Biomining GCC’s Prime Strategy for Solid Waste Management

 Chennai: At a time when public resistance brought the waste-to-energy (WtE) project to a halt, Greater Chennai Corporation (GCC) has moved decisively to revive and expand biomining operations as the prime strategy for solid waste management.

As part of its renewed effort, the civic body floated tenders for the scientific processing of additional 6 lakh metric tonnes (MT) of legacy waste.

The move is being projected by the civic administration and sections of civil society as a more viable and sustainable option for waste disposal in the city.

The Perungudi dumpyard, spread across 250 acres along the city’s southern corridor, has for decades symbolised Chennai’s waste crisis. There were frequent fires, overflow of seepage and public health concerns, causing hardships to nearby residential areas.

Biomining, officials argue, offers a way to undo that legacy without creating new environmental risks.

Biomining involves excavating old dumps, segregating biodegradable waste for composting, recovering recyclables and refuse-derived fuel (RDF) and scientifically disposing of inert material. Unlike WtE plants, which rely on continuous burning of mixed waste, biomining focuses on waste reduction, land reclamation and pollution mitigation.

A senior GCC official said the decision to push biomining at Perungudi reflects the success of biomining in Kodungaiyur and Perungudi.

“Legacy waste is our biggest environmental liability. Biomining allows us to reduce the volume of waste, control methane emissions and reclaim land without adding air pollution risks,” the official said.

According to GCC data, biomining at Perungudi and Kodungaiyur in earlier phases has already helped reclaim over 100 acres, offering scope for green buffers and non-polluting civic uses in the future.

In the Perungudi dumping ground, the biomining works have been undertaken at an estimated cost of Rs. 350.65 crore in six packages since 2022. So far, 26.35 lakh metric tonnes of solid waste (15.57 lakh MT from three packages and 10.78 lakh MT from the other three packages) have been removed, and 94.29 acres have been reclaimed.

When it comes to the Kodungaiyur dumping ground, which spans 342.91 acres, solid waste was dumped across 252 acres. The biomining works were awarded in six packages at an estimated cost of Rs. 641 crore, and the excavation and removal of waste have been under way since 2024.

So far, 22.06 lakh MT of solid waste has been removed through biomining. Approximately 6 acres have been reclaimed through packages 1, 2, 4 and 6.

The renewed emphasis on biomining comes amid strong protests against proposed WtE plants in Kodungaiyur. Residents’ groups, environmental activists and local councillors have repeatedly raised concerns about toxic emissions, ash disposal, and long-term health impacts associated with incineration.

GCC officials maintain that biomining is not a standalone solution but a crucial transitional strategy as the city reforms its waste management system.

“We cannot wish away decades of accumulated garbage. Biomining helps us correct past mistakes while we improve segregation, decentralised composting and material recovery, going forward,” another senior official explained.

Chennai generates over 6,000 MT of municipal waste daily, a figure that continues to strain processing capacity. Officials concede that without strong source segregation and decentralised treatment, even biomining gains could be overwhelmed by fresh waste inflows.

Environmental activists have already welcomed the focus on biomining, though with caveats.

“Biomining is globally recognised as a remediation tool for legacy dumps. It is far preferable to incineration in dense urban settings,” said S. Kumara Raja, convener of the Save Pallikaranai Marshland Forum.

“However, its success depends on scientific execution, strict monitoring and ensuring that recovered RDF does not simply become fuel for polluting industries,” he said.

Raja urged the civic body to focus on source segregation so that it could reduce the amount of waste going to the dumpyards. “The reclaimed land in Perungudi should be retained as marshland, avoiding any kind of developments,” he cautioned.

T.K. Shanmugam, president, Federation of North Chennai Residents Welfare Associations (FNCRWA), said every tonne of waste removed would reduce pressure on dumpyards and the surrounding areas. Biomining aligns better with ecological restoration than any high-energy industrial solution.

Biomining contracts have previously faced delays due to funding issues, contractor performance and monsoon disruptions. There are also concerns about transparency in waste quantification and final disposal of inert material, he said.

However, GCC’s additional 6 lakh MT biomining contract at Perungudi has signalled a policy recalibration. It has acknowledged public concerns while attempting to repair environmental damage caused by years of unscientific dumping.

What remains to be seen is whether biomining will become the backbone of Chennai’s waste disposal strategy.