現今政府積極推動垃圾焚化灰渣再利用的政策,但由於垃圾焚化飛灰所含之有害物質濃度較高,因此使得飛灰較少被作為再利用之用途,然而飛灰若是要進行再利用的話,就一定必須知道它對生物體的危害性。因此本研究使用垃圾焚化灰渣樣品為袋式集塵灰(Fly ash, FA)及灰渣儲坑區的底渣(Bottom ash, BA)。並將上述兩種灰渣先以傅立葉紅外線光譜儀(Fourier Transform Infrared, FT-IR)和 X 光繞射儀(X-ray Diffractometer, XRD)做初步成分分析,再以 100℃的熱水進行淋洗,將其濾液測 pH 值、重金屬、TOC、Total Cl 2 等性質,再以混濁度分析法分析灰渣淋洗液對嗜酸性乳酸桿菌的毒性,並探討淋洗液中重金屬成分與嗜酸性乳酸桿菌毒性間的關聯性,藉此評估灰渣需經過幾次的酸洗和水洗後才對生物體不具毒性,方可進行再利用。據毒性結果顯示,不同淋洗次數的灰渣淋洗液與嗜酸性乳酸桿菌作用 7 小時之毒性反應;發現嗜酸性乳酸桿菌與灰渣一次和二次淋洗液作用 7 hr 時,其毒性大小為 一次 > 二次 。而飛灰經第一次水洗其重金屬量大部分都比第二次水洗還要高,底渣經第二次水洗出來的K、Na、Ca 金屬量都比第一次水洗來的高,說明多次的水洗可有效降低灰渣中重金屬含量,因此建議灰渣若要水洗再利用的話,應要多次的淋洗。 本研究還發現,灰渣成分中 K、Na、Ca、Mg、Si、Pb、Zn、Cd、Ni、Sb、Sr、Cu、Ba 等重金屬元素的濃度經過加菌作用處理後,有呈 現 降 解 效 果 , 並 使 用 能 量 元 素 分 析 儀 (Energy Dispersion Spectrometer,EDS)分析其菌體,結果發現菌體含有大量的 Cl- 和一些部分的重金屬離子,因此推斷嗜酸性乳酸桿菌可以吸附 Cl- 和部分重金屬元素。
The reuse of ash wastes from municipal solid wastes incineration (MSWI) has been actively promoted by the government. In these ash wastes contain a high concentration of harmful substances, therefore we have to know the dangers of these ash wastes before re-use. Bag-house ash (FA) and bottom ash (BA) were selected in this study and FT-IR and XRD were used for the compositional analysis. Leaching filtrate of ash wastes were collected after leaching by 100℃hot water, the pH, heavy metals, TOC, Total Cl2, were performed on the collected leaching leachates. The eco-toxicity of the ash samples were performed on turbidity of Lactobacillus acidophilus, its correlation between heavy metal contents was also estimated. Results of seven hour-toxicity test showed that first time leachate has a higher toxicity than second time leachate. In addition, the first time leachate contains higher concentrations of heavy metals than second time leachate. Therefore we command that multiple washing process can remove most of heavy metals and is indeed for recycling of fly ashes. This study also found that the concentration of K, Na, Ca, Mg, Si, Pb, Zn, Cd, Ni, Sb, Sr, Cu, Ba ions in ash can be reduced after bacteria digestion process. The surface analysis of reacted bacteria has observed the existing of chloride and heavy metal ions, we suggested that Lactobacillus acidophilus can absorb chloride and heavy metal ions.