| Author | Choudhary, Mukesh Kumar |
| Call Number | AIT Thesis no.EV-05-18 |
| Note | A thesis submitted in pmiial fulfillment of the requirements for the
degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Abstract | Landfill leachate is a complex wastewater with considerable variation in both quality and quantity. The composition and concentration of pollutants are influenced by the types of waste deposited, hydrogeological factors, and more significantly by the age of the landfill site. Conventional biological treatments have been ineffective for leachate from relatively old landfill site. In leachate containing high concentrations of organic and nitrogen compounds such cases result in possible serious environmental problems near the landfill site. This research was undertaken to investigate the performance of membrane bioreactor (MBR) using mixed thermophilic bacterial culture in treating raw leachate containing high organic and nitrogen concentrations. Three separate sequencing batch reactors (SBRs) maintained at ambient, 40oC and 50oC were also operated in parallel to evaluate the comparative performance at different temperature conditions. The sludge characteristics in terms of EPS and its components, CST and SVI were measured. Biochemical kinetics using bioreactor setup was determined for the estimation of biokinetic coefficients at different temperatures. Furthermore, temperature effect on bacterial community development by Denaturing Gradient Gel Electrophoresis (DGGE) of Polymeric Chain Reaction (PCR) amplified 16S rRNA gene fragments were identified and analyzed. In thermophilic MBR system, the COD removal rate increased from an average value of 62 % to 79 % with gradual increase in BOD fraction from 0.39 to 0.65. The average ammonia removal efficiency decreased from 75% to 60% with increased BOD loading condition. The SBRs also followed the same trend of increased COD removal with increased loading for higher temperature conditions. This indicates that thermophilic system is suitable for the higher loading. In sludge analysis, EPS production found to be highest in thermophilic MBR and also its value increased as a function of temperature in SBRs running at different temperatures. The protein to carbohydrate ratio in soluble EPS observed to be highest at 40oC (1.4-1.55) whereas the lowest observed ratio was 0.7-0.85 at temperature of 50oC. This indicates that flocculation and thereby settling ability decreases with an increase in temperature. The same trend was observed in terms of SVI and CST, which signifies that the sludge could easily settle and dewater at lower temperatures. In the biokinetic study on sludge obtained from different temperatures, lowest sludge yield (0.19 gSS/gCODremoved) was observed at 50oC whereas, ambient condition showed its highest value of (0.44 gSS/gCODremoved). The results obtained by PCR study showed that there was a bacterial community shift with temperatures and with change in feed conditions also. The different performance statistics obtained at different conditions could be correlated with PCR results. |
| Year | 2005 |
| 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) | Visvanathan, C.; |
| Examination Committee(s) | Shipin, Oleg;Aramaki, Toshiya |
| Scholarship Donor(s) | The Government of Netherlands ; |
| Degree | Thesis (M.Eng.) -- Asian Institute of Technology, 2005 |