焚化爐底渣酸洗有機碳溶出評估及再利用於道路鋪設之長期監測

The Evaluation of Organic Carbon Leaching from Acidic Wash and the Environmental Monitoring of Municipal Solid Waste Incineration Bottom Ash Used in Road Application

吳翊齊(Yi-Chi Wu)

指導教授 ： 童心欣

國立臺灣大學/工學院/環境工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.00727

摘要

迄民國九十年至今，廢棄物焚化處理方式由約55％大幅提升至約96％，雖然焚化處理可以大幅降低垃圾體積，但仍然會產生大量的飛灰及底渣，以民國98年為例，全國焚化爐所產生之焚化底渣總量高達約85萬噸，其數量相當可觀。而依循日本及歐美等先進國家，底渣再利用於道路鋪設之歷史可追朔回1990年代；然而，國內卻缺乏關於底渣再利用應用於道路鋪面之長期監測。本研究係針對位於萬里加投段，以底渣再利用材料作為路基之試驗道路作為研究對象，監測周圍水體，作為評估底渣再利用材料是否對環境造成負面影響之依據。結果顯示，pH值、導電度、氯鹽、溶解性有機碳(DOC)濃度及重金屬溶出等各項監測數值，皆於完工兩年至三年後呈現穩定狀態，除各水體之重金屬Zn於檢測期間有濃度增加趨勢外，其餘應無污染之虞。此外，亦進行底渣再利用材料中重金屬於再利用場址之溶出比例進行推估，結果顯示，As具有最高的溶出比例2.87％，再者為Cd有1.52％溶出量。
另外於該研究中亦針對底渣再利用材料之基本特性及其酸洗特性進行研究，採集源自台北縣新店、八里及樹林等三座焚化廠及多批不同時間出廠之底渣再利用材料作為分析對象，藉由大量採樣降低底渣之非均質性。底渣在利用材料之基本特性分析部分顯示，其含水率約為17％，灼燒減量約為3.8％且TCLP結果皆於法規標準內。而酸洗特性分析部分，DOC及重金屬於不同液固比下，皆有不同之表現，以液固比為20時，DOC具有最佳溶出效率，此時重金屬溶出主要以Zn為主，於液固比為5及10時，Ba及Cu為主要溶出之金屬，預期藉由酸洗，評估底渣再利用材料作為路基時，DOC可能溶出之最大量。

關鍵字

焚化底渣 ； 酸洗 ； 道路監測

並列摘要

According to the statistics from Taiwan Environmental Protection Administration, the percentage of municipal solid waste incineration (MSWI) was increased from 55% to 96% since 2001. Although incineration could reduce the volume of the solid waste significantly, it produces large amount of fly ash and bottom ash. In 2009, overall bottom ash production from all incinerations in Taiwan was 850,000 tons. The utilization of MSWI bottom ash as road pavement has been widespread in Japan, Europe and North America. Some long term monitoring studies were completed, such as ten-year evaluation in France. The aim of this study was to monitor a test road located in Wanli, Taipei County, which was constructed with local MSWI bottom ash. . The environmental impact assessment of bottom ash utilization would be base on analyzing pH, conductivity, Cl- and DOC (dissolved organic carbon). The analysis results of surface water and ground water have been stable since the beginning. The leachate pH, conductivity and concentrations of Cl- and DOC concentration drop down quickly during the first 1.5 years and gradually reach the minimum values over 4 years, as well as heavy metals. In the later monitoring, the leachate concentration of Zn has been gradually increased due to the same status in surface water probably. Moreover, the portion of eluted heavy metals from bottom ash was estimated. The results show that As and Cd had the highest elution potential as 2.87% and 1.52% , respectively.
Another objective for this study was to test the organic carbon leaching properties from MSWI bottom ash. The bottom ashes were collected from Xindian, Bali and Zhuyin incineration plants. In order to reduce the heterogeneity of the bottom ash, different batches of sample were collected. The basic analysis results shows the moisture content of stabilized bottom ash was approximately 17%, ignition loss was 3.8% and no toxic chemical was found to over the regulation limits from TCLP tests. In acid extraction test, the elution of dissolved organic carbon (DOC) and heavy metals were corrrelated to the liquid to solid ratio (L/S). The best DOC extraction efficiency was found under the condiction as L/S=20, and Zn was the major heavy metal eluted. However, when L/S=5 and 10 the major eluted heavy metals were Ba and Cu intead of Zn.

並列關鍵字

MSWI bottom ash ； acidic wash ； road application monitoring

參考文獻

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