Study of bacterial communities underlying treatment of high-strength organic wastewater at thermo- and mesophilic conditions | |
| Author | Tran Minh Thao |
| Call Number | AIT Thesis no.EV-07-52 |
| Subject(s) | Sewage--Purification--Sequencing batch reactor process Organic wastes Bioreactors |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Patterns in changes of bacterial communities were studied in parallel with previously performed laboratory scale engineering studies of a sequencing batch reactor (SBR) and two types of membrane bioreactors (MBR): sidestream air-lift and submerged MBR (Choudhary, 2005; Raut, 2006; Halgahawaththa, 2006). The microbial consortia were treating diluted cane molasses distillery wastewater and landfill leachate at mesophilic and thermophilic conditions (27, 30, 40, 45, 50 and 55°C). The present study deals only with molecular microbiological investigation and related production of extracellular polymeric substances (EPS, both protein and extracellular polysaccharides). However, the data generated is used to analyze engineering performance of the above-mentioned reactors. Thermophilic-aerobic wastewater treatment was studied in laboratory scale and advanced chniques are applied to carry out the study such as Fluorescent In-Situ Hybridization (FISH) and Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis (PCRDGGE). FISH technique reveals the abundance of each group or taxon that express with content they occupy in activated sludge. Samples, taken from reactors that ran at 27, 40, and 55°C, were analyzed to compare and characterize the microbial community accompanied with physicochemical performances. Followed up the previous studies, this study continued to investigate the variation of microbial community structure at different conditions. With ten probes applied in FISH technique, a relatively plentiful picture on microbial communities was showed and linked to reactors' performance. That makes more understanding about microbial world in thermophilic condition compared to ambient and mesophilic condition. Relationship between microbial communities and physicochemical performance was linked through two stages: 1st stage lasted from April 1st, 2006 to June 5th, 2006 and 2nd stage lasted from June 6th, 2006 to August 20th, 2006 with different physicochemical parameters. Microbial groups were relative to Extracellular Polymeric Substances (EPS) production, Biological Oxygen Demand (BOD) removal, Chemical Oxygen Demand (COD) removal, Total Kjeldahl Nitrogen (TKN) removal, and Mixed Liquor Volatile Suspended Solids (MLVSS). Temperature and SRT effect on bacterial communities structure was elucidated by Denaturing Gradient Gel Electrophoresis (DGGE) of Polymeric Chain Reaction (PCR) amplified 16S rRNA gene fragments were identified and analyzed. It revealed similarity between microbial comnmnities' structure by Sludge Retention Time (SRT) and temperature. The change of similarity was also linked to some physicochemical parameters such as BOD, COD removal, EPS production. Investigation of microbial communities structure, linkage this to physicochemical make us well understanding operation of SBR and MBR under different temperatures in treating high-strength organic wastewater |
| Year | 2007 |
| 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) | Shipin, Oleg V. |
| Examination Committee(s) | Visvanathan, C;Ranamukhaarachchi, S. L. |
| Scholarship Donor(s) | MOET, Vietnam - AIT Fellowship |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2007 |