Composition and leachability of trace elements in coal ash and their migration in ground water at thermal power plant site at Manuguru

摘要

The Heavy Water Board at Manuguru has a captive power plant using 2500 tpd of coal producing about 1000 tpd of ash. The possible toxic metal contamination of ground water due to leaching of the ash (so that toxic elements do not seep through one pond and contaminate the ground water) are assessed. Samples of coal, fly ash, bottom ash, ash pond overflow water, river water, ash pond slurry, and soil (surface and depth) were analysed for major and trace element contents using EDXRF, INAA, AAS, and Anodic Stripping Voltammetry. The cation exchange capacity of the underlying soil and the fly ash were determined by standard method using calcium as the cation indicator. The redox potential and the pH of the samples were measured by using Pt/Mo and glass/calomel system respectively. The size distribution of fly ash particles were also determined. The study conclusively shows that the leach percent is very small and the soil has good cation exchange capacity. There is negligible probability of contamination of ground water from ash pond and therefore no dire need for providing any impervious lining for the ash pond. (author). 23 refs., 19 tabs., 16 figs., 1 appendix. (Atomindex citation 26:044701)