Functional Dynamics and Microbial Community Structure of EBPR system fde with Glucose as Main Carbon Source:Impact of COD Volumetric and Phosphorus Loading

• Main Authors: LIN,YAN-YING, 林彥穎
• Other Authors: Liu Wen-Tso
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/61197301786787075257

碩士 === 國立中央大學 === 環境工程研究所 === 89 === Enhanced biological phosphorus removal (EBPR) phenomena have drawn academic attention for many decades. However, past studies mostly focused on the biochemical mechanisms and bacterial communities of efficient EBPR systems fed with acetate as main carbon source and few investigated systems fed with glucose. In this study, two SBR reactors fed with glucose as main carbon source but with different influent P/C (2/100, 6/100 respectively) were operated at low (0.158 kg-COD/m3-d) and high (0.316 kg-COD/m3-d) volumetric loadings to study the biochemical characteristics and microbial community structures of systems influenced by glucose. Operational experiment results indicated that sludge from both reactors displayed anaerobic phosphorus release and aerobic uptake at low loading stage. As the influent loading was increased, the release and uptake of phosphorus were ceased. Anaerobic batch experiments showed that sludge from different influent P/C ratio reactor both absorbed glucose and transformed it into carbohydrate. When acetate replaced glucose as substrate, extracellular carbon was absorbed slowly and accumulated mainly as polyhydroxyalkanoate (PHA) while intracellular carbohydrate was degraded. Sludge assimilated glucose first and utilized acetate as glucose and acetate were mixed as carbon source. As lactate was applied, it was degraded by sludge slowly; this showed that no lactate utilizing bacteria existing in the SBRs. On the aspects of microbial community structure, cluster analysis of DGGE spectrum exhibited that bacterial communities were more impacted by volumetric loading rather than by influent P/C ratio. Fluorescence in situ hybridization (FISH) showed that almost 50% of DAPI-stained cell were Gram-positive HGC members and appeared tetrad forming morphologically. The second predominant group was cocci belonged to the beta-Proteobacteria and it accounted for 10-30% DAPI stained cell. The Gram-positive HGC tetrad-forming bacteria were diversified in the polyphosphate accumulating ability but they didn’t accumulate PHA. On the other hand, the beta-Proteobacteria cocci accumulated PHA but not polyphosphate. In general, the polyphosphate and PHA accumulating traits showed in batch experiments were the sum of separate physiological traits of different phylogenetical bacterial group.