Delhi plans to remediate Okhla landfill by end of 2023. How will it do this?

The Delhi government’s Finance Minister, Kailash Gahlot, declared an ambitious deadline during the Budget presentation for clearing all three dumpsites in the capital. The Okhla dumpsite will be cleared by December 2023, Bhalswa by March 2024 and Ghazipur by December 2024, he announced on March 22, 2023. 

Delhi has three major dumpsites: Ghazipur, Okhla and Bhalswa. The three dumpsites are cumulatively covering an area of 200 acres, carrying almost 28 million tonnes of legacy waste. The Okhla dumpsite is about 62 acres, with 6 million tonnes of legacy waste. 

Also read: North America discarded over 5 billion kg of industrial waste in 2018 and most of it went to landfills

The site started in 1996. The legacy waste treatment and disposal by biomining began in 2019 following instructions by the National Green Tribunal.

About 1.5 million tonnes of garbage was treated and removed by the end of November 2022, Municipal Corporation of Delhi (MCD) officials and media reports claimed. After this, a tender was given to a private contractor for treating the rest, about 4.5 million tonnes.

Nearly 700,000 tonnes of additional legacy waste have been treated and disposed of as of March 2023, leaving around 3.8 million tonnes to be treated by the contractor.

How is remediation happening?

Biomining is an environmentally friendly technique to separate fine-soil-like material, construction and demolition (C&D) waste and recyclables like plastic, textiles, rubber and other solid materials from legacy waste buried at dumpsites for years. 

The recyclable materials are sorted and segregated and are channelised for further utilisation, recycling, or scientific disposal. 

Typically, in most cases, trommels of different sizes as per capacities and requirements are used along with other machineries like air density classifiers, compost screens and conveyors for legacy waste handling and sorting. 

Also read: Ghazipur, Delhi: Just why has this landfill been simmering for so long

However, in bigger dumpsites like Okhla, Bhalswa and Ghazipur, the major issue with the use of trommels is space constraints, considering that many trommels are required to achieve the waste sorting target in a day. Also, trommels are stationary machines, limiting their usage in bigger dumpsites. 

Mobile sorting machine having capacity to sort 2,000 tonnes legacy waste per day. Photo: Richa Singh / CSE

On the other hand, mobile sorting machines have huge capacities, ranging 350-10,000 tonnes per hour, depending on the model. These machines are also portable and remote-controlled. So, the movement and operations at bigger dumpsites become easy for achieving higher capacities ranging 5,000-10,000 tonnes per day (TPD). 

Therefore, mobile screening machine are used to overcome these issues in Okhla dumpsites. There are 10 heavy-duty sorting machines, called Kleemann machines, at the site have a 2,000 TPD capacity each. However, the average daily processing is 7,000 tonnes, the private contractor reported. 

Nearly 300 truckloads carrying segregated combustible fractions, C&D waste and fine soil-like material are sent to various facilities for final utilisation and disposal every day. 

Also read: Dumpsite fires are turning cities into gas chambers. They have to be prevented, not controlled

It is important to note that the legacy waste at Okhla dumpsite is mostly decomposed and the moisture content is not high, especially during summers, making its processing easier.

The mobile screens or Kleemann machines separate the waste into three types or fractions, according to size:

• Above 70 millimetres (refuse-derived fuel or RDF and C&D waste like stones, aggregates, etc.)
• 30-70 mm (stones, RDF and inert waste). 
• Below 30 mm (inert waste or fine-soil-like material)

These different types of waste are handled differently.

• Below 30 mm containing sand, soil and small aggregates are channelled directly to the National Highway Authority (NHAI) of India.
• Above 70 mm containing RDF and bigger stones goes to a ballistic separator that segregates the stones and aggregates from RDF. Ballistic separation is a sorting equipment typically used after the material is sorted by size and density. It represents a versatile engineering solution for the high-quality separation and sorting of materials of various kinds, shapes and sizes. In the case of the Okhla dumpsite, coarser materials (above 70 mm) are subjected to the ballistic separation method for separating the stones and aggregates from textiles, plastic sheets etc.  
• Legacy waste fraction of 30 to 70 mm is further subjected to power screens, which remove the aggregates and stones of size between 30 to 70 mm from combustibles. 

Segregated combustible fraction recovered from legacy waste treatment and sorting at Okhla dumpsite. Photo: Richa Singh / CSE

Is December 2023 an achievable target?

The mandate under Swachh Bharat Mission 2.0 looks very promising, with commitments for substantial financial devolutions by the Government of India to remediate the existing dumpsites and improve the solid waste management ecosystem in all the Indian cities, including Delhi.

But a proper roadmap with timelines to achieve the target deadline is critical to the success of the whole endeavour. 

About 3.8 million tonnes of waste at the Okhla dumpsite needs to be remediated. From the pace of work, the dumpsite will need at least a year more to be remediated. 

If we assume the MCD has 14 months for clearing the waste before 31st December 2024 (excluding six months of monsoons for 2023 and 2024) would treat around 3 million lakh tonnes.

Also read: Mismanaged solid waste in Tanzania’s Mwanza city is polluting Lake Victoria

However, as per the claims of Greentech Environ Management Pvt Ltd. (the private agency currently engaged by MCD for biomining of Okhla dumpsite), around 2,000 TPD of legacy waste will also be treated during monsoon months. This would make the total quantity treated in 20 months around 3.3 million tonnes.

There could be an additional burden of 500,000-800,000 tonnes of legacy waste along with the fresh waste which is occasionally disposed of at the site. However, with the current efficiency, the city can manage to get rid of Okhla dumpsite in the coming 20 to 22 months. 

THE OKHLA WASTE CHALLENGE

What can go wrong?

Managing every day municipal solid waste (MSW) has been challenging for the MCD as there is no action plan to implement source segregation in the city. Also, there is a lack of waste treatment and recycling infrastructure to manage the waste, except for the four waste-to-energy plants. 

During a site visit to Okhla dumpsite, a team from New Delhi-based Centre for Science and Environment observed that fresh waste continues to be disposed of at one side of the site even though there is one waste-to-energy plant adjacent to the site with a processing capacity of 2,000 TPD. 

Puddles of leachate were also observed outside the boundary wall of the site due to the trucks carrying fresh MSW. Fresh waste dumping continues to increase the overall volume, making the remediation process an unachievable task for MCD. 

Also read: Europe bans disposal of decommissioned wind turbine blades in landfills: A step towards life cycle sustainability

Besides, some informal waste pickers were seen at the site segregating the recyclables from legacy waste. It is important to note that dumpsite remediation is a scientific process of excavation, treatment and disposal of legacy waste involving heavy-duty machines, equipment and vehicles. 

Engaging with the waste pickers in this activity can lead to various occupational hazards and accidents. 

The quality of fine-soil-like materials could be a matter of long-term environmental sustainability. There are no national standards or guidelines for establishing the fact that the soil-like material recovered from dumpsites is free from any toxic properties and can be used for road construction. 

Even though the ideal way of managing a huge quantum of fine-soil-like material is road construction and filling up low-lying areas. It is critical to use waste fractions recovered from dumpsite remediation safely.

Read more:

• BMC ‘rebate for waste’ scheme should divert waste from Mumbai's landfills
• Why a landfill and waste-to-energy plant in Delhi Ridge is a bad idea
• Polyester recycling: Sector largely informal; home furnishing makers in Panipat, Delhi found flouting norms
• Haryana fined Rs 100 crore: Bandhwari landlfill threat to human health, environment despite repeated orders

We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.