氣泡式呼吸儀監測被動式生物通氣法中微生物活性之探討

A Study on Bubble Respirometer to Monitor Microbial Activity in Passive Bioventing System

李冠賢(Kuan-Hsine Li)

指導教授 ： 劉敏信

朝陽科技大學/理工學院/環境工程與管理系/碩士(2015年)

摘要

受到油品污染的場址中，因為儲油槽及輸油管線長年埋在地底，當察覺到槽體或管件有洩油情形發生時，土壤中油品污染物的濃度皆已相當高。其中柴油類污染物因揮發性較低，因此可採用生物通氣法 (bioventing)供給氧氣及營養源，使污染區域中分解油品污染物的好氧微生物大量生長，達到污染去除之目的。生物通氣法的整治成果需依靠土壤微生物降解目標污染物，若能適時監測微生物的活性變化，則有助於評估生物整治的實質成效。本研究於高濃度 (大約20,000 mg/kg)柴油污染土壤風力驅動式生物通氣(wind-driven bioventing)模場中，使用氣泡式呼吸儀搭配生物泥漿法進行土壤中微生物活性監測，探討生物通氣法整治過程中土壤柴油濃度降解趨勢與微生物活性之關係。生物通氣模場植菌微生物試驗中，柴油降解菌經試驗4週後，各組柴油殘餘率(C/C0)可達0.8，以攝氧累積曲線及24小時平均攝氧率曲線得知，柴油降解菌於3週後活性上升，並持續降解柴油。生物通氣模場植菌微生物及營養鹽添加試驗中，試驗第1週之柴油殘餘率以Bacillus cereus菌、Pseudomonas putida菌及三種微生物混合菌組最佳，達到0.65，Achromobacter xylosoxidans菌約為0.8，第4週時混合菌殘餘率可達到0.3。經氣泡式呼吸儀監測活性後，Bacillus cereus菌及Pseudomonas putida菌的微生物活性可連續提高2週、Achromobacter xylosoxidans菌活性可連續提高3週、Mixture組活性則能連續提高4週後逐漸降低。24小時平均攝氧率曲線能清楚呈現營養鹽添加前後對微生物攝氧的週期變化，且能說明不同濃度下柴油污染物的降解情形，並與柴油殘餘率有4週次以上的相似變化，因此微生物活性監測若能搭配元素分析儀掌握營養鹽的消耗情形，定期維持適合微生物降解的環境，則可有效提高生物通氣法的整治成效。

關鍵字

攝氧率 ； 被動式生物通氣法 ； 柴油降解微生物 ； 氣泡式呼吸儀 ； 生物泥漿法

並列摘要

At a site of oil contamination, the concentration of contaminants is usually high in soil when leak is found, it is because oil tanks and pipelines are often buried underground for a long period of time. Bioventing is a proper technology to remove contaminants such as diesel of low volatility, as oxygen and nutrients are provided to sustain the mass growth of aerobic microorganisms that degrade oil contaminants in the polluted area, thus achieving pollutant removal. The effectiveness of bioventing depends on microorganisms in soil to degrade the target contaminants. By constantly monitoring the changes in the activity of these microorganisms, it assists to evaluate the practical performance of biological remediation. A wind-driven bioventing pilot containing diesel contaminated soil at high concentration (approximately 20,000 mg/kg) was built for this study. A bubble respirometer was introduced in combination with the bioslurry method to monitor the activity of microorganisms in soil as the experiment setup to investigate the relationship between the degradation of diesel concentration and the activity of microorganisms in soil during the biovetning process.
In the microorganism growth experiment using the bioventing pilot, the diesel-degraded microorganisms were domesticate for 4 weeks, while the relative diesel concentration (C/C0) reached 0.8. The results of accumulated oxygen uptake curve and 24-hour average oxygen uptake curve indicated that the activity of diesel-degraded microorganisms increased after 3 weeks, and the diesel degradation continued. In the microorganism growth experiment using the bioventing pilot with the addition or nutrients, the relative diesel concentration reached the highest at 0.65 in week one for Bacillus cereus, Pseudomonas putida and the mixture of three microorganism, and 0.8 for Achromobacter xylosoxidans, however in week 4, the relative diesel concentration reached 0.3 for the mixture. The activity monitoring with bubble respirometer suggested that the activity of Bacillus cereus and Pseudomonas putida continued to increase for 2 weeks, 3 weeks for Achromobacter xylosoxidans and 4 weeks for the mixture before it started to decline. The 24-hour average oxygen uptake curve showed clearly the changes in the period of microorganism oxygen uptake before and after addition of nutrients, and was related to the changes in the relative diesel concentration for 4 weeks or more. Therefore, if the microorganism activity monitoring is combined with elemental analysis to understand nutrient consumption, and the environmental conditions are maintained in favor of the microorganism degradation, the remediation performance of bioventing will be enhanced effectively.

並列關鍵字

Oxygen uptake rate ； Diesel degraded microorganisms ； Bubble respirometer ； Bioslurry method ； Passive bioventing

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