Green and gold, the colours of garbage
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COMMENTS 
How a garbage heap the size of a five-storey building was turned into a pleasant green space, whilst at the same time earning Rs 25 crore in carbon credits for the Municipal Corporation of Greater Mumbai. This points the way to innovative solutions for one of the 21st century’s biggest civic problems
Disposal of mountains of garbage that every city generates is a huge urban challenge. Urban India produces 120,000 metric tonnes of garbage every day; the city of Mumbai itself generates 6,500 metric tonnes. Given the volumes, the traditional method of landfill sites -- dumping and burning waste on open spaces of land -- is proving unviable as cities expand, open spaces become scarce and the health hazards from untreated waste mount.
Everywhere, new and innovative methods of waste disposal are being devised -- from recycling to vermicomposting, biogas plants to the scientific landfill method used in the Mumbai suburb of Gorai which has transformed a stinking garbage dump into a green and pleasant garden whilst also earning Rs 25 crore worth of carbon credits for the Municipal Corporation of Greater Mumbai.
Gorai is one of the hundreds of garbage dumps servicing Mumbai. Until recently, 1,200 tonnes of garbage was being dumped out in the open here every day. The foul smell emanating from the dump forced people living in the vicinity to keep their windows closed, and toxic leachate (the liquid that seeps through the garbage) had led to the degeneration of mangroves in the nearby creek. By the time a court order forced closure of the site in 2007 there was a 26-metre-high mountain of stinking rubbish here.
In 2008, the Municipal Corporation of Greater Mumbai partnered with United Phosphorus Ltd (UPL) and its joint venture partner, Vanderwiel Strotgas BV, to create a ‘sanitary landfill’. The garbage is buried in large, deep underground pits in between scientifically layered geo-textile material and high-density polyethelene sheets so that it is completely sealed in.
An intricate subterranean network of pipes collects the gas, 70% of which is methane, from the rotting garbage and relays it through 40 wells to a chimney where it is flared. One tonne of methane is equivalent to 21 tonnes of carbon dioxide, in terms of global warming potential. MCGM earns carbon credits for the capture and combustion of methane.
Whatever leachate is formed because of the existing moisture is channelised into a processing tank to neutralise its toxicity. The top of the site has been planted with greenery to complete the transformation from an unhealthy liability to an environmentally and financially sound showpiece.
The Gorai project has been registered under the UN Framework Convention on Climate Change. It has already earned Rs 25 crore in advance carbon credits; total carbon credit earnings from the project are expected to be in the range of Rs 72 crore, which is higher than the project’s capital cost of Rs 50 crore.
MCGM is also in talks with a leading energy company to set up a plant to convert the methane into energy, further increasing its earning potential.
There are other smaller, more decentralised methods of treating garbage. In December 2007, in an experiment on a one-hectare plot, also in Gorai, a six-metre waste heap was brought down to ground level in just 40 days using the wind row methodology which is considered to be both safe and cheap.
Almitra Patel, member of the Committee for Solid Waste Management appointed by the Supreme Court in 2000, prefers this method, also called bio-mining. Old waste is loosened by tractor-harrow and bulky items are removed manually. Then, the waste is sprayed with composting bio-culture, formed into wind rows (long heaps, two metres high) and turned into useful compost through bio-stabilising. The old waste reduces by 40%. Besides being cost-effective, it also helps eliminate methane production, Patel says.
Turning garbage into fuel is another decentralised method that has been started in one ward in Pune city. Ward No 34 -- the Model Colony area of Pune -- has a biogas plant that is run on wet waste collected locally. The wet garbage is converted into gas which currently produces 200 units of electricity a day, enough to run the biogas plant as well as power 145 street lights. The capacity can be scaled up to 300 units of electricity, enough to power 245 street lights, from five tonnes of wet waste per day. The plant also generated 250 kg of dry fertiliser that could be used in public gardens or sold.
The project allegedly saves the Pune Municipal Corporation Rs 7,000 a day in transporting and segregating the waste and in electricity costs for lighting the 245 street lights. Pune’s municipal commissioner said that if similar plants were set up in the city’s 144 wards, Pune’s garbage problem could be largely solved. The PMC is taking up the project in 100 wards.
On an even more micro level, compact biogas plants installed in homes could take care of all the biodegradable waste a home produces and convert it into gas for cooking. The invention of Dr Anand Karve of the Appropriate Rural Technology Institute (ARTI) does not use dung, as most biogas plants do, but food waste. It won the Ashden Award, the most prestigious award for innovative work in the environment field in developing countries, given by the UK-based Ashden Trust.
The Supreme Court Committee on Solid Waste Management has suggested simple technologies as a way to combating the problem of waste. It has recommended composting of waste and recycling as twin strategies.
Municipalities in India spend 10-15% of their budgets on solid waste management. Most of this is spent on the salaries of sanitation staff and collection and transportation of the garbage, very little on its scientific disposal. In most cities, the collection and transportation of garbage is chaotic. As urban sprawls spread, once-isolated dumping grounds are surrounded by buildings whose residents agitate for the dumps to be moved away or shut down.
Infochange News & Features, April 2010