飛灰常含有重金屬元素，會對生態環境造成嚴重危害。臺灣目前對於一般廢棄物與事業廢棄物主要是以焚化的方式處理，垃圾焚化後會產生飛灰，然而臺灣目前對於飛灰再利用技術尚未成熟，故現行飛灰處理方式多為固化處理，然而固化處理過後的試體體積和質量都會增加，造成廢棄物減容狀況不佳的問題，加快國內安定化掩埋場飽和速度。為了因應臺灣2050淨零碳排之政策，減少水泥的使用也是目標之一，故本研究旨在嘗試是否能夠利用微生物誘導礦化技術（Microbial-Induced-Calcite-Precipitation, MICP）以固化飛灰，進而取代傳統水泥-螯合劑的固化方式。
MICP是透過給予特定微生物特定營養鹽，使其產生碳酸鈣沉澱的一種技術。本實驗所使用之特定微生物為Sporosarcina pasteurii，其所需要之特定營養源為尿素以及鈣源，透過產生尿素酶分解尿素產生銨根離子和氫氧根離子，接著再與鈣離子反應產生碳酸鈣沉澱。在MICP參數優化實驗中，以氯化鈣作為鈣源之沉澱效果最佳，且營養鹽濃度越高，碳酸鈣沉澱效果也越佳；尿素濃度越高，所產生的碳酸鈣沉澱也越多；不同菌液OD值也會影響碳酸鈣的沉澱情形，菌液OD值越高，MICP沉澱效果越佳；不同培養基濃度也會影響碳酸鈣沉澱情形，培養基濃度越高所產生之碳酸鈣沉澱越多。以MICP工法對沙土以及石英砂分別進行固化反應皆能夠生成碳酸鈣沉澱，進而將沙土、石英砂膠結在一起；而以MICP工法對飛灰進行固化的實驗結果顯示，雖然S. pasteurii能夠在飛灰中進行碳酸鈣的沉澱反應，但其相對碳酸鈣沉澱量不高。隨著環保意識抬頭，廢棄物資源化再利用形成流行的趨勢，本研究利用廢蛋殼以及蚵殼粉做為MICP固化飛灰過程中的替代鈣源，蛋殼以及蚵殼粉不僅在MICP固化飛灰過程中提供鈣離子來源，也能夠提升固化過程的酸鹼值。雖然目前以MICP工法固化飛灰之成效還有待加強，但未來可與其他技術作結合，增強MICP技術的穩固性與安定性，故MICP技術在未來的發展性仍不容小覷。

Since the Industrial Revolution, the production of fly ash has increased rapidly, becoming a significant environmental issue due to its toxic heavy metals. In Taiwan, waste is mainly incinerated, which produces toxic fly ash. The current treatment for fly ash is through adding cement and chelating agents. Along with Taiwan's 2050 net-zero carbon policy, this research explores Microbial-Induced Calcite Precipitation, MICP, to solidify fly ash as an alternative to cement and chelating agents.
In this research, Sporosarcina pasteurii is used to induce calcium carbonate precipitation with urea and calcium chloride. The results showed that higher nutrient concentrations, both urea and calcium chloride, enhanced calcium carbonate precipitation. Different optical density values (OD600) of S. pasteurii also affected precipitation, with higher OD600 values yielding better MICP precipitation effects. MICP effectively solidified sand and quartz sand. As for the fly ash solidification through microbial-induced-calcite-precipitation, while the process showed some effectiveness, the solidification was insufficient, indicating that MICP's current feasibility for fly ash treatment is limited, but MICP shows promise for future development in sustainable waste management. The study also tested waste eggshells and oyster shell powder as alternative calcium sources in the MICP process, which not only improved calcium ion availability but also improved pH levels during solidification.

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