International Research Journal of Environment Sciences________________________________ ISSN 2319–1414Vol. 1(4), 60-64, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 60 Review Paper Impact of Coal Based Thermal Power Plant on Environment and its Mitigation MeasureAhmad Shamshad, Fulekar M.H., and Pathak Bhawana School of Environment and Sustainable Development, Central University of Gujarat sector-30 Gandhinagar, Gujrat, INDIAAvailable online at: www.isca.in Received 19th April 2012, revised 3rd May 2012, accepted 26 July 2012Abstract In the present research paper as a research article the problem associated fly ash has been highlighted mitigated measure for fly ash has also been emphasize viz development of bricks, use of fly ash for manufacturing of cement, development of ceramics, fertilizer, development of distemper and use of fly ash in road construction and road embankmen. This article gives the direction for the beneficial use of fly ash generated coal combustion power plants. Keywords: Coal, fly ash, thermal powerplant, combustion. Introduction Coal is the only natural resource and fossil fuel available in abundance in India. Consequently, it is used widely as a thermal energy source and also as fuel for thermal power plants producing electricity. Power generation in India has increased manifold in the recent decades to meet the demand of the increasing population. Generating capacity has grown many times from 1362MW in 1947 to 147,403MW (as on December 2008). India has about 90,000 MWe installed capacity for electricity generation, of which more than 70% is produced by coal- based thermal power plants. The only fossil fuel available in abundance is coal, and hence its usage will keep growing for another 2–3 decades at least till nuclear power makes a significant contribution. The coal available in India is of poor quality, with very high ash content and low calorific value, and most of the coal mines are located in the eastern part of the country. Whatever good quality coal available is used by the metallurgical industry, like steel plants. The coal supplied to power plants is of the worst quality. Some of the coal mines are owned by private companies, and they do not wish to invest on quality improvement. Combustion process converts coal into useful heat energy, but it is also a part of the process that produce greatest environmental and health concerns. Combustion of coal at thermal power plants emits mainly carbon dioxide (CO), sulphur oxides (SOx), nitrogen oxides (NOx); CFCs other trace gases and air borne inorganic particulates, such as fly ash and suspended particulate matter (SPM). CO, NOx and CFCs are greenhouse gases (GHGs) High ash content in Indian coal and inefficient combustion technologies contribute to India’s emission of air particulate matter and other trace gases, including gases that are responsible for the greenhouse effect. The present coal consumption in thermal power station in India results in adding ash estimated 12.21 million tons fly ash in to the environment a year of which nearly a third goes in to air and the rest is dumped on land or water .in spite of various research results a consistent utilization is not evident, and it expected that stocks piles of fly ash will continue to grow with the increasing number of super thermal power station in India. As reliance upon coal as a fuel source increases .This large quantities of this material will be increasingly brought into contact with the water and soil environment 3. Problems associated of increasing fly ashIndia has about 211 billion tons of coal reserves, which is known to be the largest resource of energy and presently 240MT of coal is being used annually to meet the Nation’s electricity demand. In terms of energy, India stands at world sixth position accounting 3.5% of the world commercial energy demand in 2001, but the electricity generation yet not completely fulfilled the present requirement. Environmental pollution by the coal based thermal power plants all over the world is cited to be one of the major sources of pollution affecting the general aesthetics of environment in terms of land use, health hazards and air, soil and water in particular and thus leads to environmental dangers. Fly ash water also affects the scale structure because it is a directly in contact with water. Heavy metals can also adversely affect the growth rate in major carps. Coal combustion residues (CCRs) are a collective term referring to the residues produced during the combustion of coal regardless of ultimate utilization or disposal. It includes fly ash, bottom ash, boiler slag, and fluidized bed combustion ash and other solid fine particles4,6. In India, presently coal based thermal power plants are releasing 105MT of CCRs which possess major environmental problems. Presently from all these thermal power plants, dry fly ash has been collected through Electrostatic Precipitator (ESP) in dry condition as well as pond ash from ash ponds in semi-wet condition. In India most of the thermal power plants do not have the facility for automatic dry International Research Journal of Environment Sciences_____________________________________________ ISSN 2319–1414 Vol. 1(4), 60-64, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 61 ash collection system. Commonly both fly ash and bottom ash together are discharged as slurry to the ash pond/lagoon these affect on environment, economy, and social factor. Table-1 Composition of Indian coal and fly ash in ppm Concentration Elements Coal 1 Fly ash 1 Coal 12 Fly ash 12 Na 1500 6700 289 1299 K 10,000 15,000 2075 18,275 La 22.2 94 47.6 238 Ce 42 212 30.2 145 Hg 0.6 9 11 48 Te NA NA 1.83 8.87 Th 5.1 6.6 5.34 25 Cr 55 210 62.8 404 Hf 1.8 7 7.1 32.6 Sc 8.9 64 22.9 106 Zn 170 3100 539 2027 Fe 11,000 51,000 20,088 1,06,665 Ta NA NA 153 5.05 Co 13.9 520 33.4 128 Eu 0.8 8.6 0.95 5.6 Sm NA NA 0.65 1.99 Am 0.4 0.2 0.136 0.69 NA –Not Available Table-2 Chemical Composition of Fly Ash Name Formula Percentage Silica SiO 2 62 Iron oxide Fe 2 O 3 63 Aluminum Al 2 O 3 26 Titanium oxide TiO 2 1.8 Potassium oxide K 2 O 1.28 Calcium oxide CaO 1.13 Magnesium oxide MgO 0.49 Phosphorus pentaoxide 0.40 Sulfate SO 4 0.36 Disodium oxide Na 2 O 0.28 *Critical Review in Environmental Control CRC Press, 3, (1989) Problems associated with radionuclide increase in atmosphere coal combustion: Coal, like most materials found in nature, contains radionuclides. The levels of natural radionuclides in a geological formation depend on its composition and geological history. In the production of electric power, coal is burned in a furnace operating at temperatures of up to 1700°C. In the combustion process, volatile radionuclide’s such as Pb210 and Po210 are partly released in the flue gases and escape to the atmosphere. A significant fraction of the radioactivity is also retained in the bottom ash or slag .The greatest part of the radioactivity in coal remains with the ash but some of the fly ash from coal-fired power plants escapes into the atmosphere. Air pollution in the vicinity of a coal fired thermal power station affects soil, water, vegetation, the whole ecosystem and human health10."Environmental impact of coal utilization in thermal power plant" notes that "Radon is a colorless, odorless but noble gas, which is radioactive and ubiquitously present. It poses grate health hazards not only to uranium miners but also people living in normal houses and buildings and at work place like coal mines, cement industry, thermal power plants etc. Coal, a naturally occurring fossil fuel is burnt in conventional power plants to meet out about 72% of the electricity needs in our country11. It was lesser known hitherto until recently that the fly ash which is a byproduct of burnt coal is a potential radioactive air pollutant and it modifies radiation exposure. Fly ash mitigation measureFly ash is fine glass powder, the particles of which are generally spherical in shape and range from 0.5 to 100 micron in size. The fine particles of fly ash reach the pulmonary region of the lungs and remain there for long periods of time; they behave like cumulative poisons. The submicron particles enter deeper into the lungs and are deposited on the alveolar walls where the metals could be transferred to the blood plasma across the cell membrane fly ash can be disposed-off in a dry or wet state. Studies show that wet disposal of this waste does not protect the environment from migration of metal into the soil. Heavy metals cannot be degraded biologically into harmless products like other organic waste. Studies also show that coal ash satisfies the criteria for landfill disposal, according to the Environmental Agency of Japan. According to the hazardous waste management and handling rule of 1989, fly ash is considered as non-hazardous. With the present practice of fly-ash disposal in ash ponds (generally in the form of slurry), the total land required for ash disposal would be about 82,200 ha by the year 2020 at an estimated 0.6 ha per MW. Fly ash can be treated as a by-product rather than waste12. Fly ash bricks: The Central Fuel Research Institute, Dhanbad has developed a technology for the utilization of fly ash for the manufacture of building bricks. Fly ash bricks have a number of advantages over the conventional burnt clay bricks. Unglazed tiles for use on footpaths can also be made from it (figure-1). Awareness among the public is required and the Government has to provide special incentives for this purpose12. Six mechanized fly ash brick manufacturing units at Korba are producing about 60000 bricks per day. In addition to this, two mechanized fly ash brick manufacturing units have been set up by private entrepreneurs also at Korba13, the total production being about 30000 bricks/day. Apart from this about 23 entrepreneurs have registered in DTIC proposals for establishing ash brick units. To give impetus to ash brick manufacturing13. Orissa Government in India has banned the use of soil for the manufacture of bricks up to 20 km. of a thermal power station. In the case of fly ash-clay fired bricks, a mixture of clay and fly ash is fired. The unburnt carbon of the fly ash serves as fuel for burning. Approximately 20-30% energy can be reduced by adding25-40% flyash14. International Research Journal of Environment Sciences_____________________________________________ ISSN 2319–1414 Vol. 1(4), 60-64, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 62 Figure-1 Fly ash using for making bricks Fly ash in manufacture of cement: In the presence of moisture, fly ash reacts chemically with calcium hydroxide and CO present in the environment attack the free lime causing deterioration of the concrete. A cement technologist observed that the reactive elements present in fly ash convert the problematic free lime into durable concrete15. Fly ash can substitute up to 66% of cement in the construction of dams. Fly ash in R.C.C. is used not only for saving cement cost but also for enhancing strength and durability. Fly ash can also be used in Portland cement concrete to enhance the performance of the concrete. Portland cement is manufactured with Calcium oxide, some of which is released in a free state during hydration. Studies show that one ton of Portland cement production discharges 0.87 tonnes of carbon dioxide in the environment. Another Japanese study indicates that every year barren land approximately 1.5 times of the Indian Territory need to be afforested to compensate for the total global accumulation of carbon dioxide discharged into the atmosphere because of total global cement production. Utilization of fly ash in cement concrete minimizes the carbon dioxide emission problem to the extent of its proportion in cement. Fly ash-based ceramics: Ceramic products with up to 50 wt% of mullite and 16 wt% of feldspars were obtained from binary mixtures of fly ash from the Teruel power station (NE Spain) and plastic clays from the Teruel coal mining district16. The firing behavior of fly ash and the ceramic mixtures was investigated by determining their changes in mineralogy and basic ceramic properties such as color, bulk density, water absorption and firing shrinkage. To determine the changes on heating suffered by both the fly ash and the ceramic bodies, firing tests were carried out at temperatures between 900 and 1200°C in short firing cycles17. The resulting ceramic bodies exhibit features that suggest possibilities for use in paving stoneware manufacture, for tiling and for conventional brick making (fig-2). The National Metallurgical Laboratory; Jamshedpur has developed a process to produce ceramics from fly ash having superior resistance to abrasion12. (a) (b) Figure-2 (a) Mosaic tile (b) interlocking paver Fly ash as fertilizer: Fly ash provides the uptake of vital nutrients/minerals (Ca, Mg, Fe, Zn, Mo, S and Se) by crops and vegetation, and can be considered as a potential growth improver11. Because it can be a soil modifier and enhance its moisture retaining capacity and fertility. The improvement in yield has been recorded with fly ash doses varying from 20 tone / hectare to 100 tone / hectare (figure-3). On an average 20-30% yield increase has been observed. Out of 150 million hectare of land under cultivation, 10 million hectares of land can safely be taken up for application of fly ash per year. The fly ash treated fields would give additional yield of 5 million tone food grains per year valued at about Rs. 3000 crores18. (a) (b) Figure-3 (a) Cabbage at Dodhar, fly ash amended soils (b) Reclamation of saline soils using fly ash (75% savings in Gypsum) International Research Journal of Environment Sciences_____________________________________________ ISSN 2319–1414 Vol. 1(4), 60-64, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 63 Fly ash based polymer products: Fly ashes are also being used as wood substitutes. They have been developed by using fly ash as the matrix and jute cloth as the reinforcement. The Jute cloth is laminated by passing through a polymer fly ash matrix and then cured. The number of Laminates is increased to get the desired thickness. The product can be used in many applications like door shutters, partition panels, flooring tiles, wall paneling and ceiling. The developed material is stronger more durable, resistant to corrosion and cost effective as compared to wood. This technology has been developed by the Regional Research Laboratory, Bhopal in collaboration with Building Materials and Technology Promotion Council (B.M.T.P.C) and TIFAC19. One commercial plant has been set up based on this technology near Chennai, India. The Government of India has withdrawn a 8% excise duty imposed earlier on fly ash products. Fly ash in road construction: The use of fly ash in large quantities making the road base and surfacing can result in low value–high volume utilization technology demonstration projects at New Delhi, Dadri (U.P.) and Raichur (Karnataka) have been successfully completed for use of fly ash in road / flyover embankments (figure-4). Guidelines have been prepared and approved by Indian Roads Congress (IRC) as national standard. More than 10 multiplier effects have taken place across the country. In the recent past CRRI offered advise/ consultancy services in the following road/embankment projects in which fly ash was utilized: i. Construction of plant roads at Budge-Budge thermal power plant using fly ash based pavement specifications (Collaboration with CESC Ltd, Kolkata), ii. Construction of one km long rural road near Raichur in Karnataka with fly ash based flexible/semi-rigid pavement composition (Collaboration with Karnataka PWD and Raichur thermal power station - executed as Fly Ash Mission demonstration project), iii. Construction of 1.9 km long, 6 to 9 m high road embankment forming eastern approach of the second Nizamuddin Bridge in Delhi using fly ash (Collaboration with Delhi PWD and Indraprastha thermal power station, Delhi), iv. Construction of plant road and two rural roads using fly ash (collaboration with National Capital Power Station, NTPC, Dadri, U.P)20 Roads and Embankments: Another area that holds potential for utilization of large volumes of fly ash is road and flyover embankments. Fly ash embankments at Okhla, Hanuman Setu, Second Nizamuddin bridge in Delhi and roads at Raichur, Calcutta, Dadri etc. have established that on an average Rs. 50 to 75 per MT of earth work cost can be saved by using flyash (in lieu of soil) in such works, primarily due to reduction in excavation & transportation costs18. In the recent past CRRI offered advise/ consultancy services in the following road/embankment projects in which fly ash was utilized: i. Fly ash embankment construction for Okhla flyover at Delhi adopting ‘Reinforced Embankment Technique’ (Collaboration with Delhi PWD – executed as Fly Ash Mission demonstration project), ii. Fly ash embankment construction for Hanuman Setu flyover at Delhi adopting ‘Reinforced Embankment Technique’ (Collaboration with Delhi PWD and Badarpur Thermal Power Station, Delhi), iii. Construction of reinforced approach embankment using fly ash at SaritaVihar flyover in Delhi (Collaboration with Delhi Development Authority and Badarpur Thermal Power Station, Delhi), iv. Construction of embankment for Noida-Greater Noida Expressway project (Collaboration with IRCON International and Badarpur Thermal Power Station, Delhi)19Environmental Impact of Fly ash Use Utilization of fly ash will not only minimize the disposal problem but will also help in utilizing precious land in a better way. Construction of road embankments using fly ash, involves encapsulation of fly ash in earthen-core or with RCC facing panels. Since there is no seepage of rain water into the fly ash core, leaching of heavy metals is also prevented. When fly ash is used in concrete, it chemically reacts with cement and reduces any leaching effect. Even when it is used in stabilization work, a similar chemical reaction takes place which binds fly ash particles. Hence chances of pollution due to use of fly ash in road works are negligible21. Figure-4 Nizammuddin Bridge approach road embankment at New Delhi (in flood zone of river Yamuna International Research Journal of Environment Sciences_____________________________________________ ISSN 2319–1414 Vol. 1(4), 60-64, November (2012) Int. Res. J. Environment Sci. International Science Congress Association 64 Energy Savings and Environmental BenefitsMost of the developing countries face energy scarcity and huge housing and other infrastructure shortage. Ideally in these countries materials for habitat and other construction activities should be energy efficient (having low energy demand). The following table shows some examples of energy savings achieved through the use of Fly Ash in the manufacture of conventional building materials22Conclusion Coalis used widely as a thermal energy source in thermal power plant for production of electricity but available coal in India is of poor quality, with very high ash content and low calorific value. Utilization of huge amount of coal in thermal power plant has created several adverse effects on environment leading to global climate change and fly ash management problem. Coal based thermal power plants all over the world is cited to be one of the major sources of pollution affecting the general aesthetics of environment in terms of land use, health hazards and air, soil and water in particular and thus leads to environmental dangers. So, the disposable management of fly ash from thermal power plant is necessary to protect our environment. It is advisable to explore all possible application for fly ash utilization. Several efforts are needed to utilize fly ash for making bricks, in manufacture of cement, ceramics etc. Various governmental and nongovernmental bodies working in the field of utilization of fly ash for construction of road/road embankment. The utilization of fly ash gives good result in almost every aspects including good strength, economically feasible and environmental friendly. References 1.Mishra U.C., Environmental impact of coal industry and thermal power plants in India, J Environ Radioact.,72(1-2), 35-40 (2004)2.Jamil S., Abhilash P.C., Singh A., Singh N. and BhelHari M., Fly ash trapping and metal accumulation capacity of plant, implication of for green belt around thermal power plant, J. Land Esc. And Urban Plan., 92, 136-147 (2009) 3.Fulekar M.H. and Dave J.M., Release and behavior of Cr, Mn, Ni and Pb in a flyash/soil/water environment: column experiment, IntJ. of Envin Studies, , 281-296 (1991)4.Ashoka D., Saxena M. and Asholekar S.R., Coal Combustion Residue-Environmental Implication and Recycling Potential, Resource Conservation And Recycling, , 1342-1355 (2005)5.Shrivastava Shikha and Dwivedi Sushma, Effect of fly Ash Pollution on Fish Scales, Re. J. of Che. Sci, 1(9), 24-28 (2011)6.Keefer R.F., Coal ashes-industrial wastes or benecial by-products. In: Keefer R.F., Sajwan K., editors, Trace Element in Coal and Coal Combustion Residues. Advances in Trace Substances Research, Florida: Lewis Publishers, CRC Press, 3–9 (1993)7.Kumar Vimal and Mathur Mukesh, Clean environment through fly as utilization Cleaner (2003)8.Critical Review in Environmental Control, CRC Press, 3, (1989) 9.Pvrecek, Lbendik, Pb210 and Po210 in fossil fuel at the sostanj thermal power plant (solvenia), Czechoslovak j of phy, 53 a51-a 55 (2003)10.FILIZ G ¨ UR and G ¨ UNSELI YAPRAK, Natural radionuclide emission from coal-fired power plants in the southwestern of Turkey and the population exposure to external radiation in their vicinity, J. of Environ. Sci. and Health Part A, 45, 1900–1908 (2010)11.Kant K., Chakarvarti S.K Environmental impact of coal utilization in thermal power plant, J. of Punjab Acad. of For. Med. &Toxi, , 15-18 (2003) 12.Senapati Manas Ranjan, Fly ash from thermal power plants – waste management and overview current science, 100, 1791- 1794 (2011) 13.korba.gov.in/kwflyash.htm (2012) 14.www.wealthywaste.com/fly-ash-utilization-in-india (2012)15.Cement Manufacturing Association, (1999)16.IgnasiQuerlt,XavierQuerol ,Angel Lopez-Solar ,Felicano Plana ,Use of coal fly ash for ceramics ;a case study for large Spanish power station, fuel, , 787-791, (1997) 17.SaikatMaitra, Cremic product from fly ash global prospective. In preceding of the national seminar on fly ash utilization, February 26-27 NLM jamshedpur India,(1999) 18.Kumar Vimal and MathurMukesh, Clean environment through fly as utilization. Cleaner Technology, Impacts/12/2003-2004, MOEF-CPCB, Govt. of India, 235-255, (2003)19.Fly Ash Mission’, (TIFAC), Department of Science and Technology, Ministry of Science and Technology, Government of India, Technology, (1994)20.www.crridom.gov.in/techniques-facilities/10.pdf (2012)21.M.Ahmaruzzaman, A review of utilization of fly ash In Energy AndCombu. Sci.30, 327-363 ,201022.Jha C. N. & Prasad J. K. Fly ash: a resource materifsinceal for innovative building material - indian perspective substitute and paint from coal ash” 2nd international conference on “fly ash disposal & utilization”, new delhi, india, (2000)23.ShabudeenP.S.Syed, Study of the Removal of Malachite Green from Aqueous Solution by using Solid Agricultural Waste Res. J. Chem. Sci.,1(1), 88-104 (2011)24.PandeyBhawana and Fulekar M. H Environmental Management- strategies for chemical disaster, Res. J. Chem. Sci.,1(1), 111-117 (2011)25.Murhekar Gopalkrushna H., Assessment of Physico-Chemical Status of Ground Water Samples in Akot city, Res. J. Chem. Sci.,1(4), 117-124 (2011)26.Bhattacharya Tanushree, Chakraborty S., Fadadu Bhumika and Bhattacharya Piyal, Heavy metal concentrations in Street and Leaf Deposited Dust in Anand city, India, Res. J. Chem. Sci., 1(5), 61-66 (2011)