The relationship between unconfined compressive strength and leachate concentration of stabilised contaminated sediment

Abstract

Solidification/Stabilization (S/S) treatment was used in this study to immobilise copper (Cu) in contaminated river sediment. The sediment was artificially contaminated by spiking the solution of Copper sulphate (CuSO4.5H2O) to so as to get an average of 1000 ppm target concentration. Portland composite cement and Rice husk ash (RHA) were used as S/S agents. The amount of cement added to the mixture was l0% and while rice husk ash at the rate of 5%, l0%, 15% and 20% to the total dry weight of the mixture and then was cured for 7, 14 and 28 days. The unconfined compressive strength test (UCS) and toxicity characteristic leaching procedure (TCLP) were used to evaluate the effectiveness of the S/S treatments. From the results obtained it indicates that the partial replacement of cement with RHA in the binder system has increased the strength and the leachate concentration of copper was less in the treated sediment samples if compared with the untreated ones.

Analytical chemistry in technical approaches: immobilization of biosorbent waste containing heavy metals in cemented materials

“…The addition or replacement of other components to cement-based materials could either decrease or enhance the compressive strength. Therefore, it is necessary to consider the amount of cement and additives to establish the right composition in the formation [28,34,[46][47][48].…”

“…Heavy metals were undetectable during XRD analysis because their concentrations were too low. According to Aliyu et al [34], the heavy metals were able to establish metal hydrate or precipitation due to cement hydration, and the production of C-S-H assisted immobilization of heavy metals by trapping them in their structure [34,67]. C 3 S and C 2 S were the main compounds that produced C-S-H and portlandite during cement hydration [42].…”

“…The modified materials obtained have shown improved compressive strength and low leachability of metal ions. Aliyu and Karim [34] discovered that the compressive strength of a mortar material reached the optimal value when 15-20% of rice husk ash was added to the mixture. Rice husk ash is rich in SiO 2 , which is required in C-S-H formation, so the addition of rice husk ash supplemented the SiO 2 available from the cement itself.…”

Laboratory assessment of rice husk ash (RHA) in the solidification/stabilization of heavy metal contaminated slurry

“…The presence of RHA in cement-based materials contributes to the modification of the chemical as well as the physical properties of the materials. RHA as much as 20% has been used to replace cement in the treatment of sediment contaminated with Cu, Cr and Pb [25,26]. The use of RHA for the s/s of waste form have been found to be promising.…”