Application of electrochemical process for landfill leachate treatment with emphasis on heavy metal and organic removal | |
| Author | Yongyod Thaveemaitree |
| Call Number | AIT Thesis no. EV-02-31 |
| Subject(s) | Sewage--Purification--Heavy metals removal Sewage--Purification--Organic compounds removal |
| 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-02-31 |
| Abstract | This study was conducted to investigate the mechanisms of electrochemical (EC) treatment of a landfill leachate with emphasis on Pb, BOD, COD and color removal. Laboratory EC experiments were conducted using both synthetic wastewater and landfill leachate samples collected from the Pathumthani municipal sanitary landfill central, Thailand. From the batch EC experiments, the Pb removal efficiencies from the EC unit were found to be more than 99% with the reduction of Pb concentrations from 100 mg/L to below 1 mg/L. The Pb removal was observed to be dependent on: the electrical current (I), ratio between reacting surface area and volume of reactor (Av) and operation time (t), and following the first-order reaction as shown below: In _f_ = -0.019/i.028 f\, 0 ' 882 • t Co where C and Co are the supernatant and initial Pb concentrations, respectively. The sludge generated from the EC reactions using the synthetic Pb wastewater, analyzed by the X-ray diffractometry (XRD), were found to compose mainly of maghemite (Fe203), magnetite (Fe30 4), and laurionite (PbClOH). Based on the X-ray fluorescence spectrometry (XRF) analysis, the percent contents of Fe and Pb were 68.6% as Fe203 and 10.1 % as PbO, respectively. The percent of Pb removal by precipitation as the EC sludge and adsorption on the reactor wells and the electrode plates were 85.l and 0.87%, respectively. The EC unit could effectively remove Pb in the landfill leachate from 30 mg/L to about 1 mg/L or less within the 20-min operation time, and under the following suitable operating conditions: 46.51 m1 of Av and 5-10 A of electrical current. The Pb removal efficiencies followed the above first-order reaction, but because the landfill leachate contained high concentrations of organic and other compounds, a correction factor 0.10 had to be incorporated to the coefficient 0.0019. The percent removal of BOD and COD concentrations from the landfill leachate during the EC treatment were only 30-60%, while the color removal was 72. 7%. Based on the continuous EC experiments, the Pb concentrations in the landfill leachate could be effectively removed from 30 mg/L to less than 1 mg/L, and under the following suitable operating conditions: 46.51 m1 of Av, 10 A of electrical cunent and 45 min of HRT. The percent removal of BOD, COD and color from the landfill leachate were only 20-50%. The sludge generated from the EC treatment of the landfill leachate containing Pb, analyzed by the XRD, were found to compose mainly of maghemite (Fe203). Based on the XRF analysis, the percent contents of Fe and Pb in the EC sludge were 69.49% as Fe203 and 0.63% as PbO, respectively. The SVI and CST values of the EC sludge samples were 68 mL/g and 10.2 s, indicating that these EC sludge could be easily settled and dewatered. The EC sludge leachability was 0.53 µg of Pb I g of sludge, indicating that the EC sludge had less risk to environments, when compared with the conventional chemical precipitation sludge samples. |
| Year | 2002 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-02-31 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Chongrak Polprasert |
| Examination Committee(s) | Chettiyappan Visvanathan ;Lee, Seung-Hwan |
| Scholarship Donor(s) | H.M. (Queen) |
| Degree | Thesis (M.Eng.). - Asian Institute of Technology, 2002 |