Metal Leaching from Road Base Incorporating Incineration Bottom Ash

焚化底渣道路基底之金屬溶出

10.6652/JoCICHE.201506_27(2).0004

吳佩勳(Pei-Hsun Wu)；林正芳(Cheng-Fang Lin)；林彥妗(Yen-Ching Lin)；康佩群(Andy Pui-Kwan Hong)

底渣 ； 道路基底 ； 金屬溶出 ； 管柱溶出試驗 ； 現地監測 ； bottom ash ； road base aggregate ； metal leaching ； column leaching ； in situ monitoring

中國土木水利工程學刊

27卷2期（2015 / 06 / 01）

125 - 137

英文

焚化底渣佔1/5生垃圾質量，底渣再利用可適度減輕天然資源開採之環境負擔，本研究探討道路基底摻配底渣之金屬及其內物質溶出情境，就已設置之底渣試驗道路，利用已埋置之入滲水收集系統收集入滲雨水並監測七年，於道路鋪設使用七年後採集摻配底渣道路之基底材料進行管柱溶出試驗，選定觀測參數為pH、導電度、氯鹽、TOC及重金屬離子等項目進行分析，先經化學穩定後之底渣所含有機物及金屬於初期溶出並隨時間快速趨於平穩，滲出水之TOC三天後由900mg/L降至＜50mg/L及Cu離子濃度10天後由10mg/L至微量溶出；預水洗程序底渣與底渣摻配天然骨材作為道路基底材料之試驗結果均可減少有機物及重金屬離子溶出，水洗底渣之Cu濃度由35mg/L減少為＜2.1mg/L；底渣摻配天然骨材之Cu濃度由10mg/L減少為＜0.8/2.5mg/L。長時間道路環境監測及相當於3年降雨量管柱實驗，皆證明底渣作為道路基底材料環境風險低並具有綠色工程應用潛勢，明顯之底渣再利用經濟效益是減輕開採天然骨材的環境負荷。

Bottom ash (BA) of municipal solid waste incinerators represents one fifth of the original weight and a pressing environmental burden for which relief in the form of BA reuse is highly desired. We examined leaching of metals and others from BA when it was incorporated as a road base ingredient. A road segment was constructed with BA and infiltration rainwater was obtained through a leachate collection system and monitored for 7 y. In addition, road base samples containing BA were collected after 7 y and studied for leaching in column experiments. The measured results of leachate pH, conductivity, chloride, total organic carbon (TOC), and metals suggested the initial occurrence of leaching of organics and metals from stabilized BA, followed by its rapid subsidence soon after (stabilized BA: TOC from 900 to ＜50 mg/L after 3 d and Cu from 10 to very low after 10 d). The results also suggested that using water-washed BA and nature aggregate-amended BA as a road base material reduced leaching of organics and metals (water-washed BA: Cu from 35 to ＜2.1 mg/L; nature aggregate-amended BA (type C and D): Cu from 10 to ＜0.8/2.5 mg/L). Both the long-term monitoring results from road segment with BA and the accelerated column results simulating 3 y of natural precipitation corroborated a low risk of using BA in road construction and thus the potential as a green engineering practice. The immediate benefits of recycling and reuse incineration bottom ash would be the conservation of natural aggregate resources thus reducing the environmental burdens.