1 AIT Asian Institute of Technology

Plug-flow model for organic removal in constructed wetlands

AuthorChanetta Phanuwan
Call NumberAIT Thesis no.EV-99-24
Subject(s)Constructed wetlands

NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources & Development
PublisherAsian Institute of Technology
AbstractThis study was conducted to investigate the main parameters affecting treatment performance of FWS CWs treating a domestic wastewater in tropical region. The kinetics of organic removal were evaluated. Four pilot-scale FWS CW units planted with cattails (Typha angustifolia) were set up, while a full-scale CW unit was used to compare the results. The effects of hydraulic retention time (HRT) on organic removal were studied by varying the HRTs of 5, 8 and 14 days, while the OLR was maintained at 100 kgCOD/(ha·d). The COD and BOD remoyal efficiencies were 91, 96 and 98% and 95, 97 and 98% for units operating at the HRT of 5, 8 and 14 days, respectively. The firstorder plug-flow kinetic rate constants (k20) were in the range of 0. 113-0.230 d"1 and 0.151-0.281 d-1 for COD and BOD, respectively. The k values increased with decreasing HRT. The effects of organic loading rate (OLR) were studied by varying the OLR at 35, 84 and 137 kgCOD/(ha·d), while the HRT was maintained at 8 days. The COD and BOD removal efficiencies were 67, 79 and 77 % and 81, 85 and 81 % for units operating at the OLR of 35, 84 and 137 kgCOD/(ha·d), respectively. It was found that the highest COD and BOD removal efficiencies were found in the unit operating at the OLR of 84 kgCOD/(ha·d). The k20 values ranged 0.060-0.095 day"1 and 0.109-0.112 day"1 for COD and BOD, respectively. Based on ANOVA test at p > 0.05, there was no significant difference between the mean COD and BOD5 removal efficiencies at the HRT of 8 and 14 days, but the HRT of 8 days was recommended on economic reason. The OLR at the range of 35- 137 kgCOD/(ha·d) did not appear to have significant effects on organic matter removal efficiencies and the k values.
Year1999
TypeThesis
SchoolSchool of Environment, Resources, and Development
DepartmentDepartment of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC))
Academic Program/FoSEnvironmental Engineering and Management (EV)
Chairperson(s)Chongrak Polprasert;
Examination Committee(s)Ozaki, Hiroaki ;Dahl-Madsen, Karl Iver;
Scholarship Donor(s)Asian Institute of Technology Partial Scholarship;
DegreeThesis (M.Sc.) - Asian Institute of Technology, 1999


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