Stability evaluation of a cement based waste form to microbially induced degradation

Abstract

In this study the current Nuclear Regulatory Commission (NRC) protocol is used to evaluate the stability of Tuskegee cement/cobalt chloride waste form in the presence of Thiobacillus thiooxidans (T. thiooxidans). A critical examination of this protocol and identified limitations are reported also. Tuskegee cement/cobalt chloride waste forms were shown to exhibit considerable instability to microbial degradation as indicated by significant physical deterioration, and increased leaching of calcium and cobalt on exposure to T. thiooxidans. The instability was aggravated with higher levels of cobalt chloride content of the waste forms. The degradative capability of T. thiooxidansclosely followed its ability to significantly decrease the pH of its environment. Inherent limitations in the NRC protocol were observed which could lead to serious result interpretation errors. The use of a T. thiooxidansculture that is significantly lower in pH in comparison to the control medium could lead to an overestimation of the degradative effect of T. thiooxidans, while the use of a culture that is substrate limited could result in an underestimation of T. thiooxidans capability.

Keywords

Tuskegee cement/cobalt chloride waste form Thiobacillus thiooxidans Nuclear Regulatory Commission degradation leaching

Get full access to this article

View all access options for this article.

References

Baker, P. G. , Bishop, P. L. (1997) Prediction of metal leaching rates from solidified/stabilised wastes using the shrinking unreacted core leaching procedure. Journal of Hazardous Materials 52(2–3), 311–333.

Cocke, D. L. , Mollah, M. Y. A. (1993) The chemistry and leaching mechanisms of hazardous substances in cementitious solidification/stabilisation systems. In: Chemistry and Microstructure of Solidified Waste Forms( D. S. Roger , ed). Lewis Publishers, Boca Raton, Ann Arbor, London, Tokyo, p. 187-187.

Conner, J. R. (1993) Chemistry of cementitious solidified/stabilised Waste Forms. In: Chemistry and Microstructure of Solidified Waste Forms( D.S Roger , ed.). Lewis Publishers, Boca Raton, Ann Arbor, London, Tokyo, p. 41-41.

Diercks, M. , Sand, W. , Bock, E. (1991) Microbial corrosion of concrete. Experientia 47, 514–516.

Eaton, A.D. , Clesceri, L.S. & Greenberg, A.E. (1995) Standard Methods for the Examination of Water and Wastewater, 19th edition. American Public Health Association, American Water Works Association, Water Environment Federation, Washington DC, p. 4–136.

Kirk, D.R. (1996) Summary of US EPA Research on Solidified/Stabilised Waste Form Long – Term durability. In: Stabilisation and Solidification of Hazardous, Radioactive, and Mixed Wastes, 3rd Volume, ASTM STP 1240 ( M.T Gillan & C.C. Wiles , eds). American Society for Testing and Materials, p. 239-239.

Landreth, R.E. (1979) Survey of Solidification / Stabilisation technology for hazardous industrial wastes. EPA-600/2–79–056, p 1-1.

Libert, M.F. , Sellier, R. , Jouquet, G. , Trescinski M. , Spor, H. (1993) Effects of microoganisms growth on the long-term stability of cement and bitumen. In: Scientific Basis for Nuclear Waste Management XVI, Materials Research Society Symposium Proceedings vol 294 ( C.G Interrante & R.T Pabalan , eds). Materials Research Society, Pittsburgh, p. 267-267.

Milde, K. , Sand, W. & Bock, E. (1983) Thiobacilli of the corroded concrete walls of the Hamburg sewer system. Journal of General Microbiology 129, 1327–1333.

10.

Rogers, R.D. , Hamilton, M.A. , Veeh, R.H. & McConell, J.W., Jr (1996) Microbially Influenced Degradation of Cement-Solidified Low-Level Radioactive Waste Forms. In: Stabilisation and Solidification of Hazardous, Radioactive, and Mixed Wastes, 3rd Volume, ASTM STP 1240 ( M.T Gillan & C.C. Wiles , eds). American Society for Testing and Materials, p 116-116.

11.

Sand, W. & Bock, E. (1984) Concrete corrosion in the Hamburg sewer system. Environmental Technology Letters 5, 517–528.

12.

Sand, W. & Bock, E. (1988) Biogenic sulphuric acid attack in sewage systems. In: Biodeterioration volume 7 ( D.R. Houghton , R.N. Smith & H.O.W. Eggins , eds). Elsevier Applied Science, London and New York, p. 113-113.