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EPA-99-GA103-03-A236-6

099

996 千元

2010/12/29

2011/12/28

林啟文

土污基管會

尤衍翔

國立雲林科技大學環境與安全衛生工程系

土壤及地下水

釋氧物質、生物毒性、固定化菌體顆粒、活化過硫酸鹽氧化

Oxygen-releasing material, biotoxicity, cell-immobilized beads, activated persulfate oxidation

陳谷汎;張時獻

林啟文

05-5342601#4425

linwen@yuntech.edu.tw

本計畫主要利用生物毒性偵測法Vibrio fischeri light inhibition test方法，檢測地下水污染物生物毒性範圍，若地下水具高毒性水質則採用化學法方式進行整治；若具中低毒性則以生物法方式進行復育。地下水整治方法選擇係採用釋氧型生物法與活化過硫酸鹽氧化法等二種方式進行。其中，「化學法」採用不同低價吸附劑(高爐石、轉爐石)種類與劑量，以異相活化過硫酸鹽方式進行對BTEX降解效率評估。「生物法」則以生物可分解之固化材料(聚乙烯醇)，將可降解油品污染物之分解菌種(BTEX分解菌)及釋氧物質(過氧化鈣)共同包埋而形成釋氧型固定化菌體顆粒。 在異相活化批次實驗結果得知，過硫酸鹽濃度越高，去除MTBE及BTEX所需時間將越短。當於適當條件下(以高爐石、轉爐石活化)，MTBE降解副產物—TBF與TBA亦可被有效去除，且無殘留問題產生。此外，二種吸附劑(高爐石、轉爐石)皆有活化過硫酸鹽效果，可促進污染物(BTEX與MTBE)之降解成效，未來可代替二價鐵做為活化劑之優先考量，降低整治成本及解決三價鐵沉澱問題。研究結果顯示：以「PVA水凝膠包埋膠囊式冷凍法」包埋CaO2製成之釋氧型固定化菌體顆粒，可獲得較高釋氧量，且添加緩衝物質(檸檬酸)可穩定釋放氧氣，同時釋氧率隨固化劑體積比減少而增加。由管柱試驗結果獲知，包埋BTEX分解菌株(Mycobacterium sp. CHXY119與Pseudomonas sp. YATO411)之釋氧型固定化菌體顆粒具可釋出氧氣，可供給包埋之菌株所需溶氧，促進微生物降解BTEX之速率。 經由管柱實驗結果顯示，管柱內釋氧化劑物質之氧化能力約可維持6天，爾後隨釋氧化劑物質所釋出之過硫酸鹽濃度之衰退，氧化劑氧化降解污染物能力亦隨之下降。由DGGE分析菌群結構獲知，透水性釋氧反應牆長期於BTEX環境操作下，系統內之菌種變化趨於簡單化呈現；當有機負荷瞬間過高時，將導致菌群結構變動大，但隨系統逐漸趨於平穩時，菌群回復原有簡單化結構。由電子顯微鏡(SEM)拍攝結果獲知，利用PVA-alginate材料可有效包埋特定污染物之分解菌種，微生物可於顆粒內部空間中生長。 研究結果指出Vibrio fischeri對於油品污染物之生物毒性偵測具高度敏感度，污染物濃度與V. fischeri抑光率呈高度正相關；當使用 1%過硫酸鹽及在1及5 g/L轉爐石可以有效降低污染地下水生物毒性。但使用過高過硫酸鹽(5%)，則會造成生物毒性增加。使用釋氧型固定化菌體顆粒管柱及釋氧型透水性反應牆則可有效降解污染地下水，隨污染物濃度降低，生物毒性也隨之下降。

釋氧物質、生物毒性、固定化菌體顆粒、活化過硫酸鹽氧化

EPA-99-GA103-03-A236-6.pdf

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2012/2/1 上午 12:00:00

The objective of the project was to establish a framework for the integration remediation in a contaminated groundwater. First, the bioassay, Vibrio fischeri light inhibition test, was used to determine the toxicity of petroleum-contaminated groundwater. The highly toxic groundwater was treated with chemical oxidation method. In contrast, biological method was applied for groundwater of moderate-to-low toxicity. The oxygen-releasing type for a biological method and activated persulfate oxidation were selected to remediate a BTEX-contaminated groundwater. For the biological method, novel immobilized beads for oxygen releasing were manufactured by incorporating calcium peroxide (CaO2), with BTEX-degrading bacteria using a biodegradable material composed of polyvinyl alcohol (PVA) and alginate. For the chemical method, two types of adsorbents (blast-furnace slag (BF slag), blast oxygen furance slag (BOF slag)) were used to activate sodium persulfate. Moreover, batch or column tests were conducted to investigate the amounts of beads and concentrations of sodium persulfate and adsorbents on BTEX decomposition for biological and chemical methods, respectively. Both BF and BOF slags show the capability in activating sodium persulfate leading to the biodegradation of BTEX and MTBE. The activation capability was increased with the increase of the amount of slags. To reduce the remediation cost and lessen the Fe (III) precipitation commonly occurred in the groundwater remediation site, BF and BOF slag were predominantly selected as activated agents in replacing Fe (II). Moreover, the MTBE degraded by-products (TBF and TBA) were also effectively degraded under activated conditions by BF and BOF slags. The higher oxygen released rate was observed using PVA/alginate-based hydrogel-encapsulated CaO2 freezing method. Oxygen was also consistently released with the addition of buffering material (citric acid). The oxygen-releasing rates were increased with the decrease of the volumetric ratio of binding material, which is attributed to due to the better oxygen transfer under less amount of binding material condition. DGGE analysis suggested that the microbial community in the PRB system acclimated by BTEX became simplified and approached to certain particular microorganisms. Microbial community structure changes were observed under transient shock organic loading conditions. However, microbial community gradually recovered to its simplified structure when system operated in normal conditions. The SEM photographs show that PVA/alginate beads were suitable for the immobilization of microbial cells. The photograph also indicated that microorganisms could be successfully entrapped inside the pores with homogenous distribution in the PVA/alginate beads. High sensitivity of Vibrio fischeri light inhibition test as a biotoxicity indicator for BTEX detection was observed. The relationship between BTEX concentrations and light inhibition rates was significantly positive. The application of 1% of persufate with 1 and 5 g/L BOF effectively reduced the toxicity of groundwater samples. However, the application of high dose of persulfate (5%) induced the high toxicity. Both immobilized beads-BTEX degrader column and PRB system were proved to effectively degrade the groundwater pollutants, thereby decreasing their biotoxicity.

Oxygen-releasing material, biotoxicity, cell-immobilized beads, activated persulfate oxidation