Environmental Engineering Reference
In-Depth Information
3.
T
ECHNIQUES
There are many techniques practiced to solidify, concentrate or precipitate
cadmium from liquid and gaseous waste material. Some of them are as
follows:
3.1. Adsorption by Activated Carbon
3.2. Reverse Osmosis
3.3. Composting
3.4. Precipitation by Chemicals
3.5. Solidification/Stabilization
All these techniques may be used to convert liquid/gaseous cadmium
waste into solid or immobilized material followed by inertization and disposal.
The details of each of the process are discussed henceforth.
3.1. Adsorption by Activated Carbon
Although the ability of activated carbon to remove cadmium in high
concentrations from wastewater has been established by number of researchers
(Gabaldon and Gonzalez 2000, Seco and Marzal 1999, Periasamy and
Namasivayam 1994), only a few studies are available on the use of activated
carbon to remove Cadmium in low concentration from contaminated surface
or subsurface waters (Jaffar and Ehsan, 1993). Activated carbon has been an
effective adsorbent for the removal of many organics substances in water, its
use for metal removal from water is rather scarce.
Tilaki and Ali (2003) studied to determine the efficacy of using GAC
(granular activated carbon), Biofilm and BAC (Biofilm/GAC) columns to treat
low concentration Cadmium bearing water streams and also studied the effects
of temperature and pH on the adsorption isotherms. They concluded from the
study that BAC was more efficient than GAC in the removal of Cd from water
environment. The BAC columns can tackle only low concentrations, as the
concentrations become higher, they become inhibitory to the growing biofilm
consecutively affecting the overall efficacy.
Search WWH ::
Custom Search