Ispitivanje mogućnosti primene ubrzane karbonizacije u procesu solidifikacije/stabilizacije sedimenta zagađenog teškim metalima
Abstract
This dissertation investigates the application of accelerated carbonization as a
technique for improving the solidification/stabilization treatment of sediment
contaminated with heavy metals. In the first part of the research, the accelerated
carbonization method is optimised for use to improve the treatment of
solidification/stabilization of contaminated sediment. In the second part of the
research, solidification/stabilization (S/S) and solidification/stabilization with
accelerated carbonization (S/S/K) treatments are applied to contaminated sediment
of the Begej canal which had previously undergone electrokinetic treatment. Wheat
and soybean straw bio-ash and molasses bio-ash were used as immobilizing agents.
After treatment of the monolithic mixtures, risk assessment was performed using a
sequential extraction procedure and the DIN 3841-4 S4 and TCLP leaching tests.
The influence of accelerated carbonization on the efficiency of S/S treatment was
assessed, and the most efficient immobilizing agent was investigated, in order to
provide an in depth insight into the application of the S/S and S/S/K treatments on the metals-contaminated sediments of the Veliki bački canal. In addition to bio-ash
from wheat and soybean straw, calcium oxide was also used as an immobilizing
agent. Leaching tests and the sequential extraction showed that accelerated
carbonization has a positive effect on the immobilization of critical metals (Zn, Cu
and Cd) in monolithic mixtures, which correlates with an increase in carbonate
phase (confirmed by XRD and SEM/EDS analysis), as well as a lower toxicity of
the monolith relative to the contaminated sediment. The results of the applied DIN
3841-4 S4 and TCLP tests show that all the monolithic mixtures are categorized by
the relevant Serbian Regulations as non-hazardous and safe for disposal, based on
the leached concentrations of Zn, Cu, Cd and Ni. The newly developed S/S/K
method for treating polluted sediment enables the use of large amounts of bio ash
(waste use) and the reduction of carbon dioxide emissions into the atmosphere by
its long-term storage and sequestration in monolithic mixtures which are safe for
disposal.