| Author | Htun Oo |
| Call Number | AIT Thesis no. EV-91-8 |
| Subject(s) | Sewage--Purification--Activated sludge process
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| 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 | The microbial interaction between methanogenic bacteria, sulfate reducing bacteria and acidogenic bacteria in anaerobic sludge consortia cultivated in UASB reactor was experimentally evaluated in this study. Anaerobic sludges were harvested from two semi-pilot scale UASB reactors, one treating a relatively low strength synthetic waste water (500 mg COD/l) which is composed of 100 mg COD/l of particulate organic matter (cellulose) and 300 mg COD/l of soluble organic (sucrose), and the other treating a strong industrial waste water from alcohol distillery waste water at an influent COD of 10,000 mg COD/l. The low strength waste water UASB (hereafter refer to as UASBl) was inoculated with a mesophilic digested sludge from municipal sewage plant and operated at ambient temperature by increasing loading rate in the stepwise mode from 0.5 kg COD/m3-day at the start-up period to 1.55 kg COD/m3-day at the final stage. On the other hand, the UASB reactor receiving the high strength waste water (refer to as UASB2) was seeded with thermophilically digested sludge from the alcohol distillery plant. The UASB2 was started-up at a loading rate of 2 kg COD/ m3-d and operated by raising up of loading rate to 25 kg COD/m3-d stepwisely by shortening the hydraulic retention time throughout the 6 month experimental duration. At an appropriate time interval, the anaerobic sludges were taken out from both UASB reactors and the microbial activities of the sludges were determined by vial bottle technique in terms of hydrogentrophic methnogenic potential, acetotrophic methanogenic potential and sulfate reducing potential using H2, formate, acetate, propionate and lactate as a electron donor, and acetogenic potential using propionate, butyrate and glucose. As for the sludge grown in UASB2, the temperature dependency of methanogenic activities was also assessed by vial test using H2/C02, acetate, formate and raw waste water (alcohol distillery wastewater) as individual test substrates. In addition, the morphological observation of granulated sludge developed in UASBl was done by scanning electron microscopy. Moreover the viable cell counting of the sludge grown in both reactors were determined in terms of hydrogentrophic methanogen, acetotrophic methanogen, hydrogen utilizing SRB and homoacetogen by MPN method. The main conclusions drawn from this experiment are: (1) pH variation affect the methanogenic activity, esp. on formate as substrate; (2) UASB reactor' performance can be assessed by serum bottle vial test; (3) Inhibition phenomena is more convinced by increased MPB activity after sulfate depletion; (4) Lag phase phenomena of hydrogenotrophic MPB activity of UASB2 sludge further strengthen the hypothesis of homoacetogenic activity of H2/C02. |
| Year | 1991 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Harada, Hideki |
| Examination Committee(s) | Tran, Francis T. ;Mino, Takashi |
| Scholarship Donor(s) | The Government of Finland |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1991 |