The demolition of Supertech twin towers left behind 80,000 tonnes of debris, of which 28,000 tonnes will be scientifically processed at a concrete & demolition (C&D) waste plant in Noida by Re Sustainability and Recycling Private Ltd, formerly known as Ramky Reclamation and Recycling Private Ltd.

The company, part of the Hyderabad-based Ramky group, is known to deploy a scientific process for recycling concrete and demolition waste. In 2019, it was granted a tender by the Noida Authority, and a 15-year concession agreement on a public-private partnership (PPP) model was signed between the two.

The plant, located in Noida’s Sector 80, took five months to set up between March and August 2020, and the processing of waste began on October 15, 2020. Spread over five acres, it functions seven days a week. The company has similar plants in Hyderabad, Nagpur, Kolkata, Tirupati and Vijayawada. In the past two years, this plant has recycled 2 lakh metric tonnes of waste.

Mukesh Dhiman, project manager at the plant, has an experience of nearly 10 years in C&D waste management, and heads a team of 16 people including engineers, administrative staff, field and plant operators along with 30 labourers — 10 deployed at the plant and rest in the field.

For processing the debris from the twin towers, staff will work between 8 am and 8 pm, with two hours before and after the shift being dedicated to carrying out maintenance work at the plant.

“It is a very quick process; concrete debris of around 250-300 tonnes/per day from the demolition site will be processed daily. But first, Edifice (Engineering, the firm tasked with the demolition) will be segregating the steel from the debris as the plant can only process concrete. Our per day capacity is 850 tonnes… The debris collected from the demolition site will be brought to the plant, where it will be weighed first at the weighbridge. Pursuant to this, the debris will be unloaded at a vibrating grizzly feeder hopper, which separates and carries the debris to a jaw crusher as it vibrates,” Dhiman told The Indian Express.

“Around 10-15 trucks, each carrying 20 tonnes of concrete debris, will be sent by Edifice for processing at the plant; at a time, the grizzly hopper can accommodate 20 tonnes of concrete debris wherein each block of concrete should not be more than 200 mm,” he said, adding that the machine can process 20 tonnes of concrete in 10-15 minutes.

He further explained the intricate process of recycling the waste:

🔴 After entering the premises, the truck is weighed at the weighbridge, which is linked to a control room at the Noida Authority and real-data time is fed there. Just as the vehicle is about to enter the processing unit, it is drenched in water.

🔴 Then the rubble is unloaded into the grizzly hopper at the processing unit. It is crushed by a jaw crusher installed beneath the grizzly hopper into smaller bits — each block of concrete cannot measure more than 200 mm. From this size, the concrete bits are crushed into smaller sizes — 10 mm, 20 mm and 40 mm. These are called recycle aggregates, which are important for manufacturing sand.

🔴 These various recycle aggregates are separated and transferred through various conveyor belts and collected separately.

🔴 Among these aggregates, the 10 mm, 20 mm and core sand is mixed with cement and hardening chemical to create interlocking tiles, which are used to construct footpaths. The mixture is kept in moulds, wrapped in a large sheet of plastic, and within 12 hours, the final product is ready. The plant manufactures 2,500 tiles every day. Dhiman explained that bricks called CC bricks are also created from the same mixture as a substitute for red bricks.

🔴 Aggregates above 20 mm and 40 mm are used for constructing granular sub-base, which is the foundation for constructing roads, and is also used for filling places that have quicksand. This whole process is guided by wet waste technology as per the C&D waste management rules, 2016.

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🔴 When the concrete debris is fed into the jaw crusher, it converts it into aggregates measuring 10 mm, 20 mm and 40 mm. For converting the aggregates into sand, they are again washed with water and are fed into a hydrocyclone, an equipment which generates centrifugal force and flow to separate sand/soil from water. Around 70,000 litres of water from the sewage treatment plant is used in the manufacturing of sand as well as end products such as tiles and bricks. 70% of this water is reused in the plant. The slurry which is discharged from the plant is treated with a chemical which separates the water from the soil and other particles and is ready for reuse.

🔴 There are several pieces of equipment used at the plant to break down the concrete and recycle it. These are a grizzly feeder hopper, a jaw crusher which crushes the 200 mm of concrete into small bits, a cone crusher which is also used to break large pieces of concrete into finer pieces, a screener which aids in preventing solids like plastics or rags from entering the plant and a hydrocyclone.

🔴 As per sources, a processing charge of Rs 156/per metric tonne will be levied on Supertech Ltd by Noida Authority for processing C&D waste at the plant. Removal of debris from the site will take three months.

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Malavika PrasadMalavika Prasad is a former lawyer and now a City Reporter covering De... read more