Sediment Fixation of Arsenic in the Ash Lagoon of a Coal-Fired Power Plant, Philippines

Authors: Joselito P. Duyanen, Aries Milay

Abstract:

Arsenic in the sediments of the ash lagoons of the coal-fired power plant in Pagbilao, Quezon Province in the Philippines was sequentially extracted to determine its potential for leaching to the groundwater and the adjacent marine environment. Results show that 89% of the As is bound to the quasi-crystalline Fe/Mn oxides and hydroxide matrix in the sediments, whereas, the adsorbed and exchangeable As hosted by the clay minerals, representing those that are easiest to release from the sediment matrix, is below 10% of the acid leachable As. These As in these sediment matrices represent the possible maximum amount of As that can be released and supplied to the groundwater and the adjacent marine environment. Of the 89% reducible As, up to 4% is associated with the easily reducible variety, whereas, the rest is more strongly bonded by the moderately reducible variety. Based on the long-term As content of the lagoon water, the average desorption rate of As is calculated to be very low -- 0.3-0.5% on the average and 0.6% on the maximum. This indicates that As is well-fixed by its sediment matrices in the ash lagoon, attenuating the influx of As into the adjacent groundwater and marine environments.

Keywords: Arsenic, natural attenuation, coal-fired power plant, Philippines.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1073170

References:

[1] R. Finkelman, 1994, "Modes of occurrence of potentially hazardous elements in coal: level of confidence," Fuel Process. Tech., vol. 39, pp. 21-34, 1994.
[2] M. R. Martinez-Tarazona, and D. A. Spears, "The fate of trace elements and bulk minerals in pulverized coal combustion in a power station," Fuel Processing Technology, vol. 47, pp. 79-92, 1996.
[3] J. W. Yager, J. B. Hicks, and E. Fabianova, "Airborne arsenic and urinary excretion of arsenic metabolites during boiler cleaning operations in a Slovak coal-fired power plant," Environmental Health Perspectives, vol. 5, no. 8, 1997.
[4] Z. Ding, B. Zheung, J. Long, H. E. Belkin, R. B. Finkelman, C. Chen, D. Zhou, and Y. Zhou, "Geological and geochemical characteristics of high arsenic coal from endemic arsenosis areas in seouthwest Guizhou Province, China," Applied Geochem., vol. 16, pp. 1353-1360, 2001.
[5] R. Gieré, L. E. Carleton, and G. R. Lumpkin, "Micro- and nanochemistry of fly ash from a coal-fired power plant," American Mineralogist, vol. 88; no. 11-12, p. 1853-1865, 2003.
[6] J. F. Llorens, J. L. Fernandez-Turiel, and X. Querol, "The fate of trace elements in a large coal-fired power plant," Environmental Geology, vol. 40, nos. 4-5, 409-416, 2001.
[7] A. Kolker, F. E. Huggins, C. A. Palmer, N. Shah, S. S. Crowley, G. P. Huffman, and R. B. Finkelman, "Mode of occurrence of arsenic in four US coals," Fuel Process. Tech., vol. 63, pp. 167-178, 2000.
[8] X. Querol, J. L. Fernandez-Turiel, and A. Lopez-Soler, "Trace elements in coal and their behavior during combustion in a large power station," Fuel, vol. 74, no. 3. pp. 331-343, 1995.
[9] R. Meij, "Trace element behaviour in coal-fired power plant," Fuel Process. Tech., vol. 39, pp. 199-217, 1994.
[10] GHD, "Hydrogeologic monitoring: Six year trend analysis - 1997- 2002," Makati, Metro Manila, 2003.
[11] Duyanen, J. P. 1995. "The sedimentology and environmental geochemistry of the bottom sediments of Manila Bay, Philippines," PhD Dissertation, Institute of Environmental Geochemistry, Heidelberg University, Germany, 1995.
[12] A. I. Karayigit, T. Onacak, R. A. Gayer, and S. Goldsmith, "Mineralogy and geochemistry of feed coals and their combustion residues from the Cayirhan power plant, Ankara, Turkey," Applied Geochem, vol. 16, pp. 911-919, 2001.