The Supertech twin towers took nine seconds to vanish from the Noida skyline, but the mountain of rubble they left behind would take months to clear and is likely to pose a hazard to building structures nearby and add to air pollution.
The Apex and Ceyane towers in Emerald Court in Noida’s Sector 93A on August 28 became the highest buildings to be demolished in India, a little over a year after the Supreme Court ordered them razed for illegal construction.
Approximately 35,000 cubic metres of rubble would be left behind after the demolition, according to calculations made by project officials. As per the plan, the basements of the towers would house a big chunk of the debris, while the remainder would be transported to a remote area of Noida and processed scientifically.
Experts, however, have flagged concerns over construction and demolition (C&D) waste created by the demolition.
Where will the waste go?
The Noida planning authority states that 21,000 cubic metres of debris will be transported to and dumped in a remote area within the city's Work Circle 7 boundaries. According to reports, the identified area is six hectares in size. The remaining waste will be buried/stored in a pit dug at the twin tower site.
This implies that approximately 1,200 to 1,300 "truckloads" of debris would be removed from the site.
Also read: Noida Supertech buildings razed. What happens to the homebuyers now?
Experts raise concerns
Rajesh K, a C&D waste demolisher in Bengaluru said, "The plans for C&D waste in Supertech demolition seem ambiguous and vague. The recycling plant in Noida has a capacity of 300 tonne per day and it will take almost three months to recycle the waste carried to the plant."
According to a 2016 notification by the Central Pollution Control Board (CPCB), every state to set up C&D waste recycling plants in all cities with a population of more than 10 lakh.
Rajesh said the waste left behind in the basement will pose serious threats to the environment and nearby residents. "When we leave the waste in the basement, there are chances of water seeping into the holes created by the explosion leading to water accumulation. This may affect the stability in the soil around the site, weakening the building structures nearby," he added.
Experts also said that the rubble from the demolition is in large chunks and needs to be cut into smaller pieces for transportation to recycling plants. "This will happen over the next three months, and may add to the air pollution as we will be adding fine particulate matter into the air," Rajesh said.
"At this moment, some parts will be taken to the recycling plant. Now, we have to ensure what has been taken to the recycling site should be quickly turned back into recycled materials to minimise the impact on carbon footprint," Anumita Roychowdhury, Executive Director, Centre for Science and Environment said.
The waterlogging at the cavity area may have several impacts including pollution of groundwater, she said. "The debris will contain several toxic chemicals due to the explosives, and when water percolates into the water table below, it may carry chemicals with it," she added.
"We need to understand if the builder has a clear plan to take the debris away from the site. As of now, their strategies are unclear, she said.
Also read: Noida twin towers demolition: Timeline of key events
Debris clearance
Experts said while there are rules about recycling building waste, most of the time it is dumped in landfills or on city outskirts.
"This problem is prevalent across the country," Akash Vashisht, an environmental lawyer, said, adding the damage it does to the environment is equivalent to that wrought by plastic or other forms of waste.
"After the demolition, we have to segregate the waste into different components like steel, soil, etc and transport them for recycling. It is an opportunity for local authorities to show the best practices of implementing C&D waste management rules," he said.
Also read: Twin tower demolition 'largely successful'; residents can return after 6.30 pm: Noida CEO
Past demolitions
Rajesh said Edifice Engineering, the Mumbai-based firm that carried out the Supertech demolitions, has done two major demolitions in the past, one in Kochi and another in Bengaluru two months back.
"In the case of apartments in Maradu, Kochi, Edifice has removed the steel and left behind the debris for months that led to several National Green Tribunal cases," he said.
Also read: Twin towers demolition: Supertech says it lost Rs 500 crore
In 2021, the Kerala State Pollution Control Board said, the Maradu municipality has not yet provided facilities following the requirements of the Solid Waste Management and Construction and Demolition Waste Management Rules, 2016.
"In the case of Bengaluru, the recent demolition of floors at Raheja building in Koramangala, we did not get a single truckload of construction waste," he added. Other environmental experts in Bengaluru add nobody knows where the construction debris was sent.
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