The Calcutta Municipal Corporation will mine the 35-metre tall mound of garbage at Dhapa and recover recyclable items from it, a process known as biomining, mayor Firhad Hakim said on Saturday.

The recovered waste will be sent to recycling units to reduce the volume of waste lying at Dhapa and create new space at the site that is overflowing with city's waste.

The CMC has been on the lookout for a new plot for many years but is yet to get hold of any.

There is no new land to dump the city’s daily waste and the CMC was worried where to dump the waste in a few years from now. A CMC engineer said that biomining would help them reclaim the land that now looks out of use.

“We are introducing bio-mining at Dhapa,” Hakim said on Saturday. The mayor, who is also the urban development minister, said the waste management model would be replicated across the state.

“The site at Dhapa where wastes are still dumped is about 60 acres. The accumulation of wastes over the years has made the mounds nearly 35-metres high, which is equal to the height of a 10-storey building, and there is hardly any space for dumping waste. We need new land but that is hardly available,” said an engineer.

An engineer of the civic body said that they had already floated a tender inviting expert companies to do the work. “Under the project, plastic, soil and construction waste will be segregated. Each of these will be sent to recycling plants where they will undergo processing and made fit for reuse,” said the engineer.

Ayan Majumder, a waste management specialist who is advising the state government on similar bio-mining projects elsewhere, said construction and demolition waste could be processed and paver blocks or bricks made from them. The plastic waste can is used in the cement industry, he added.

“In biomining, the legacy waste is screened and its various varieties recycled for new use,” he said. CMC officials said with the removal of legacy waste from Dhapa, free space would be available for use.

But indiscriminate dumping of waste on the recovered land would again give rise to the same problem after a decade or two.

“The CMC is simultaneously looking for agencies to who will build recycling units at Dhapa where the new waste that is coming can be recycled,” he said.

This will naturally extend the life of the waste-dumping site.

Waste management specialists said that across the world recycling and reprocessing of waste is being implemented to deal with the land scarcity challenge.

But the Calcutta Municipal Corporation has an uphill task of introducing waste segregation at source throughout the city. Segregation at source is being done in only 27 of 144 wards managed by CMC.