This paper presents the experimental findings of electrokinetic (EK) studies conducted to remove cadmium (Cd ?? ) and copper (Cu ?? ) present together as contaminants in clayey soil. Competitive sorption between cadmium and copper has been studied, which provides an insight into selection of Cd ?? and Cu ?? concentrations for maximum contamination of soil in the EK study. To explore the effect of pH on the desorption of both Cd ?? and Cu ?? and to compare the efficacy of different agents in enhancing the removal of these ions during the EK remediation process, the desorption studies have also been conducted using ammonium citrate (1 M), sodium citrate (1 M) and non-ionic surfactant Tween-20 (0.2 % v/v) at pH 2, pH 7, and pH 12. It was found that maximal sorption capacity of the soil for Cd ?? and Cu ?? was 8.34 and 12.1 mg g -1 , respectively. The desorption of both Cd ?? and Cu ?? influenced by pH for all desorbing agents is considered in the study. Overall desorption values for both Cd ?? and Cu ?? have been observed to be higher when ammonium citrate (1 M) was used as desorbing agent in the study. The results indicate the possibility of competition of complexation of Cd ?? and Cu ?? leading to desorption mechanism in the presence of desorbing agents. The EK tests on the Cd ?? and Cu ?? contaminated soil are carried out at a voltage of 35 V (1.0 V/cm) DC for 5 days. Sequential extraction experiments were conducted to determine fractionation of Cd ?? and Cu ?? in the EKtreated soil using deionized water at pH values of 2, 7 and 12. It is observed that current, electroosmotic flow and mobilization of Cd ?? and Cu ?? depend on pH, zeta potential (1) and specific conductance. Removal of these heavy metals was observed to be higher when ammonium citrate was used both for saturation as well as flushing solution during EK process.

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Though the majority of research on fly ash has proved its worth as a construction material, the utility of bottom ash is yet questionable due to its generation during the pulverized combustion process. The bottom ash produced during the fluidized bed combustion (FBC) process is attracting more attention due to the novelty of coal combustion technology. But, to establish its suitability as construction material, it is necessary to characterize it thoroughly with respect to the geotechnical as well as mineralogical points of view. For fulfilling these objectives, the present study mainly aims at characterizing the FBC bottom ash and its comparison with pulverized coal combustion (PCC) bottom ash, collected from the same origin of coal. Suitability of FBC bottom ash as a dike filter material in contrast to PCC bottom ash in replacing traditional filter material such as sand was also studied. The suitability criteria for utilization of both bottom ash and river sand as filter material on pond ash as a base material were evaluated, and both river sand and FBC bottom ash were found to be satisfactory. The study shows that FBC bottom ash is a better geo-material than PCC bottom ash, and it could be highly recommended as an alternative suitable filter material for constructing ash dikes in place of conventional sand.