| Author | Nonglak Rungruang |
| Call Number | AIT Thesis no.EV-98-32 |
| Subject(s) | Sewage--Purification--Activated sludge process
Sewage--Purification--Ozonization
|
| 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 | This study aimed to determine the performance of combined processes of ozonation
as a pretreatment and followed by activated sludge process. This investigation was focused
on the BOD; NH3-N removal efficiency of such combined processes. A laboratory-scale unit
of combined process was set up. Wastewater samples from latex concentrate processing
taken from the factory at Chonburi Province were employed in this investigation. The
following operational strategies: ozonation in semi-batch mode, activated sludge processes
under batch mode of operation and combination of both processes was conducted. Based on
this investigation, the optimum operating conditions obtained are as follows: Ozonation:
ozone dosage of 66.44 mg 03 IL 02, contact time of 30 minutes, initial pH of 9.00; Batch
activated sludge process: initial F/M ratio of 0.4 d-1
, reaction time 6-7 hr; Combined process:
F/M ratio 0.4 d-1
, initial pH 9.00, reaction time 30 min (ozonation) and 6 hr (activated sludge
process).
Ozone can be employed to alleviate the toxic and oxygen-demanding characteristics
of ammonia-containing wastewater by converting the ammonia to nitrate. The oxidation of
ammonia is strongly pH-dependent reaction. The efficiency of ammonia oxidation by ozone
depends significantly upon the buffer capacity of the wastewater and it's ability to maintain
the elevated pH conductive to a rapid oxidation of ammonia. It was found that at the high
initial pH the decrease in ammonia might attribute both to ammonia oxidation by ozone and
ammonia stripping.
The combined processes can improve the removal efficiency of activated sludge
process on BOD, COD, NH3-N, SS and TKN up to 95.46, 90.95,75.11, 74.52 and 67.90 %,
respectively (under the optimum operating conditions). Such combined processes were found
to be very effective in removal of BOD, COD, NH3-N, SS and TKN in wastewater and also
produced a final effluent low in suspended solids, clear and odorless. It was observed that the
pungent odor of wastewater was significantly decreased after ozonation and completely
disappeared after activated sludge process. |
| Year | 1998 |
| 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) | Samorn Muttumara; |
| Examination Committee(s) | Takizawa, Satoshi ;Dahl-Madsen, Karl Iver; |
| Scholarship Donor(s) | Asian Institute of Technology Partial Scholarship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1998 |
