waste remains untreated. They are getting dumped on lands or areas drained by water and river bodies. These legacy wastes pose various challenges to India.
India needs to reclaim or recycle or permanently close more than 3,000 dumpsites. It is because of various issues such as unscientific construction, attained maximum capacity, etc. The legacy wastes dumped for a long time create irreversible damage to the environment by leachate, emitting greenhouse gases, pollutes groundwater, etc.
What is legacy waste?
Legacy wastes or aged wastes are the wastes that are collected and kept for years at some barren land or a place dedicated to a Landfill (an area to dump solid waste). Legacy waste can be grouped into four categories:
- Contained and stored wastes (wastes stored in tanks, canisters, and stainless steel bins etc will come under this category)
- Buried waste
- Contaminated soil and groundwater
- Contaminated building materials and structures waste.
Composition of Legacy Waste
Legacy waste composition majorly depends upon the age of the landfill. The legacy waste composition primarily based on four significant fractions. Such as,
- Fine soil / sand-like material: These are the decomposed and mineralized organic wastes mixed with silt, sand, and fine fragments of construction and demolition (C&D) wastes. This is the major fraction in the majority of landfills.
- Scrap polymeric and combustible materials: These include plastics, paper, cardboard and textiles etc.
- Stones (greater than 20 millimetres in size)
- Miscellaneous items: These include broken glass, sanitary waste and diapers, metallic fractions such as razors, needles, etc.
The composition shows few important things:
- The proportion of metals found in legacy waste is almost negligible due to the informal sector engaged in recycling activity.
- The composition of aged waste is not the same as fresh municipal solid waste. The fine soil is the major waste in legacy wastes.
- Nearly 44-75 per cent of the waste (by weight) comprises fine sand/soil-like material alone. According to a study by IIT Bombay, the fine sand will increase according to the age of landfill. Because with increasing time the degradation of organic waste also increases.
The Potential applications of legacy waste
Legacy waste has the potential to create a sustainable business model (SBM). They are,
- The polymeric wastes obtained from dumpsites can be utilised in manufacturing refuse-derived fuel (RDF). Electricity produced from RDF can be utilised by energy-intensive industries and households.
- The fine fraction can be used for several constructions and geotechnical applications such as soil cover in scientific landfills etc.
Need to recover the landfills
- Reclamation of Land: India generates 13% of the global waste but only recycles about 20-25% of them. So landfills gets increased every day. At present India has 48 recognised landfills in India. They collectively occupy nearly 5000 acres of land (few of them are in prime locations). Without considering the environmental and societal benefits, these lands alone considered worth about Rs 100,000 Crore.
- The Capacity of Landfills: It is also important to note that most of the landfills of megacities have already reached their maximum capacity and permissible height limit of 20 meters. For example, Delhi’s oldest Ghazipur landfill and Asia’s largest dumping ground, Deonar in Mumbai, continued to accumulate waste despite the Supreme Court’s order regarding closure of these landfills. Often these landfills are criticised as urban man-made mountains. So treating all these waste itself is a challenge.
- Source for Pollution: The untreated waste is the source of many environment pollution e.g. land, water, air etc. For example,
- Leachate (black liquid oozing out from the waste) contaminates soil and groundwater.
- The release of methane from the decomposition of biodegradable waste under anaerobic conditions can cause fires and explosions. The incident of fire is particularly high during summers. For example, frequent fires in the Deonar landfill in Mumbai and the Bhalswa landfill in Delhi.
- Health Impacts of landfills:
- Uncontrolled burning of waste releases fine particles which are a major cause of respiratory disease and cause smog.
- Dumping sites provide breeding sites for mosquitoes thus increasing the risk of diseases such as malaria and dengue.
Challenges in Managing legacy waste
- The presence of heavy metals poses challenges in managing legacy waste. The finer sand materials consist of chemicals such as cadmium, nickel, mercury, and organic pollutants also.
- There is not enough data available on legacy waste in India. Even if the government wants to reclaim the land by processing the legacy waste, there is no data available with the government on the quantum of legacy wastes in all the landfills.
- One policy is not feasible: The legacy waste components depend upon the age of the landfill. In India waste is dumped in various landfills at various times. This makes the character of legacy waste differ from one landfill to another and even within the landfill itself.
- India do not have enough capacity to process these landfills. At present, India only has 1604 solid waste treatment plants. These plants are not enough to treat the present landfills.
- Unable to follow the CPCB guidelines. The Central Pollution Control Board recommended ‘bioremediation’ to treat the legacy waste and reclaim the old landfills. But bioremediation is only possible for dumpsites having a higher organic content. Since the waste segregation is not done at the source treating wastes with bio-remediation is not feasible.
Note: Bioremediation is the process of using living organisms, like microbes and bacteria, to remove contaminants,
Suggestions to recover landfills
- The government needs to take few important steps to recover the landfills from legacy waste. Such as,
- Carrying out a drone study to assess the exact volume of legacy waste.
- Analysing the technical parameters such as characteristics and composition of legacy waste. This will help in bio-remediation.
- Create mandatory use criteria for recycled materials from legacy waste in government procurements. This will incentivise private players.
- Defining the quantum of heavy metals in recycled materials.
- Encouraging private players by providing incentives like the production linked incentive scheme. This will attract the large private sector to work on waste to wealth-related activities.
- Further, the government also needs to equip local bodies to have affordable technology to treat the legacy wastes. As the legacy wastes demand decentralized solutions.
- Apart from that, India also has to develop skilled and trained professionals to operate and maintain the entire waste management chain. Right from the collection, operation and maintenance of waste-handling plants.
The Municipal Solid Waste Management Rules might talk about the circular economy of solid waste management. But that will be feasible only if the government provides more attention to the legacy wastes. Subsequently, creating awareness to the public on the importance of waste segregation at source.