不同溫度下重金屬突增負荷對生物除磷機制之影響

Impacts of the Heavy Metals Invasion on Mechanisms of Biological Phosphorus Removal under Short-Term Temperature Conditions

胡皪元(Li-Yuan Hu)

指導教授 ： 蔡勇斌

共同指導教授 ： 卓伯全

國立暨南國際大學/科技學院/土木工程學系/碩士(2008年)

https://doi.org/10.6837/NCNU.2008.00183

摘要

本研究主要探討不同溫度條件下，重金屬種類及濃度對活性污泥厭/好氧相釋/攝磷反應、PHAs合成/分解、體內肝醣分解/合成之影響，實驗進行以SRT 10天馴養達穩定之B-SBR系統活性污泥為研究對象，其對COD及PO43-之去除率均可維持在90%以上。為研擬B-SBR系統操作控制EBPR程序之基準，瞭解低濃度重金屬離子對活性污泥除磷能力的影響及毒性抑制效應，本研究分別利用比釋/攝磷速率、PHAs及肝醣之合成/分解率等批次實驗，藉控制不同溫度條件(10∼30℃)，探討微生物於溫度變異環境下對不同重金屬種類(Zn2+、Cu2+)、濃度(0∼2 mgl-1)之耐受性。結果顯示，未添加重金屬時微生物之比基質利用率、釋/攝磷率、PHAs及肝醣之合成/分解率，皆隨溫度增加而增加，惟10℃環境下微生物已喪失好氧分解PHAs之能力。此外，整體而言20℃環境下微生物對重金屬Zn2+、Cu2+之耐受性略高30℃者，而10℃時最差；毒性比較部份則以重金屬Zn2+之毒性影響略高於Cu2+。本研究亦發現污泥體內肝醣分解受重金屬毒性抑制時，微生物無法藉分解肝醣提供合成PHAs所需之能量(NADH2)，導致好氧環境無充足PHAs供攝磷之用，亦使好氧肝醣還原率下降；再者好氧相水體存在之重金屬亦對PHAs分解造成影響，此時微生物同時受體內碳源不足及外部毒性物質之影響，抑制代謝行為，進而惡化系統除磷效果；由此可知PHAs及肝醣兩者於厭/好氧環境下之消長相互影響、牽制。

關鍵字

重金屬 ； 生物除磷 ； PHAs ； 肝醣 ； B-SBR系統

並列摘要

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.

並列關鍵字

heavy metals ； phosphate removal ； PHAs ； glycogen ； carbohydrate ； SBR

參考文獻

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