以現場型固體床式生物溶出技術處理受重金屬污染底泥之研究
| 中文摘要 | 在河川或湖泊污染整治中，除污染源管制及興建下水道系統之外，底泥之浚渫亦是整治方案之一。底泥因已承受相當程度之污染物，浚渫後之污染底泥需經適當之處理及處置，方可達到不造成二次公害之目標。目前國內針對受污染水體底泥處理技術之研究極少，未來極需要此方面之技術，以處理浚渫後之大量底泥。但是，污染底泥量增加、處理費用升高，加上更嚴格管制要求，以致於未來底泥之處理與處置技術將必須脫離傳統方法並且重新調整，始能因應實際之需要。在大自然之生物性硫循環中，對於環境生物技術之開發，蘊藏著之無限生機。由於在硫之生物循環中，除硫化合物種之型態有所轉變外，通常亦含會牽涉到重金屬、有機物或氮於自然或人為生態系統中之轉變與移動。因此，若能將硫細菌之生理代謝能力善加利用，應用硫生物循環於環境生物技術中，對於生物科技及環境保護將有極大之助益。 本研究之主要目標為利用硫生物循環中之硫氧化作用，發展出一套應用於現場處理重金屬污染底泥之環境生物技術，以達污染預防與資源循環再利用之目的。經由研究發現，藉由反覆進行馴養作業，馴養溶液 pH值下降速率明顯加快，顯示硫氧化菌之活性相當好且穩定。馴養後可以順利得到活性較佳之硫氧化菌植種，以供含固體床式生物溶出程序之用，進行底泥中重金屬之溶出反應。在營養鹽配方之影響方面，採用氯鹽為主之營養鹽時，硫氧化菌具有較高之活性，系統中 pH、ORP、硫酸鹽濃度變化速率因而加快，使得底泥中重金屬溶出具有較高之速率及效率。而在淋洗流量之影響方面，採用高淋洗流量之操作時，硫氧化菌之生物活性亦可有效提昇，造成底泥中重金屬之溶出速率與效率明顯升高。經過生物溶出程序之處理後，底泥中除殘存態的銅及鉛有增加之情形外，各重金屬之可交換態、碳酸鹽結合態、鐵錳氧化物結合態與有機物/硫化物結合態等皆能有效地溶出，由此可知，生物溶出程序除能有效地去除底泥中重金屬外，亦可減少殘留於底泥中重金屬之移動性及為害性。固體床式生物溶出程序中，在固液比(即底泥量/淋洗液)為1 kg/L，硫添加量為 2%，及採用氯鹽淋洗液配方時，經過 40 天之操作後，底泥中鋅、鎳、銅及鉛之最高溶出效率分別為 50%、60%、22% 與 5%。由本計畫之結果可知，固體床式生物溶出程序適用於重金屬污染底泥之現場整治，可同時處理較多量之污染底泥，惟其所需操作時間較長 (超過 30 天)。同時，對於微細顆含量較高 (具黏土性質)之底泥可能較不適合以固體床式生物溶出程序進行處理。 | ||
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| 中文關鍵字 | 底泥、重金屬、生物溶出、硫氧化菌、固體床 | ||
基本資訊
| 專案計畫編號 | EPA-99-GA103-03-A236-13 | 經費年度 | 099 | 計畫經費 | 980 千元 |
|---|---|---|---|---|---|
| 專案開始日期 | 2010/12/29 | 專案結束日期 | 2011/12/28 | 專案主持人 | 陳勝一 |
| 主辦單位 | 土污基管會 | 承辦人 | 尤衍翔 | 執行單位 | 國立高雄第一科技大學 |
成果下載
| 類型 | 檔名 | 檔案大小 | 說明 |
|---|---|---|---|
| 期末報告 | EPA-99-GA103-03-A236-13--期末報告定稿_公開版_.pdf | 0MB |
On-site remediation of metal-contaminated sediments using solid-bed bioleaching technology
| 英文摘要 | In the restoration strategies of river and lake, besides controlling pollution sources and building sewer system, the contaminated sediment may need dredging from the rivers or lakes. Most of sediment dredged from contaminated rivers or lakes often contain substantial amount of heavy metals and thus can not be disposed of on the land and in the water body without any treatment. To date, there are relative few researches for detoxification and decontamination processes of heavy metals in aquatic sediments in Taiwan. In future, it is important to develop the techniques for treatment of the large quantity of dredged sediments in the remediation of contaminated rivers or lakes. Sulfur cycle conversions do not only involve the elemental sulfur, but also directly influence organic matter, nitrogen and heavy metal conversions and fluxes within natural or man-made ecosystems. Therefore, one can also use the sulfur cycle as the driving force behind some specific related environmental biotechnological applications. Sulfur-oxidizing bacteria utilize reduced sulfur as an energy source for chemolithotrophic growth, producing soluble metal sulfates and sulfuric acid. A bioleaching process uses these biological oxidation processes of sulfur-oxidizing bacteria to extract and concentrate metals from polluted soils, sediments or solid waste. The purpose of this study was to develop a microbial process of sulfur cycle for the bioremediation of metal-contaminated sediments. In this project, a bioleaching process for on-site remediation of metal-contaminated sediments was studied. The results showed that the rates of pH reduction, ORP increase, sulfate production and metal solubilization obtained in the solid-bed bioleaching experiment with chloride salts (medium C) were higher that those with sulfate salts (medium S). Based on the results obtained from this study, it was found that the medium C was more suitable for sulfur-oxidizing bacteria in the solid-bed bioleaching process. On the other hand, the rate and efficiency of metal solubilization were enhanced by increasing the flowrate of process water sprinkling into the solid-bed bioreactor. After 40 days of reaction time, the highest efficiencies of heavy metals leached from sediments in this solid-bed bioleaching process were 50%, 60%, 22% and 5% for Zn, Ni, Cu and Pb respectively. Meanwhile, the treated sediment was stable and the residual heavy metals were no longer harmful to the environment after the bioleaching process. Meanwhile, it was found that the sold-bed bioleaching process is not suitable for the treatment of clay-like contaminated sediment. | ||
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| 英文關鍵字 | Sediment; Heavy Metal; Bioleaching; Sulfur-oxidizing bacteria; Solid-bed | ||