| Author | Ni Ni Lwin |
| Call Number | AIT Thesis no.EV-96-25 |
| Subject(s) | Sewage--Purification--Activated sludge process
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Tapioca starch wastewater containing Chemical Oxygen Demand (COD) of 10,000-
15,000 mg/L was treated in a Upflow Anaerobic Sludge Blanket (UASB) reactor. The startup
of reactor was successfully achieved using seed sludge from anaerobic lagoon treating starch
wastewater. At steady state, COD conversion of over 80% and gas productivity· of 10-15
m3/m3.d was achieved for Organic Loading Rate (OLR) of over 17-30 kgCOD/m3d when
wastewater with Suspended Solids (SS) less than 1,000 mg/L was fed to the reactor.
Separate investigations on acid state revealed that 12 hours residence time was
adequate to achieve sufficient solubilization of starch particles yielding the VF A concentration
up to 1,200 mg/L. The UASB process performance was satisfactory even when undiluted
wastewater with SS up to 3,000-7,000 mg/L was used as feed. The process was not adversely
affected due to presence of SS yielding of gas productivity (10-15 m3/m3d) at feed stream
OLR of 21-31 kg COD/m3d, upflow velocity 0.32 m/h and 4:1 recirculation ratio
(recirculation:feed) beyond day 149 to the end of research (day 191). This was probably
because of biodegradable nature of starch.
TOC/E260 was used as a surrogate parameter to monitor wastewater quality and
treatability. The TOC/E260 ratio reduced from 4,000 mg/L for undiluted wastewater to 300-
500 mg/L after UASB treatment. |
| Year | 1996 |
| 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) | Annachhatre, Ajit P.; |
| Examination Committee(s) | Yang, Byung-Soo;Kamei, Tasuku; |
| Scholarship Donor(s) | Government of Switzerland; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1996 |