Process analysis of canal-based sanitation system in Thailand : towards sustainable development | |
| Author | Umeyama, Kenichi |
| Call Number | AIT Thesis no.ET-SUD-14-03 |
| Subject(s) | Sustainable development--Thailand Sanitation--Thailand Canals--Thailand--Environmental aspects |
| Note | A thesis submitted in partial fulfillment of the requirement s for the degree of Master of Science in Environmental Engineering and Management at the Asian Institute of Technology with specialization in Environmental Technology for Sustainable Development and degree of Master of Science at the UNESCO - IHE |
| Publisher | Asian Institute of Technology |
| Abstract | This research was done to study existing canal-based sanitation system, which is composed of on-site sanitation systems (OSS) followed by canals as a natural treatment system, in peri-urban Thailand and its possibility of sustainable development. As a 1st step, current on-site sanitation systems and canal operation was studied. Then, material flow of organic carbon (OC), total nitrogen (TN), total phosphorus (TP) at OSS and removal efficiency of the canal was estimated as a 2nd step. Further, material flow and fate of OC, TN and TP in the study area was determined. Finally, alternative options of OSS and floating aquatic plants are developed and most appropriate option was selected with consideration on legal obligations and technological, socioeconomic and environmental criteria. In this study, it was found out that old individual houses use cesspools (approx.90%), though some modern individual houses (approx.10%) and residential buildings use prefabricated septic tanks. Consequently, nearly one-fourth of OC (24.6%), TN (24.3%) and TP (21.7%) is discharged to the soil and groundwater. Significant portion of OC (27.8%), TN (66.6%) and TP (21.5%) was discharged to the canal, which is considered as a waste. Therefore if a sustainable scenario is to be effected, nutrients can be recovered via aquatic plants. Unlike OC (3.9%) and TN (9.1%), the largest portion of TP (56.8%) was transported to the offsite. Hence recovery of TP at the offsite plant could be an effective measure for TP recovery. Regarding to the canal operation, average removal rate of BOD, TN and TP in the selected canal were 23.1%, 40.5% and 13.4% respectively. It was also found out that BOD removal of the canal fits the plug-flow model rather than the dispersed flow-model, however its BOD removal efficiency was 1.4 times higher than estimation based on plug-flow model for facultative ponds. BOD removal rate constant obtained based on plug-flow model was 1.6 times larger than the value in literature. Further, actual removal rate of TN was 1.4 times higher than estimation based on the model for plug-flow regime. For the sustainable development of the study area, prefabricated septic tank and morning glory (Ipomoea aquatica) was selected as an appropriate sanitation options. In this sustainable scenario, it was estimated that morning glory cultivation achieves 10.0% of TN and 6.6% of TP recovery from domestic wastewater. Again, by the replacement of cesspools with septic tanks, the load of BOD, TN and TP flowing into the canal increases 1.4, 1.4 and 1.5 times respectively. However, aquatic plants farming offsets the increased load of TN and TP. Hence, it brings about environmental and socioeconomic benefits which make up for installation cost of septic tanks with limited impact to downstream people. |
| Year | 2014 |
| 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 | Energy Technology (ET) |
| Chairperson(s) | Shipin, Oleg V.;Steen, Peter van der; |
| Examination Committee(s) | Annachhatre, Ajit P.;Nguyen, Thi Kim Oanh; |
| Scholarship Donor(s) | ITO Foundation for International Education Exchange, Japan; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology - UNESCO-IHE, 2014 |