Occurrence and fate of microbial pathogens in polluted surface water bodies and wastewater | |
| Author | Dang Diep Yen Nga |
| Call Number | AIT Thesis no.EV-06-8 |
| Subject(s) | Pathogenic microorganisms Water--Microbiology--Thailand--Pathum Thani Sewage--Microbiology--Thailand--Pathum Thani |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | In an attempt to expand the limited knowledge of surface water and wastewater pathogens (faecal coliforms, Escherichia coli, Cryptosporidium parvum and Giardia lamblia) in the developing Southeast Asian countries like Thailand, the occurrence and fate of these pathogens in two irrigation canals (Canal One and Canal Two) as well as in the AIT pond-based Wastewater Treatment (AIT-WWT) plant in Pathumthani was studied in the context of various biogeochemical factors and climatic conditions over the period of May 2005-March 2006. Surface water of irrigation canals in this study area was found to be significantly polluted in terms of the waterborne pathogens as compared to the surface water standards of Thailand and generally recommended international criteria. Although the spatial distribution of concentrations of the selected waterborne pathogens along the 3.5-km stretch of the canals investigated was found to depend on the sampling locations, the data on the occurrence and fate of the selected waterborne pathogens in surface water in the study area was found to correlate satisfactorily with the non-point pollutional pressure originated from the population residing around the canals, industrial activities, street nm-off and agricultural run-off. The possible removal mechanisms for the coliform bacteria in the canals appeared to be the natural attenuation process or solar irradiation, while it appeared to be time-dependent sedimentation for C. parvunn oocysts and G. lamblia cysts. Moreover, great significance of seasonal effect on the concentrations of waterborne pathogens in canal waters was found. In the case of AIT WWT plant, the concentrations of faecal coliform, E. coli and protozoan pathogens enumerated in the raw wastewater were reduced in the final effluent discharged to Canal One which was by far lower than the concentration in this receiving water body. Concentrations of coliform bacteria in treated wastewater discharged into the Canal One met the WHO guidelines for the restricted irrigation, prominently no oo(cyst)s of C. parvum and G. lamblia were discharged as well. A distinct trend of overall higher removal of coliform bacteria (faecal and E. coli) was observed in the pond series during the dry season in comparison to the rainy season and the overall trend of a better removal during the dry season observed during the long term regular monitoring was confirmed. Hence it can be concluded that pH-dependent algae-mediated photooxidation played main role in the faecal coliform bacteria removal both in the rainy and dry seasons. Furthermore, no correlation was observed between the protozoan pathogens removal and main killing factors of bacteria such as temperature, pH and dissolved oxygen confirming important role of HRT-dependent sedimentation of pathogens in the ponds |
| Year | 2006 |
| 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) | Shipin, Oleg V.; |
| Examination Committee(s) | Thammarat Koottatep ;Nguyen Thi Kim Oanh ; |
| Scholarship Donor(s) | Ministry of Education and Training, Viet Nam |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2006 |