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年度	100	專案性質	實驗性質
專案類別	研究專案	研究主題	底泥
申請機構	國立高雄第一科技大學	申請系所	環境與安全衛生工程系
專案主持人	陳勝一	職等/職稱	副教授
專案中文名稱	重金屬污染底泥整合性生物復育技術之研究
中文關鍵字	底泥；重金屬；生物溶出；零價鐵
專案英文名稱	An integrated bioremediation technology for sediments contaminated by heavy metals
英文關鍵字	Sediment; Heavy Metal; Bioleaching; Zero-Valent Iron
執行金額
執行期間	2011/11/26 至 2012/11/25
計畫中文摘要	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。本 研究計畫中首要之研究重點在於設計建立氣提式生物溶出技術，探討主要操作參 數對於底泥重金屬生物溶出技術之影響，以決定最佳化操作參數。本研究中同時 將以零價鐵處理生物溶出技術中所產生之金屬廢液，並探討主要操作參數對於零 價鐵處理金屬廢液之影響，以決定最佳化之操作參數，最後希冀能結合生物溶出 技術及零價鐵處理金屬廢液技術以發展一套經濟且可行之整合性生物復育技術用 以整治重金屬污染底泥。研究果發現，在氣提式生物溶出程序之操作過程中，由 於固體物含量較高之底泥具有較高之緩衝能力，pH 值下降速率隨之減緩。而當硫 顆粒添加量越多時，可硫氧化菌利用之硫表面積越多，因此產生之硫酸也會越多， 以致於造成 pH 值下降較快。在底泥固體物含量越高時，底泥中重金屬之溶出效 率會隨之降低；而當硫顆粒添加量增加時，底泥中重金屬之溶出效率則呈現增高 之趨勢。在底泥固體物含量為不高於 8% 時，在經 16 天之操作時間後，銅、鋅 及鎳之最終溶出效率分別可達 50%、60% 與 50% 以上，鉻之溶出效率則低於 30%。整體而言，底泥中重金屬之最終溶出效率中以鋅及鎳較高，其次為銅，鉻之 溶出效率則為最低。生物溶出程序可將底泥中可交換態、碳酸鹽結合態、鐵錳氧 化物結合態及有機物/硫化物結合態之重金屬有效地溶出，進而降低底泥中重金屬 之生態危害性。由實驗設計之結果可知，本研究之零價鐵處理金屬廢液實驗中， 零價鐵添加量及初始濃度設定之最佳操作值分別為 2.5 ~ 4.5 g/L 及 20 ~ 50 mg/L 間，金屬廢液中銅、鋅、鎳及鉻分別有 100%、80%、40% 及 98% 以上之去除效 率。
計畫英文摘要	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 sediments, soils or solid waste. The purpose of this study is to develop an integrated bioremediation technology for sediments contaminated by heavy metals. A bioleaching process employing sulfur-oxidizing bacteria for remediation of metal-contaminated sediments was first studied. This bioleaching process will be conducted in a laboratory air-lift bioreactor. The optimal parameters of the above bioleaching process will be examined by the experiment design methods. Meanwhile, the zero-valent iron (ZVI) was also applied for treatment of the metal-containing solution produced from the bioleaching process. The affecting factors, such as dosage of ZVI and initial concentration of heavy metal, on the removal efficiency of heavy metals by ZVI in the metal-containing solution will be examined in this project. The remediation strategy of this project links bioleaching process with treatment of the resulting metal-containing solution by ZVI. The results showed that the rates of pH reduction and metal solubilization obtained from the bioleaching experiments increased with decreasing sediment solids content and increasing sulfur concentration added. After 16 days of reaction time, the final efficiencies of Cu, Zn and Ni leached from sediments in this bioleaching process were all greater than 50% when the sediment solids content did not exceed 8%. Meanwhile, it was found that the ZVI investigated in this study effectively removes heavy metals from the metal-containing solution produced after the bioleaching process. The results of response surface methodology indicated that the maximum efficiency of metal removal was achieved at 2.5-4.5 g/l of ZVI dosage with 20-50 mg/l of initial metal concentration, where up to 100%, 80%, 40% and 98% of Cu, Zn, Ni and Cr were removed from the waste solution.