| Author | Thayalakumaran, Nagalingam |
| Call Number | AIT Thesis no. EV-94-31 |
| Subject(s) | Sewage--Purification--Heavy metals removal
|
| Note | A thesis submitted in ยท partial fulfillment of the requirements for the degree of Master of
Engineering, School of Environment, Resources & Development |
| Publisher | Asian Institute of Technology |
| Abstract | Various industrial activities such as electroplating and metal finishing generate tons of
metallic pollutants into the air and water bodies. There are a number of techniques available
for the removal of heavy metals from wastewaters. Electroplating industries produce Cr and
Ni wastewaters. Because constructed wetlands are cost-effective and energy-efficient, they
were used to investigate efficiencies in treating an electroplating wastewater.
One pilot-scale and three lab-scale constructed wetland units were constructed at the
Environmental Research Station, AIT campus where cattail plants were grown. These
constructed wetlands were fed with mixtures of the electroplating wastewater and a domestic
wastewater and maintained at a hydraulic retention time of 7 days. Physico-chemical
parameters such as pH, SCOD, TSS, DO and influent and effluent heavy metal concentrations
were measured at three days interval.
Heavy metal removal efficiencies of more than 99 3 were observed in pilot-scale unit
even when the influent heavy metal concentrations were 25 mg/l. The heavy metals were
removed mainly by precipitation and adsorption. The soil adsorbed more Cr and Ni than the
plants. The Cr and Ni ions were strongly held by the root cells showing high concentrations
in the roots. Cr was more strongly chelated in the root than Ni. Ni fed wetland plants showed
some phytotoxic effects. In the pilot-scale unit, removal efficiencies of SCOD, TSS, TKN
were more than 64, 89 and 85 3 respectively. |
| Year | 1994 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Chongrak Polprasert |
| Examination Committee(s) | Samorn Muttamara ;Umita, Teruyuki
|
| Scholarship Donor(s) | Government of Finland |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |