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On the northeast edge of Mumbai city is its largest waste dumping ground located in the suburb of Deonar. It receives more than 5000 tons of garbage every day. That garbage has piled up so high, that the Municipal Corporation (BMC) had to seek permission from the Airports Authority of India, lest it obstruct landing flights. But the 18-storey height of the garbage is the least of its nuisance. Nor is its foul smell. In the last couple of years the dumping ground has become a deadly menace. Frequently fires break out, causing acrid smoke, suffocating the people who live in nearby suburbs. The fire smolders for several days, and the smog makes the air quality so bad that it can be life threatening for asthmatic patients. One can imagine the plight of slum dwellers and their kids who reside nearby. In more recent fire incidents the entire city was blanketed and even visibility was affected. These frequent incidents of the toxic fires at the garbage dump have now made it into a political issue.
One lasting solution that is eminently feasible is to convert the solid waste into electricity. Mumbai is uniquely placed, because there is a thermal power plant located in close proximity to the Deonar dump. The technology to convert unsegregated waste into briquettes is tried and tested all around the world.
Residents have taken to the streets in protest asking for strict action against the culprits. In response the government promised to catch the miscreants, to install dozens of CCTVs, increase policing and fire engines. The BMC also cancelled the licenses of 3000 rag pickers who rummage the dump for their livelihood. The Union Ministry for Environment also announced a special probe to determine who was behind these fires. The one thing missing from all these responses was to explore whether we can “harness the fire” potential of garbage.
One lasting solution that is eminently feasible is to convert the solid waste into electricity. Mumbai is uniquely placed, because there is a thermal power plant located in close proximity to the Deonar dump. The technology to convert unsegregated waste into briquettes is tried and tested all around the world. These briquettes are then used as fuel (much like coal) in the thermal plant. Sweden converts 99 percent of its national solid waste to electricity. To meet its requirement it often has to import solid waste from neighboring countries. Germany too has many waste-to-energy plants across its many cities. In fact European cities give a hefty tipping fee for garbage to be hauled away to the dumping sites. China plans to build 300 such waste-to-energy plants in the next three years. The city of Shenzen is set to build the world’s largest such plant. Technology makes it possible to have zero emission of toxic elements from the waste-to-energy conversion. Even the carbon dioxide emission can be reduced to one kilo per kilo of garbage, if incineration combines solar power as well. The most profitable and clean way to incinerate municipal solid waste (MSW) is to use it in cement kilns. It serves both as fuel and raw material in such kilns. Unfortunately most cement plants in India are not located near cities. Which means that the MSW has to be transported (by burning diesel) over long distances. That cost of transportation defeats the economics of using MSW in cement production. Hence most waste-to-energy solutions involve producing power instead.
In Mumbai the power plant need not come up in-situ, since a running thermal plant is nearby. BMC just needs to incur some capital expenditure to make compressed briquettes, and transport them to the thermal plant. Assuming a price of rupees 8 per unit, an estimated 200 megawatt power can be produced, earning Rs 1300 crore annually. This revenue will not only cover initial capex, but will also make it possible to compensate the rag-pickers whose livelihood may be disrupted. The dump in Deonar is already in legal trouble, since it was supposed to be closed down as per a High Court order. In continuously delaying its closure, the BMC may be guilty of contempt of court. But if the solution does not factor in waste-to-energy plant, and instead only looks for new dump sites, then it is doomed to failure. The BMC is reportedly looking at Taloja for a giant alternate site. But it is puzzling as to why is the BMC not looking at an obvious solution that’s staring at it, viz converting waste to watts.
Assuming a price of rupees 8 per unit, an estimated 200 megawatt power can be produced, earning Rs 1300 crore annually. This revenue will not only cover initial capex, but will also make it possible to compensate the rag-pickers whose livelihood may be disrupted.
Mumbai’s Deonar dump is part of a larger national challenge. Many cities are running out of space for dumping yards. The yards pose health hazards and risks like Deonar fires. They also occupy valuable urban space. The long-term solution for solid waste management involves radical change in habits of India’s city dwellers. It calls for voluntary segregation of wet and dry garbage, localized composting, increased re-use and recycle practices and reduction in the very generation of waste. But in the medium term, as India urbanizes rapidly, waste-to-energy is inescapable and probably a necessity. It is a form of renewable energy too. India generates about 55 million tons of municipal solid waste (MSW) annually. Waste generation will grow in per-capita terms by 1 to 2 percent every year. Thus we have a national opportunity of between 1500 to 2000 megawatt of electricity generation from MSW. The sale of this electricity will generate enough revenue to compensate rag pickers whose livelihoods depend on salvaging rubber, plastic, paper and wood from the waste. If these ingredients are stripped away, then the MSW loses its calorific value, making it even more expensive to produce power. Thus mega-waste to megawatts has to be a carefully planned city by city project which takes into account the interests of all the stakeholders.