Thayalakumaran, Nagalingam creator Chongrak Polprasert Chairperson Samorn Muttamara Examination Committee Umita, Teruyuki Examination Committee Government of Finland Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 1994 continuing eng 99 leaves 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. A thesis submitted in · partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources & Development Thesis (M.Eng.) - Asian Institute of Technology, 1994 Sewage Purification Heavy metals removal Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B15821 http://203.159.5.9/ait-thesis/detail.php?q=B15821 050499 20260817162845.0