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Lignite fly ash (LFA), being alkaline and endowed with excellent pozzolanic properties, a silt loam texture, and plant nutrients, has the potential to improve soil quality and productivity. Long-term field trials with groundnut, maize, and sun hemp were carried out to study the effect of LFA on growth and yield. Before crop I was sown, LFA was applied at various doses with and without press mud (an organic waste from the sugar industry, used as an amendment and source of nutrients). LFA with and without press mud was also applied before crops III and V were cultivated. Chemical fertilizer, along with gypsum, humic acid, and biofertilizer, was applied in all treatments, including the control. With one-time and repeat applications of LFA (with and without press mud), yield increased significantly (7.0-89.0%) in relation to the control crop. The press mud enhanced the yield (3.0-15.0%) with different LFA applications. The highest yield LFA dose was 200 t/ha for one-time and repeat applications, the maximum yield being with crop III (combination treatment). One-time and repeat application of LFA (alone and in combination with press mud) improved soil quality and the nutrient content of the produce. The highest dose of LFA (200 t/ha) with and without press mud showed the best residual effects (eco-friendly increases in the yield of succeeding crops). Some increase in trace- and heavy-metal contents and in the level of gamma-emitters in soil and crop produce, but well within permissible limits, was observed. Thus, LFA can be used on a large scale to boost soil fertility and productivity with no adverse effects on the soil or crops, which may solve the problem of bulk disposal of fly ash in an eco-friendly manner.

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In India, a significant area of land is occupied by preexisting coal-fired thermal power plants (TPPs) for the storage of fly ash slurry in ash ponds. However, the area available for storage of fly ash at these TPPs is limited. In addition, this type of fly ash disposal poses a problem due to restricted land availability and potential contamination issues. A viable alternative is the reclamation of fly ash ponds by plantation. A study at the Ramagundam Super Thermal Power Station (RSTPS) in AndhraPradesh, India, on reclamation of a portion of an ash-filled, low-lying area has been performed. This article describes the characteristics of the RSTPS pond ash, ash leachates, and improvements in the fertility status of the reclaimed area over a three-year period. Furthermore, morphometric observations of different planted species indicate that these types of ash-filled, low-lying areas can be suitably reclaimed and the nutrient-rich leachate from ash-filled areas potentially can be used for irrigation purposes. O c 2008 Wiley Periodicals, Inc. INTRODUCTIONCoal will indubitably continue to play a major role in meeting the global demand for energy. The world's coal production is about 5.4 billion metric tonnes per year, most of which goes toward generating 38 percent of the world's electricity requirement (Australian Uranium Association [AUA], 2007). In India, about 70 percent of the total energy requirement is met from the combustion of pulverized coal in thermal power plants (TPPs). This practice will likely continue for the foreseeable future due to the excessive coal reserves in India, estimated at 287 × 10 9 metric tonnes per acre in some areas (Coal India, 2007). However, during combustion of coal in TPPs, various solid wastes, such as fly ash (FA), bottom ash (BA), boiler slag, and flue gas desulfurization (FGD) materials, commonly known as coal combustion by-products (CCBs), are produced (Vom Berg, 1998). The total quantity of these ashes produced is enormous and has been estimated at 118 million metric tonnes per year in India, and exceeds 550 million metric tonnes per year worldwide (Querol et al., 2001). To add perspective, some of the countries with high rates of FA production include Australia, Canada, China, India, the United States, and South Africa (Exhibit 1). This generation rate is expected to increase in light of an ever-increasing demand of electricity. Another concern is the availability of high-ash, low-calorific-value coal for the future due to the potential decrease in the quality of coal over time, especially in view of four to ten times concentration of elements of environmental concern in ash (mineral matter) during combustion (Fernandez-Turiel et al., 1994). In TPPs, FA is disposed of as a slurry into the ash lagoons. Yet, fly ash disposal in ash lagoons poses the potential to cause soil and groundwater contamination due to the high concentration of heavy metals (Jankowski et al., 2006) and radionuclides in fly ash (Vijayan & Behera, 1999). Thousands of hectares of land in India have been...

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