Sunday, December 28, 2008

KMC Has No Alternative To Overburdened Dhapa

By S. P. Gon Chaudhuri

Garbage is gold. That's what the tonnes of waste that gets generated in Kolkata can actually be turned into. The city generates a whopping 4,000 tonnes of municipal waste, which is now being dumped at Dhapa. The present site is overburdened and KMC isn't ready with an alternative. But when the civic body does decide to switch to another place, it has to be a paradigm shift in the way it views and handles waste. Simply dumping the entire garbage is neither environment-friendly, nor commercially sound.
Had a little more attention been paid to the issue, Kolkata could have gone in for landfill engineering, where garbage is disposed scientifically in a way that prevents soil and ground water contamination and enables generation of electricity through methane extraction. But given the sheer quantity of garbage generated in Kolkata, it isn't possible to adopt landfill engineering, as it requires a large tract of land, which one cannot locate near the city.
Moving away will not serve the purpose, as transportation cost of garbage will go up, and so will pollution. The way forward for Kolkata is to go in for refuse derived fuel (RDF) technology, where waste is segregated into biodegradable and non-degradable segments. The biodegradable portion can be dried to form cakes for use as fuel in boilers that generate electricity. Some of it can also be used in making bricks. There is also plasma technology,
which entails combustion of biodegradable waste at very high temperature, so that there is no pollution. Given the amount of pollution in Kolkata, the city can seriously look at this technology that has been adopted in all major cities in the world, including Washington DC, Shanghai and Tokyo.
Of the 4,000 tonnes of waste generated in Kolkata, at least 40% should be biodegradable. If properly utilized, I believe it is possible to generate 40 MW of electricity from the refuse. The non-degradable portion can be sorted to recycle ferrous and non-ferrous metals. The rejects can be processed into compost or mixed with stones to go in for brick-making.
One can convert the mounds of rubbish into hillocks that develop into destination points like Swabhumi and PC Chandra Gardens have come up on rubbish heaps.

(The author is managing director, West Bengal Green Energy Development Corporation)