| Author | Tran Duc Thang |
| Call Number | AIT Thesis no. EV-02-28 |
| Subject(s) | Water--Pollution--Mekong Delta
|
| Note | A thesis submitted in partial fulfillment of thtH=equirements for the degree of Master of
Engineering. School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-02-28 |
| Abstract | The water usage in Vietnamese rural areas was investigated in an extensive field study of
the Can Gio and Go Cong Dong districts of southern Vietnam. Questionnaire and sampling
survey were carried out at the same time. The results indicated these coastal communities
were dependant on water obtained from dry wells, boreholes with hand pumps, rainwater
harvesting and surface water. 67 % and 55 % of total households in Go Cong Dong and
Can Gio use clean water, respectively. The existing clean water consumption in rural
coastal household is 30 to 40 L/capita/day. The improper water resource management has
resulted in the majority of these sources being contaminated with high total dissolved
solids (TDS), iron content and organic pollution of up to 6 g/L (in Can Gio1
s ground
water), 30 mg/L and 20 mg TOC/L, respectively.
The selection of an abundant brackish water source combined with feasible desalination
techniques can be reasonable approach in rural coastal areas. RO is now a prominent
method used for seawater desalination due to high purity effluent. The most important
maintenance problem associated with RO operation is the membrane fouling, especially
biological fouling (biofouling). The second part of this thesis work focuses on the aspects
to eliminate biofouling on RO membrane. Lab-scale experiments, which were separated
into batch and continuous experiment, were conducted. Brackish water of 10 g TDS/L was
used as feed water in both experiments.
The batch experimental (biological granular activated carbon) filter results revealed that
fluidized bed (BGAC) at 30 min empty bed contact time (EBCT), with initial dissolved
organic carbon (DOC) concentration of 40 mg/L can be utilized effectively to remove
nearly 100% biodegradable DOC from brackish water. Continuous pretreatment system,
which was employed at the optimum condition from the batch experiment, included
attached growth and suspended growth. Attached growth system composed BGAC
combined with microfiltration membrane (MF), whilst, suspended growth one employed
membrane bioreactor (MBR) concept. The performance of membrane fouling, DOC
removal efficiency, transmembrane pressure was investigated in both attached growth and
suspended growth system. The results show that attached growth system produced better
effluent with 80 % DOC removal efficiency and quasi-total biodegradable DOC removal.
Even after 40 days of operation, chemical cleaning was not necessary and both systems
showed a good performance of transmembrane pressure. |
| Year | 2002 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-02-28 |
| 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 (EV) |
| Chairperson(s) | Visvanathan, C. |
| Examination Committee(s) | Lin, C. Kwei ; Nguyen Cong Thanh |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2002 |