Waste to Energy Incineration is a proven mixed waste handling technology world over but with lesser success in countries like the US when compared to Europe and Japan due to different reasons, the most prevalent one being cheaper landfilling in the US due to larger land availability. But in the case of New York, New York pays just $60 per ton as a tipping fee for each of several million tons of trash it generates that are thermally treated at a WTE plant in Newark, NJ, while paying over $100 per ton to haul waste to remote landfills in South Carolina, Ohio, and elsewhere 14. The probability of WTE becoming economically cheaper than landfilling in India is less because of loosely implemented regulations. However, with an increasing middle class and increase in public health awareness, Waste to Energy will become an important part of Integrated Solid Waste Management in India as there always exists a fraction which can neither be composted nor recycled.The greatest drawback for WTE in India is its bad track record.
A conveyor belt for feeding the RDF to boiler
The incinerator in Delhi was designed to produce 3.75 MW of electricity, based on technology imported from a Danish firm, Volund Milijontecknik, at a cost of Rs. 41 crore then ($ 8.5 million, not adjusted) 16, it was on a trial run until 1990 when it was closed due to a mismatch of the quality of incoming refuse with the plant design of 1460 Kcal/Kg net calorific value 3. India lost at the Hague because the “suitable waste” to be provided by the city was not defined in the agreement. Current interest and caretaking costs have totaled a staggering Rs 221 Crore or more to date ($ 47 million, not adjusted) 15. The reasons for the ‘failure’ are reportedly not entirely on account of low heat value but also on short comings of the solid waste management systems in vogue at that time 3. Citing the failure of Timarpur plant (WTE technology), which was because of calorific value and solid waste collection systems after two decades of economic growth (since 1990’s economic reforms) and resulting change in lifestyles in India and advancements in WTE worldwide will not be valid as an argument against forth coming WTE projects.
Southern Indian state Andhra Pradesh has two RDF demonstration plants built near the cities Hyderabad and Vijayawada with 6 MW capacity each, both of which failed to operate for long. I visited the plant at Hyderabad in which the waste is dumped at ground level and fed into a traveling grate, stoker fired boiler by inclined conveyors (as shown in the figure below). The boiler in this plant is still working and the facility produced above 6.6 MW (more than design power) power during its initial years of operation. As of January, 2010, this plant was last operated in November, 2009. It is run twice every month just to keep the machines working.
The reason for this failure is mechanical problem in the condenser (also few leakages in condenser piping), which has to be replaced to get the plant running. In additio The problem at this plant is not the WTE boiler technology used but a mechanical problem in the condenser, which could be fixed. Also, a condenser is a common component in almost all process industries, not unique to WTE plants. The reasons behind the failure of Vijayawada RDF plant is believed to be a problem with the supply of waste to the facility and the plant operated for only 5 – 6 years 23. The common observation in all these failures was the lack of institutional framework and legal agreements between the municipalities, the plants and the electricity boards. The technology seems to do well but with additional fuel like rice husk as is the case with the RDF incineration plant at Hyderabad, where 20 - 25% by weight of the feed to boiler is rice husk, which has a calorific value of around 13.2 MJ/kg 16. Assuming 6.2 MJ/kg calorific value for MSW 17 and 25% by weight fraction of rice husk in the boiler feed, we get a mixed fuel with calorific value of 7.9 MJ/kg which is sufficient for self sustained combustion.
Picture 2: Board with details of RDF combustion boiler near Hyderabad
Picture 3: Condenser out of order at RDF combustion plant near Hyderabad
Another waste to energy technology, Anaerobic digestion (also called Biomethanation) fairs poorly in India due to the high soil content in the wastes which is around 35 – 50% 2 making pretreatment of solid waste for anaerobic digestion difficult. The second major failure of Waste to energy was the solid waste Biomethanation plant at Lucknow designed to treat 300 TPD of wastes and generate 5 MW of electricity. Biomethanation plants are very sensitive to impurities in the feed; due to supply of improperly separated organic waste this biomethanation plant ceased operation in 2005 after an operational history of 6 months 23 characterized by hiccups. Another biomethanation plant in Chennai was closed down in a couple of years 23. Although the plants in Lucknow and Chennai were Waste to Energy facilities working on biomethanation, these failures are attributed to Waste to Energy “incineration technology” in efforts to raise mass opposition to Waste to Energy incineration and RDF by some environmental groups.