Consider the following statements:
1. Coal ash contains arsenic, lead and mercury.
2. Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment.
3. High ash content is observed in Indian coal.
Which of the statements given above is/are correct?
(a) 1 only
(c) 2 and 3 only
(b) 3 only
(d) 1, 2 and 3
9. Ans: d
Explanation:
Coal-based Thermal Power Plants (TPPs) are better responsible for a disproportionately higher share of emissions than the industrial sector (60 per cent of PM, 45 per cent of SO2, 30 per cent of NO2 and 80 per cent of mercury (Hg)).
Hence, statement 2 is correct.
Coal ash, also referred to as coal combustion residuals or CCRs, is produced primarily from the burning of coal in coal-fired power plants. Coal ash contains lead, arsenic, mercury, cadmium, and uranium. Coal ash includes a number of by-products produced from burning coal, including:
- Fly ash, a very fine, powdery material composed mostly of silica made from the burning of finely ground coal in a boiler.
- Bottom ash, a coarse angular ash particle that is too large to be carried up into the smokestacks so it forms in the bottom of the coal furnace.
- Boiler slag, molten bottom ash from slag tap and cyclone type furnaces that turn into pellets that have a smooth glassy appearance after it is cooled with water.
- Flue gas desulfurization material, a material leftover from the process of reducing sulphur dioxide emissions from a coal-fired boiler that can be a wet sludge consisting of calcium sulfite or calcium sulphate or a dry powdered material that is a mixture of sulphites and sulphates.
Hence, statement 1 is correct.
Coal / Lignite based Thermal Power Generation has been the backbone of power capacity addition in the country. Indian coal is of low grade with ash content of the order of 30-45 % in comparison to imported coals which have a low ash content of the order of 2-15 %. A large quantity of ash is, thus being generated at Coal / Lignite based Thermal Power Stations in the country, which not only requires a large area of precious land for its disposal but is also one of the sources of pollution of both air and water.
Hence, statement 3 is correct.
Read: Previous Year UPSC Environment Questions (PYQs) With Explanation 2020