| 摘要: | 本研究利用自然熟化、加速熟化兩種方法，分別將細粒徑(≦ 4.75 mm)底渣樣品於靜置貯存、浸漬水中與飽和石灰水等不同條件下進行養護，探討自然熟化及加速水化反應將底渣穩定化之效能。研究過程採用毒性特性溶出程序 (Toxicity Characteristic Leaching Procedure,TCLP)、美國EPA SW-846 Method 1320 (Multiple Toxicity Characteristic Leaching Procedure, MTCLP)、歐盟管柱滲出試驗 (CEN/TS 14405)、細粒料中水溶性氯離子含量試驗 (CNS 13407)及逐步萃取法 (Sequential Extraction Procedure, SEP)，探討底渣中重金屬、氯鹽之溶出特性，作為研擬底渣再利用之前處理/處置之參考。
研究結果得知分選後底渣雖整體而言都符合我國法定重金屬溶出標準，但發現自然熟化後底渣重金屬的溶出並無因長時間貯存而降低反而有逐漸增加之趨勢，顯示底渣經長時間的貯存仍無法確保其穩定度；而在加速熟化方面無論採浸漬水中或飽和石灰水加速養護後，底渣中重金屬溶出量皆有降低之情形，隨浸漬時間之增加重金屬溶出量隨之減少。另外，雖TCLP及MTCLP實驗結果顯示加速熟化程序能有效降低重金屬溶出量，但比較歐盟整合環境性試驗方法標準與參照荷蘭建築材料之法規標準，則反映出底渣之長期穩定性仍有顧慮，重金屬Cu及Pb之釋出量未符合荷蘭法規標準。而由逐步萃取法得知本研究之底渣中各種金屬鍵結型態多屬不易移動之型態。
To reduce the environmental impact during the utilization and disposal of bottom ash from municipal solid waste incinerator (MSWI), the leachability of the heavy metals in the ash should be taken into consideration. In the present work, different curing processes have been used for stabilization of heavy metals in bottom ashes. To understand the effects of different curing processes on the leaching characteristics of heavy metals in the bottom ash from MSWI, bottom ash with particle size less than 4.75 mm diameter was stabilized by natural and accelerated aging. In natural aging process, the bottom ash was posed in the ambient air condition. In accelerated aging processes, ashes were soaked in tape water and saturated lime solution. Toxicity characteristic leaching procedure (TCLP), EPA SW-846 Method 1320 (Multiple Toxicity Characteristic Leaching Procedure, MTCLP), column test (CEN/TS 14405), water-soluble chloride content (CNS 13407) and sequential extraction procedure (SEP) were used to evaluate the leaching characteristics of heavy metal and chloride ion in the aged bottom ashes.
It was found that leaching of heavy metals in naturally aged bottom ash was not reduced with increasing curing time. However, leaching of heavy metals in accelerated aging bottom ash declined with increasing curing time. In addition, based on the TCLP, MTCLP and column test results of aged ashes through natural aging and accelerated aging processes, it was found that the heavy metals leachability can meet the requirement of TCLP standards in Taiwan, but results based on column test elucidates the bottom ash had some problems in the long-term stability. The accumulation leachability of Cu and Pb can’t meet the requirement of building materials decree (BMD) standards of Netherlands.
According to the SEP analysis, mainly bounded patterns of the heavy metals in the aged ashes through natural aging and accelerated aging processes are Fe-Mn oxides bound, organic matter bound and residual bound. |
