| Author | Siriwardhena, Vasantha Kumar |
| Call Number | AIT Thesis no.EV-86-9 |
| Subject(s) | Sewage lagoons
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| Note | A research study 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 |
| Abstract | Waste stabilization ponds (WSP) are considered for design as plug, fully mixed or dispersed flow reactors employing first-order kinetics for the removal reactions. These models assume uniform and steady physical conditions throughout the WSP. But it has been found that such properties are neither steady nor uniform. Pond temperature is one such parameter which shows variations with time and with depth. Still there is no proper methodology to determine a representative temperature for use in the above WSP models. To overcome this difficulty, a procedure based on layered analysis of WSP was proposed, in which a WSP was divided into horizontal layers of equal size and the temperature of each layer was determined at discrete time intervals by using a dynamic temperature model developed in this thesis, by considering the WSP temperature as a only a function of time and depth. The exit age distribution curve provided the exit age of each fraction in the effluent. The temperature model provided the data necessary to determine the temperature path taken by each fraction during its stay in the WSP thereby, the final concentration of each fraction could be determined. By summing up these concentrations for each layer and for the full WSP, respectively, equivalent concentration for each layer and for total pond were obtained. This equivalent concentration of the WSP was used for the determination of the equivalent temperature of the pond. An explicit finite difference scheme was used to obtain the temperature values at finite time and depth intervals. The temperature model and the proposed methodology for the computation of representative temperature were compared and validated with the data obtained from the AIT pond. |
| Year | 1986 |
| 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) | Orth, H.M. ; Samorn Muttamara |
| Scholarship Donor(s) | Royal Netherlands Government |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1986 |