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年度	113	專案性質	實驗性質
專案類別	模場試驗	研究主題	整治
申請機構	國立中山大學	申請系所	環境工程研究所
專案主持人	高志明	職等/職稱	教授
專案中文名稱	以微生物轉化CH4及CO2吸收材料降低整治系統溫室氣體排放:技術開發及模場應用
中文關鍵字	溫室氣體排放, 甲烷氧化菌, 碳吸收, 綠色吸收劑, 現地整治
專案英文名稱	Reduction of greenhouse gas emissions in remediation systems through microbial CH4 conversion and CO2 adsorption materials: Technology development and pilot-scale application
英文關鍵字	greenhouse gas emission, methanotroph, CO2 adsorption, CH4, green absorption material, in situ remediation
執行金額
執行期間	2024/12/1 至 2026/11/30
計畫中文摘要	二氧化碳(carbon dioxide, CO2)的排放被認為是造成氣候變遷的重要因子之一，而甲烷(methane, CH4)是僅次於CO2的第二大溫室氣體，且因其暖化潛能為CO2之27.9倍，因此受到聯合國的高度重視。本研究主要目標為：(1)篩選CH4氧化菌，利用CH4氧化菌將厭氧生物整治產生之CH4進行轉化去除；(2)將CH4氧化菌製成固定化材料，提升CH4轉化及實場應用效益，使之更易進行運送及環境應用；(3)使用工業鹼性廢棄物(basic-oxygen-furnace (BOF) slag)及硫酸鈣(calcium sulfate hemihydrate, CSH)開發具緩釋及長效CO2吸收材料(slow-release CO2 absorbent material, SCAM)，以有效捕捉生物或化學整治程序所產生之CO2，並提升循環經濟效益；及(4)結合二種系統為單一系統，將甲烷氧化菌固定化顆粒添加於CO2吸收材料中，並應用於污染整治系統，達到同時處理CH4及CO2目的，以降低土壤及地下水整治過程中之溫室氣體排放。本研究第一階段包括：(1)開發溫室氣體CO2吸收材料並篩選CH4氧化菌，以削減土壤及地下水污染整治所產生之CO2及CH4；針對開發之CO2吸收材料進行效益分析，並評估整治過程之反應機制及CO2動力吸收模式；(2)針對影響因子進行評估，以探究環境變因對於溫室氣體削減處理效益影響；(3)評估CH4氧化菌及固定化顆粒對CH4之氧化效益，利用次世代定序及即時定量聚合酶連鎖反應、菌量及菌相分析，建立生化代謝及特徵基因和優勢菌之變化圖譜；(4)評估結合二種技術之可行性，以達到完全處理CH4氧化菌及CO2之目標；及(5)現地模場勘查與前置作業。第二階段包括：(1)現地模場之現場監測點規劃、背景溫室氣體評估及土壤/地下水分析；(2)結合CH4氧化菌固定化菌株及CO2吸收材料，在實驗室評估此複合材料應用效益；(3)以CO2吸收材料、CH4氧化菌固定化顆粒及複合材料進行現地模場應用之程序規劃、設計與評估，建立現地整治作業標準流程；及(4)藉由現地模場試驗成果，完成操作最佳化、溫室氣體減量成效、碳匯計算及效益評估。本計畫透過減少溫室氣體排放之環境永續治理理念，開發綠色CH4及CO2移除的技術，可針對污染整治及復育程序所產生之CH4及CO2溫室氣體分別以生物分解及化學吸收機制完全移除。 現階段主要成果為: (1)本計畫已從環境中篩選出甲烷氧化菌，並於系統中將CH4轉化成CO2，實現甲烷去除目標，最高可達83.4% 之CH4去除率；(2)本研究於硝酸無機鹽培養基中添加5 µM銅離子 以促進甲烷單加氧化酶(pMMO)活性，結果顯示16S rRNA與功能性基因pmoA表現量均顯著提升；(3)本研究所開發之CO2吸收劑，每公斤可有效捕捉150-160 g的二氧化碳；(4)當BOFs與CSH的比例為1.5:0.5、1:1和0.5:1.5時，鈣離子(Ca2+)濃度分別顯著增加至341 mg/L、502 mg/L 和568 mg/L。另外，當BOFs與CSH的比例為2:0、1.5:0.5、1:1、0.5:1.5和0:2時，初始pH值為分別11.5、8.87、7.62、7.09、和6.11，可以觀察出CSH添加量的增加有利延長氫氧離子(OH-)的釋放，從而控制pH值影響和Ca2+釋放，相較於原先的BOFs，Ca2+釋放能力提高了約2倍；(5)根據傅立葉轉換紅外光譜(Fourier-transform infrared spectroscopy, FTIR)的分析觀察到的碳酸根(CO 32–)譜帶加以輔證推斷SCAM能夠有效且緩慢地釋放OH–和Ca2+，因為SCAM可以將CO2轉化為CO32-並與釋放的Ca2+進行礦化沉澱生成碳酸鈣(CaCO3)；(6)在掃描電子顯微鏡(Scanning Electron Microscope, SEM)下可觀察到吸附飽和的SCAM有明顯的方解石，其晶體形成之推測，所有無定型顆粒和球霰石晶體，通過文石的溶解轉化為方解石，與碳酸鈣型態吻合；(7)本研究在製作SCAM的經濟成本中，因只添加CSH與水，每公斤花費約100元(NTD)。在碳足跡方面，生產CSH的碳足跡約為0.06 kg CO2/kg。因此，製作每公斤的SCAM過程中，僅排放0.06 kg CO2，但其捕捉能力為0.16 kg，最終實現淨捕捉0.1 kg CO2；(8)吸收飽和的CO2吸收劑屬無害的產物，因本研究在改良過程中添加硫酸鈣，可促進作物生長的必要營養，未來可做為土壤回填的材料來改善土壤結構，增加土壤的透水性和通氣性，保持土壤中的微生物高活性，有助於原生土壤有機質含量的提升，提高土壤肥力，增加土壤的碳匯效果；(9)本研究利用微生物固定化及冷凍乾燥之創新技術，後續將甲烷氧化菌製備成固定化顆粒或粉末化，使該菌在特定處理系統中具有活性高、專一性強、耐受性強(如可適應pH、溫度、有毒有害物質影響)、處理效果穩定、分解速率快之優點，並更易進行運送及環境應用；(10)本研究將結合二種系統為單一系統，將甲烷氧化菌固定化顆粒結合CO2吸收劑，並應用於模場試驗中，達到同時處理CH4及CO2目的。與其他物理化學技術相比，生物轉化過程屬於綠色、環保且環境友善技術。 本技術為結合微生物轉化CH4及緩釋及長效CO2吸收材料製備之綠色淨零系統開發及應用，此綠色淨零系統屬於綠色、節能、無二次污染、經濟有效且務實的溫室氣體移除技術，可降低溫室氣體排放及減緩氣候變遷之衝擊，在低排放、節能和高效益的多重考量下，解決CO2與CH4排放造成之全球暖化問題，達到綠色永續整治及2050淨零排放之目的。 關鍵字: 溫室氣體排放、甲烷氧化菌、碳吸收、綠色吸收劑、現地整治
計畫英文摘要	Carbon dioxide(CO2) emissions are regarded as one of the main contributors to climate change, while methane(CH4), the second-largest greenhouse gas after CO2, has garnered significant attention from the United Nations due to its global warming potential being 27.9 times greater than CO2. This study primarily aims to: (1)screen CH4-oxidizing bacteria and utilize them to convert and remove CH4 produced through anaerobic bioremediation; (2)immobilize CH4-oxidizing bacteria into materials to enhance CH4 conversion efficiency and field application, facilitating easier transport and environmental deployment; (3)develop the slow-release CO2 absorbent material(SCAM) using industrial alkaline waste (basic-oxygen-furnace (BOF) slag) and calcium sulfate hemihydrate(CSH) to efficiently capture CO2 produced in biological or chemical remediation processes, thus enhancing the circular economy; and (4)integrate these two systems into a single approach by incorporating immobilized CH4-oxidizing bacteria particles into the CO2 absorbent, applying this composite material to a pollution remediation system for simultaneous treatment of CH4 and CO2, and thereby reducing greenhouse gas emissions during soil and groundwater remediation. The first phase of this study includes: (1)developing the slow-release CO2 absorbent material and screening CH4-oxidizing bacteria to mitigate CO2 and CH4 emissions from soil and groundwater pollution remediation processes. A cost-effectiveness analysis of the developed SCAM will be conducted, along with an evaluation of the reaction mechanisms and CO2 dynamic absorption models of the remediation process; (2)assessing various influencing factors to explore how environmental variables affect the efficiency of greenhouse gas reduction treatments; (3)evaluating the CH4 oxidation efficiency of the CH4-oxidizing bacteria and immobilized particles by utilizing next-generation sequencing(NGS), Real-time polymerase chain reaction(real-time PCR, or qPCR when used quantitatively), bacterial count, and microbial community analysis to establish a biochemical metabolism and mapping of characteristic genes and dominant bacterial species; (4)evaluating the feasibility of combining these two technologies to achieve complete treatment of CH4-oxidizing bacteria and CO2; and (5)conducting on-site field surveys and preparatory work. The second phase involves: (1)planning on-site monitoring points, conducting background greenhouse gas assessments, and performing soil/groundwater