| Author | Suwasa Kantawanichkul |
| Call Number | AIT Diss. no. EV-90-2 |
| Subject(s) | Sewage--Purification--Oil removal
|
| Note | A dissertation submitted in partial fulfillment of the
requirements for the degree of doctor of technical science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The hollow fiber membrane bioreactor combined with
photosynthetic bacteria ,Rhodobacter sphaeroides was proved to b e
suitable for only wastewater treatment The hollow fiber
membrane enhanced the removal of grease and oil efficiency t o
over 90% while the degradation by photosynthetic bacterial one
could achieve 65-75%. The hollow fiber membrane was also
necessary for solid/liquid separation since the settle able sludge
of t his bacteria was only 10 ml/l in 30 min. which is difficult
to settle b y gravity.
Sludge treatment and disposal were not needed for this
system since bacterial cells in the sludge can be directly used
as sing l e cell protein for animal feed and fertilizer .
The protein content o f the wasted sludge was 40% which was
high enough to be used as single cell protein.
Under long solid retention time ( SRT) of 3 0 d a nd s h or t
hydraulic retention time (HRT) of 1. 5 d, maximum ML SS
concentration of 3 , 910 mg/l could be obtain e d, and under short
SRT ( 5 d ) and short HRT (1 .5 d), the maximum biomass harvested
per d ay (660 mg/ d) was achieved. Too s h ort HRT caused clogging
of the membrane a nd too short SRT caused cell washout of the
system .
When high organic loading (8 kgCOD/(m3 .d)) or high hydraulic
loading (1.3 m3 /( m3 .d )) was applied to the system, the high
concentration of grease and oil occurred a nd inhibited t h e
bacterial growtl1 in the reactor. Never the less, the system was
proved to b e stable to high organic loading and high hydraulic
loading (8 kgCOD/(m3 .d) and 1. 3 m3 /(m3 . d ) respectively ). The COD
removal efficiency of the system was 70 - 85%, and further
treatment by other bio- oxidation processes is necessary.
Batch study in small bottles was a l so conducted to study t h e
performance o f Rhodobacter sphaeroides. The inoculum size of 596
was suitable for the system. The growth rate a nd the removal
efficiency of this bacteria were more active under continuous
illumination than under intermittent illumination either by
artificial or s un light.
The kinetic coefficients of Rhodobacter sphaeroides (µm, Y,
Ks and kd ) were d e t ermine d. The value of kd for the bioreactor
with membrane was bigger than the bioreactor with out membrane.
This was possibly caused by some attached growth a t the membrane
fibers which reduced the MLSS concentration in the reactor . |
| Year | 1990 |
| Type | Dissertation |
| 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 ;Yamamoto, Kazuo
|
| Examination Committee(s) | Vigneswaran, Saravanamuthu ;Mino, Takashi ;Athapol Noomhorm ;Somiya, I.
|
| Scholarship Donor(s) | Royal Norwegian Government |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1990 |