垃圾焚化底渣碳酸化浸漬穩定之研究

A Study on the Stabilization of MSWI Bottom ash by Soaking Carbonation

黃政隆(Cheng-Lung Huang)

指導教授 ： 高思懷

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2014年)

https://doi.org/10.6846/TKU.2014.00632

摘要

都市垃圾焚化底渣於再利用之前仍須妥善前處理，以降低重金屬釋出污染環境之風險。碳酸化穩定為一熟知之技術，但仍有需時較久之問題。本研究回收水洗底渣之廢水，以10%之二氧化碳曝氣，使形成含有碳酸之水溶液，利用浸漬方式使CO32-與底渣中的Ca2+形成CaCO3化合物，以期提升底渣中重金屬穩定的效率。
本實驗分為批次式實驗以及循環式實驗兩部分；批次式實驗是將兩段經五分鐘攪拌水萃後的底渣，以碳酸水浸漬反應3、6、18小時，觀察TCLP降低及氯離子的洗出成效；循環式實驗部分，將浸漬液迴流，取代第一段水洗的自來水，兩次水洗配合磁石攪拌五分鐘，並以碳酸水浸漬反應0.5、1及3小時，連續三次為一循環後檢測分析。
批次式碳酸化實驗結果顯示，以TCLP檢測浸漬後底渣，發現重金屬溶出確實有顯著減少的趨勢。其中Pb及Cd不隨浸漬時間長短而改變溶出量；而浸漬時間愈長，Zn及Cu的溶出比例則愈高；浸漬後Cr溶出增加，可能是低pH值環境所致；水溶性氯離子於3、6、18小時溶出率分別為44.2、45.2及46.3%；而水中鹼度之消耗則與浸漬時間成正比。
循環式碳酸化實驗結果顯示，浸漬0.5小時就有抑制重金屬Pb、Zn、Cu、Cd溶出的效果，其溶出濃度分別為0.02、8.23、1.49、0.09 mg/L，Cr的溶出已無法測得；浸漬反應時間愈長，水溶性氯離子洗出量愈多0.5、1、3小時浸漬洗出量分別為74.3、76.2、85.7%。建議將浸漬時間控制在0.5小時並配合105℃烘乾，可達到穩定重金屬及增加氯溶出之效果。

關鍵字

垃圾焚化底渣 ； 碳酸化 ； 浸漬 ； TCLP ； 無機成分可溶出量測定

並列摘要

Municipal solid waste incinerator (MSWI) bottom ash should be pretreated before reusing, which can reduce the risk of polluting the environment by leaching the heavy metals from bottom ash. It is significant scientific and engineering benefit of carbonization for stabilization of solid waste. Nevertheless, taking too much time is the defect of the carbonization. In this study, the retrieved water of washing bottom ash aerated carbon dioxide about 10% to become carbonated water. Let calcium from bottom ash and carbonate ion from carbonated water reacted to form calcium carbonate by dipping process to raise the stability rate of heavy metals.
The experiment of this study has divided into two parts of batch and circulation. In the batch experiment, the bottom ash through two steps of five minutes stirred and then dipped in carbonated water for 3, 6 and 18h. The aim of this experiment is to observe the concentrations of TCLP for heavy metals and the remove rate of chlorine ion. In the circulation experiment, the dripped solution would be recycled to substitute the tap-water of the first step wash water. The bottom ash through two steps of five minutes stirred and then dipped in carbonated water for 0.5, 1 and 3h. In a circle, the process needs to repeat three times.
The result of the batch experiment shows that the dripping process really can reduce the TCLP concentration of heavy metals. The concentrations of lead and cadmium do not decrease with the dripping time. Zinc and copper would increase the leaching rate with the dripping time increased. The leaching rates of the water-soluble chloride ion were 44.2%, 45.2% and 46.3% at dipping time of 3, 6 and 18 h respectively. The consummation of alkalinity in the water increases with the dripping time.
The results of the circulation experiment indicate that the leaching concentration of Pb, Zn, Cu and Cd were 0.02, 8.23, 1.49 and 0.09 mg/L and would be restrained after dripping time of o.5h. Specially, the Cr concentration was not detectable. The leaching amount of the water-soluble chloride increased with the dripping time increased. The leaching rates were 74.3%, 76.2% and 85.7% after dripping time of o.5, 1 and 3h respectively. The dripping time of 0.5h and dry in 105 oC of oven could reach the aim of stabilization of heavy metals and increase the leaching rate of chloride.

並列關鍵字

bottom ash ； carbonation ； soaking ； TCLP ； inorganic components for leaching

參考文獻

曾淑滿 ，「高氯含量廢水去除氯離子之研究」，碩士論文，國立臺北科技大學資源工程碩士班，2011。

吳靜薇，「水庫淤泥添加改善都市垃圾焚化灰渣燒製輕質骨材之研究」水資源及環境工程所，淡江大學，2007。

何欣怡，「垃圾焚化飛灰水萃廢水處理之研究」，水資源及環境工程所，淡江大學，2004。

陳雨詩，「粗粒徑垃圾焚化底渣燒製高強度輕質骨材之研究」，水資源及環境工程所，淡江大學，2005。

陳政綱，「都市垃圾焚化底渣燒製輕質骨材膨脹機制之研究」，水資源及環境工程所，淡江大學，2007。