| Author | Myo Min Cho |
| Call Number | AIT Thesis no.EV-01-11 |
| Subject(s) | Sewage--Purification--Biological treatment
|
| Note | A thesis submitted in pa1iial fulfillment of the requirement for the degree of Master of
Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Yeast system coupled with microfiltration membrane, also called yeast membrane
bioreactor, and is a promising technology used as pretreatment of biodegradable organic
matter from saline seafood wastewater prior to secondary treatment for high organic strength
wastewater and as secondary and advanced treatment for low organic strength wastewater.
The experimental investigations were conducted by using lab-scale experiments, which were
separated into five stages.
In the first stage, biokinetic constant experiments were conducted in order to
determine the growth rate of yeast sludge. The effects of different salt concentrations on
growth rate were studied in this stage. It was concluded that growth rate of yeast mixture at
high salt concentrations (32 and 45 g/L) was higher than that of activated sludge.
In the second stage, the batch experiments were conducted in order to determine the
optimum operating condition for yeast membrane bioreactor. The effects of different sludge
retention time and nutrient loading were studied in this stage. The results showed that yeast
reactor run at SRT of 10 d, influent COD of 5000 mg/L could obtained around 80% COD
removal. Main mechanism of nitrogen removal in yeast reactor is nitrogen uptake process into
biomass. However, precipitation of protein at low pH which is adjusted to 3.5 to 3.8 for yeast
growth and inhibition of bacteria contamination may attribute to nitrogen removal.
In the third stage, the continuous YMBR experiment was conducted in order to
determine the optimum hydraulic retention time. The results show that the YMBR run at HRT
of 24 h with influent COD concentration of 5000 mg/L could remove 85% of COD.
Moreover, membrane bioreactor run at HRT of 8 h with influent COD concentration of 1000
mg/L could achieve effluent COD quality met the effluent standard set in Thailand after
neutralization.
In the fourth stage, membrane-clogging experiment was conducted. From the
experimental results, it was concluded that yeast system could prolong the operation period of
membrane without chemical cleaning than that of bacteria system.
In the fifth stage, characteristics of sludge with different salt concentration were
determined on the dewaterability of the sludge. It can be concluded wide yeasts acclimatized
in this study has poor settling ability, but inversely it has good dewatering ability. Therefore
using membrane technique for yeast treatment could overcome this disadvantage and as well
as obtain high effectiveness for dewatering, increasing membrane performance and running
with low pump pressure |
| Year | 2001 |
| 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) | Trankler, Josef; Fukushi, Kensuke |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |