Empirical Partitioning Leach Model for Solidified/Stabilized Wastes
Publication: Journal of Environmental Engineering
Volume 127, Issue 3
Abstract
A model has been developed to describe dynamic leaching of metal contaminants from solidified wastes using data for calibration that are taken only from batch tests. The model describes the three major factors affecting leaching: (1) acid/base reactions that determine the pH within the waste; (2) pH-dependent reactions that determine whether the contaminants are in mobile or immobile forms; and (3) diffusion that transports mobile contaminants from the waste. Acid/base reactions and mobilization/immobilization reactions of contaminants are described by empirical equations calibrated from batch equilibrium tests. Precipitation or sorption reactions are used to describe partitioning of contaminants among mobile and immobile forms. Fickian diffusion is used to describe transport of soluble compounds. Model predictions for observed diffusivities of copper, chromium, lead, and zinc agreed well with the experimental data obtained from dynamic leaching tests. Little difference was observed in model predictions when contaminant immobilization was assumed to be caused by precipitation or by sorption. Model simulations indicate that the assumption of an infinite bath may not apply to dynamic leach tests when contaminants are strongly immobilized.
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References
1.
American Nuclear Society. ( 1986). “Measurement of the leachability of solidified low-level radioactive wastes by a short-term test procedure.” ANSI/ANS-16.1-1986, Standards Committee Working Group, LaGrange Park, Ill.
2.
Baker, P. G., and Bishop, P. L. ( 1997). “Prediction of metal leaching rates for solidified/stabilized wastes using the shrinking unreacted core leaching procedure.” J. Haz. Mat., 52, 311–333.
3.
Batchelor, B. ( 1990). “Leach models: Theory and application.” J. Haz. Mat., 24, 255–266.
4.
Batchelor, B. ( 1992). “A numerical leaching model for solidified/stabilized wastes.” Water Sci. Technol., 26(1–2), 107–115.
5.
Batchelor, B. ( 1997). “A framework for risk assessment of disposal of wastes treated by solidification/stabilization.” Envir. Engrg. Sci., 14, 3–13.
6.
Batchelor, B. ( 1998). “Leach models for contaminants immobilized by pH-dependent mechanisms.” Envir. Sci. and Technol., 32(11), 1721–1726.
7.
Cheng, K. Y., and Bishop, P. L. ( 1990). “Developing a kinetic leaching model for solidified/stabilized hazardous wastes.” J. Haz. Mat., 24, 213–224.
8.
Conner, J. R. ( 1990). Chemical fixation and solidification of hazardous wastes, Van Nostrand Reinhold, New York.
9.
Cote, P. ( 1986). “Contaminant leaching from cement-based waste forms under acidic conditions.” PhD thesis, McMaster University, Hamilton, Canada.
10.
Crank, J. ( 1975). The mathematics of diffusion, Clarendon Press, Oxford, U.K.
11.
Hinsenveld, H., and Bishop, P. L. ( 1996). “Use of the shrinking core/exposure model to describe the leachability from cement stabilized wastes.” Stabilization/solidification of hazardous, radioactive and mixed wastes, Vol. 3, ASTM, West Conshohocken, Pa.
12.
Isenberg, J., and Moore, M. ( 1992). “Generalized acid neutralization capacity test, stabilization, and solidification of hazardous, radioactive, and mixed wastes.” ASTM STP 1123, Vol. 2, ASTM, West Conshohocken, Pa., 361–377.
13.
Johnson, C. A., Brandenberger, S., and Baccini, P. ( 1995). “Acid neutralizing capacity of municipal waste incinerator bottom ash.” Envir. Sci. and Technol., 29(1), 142–147.
14.
Kosson, D. S., Kosson, T. T., and van der Sloot, H. A. ( 1993). “Evaluation of solidification/stabilization treatment processes for municipal waste combustion residues.” EPA/600/R-93/167, U.S. Environmental Protection Agency, Cincinnati.
15.
Kovalick, W. W. ( 1992). “Trends in innovative treatment technologies at contaminated sites.” Water Sci. and Technol., 26(1–2), 99–106.
16.
MacMullin, R. B., and Muccini, G. A. ( 1956). “Characteristics of porous beds and structures.” AIChE J., 2(3), 393–403.
17.
Morel, F. M. M., and Hering, J. G. ( 1993). Principles and applications of aquatic chemistry, Wiley-Interscience, New York.
18.
Taffinder, G. G. ( 1991). “Determining the effective diffusivity of ions in hazardous wastes solidified by Portland cement.” MS thesis, Texas A&M University, College Station, Tex.
19.
Trussell, S. ( 1993). “A study of immobilization of four heavy metals by solidification/stabilization with Portland cement.” MS thesis, Texas A&M University, College Station, Tex.
20.
U.S. Environmental Protection Agency (U.S. EPA). ( 1993). “Technical resource document solidification/stabilization and its application to waste materials.” EPA/530/R-93/012, Columbus, Ohio.
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Received: Jul 12, 1999
Published online: Mar 1, 2001
Published in print: Mar 2001
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