Author – Sahana Rajan
Solid waste management is a huge challenge faced by urban areas and metropolitan cities across India. For instance, the capital city Delhi itself produces 7,500 metric tons of waste, which is estimated to grow to 18,000 metric tons by 2021. While there are various solutions to tackle the waste problem, no single perfect solution has been found. Typically, waste is thrown in landfills that can handle copious amount of waste, but land-filling pollutes the ground water and occupies land that could be put to better use. There are 14 landfill sites and 3 disposal sites in the National Capital Region that are currently operating beyond their capacities.
A ‘waste to energy’ (WTE) solution was introduced as an alternative to landfills, which directly incinerates waste for generating power. WTE burns solid waste to convert it into energy in the form of electricity and heat. The energy produced by using 1 ton of municipal solid waste (MSW) is equivalent to the energy produced by 1 barrel of oil or 0.25 tons of coal.
In 2007, Jindal Group established the Timarpur-Okhla Waste Management Plant in Delhi at a cost of INR591.27 million. Despite controversies surrounding it, this became the first waste-to-energy plant in India. The plant was originally planned to have a 650-tons-per-day (TPD) refuse-derived fuel processing facility, a 50TPD bio-methanation plant, 6 million gallons per day sewage treatment plant and a 6 megawatt (MW) power plant.
These processing facilities consume 643,500 tons of solid waste every year and generate 222,750 tons of refuse-derived fuel every year and 5,000 cubic meters of biogas per day. The plant generates 21MW of electricity everyday with its 3 boilers and so far, 2 million metric tons of waste has been processed to generate 350.1 million units of electricity. The power is sold to the BSES grid at INR2.5 per unit, which at a loss because the generation cost is approximately INR6.5 per unit.
Waste to energy process
• The delivered MSW waste is compacted and kept in a storage pit maintained at negative pressure to prevent emanation of bad odor
• Reuse of the sucked air to enhance the combustion process;
• Waste is segregated to remove recyclable material like metal scraps, rubber, etc.
• Refuse derived fuel kept in a storage pit and mixed with homogenous fuel using cranes;
• Pressurizing the fuel in reduced levels of humidity and generation of leachate, which is sent to sewage treatment plant and the fuel is sent to the pre-heating chamber to raise its calorific value
• Burning of waste to generate heat from combustion process to boil water and generate electricity
Noxious gases such as NOx, Dioxins and Furan levels are maintained at a safe level, which are controlled by maintaining a temperature above 850 degree Celsius and by providing residence time. Fabric filters are installed for improving performance. While the emissions are controlled through an extensive mechanism, harmless hot air comprising carbon dioxide is released into the atmosphere. The company uses the residual bottom ash for civil construction projects such as filling up land, making bricks etc., while research is underway to use the fly-ash as well.
Why is waste-to-energy controversial?
The energy production capacity of the plant was altered thrice. While the project was planned to produce 15MW of power, this was increased to 16MW and a proposal for further expansion of additional 4.9MW was submitted in March 2011. No studies were undertaken to evaluate the effect of these alterations. The expansion proposal is still on hold, while the former alterations have been made.
Non-inclusion of biodigester & bio-methanation plants
Typically, municipal solid waste in India contains 40-50% of organic material that does not burn properly. The Timarpur-Okhla Waste Management plant was intended to have a biodigester that would handle 100TPD of organic waste. Similarly, the plant was supposed to house a bio-methanation plant that would produce methane gas from rotting wet waste for further use as fuel. Currently, the plant does not have a biodigester or a bio-methanation plant, which implies that about 100TPD of green-waste is currently wasted.
Loss of revenue to rag pickers
In Delhi, around 100,000 people are involved in rag picking, who gather 20% of reusable material like paper, plastic, metal and cardboard from garbage. These items are manually or mechanically refined for supply to other industries as raw material. The Timarpur-Okhla plant burns up large amount of recyclable materials to increase the calorific value of organic waste. According to Chintan NGO, this plant not only wastes valuable resources, but also harms the daily earnings of the rag-picking community.
Marginal reduction in emissions
Methane is produced by green and organic waste that does not burn properly, so such organic waste of landfills cannot be used as raw material for this project. Meanwhile, the recycling market of Delhi prevents emissions three times more than the incinerator’s estimated emission reduction, offsetting of about 262,791 tons of CO2 every year. The Clean Development Mechanism, under which the Timarpur-Okhla project was built, assumes that burning of biomass does not have any large-scale impact on the global climate. Only about 16% of the CO2 emissions is reported and the remaining 84% is taken to be biogenic by nature. However, biogenic emissions of carbon dioxide have a significant contribution toward global warming.
Health risk to communities
The plant is located in a densely populated region of Delhi which includes colonies such as Sarita Vihar, Gaffar Manzil, Sukhdev Vihar, Johri Farms and Jasola Vihar. Residents of Sukhdev Vihar have complained to the Central Pollution Control Board (CPCB) and Delhi Pollution Control Committee (DPCC) regarding the generation of toxic ash from the plant. Gopal Krishna, working with the NGO Toxics Watch Alliance pointed out the significant rise in lung cancer due to the incinerator.
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