The saga of clearing legacy waste

Bengaluru: Mandur and Mavallipura, the first two famous backyards of Bengaluru, where the waste of the city found its way, bore the burden of the growing city in ways that other areas did not experience. People there suffered in various ways, their quality of life being hit by poor air, contaminated water and poisoned soil. Skin diseases and respiratory illnesses were common then, and the Bruhat Bengaluru Mahanagara Palike (BBMP) supplied water to the village through tankers. This was in 2013.

When villagers and real estate lobbies protested against these two landfills, it also led to a public interest litigation and a court-monitored process to set right the garbage collection and transportation in Bengaluru. 

Today, occasional garbage fires are common in Mandur, though no more waste is dumped here by Bruhat Bengaluru Mahanagara Palike (BBMP). Many villa and apartment communities here have been working with the BBMP and local Panchayat to fix the issue.

According to Mandur Panchayat members and staff, all is well, and the water quality is good. “We have been supplying clean water to the villagers. Apartments take care of their water needs through tankers and groundwater, but the villagers get clean water from the panchayat. There is no complaint from anyone,” said a worker from Mandur Gram Panchayat. 

He added that borewell water extracted from the ground is used for washing and other cleaning purpose, while reverse osmosis-based water filtration plants provide drinking water.

Mandur Panchayat President Timmaraju said there have been no issues as of now, as the dump fire is under control because of the efforts by Panchayat and BBMP officials. However, the Panchayat has been slow in learning by observing the problems that legacy waste has created for years. They also dump the trash in a nearby vacant plot. Officials said there will be a plan soon to sort this out and have a segregated waste management system.

No one yet knows when the work of biomining will start at the second dump that catches fire. Staff at the site said that work is currently being done to control the fire and that the biomining work will begin soon.

The work of biomining is in the north part of the dumping. A staff of the firm that was awarded the biomining work said the process has been smooth. He said the process involves opening the waste in layers for drying and then segregating it into plastic and biodegradable waste. 

“All leachate goes into a pond inside the dump yard, and it does not pollute larger groundwater table,” he added. When asked what happens to the compost, he said interested farmers take it free of cost.

However, a person in the know who preferred anonymity said the compost, or bio-earth, was being sold to farmers, but this was stopped after an inspection by Bengaluru Solid Waste Management Limited (BSWML). “It is a risk; sometimes the quality does not match the guidelines prescribed by CPCB. Therefore, we do not give it away to farmers anymore,” the source added.

According to staff, the biomining produces four byproducts:1) bioearth, which is the compost mixed with soil; 2) refuse-derived fuel made from plastic which is sent regularly to the Karnataka Power Corporation Limited’s biogas plant at Bidadi; 3) recyclables such as metals and plastics 4) Inserts that go to designated landfill provided by BBMP.

Bagaluru landfill was the first to be capped with mud, but methane emissions were a norm even there. Other landfills, such as Lakshmipura and Bingipura, also saw methane emissions and water contamination in the area. The latest dumpsite, Mitaganahalli, has been no exception to any of the problems.

Residents around landfills say no action is taken by the Karnataka State Pollution Control Board or the BBMP to improve their lives.

Mavallipura has a slightly different story than Mandur, with no biomining work occurring here and cases still running the court. “The court ordered that purified water be provided and the filtration process be monitored. This was done as per the court’s direction, and we used to receive lab reports about groundwater pollution. It stopped in 2017. Borewell water is polluted, and no one is monitoring water quality these days,” says Srinivas, a farmer leader from Mavallipura. 

He said no water is being supplied by the BBMP either, and groundwater at borewells 500 metres away from the landfill was polluted and unpotable. He termed statements of officials as whitewashing. He said biomining would help sort out some of the issues in the Mavallipura landfill.

What is biomining?

Unsegregated, mixed municipal solid waste dumped over the years, also called legacy waste, contaminates air, water and soil through various forms of emission. Methane emission is the most hazardous, which causes natural fires at dumpsites. Leachate from the waste causes water and soil pollution in the area, as it can contain all forms of chemicals and hazardous waste.

To stop odours and methane emissions, landfills are usually capped with soil. Landfills such as Mandur and Mavallipura were mud-capped, as biomining or bioremediation of legacy waste had not taken off in India in 2012 at a big scale.

The Solid Waste Managament Rules 2016 mandate clearing of sites as a first option, by bio-mining and bio-remediation. The handbook by CPCB, titled Guidelines for Disposal of Legacy Waste (Old Municipal Solid Waste), was created in 2019 in accordance with Solid Waste Management Rules, 2016, Plastic Waste Management Rules, 2016 as amended 2018, IPCC Third Assessment Report, 2001 and other standards and rules. 

This says clearing a dumpsite rather than capping it is a better option for permanent pollution prevention. Cleared sites require no after-care, but capping requires at least 15 years of continuous leachate pump-out and treatment in a dedicated effluent treatment plant. Extracting methane gas is complex and inefficient as pipes are inserted into dumped waste instead of before dumping begins, notes the guidebook.

Clearing the legacy waste by bio-mining recovers the entire base area of a dump at almost ground level. Capping the waste makes only one-third of the base area usable and increases the height. There is no guarantee that the capped land will stay firm, so it cannot be used for more than 30 years for any stable structures. The leachate from this will continue to pollute the water table for years.

Therefore, clearing the legacy waste by recovering whatever can be salvaged and sending the rest to landfill makes sense. After a commitment in 2013 by the Bruhat Bengaluru Mahanagara Palike (BBMP) at the hearings related to garbage at the high court of Karnataka to bio-mine the legacy waste at Mandur, the plan was back on the table in 2019 after the National Green Tribunal also ordered that the legacy waste be cleared soon.

The CPCB guidelines say a buffer zone must be demarcated and declared to ensure no new habitation for upto 500 metres around the cleared site in order to prevent real-estate activity from encroaching the buffer as soon as the dump is removed.

In dumpsites located inside a growing city where biomining is in progress, the contractors must identify the planned future use of that site and put up a signboard indicating that usage. This ensures public acceptance of the biomining operations, which will be temporarily noisy and dusty, and protects it from land grabbers as well, says the guidebook. Nothing of such sort is visible on the Mandur site, and the land where the work is ongoing belongs to a charity trust.

The guidebook specifies how the activity of biomining and bioremediation should be carried out. The contractor must create facilities to control or mitigate the emission, pollution and contamination of air, water and soil, as well as mitigation for of dust, odour and noise. The excavated waste should be segregated into compost, soil conditioner, recyclables, raw RDF, filler material (soil, construction and demolition material) and residual solid waste. 

All useful materials must be packed, stored, stacked, and sold for recycling without being stored at the project site for more than 30 days. The contractor can take the revenue from such a sale. However, getting the materials tested by an NABL-accredited laboratory for heavy metals and hazardous materials is essential.

In addition, cleared dumps are not permitted for habitation for at least 15 years. This is because the leachate below the site and the flammable gases from waste pockets may remain unexcavated and can affect the activities and habitations in the long run.

The book also specifies permissible reuse options of the land — solid waste management, open stadiums, sports grounds, parks and gardens, parking lots, container yards, warehouses of non-flammables and similar facilities where people are not living or working all day and night.

A defunct water ATM in Mavallipura