Chemistry and kinetics of calcite dissolution in passive treatment systems
Reaction of calcite with AMD is a key remediation process in anoxic limestone drains, (ALD), SAPS, and many wetlands, but predictions of effluent quality are currently based mainly on rules of thumb and prior experience. The PHREEQC computer program can be used to calculate the progress of this and similar reactions, and aid in understanding, design and evaluation of these systems. At pH values less than 5, calcite dissolution rates are strongly influenced by transport parameters such as flow velocity. Estimated calcite dissolution rates from ALD's and column experiments indicate little change in rate with pH, in contrast to published data for well stirred lab experiments. The dissolution rate is affected by concentration of SO{sub 4}, Fe, Al, Ca, P, and other trace solutes. The optimum contact time and sizing of ALD's will be dependent on these and possibly other parameters. Additional experiments are needed to evaluate these dependencies.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (US)
- OSTI ID:
- 20026848
- Resource Relation:
- Conference: 16th annual national meeting of the American Society for Surface Mining and Reclamation, Scottsdale, AZ (US), 08/13/1999--08/19/1999; Other Information: PBD: [1999]; Related Information: In: Mining and reclamation for the next millennium. Proceedings of the 16th annual national meeting of the American Society for Surface Mining and Reclamation, by Bengson, S.A.; Bland, D.M. [eds.], 745 pages.
- Country of Publication:
- United States
- Language:
- English
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