Author/Authors :
Saeedi، M نويسنده Environmental Research Laboratory, Department of Hydraulics and Environment, School of Civil Engineering, Iran University of Science and Technology, 16846, Narmak, Tehran, Iran , , Rezaei Bazkiaei، A نويسنده Environmental Engineering, State University of New York at Buffalo (UB), 218 Furnas Hall, USA , , Torkaman، Z نويسنده Department of Chemistry, Shahid Beheshti University, Tehran, Iran ,
Abstract :
Solidified samples of fuel oil combustion bottom ash with two sets of Ordinary Port-
land Cement (OPC) and Pozzolan added OPC were investigated with three sets of chemical leaching
tests. Toxicity characteristic leaching test (TCLP) results classified waste material and its solidifica-
tion products as hazardous. Although Ni and Cr have over-leached, but their close examination with
Sequential Chemical Extraction (SCE) test revealed new insights as follows. Nickel fixation in cement
matrix has shifted over 20% of leachable Ni from first 4 fractions of SCE test to residual fraction with
less likelihood of leaching. Chromium fixation in matrix has made shifts on leachable fractions that
are not generally in favor of a successful fixation in matrix. In the case of Cd leaching, the only
obvious finding from SCE test is that solidification processes have made a slight shift between
fractions in bound to Iron and Manganese oxide and fraction in bound to carbonates. Compared to
TCLP results for different mixtures, it can be concluded that Cd fixation has been done properly and
significant change in leaching probability was not caused by solidification processes. Results of
“Alkalinity, Solubility and Release as a function of pH” test indicate over regulation in the case of Pb
and Cr leaching in different pHs. Results indicate need for more delicate interpretation of TCLP test
results when several management scenarios are available and practical.
