1 AIT Asian Institute of Technology

Design and operation of waste stabilization ponds : a case study in Thimphu, Bhutan

AuthorPema Choda
Call NumberAIT Thesis no. EV-97-13
Subject(s)Sewage lagoons--Bhutan--Thimphu

NoteA thesis submitted in partial fulfillment of the requirements for the degree of the Master of Engineering, School of Environment, Resource and Development
PublisherAsian Institute of Technology
Series StatementThesis ; no. EV-97-13
AbstractThe research was carried out to evaluate the operational performance of the waste stabilization ponds in Thimphu and design a waste stabilization ponds system to serve the population not covered by the present waste treatment plant. Chemical analysis of the pond influent and effluent were carried out and analysed. Besides other parameters like meteorological data and field observations were used to assess the pond performance. The analytical results revealed that the two anaerobic ponds and the facultative pond were under-loaded due to low flow. On the other hand maturation pond was found to be overloaded. The effluent suspended solids contain almost entirely of algal cells, which increases from low dl:lring winter to almost three times during spring (April 1997). Ammonia - nitrogen in the raw wastewater was quite high and removal rate was around 50% only. Faecal coliform removal was satisfactory, however it was observed that the removal decreased as the effluent suspended solids increased. In general the ponds were found to be working quite satisfactorily. The pond design was based on the mean pond temperature of the coldest month. Anaerobic ponds were designed based on volumetric loading and facultative pond design was based on surface areal loading. Maximum loading rate applied were 1 OOg BOD5 /m3 .d for the anaerobic ponds and 1 OOkg BODs/ha.d for facultative ponds. Design of maturation pond was mainly based on the removal of faecal coliform, however, some BOD removal is achieved also.
Year1997
Corresponding Series Added EntryAsian Institute of Technology. Thesis ; no. EV-97-13
TypeThesis
SchoolSchool of Environment, Resources, and Development (SERD)
DepartmentOther Field of Studies (No Department)
Academic Program/FoSEnvironmental Engineering (EV)
Chairperson(s)Annachhatre, Ajit P.;
Examination Committee(s)Nguyen Thi Kim Oanh;Purkar, Nitin Afzul ;
Scholarship Donor(s)DANIDA;
DegreeThesis (M.Eng.) - Asian Institute of Technology, 1997


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