| Author | Rijal, Shambhu Prasad |
| Call Number | AIT Thesis no. EV-90-20 |
| Subject(s) | Hazardous wastes
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-90-20 |
| Abstract | Solid sludge was prepared from the liquid waste generated by
the Environmental Engineering Laboratory , AIT, Bangkok. A
laboratory study on solidification of this sludge by using
cementitious binders was conducted for
stabilization/immobilization of heavy metals ( Cr and Zn)
present in the sludge . The binders used in this study were
Ordinary Portland Cement (OPC), and a mixture of OPC and Rice
Husk Ash in 1:1 ratio , commonly known as PRHAC. The sludge was
mixed in various proportions with binder-sand mortar ( 1: 2) ,
having a water to cement ratio of 0.5 for OPC and 0.65 for PRHAC
mortars.
Compressive strength and leachability of solidified samples
were studied to assess the effectiveness of the binders in
holding the heavy metals (Cr and Zn) in their
matrix. Leachability was determined by USEPA extraction procedure.
Compressive strength of solidified samples were found to
decrease with the increase of sludge/binder ratios. Leachability
was directly proportional to the sludge/binder ratio. Compressive
strength of OPC samples were higher than those of PRHAC samples
in all the tests. Chromium leachability was slightly less in OPC
than PRHAC mortar at sludge/cement ratio lower than 0.2.But
PRHAC was found better in immobilizing chromium , when
sludge/binder ratios higher than 0.5 were used. Zinc was
generally better immobilized by OPC mortar. The optimum
sludge/binder ratio for both mortar was found to be 0.5.
The amount of bulk sludge, rather than the concentrations of
heavy metals in the dry sludge, was responsible for strength
degradation of the solidified mass.
The applicability of Freundlich desorption isotherm was
studied for the leachability of Cr and Zn from the solidified
samples. The leachability data of both the mortars were found to
closely follow the disorption isotherm. |
| Year | 1990 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-90-20 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Chongrak Polprasert; |
| Examination Committee(s) | Tran, Francis T. ;Harada, Hideki ; |
| Scholarship Donor(s) | FINNIDA (GOVERNMENT OF FINLAND); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |