Impacts of the Heavy Metals Invasion on Mechanisms of Biological Phosphorus Removal under Short-Term Temperature Conditions
| Autor: | Li-Yuan Hu, 胡皪元 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 This study mainly investigated the effects of heavy metal category（Zn2+、Cu2+）and concentration (0~2 mgl-1) on the anaerobic/aerobic reactions, including phosphorus release/uptake, polyhydroxyalkanoates (PHAs) synthesis/degradation, and total intercellular glycogen (carbohydrate) synthesis/degradation of the activated sludge under short-term temperature conditions. The performance of the B-SBR activated sludge, which was acclimated by the condition of sludge retention time (SRT) 10 days until reaching steady state, maintained the removal ratios of COD and PO43--P above 90%. In order to realize the operational strategy for EBPR system under metal(s) invasion situation, the performances of batch experiments of phosphate release and uptake, PHAs synthesis/degradation, and total intercellular glycogen synthesis/degradation were used as indicators to investigate the effects of heavy metal category and concentration on phosphate removal ability and toxic inhibition of microorganisms under different temperature conditions (10℃~30℃). Results of batch experiments under the condition of without any metal addition showed that specific substrate utilization rate（SSUR）, specific release/uptake phosphorus rates（SPRR,SPUR）, PHAs and intercellular glycogen synthesis/degradation rates were increased with the increase of the temperature. However, the microorganisms in aerobic phase lost the ability to degrade PHAs under 10℃ situation. In addition, the temperature order of the tolerant ability of microorganisms to heavy metals invasion was 20℃＞30℃＞10℃. On the other hand, toxicity of Zn2+ was greater than that of Cu2+. It was also found in the study that, the microorganism was unable to decompose the intercellular carbohydrate to provide the energy (NADH2) needed for synthesizing PHAs while the intercellular carbohydrate decomposition mechanism was suppressed by heavy metal(s). This phenomenon might be the major reason resulting in insufficient production of PHAs for phosphate uptake and the decrease of total intercellular glycogen synthesis rate in aerobic phase. In addition, the existence of heavy metal(s) also influenced the decomposition of PHAs in aerobic phase. At the same time, the phosphate removal ability was further deteriorated due to the insufficient of intercellular carbohydrate and external toxic inhibition. Thus, it could be known that the increase or decrease of PHAs and total intercellular carbohydrate was influenced and impeded by each other both in anaerobic/aerobic phase. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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