analysis for the field simulation; (2)combining immobilized CH4-oxidizing bacteria strains and SCAM in laboratory evaluations to assess the application benefits of this composite material; (3)planning, designing, and evaluating the process of field simulation applications using SCAM, immobilized CH4-oxidizing bacteria particles, and composite materials, to establish a standardized process for field remediation operations; and(4)optimizing operations, assessing greenhouse gas reduction effectiveness, calculating carbon sequestration, and evaluating the overall benefits based on results from the field simulation experiments. This project develops green technologies for CH4 and CO2 removal based on the concept of environmental sustainable management to reduce greenhouse gas emissions. CH4 and CO2 greenhouse gases generated from pollution remediation and restoration processes can be completely removed via biological degradation and chemical absorption mechanisms, respectively. Key achievements to date include: (1)The project has successfully isolated CH4-oxidizing bacteria from the environment and has converted CH4 into CO2 within the system, achieving a maximum CH4 removal rate of 83.4%; (2)In this study, 5 µM of copper ions were added to the nitrate mineral salts medium to enhance the activity of particulate methane monooxygenase (pMMO). The results showed that both 16S rRNA and the functional gene pmoA exhibited significantly increased expression levels.; (3)The SCAM developed in this study can effectively capture 150-160 g of CO2 per kilogram; (4)When the ratio of BOFs to CSH is 1.5:0.5, 1:1, and 0.5:1.5, the calcium ions(Ca2+)concentration increased significantly to 341 mg/L, 502 mg/L, and 568 mg/L, respectively. Furthermore, the initial pH values of BOFs to CSH ratios of 2:0, 1.5:0.5, 1:1, 0.5:1.5, and 0:2 were found to be 11.5, 8.87, 7.62, 7.09, and 6.11, respectively. The increase in the amount of CSH added was found to prolong the release of hydroxide ion(OH-), thus controlling the pH effect and Ca2+ release, with calcium ion release capacity nearly doubling compared to the original BOFs; (5) Fourier-transform infrared spectroscopy(FTIR) analysis of the carbonate ion(CO32-)bands suggests that SCAM can effectively and gradually release OH- and Ca2+, as it can convert CO2 into CO32- and mineralize and precipitate with the released Ca2+ to form calcium carbonate(CaCO3); (6) Scanning Electron Microscope(SEM) analysis shows that SCAM in saturation has distinct calcite crystals. It is speculated that all amorphous particles and vaterite crystals are converted into calcite through aragonite dissolution, which aligns with the morphology of calcium carbonate; (7)The economic cost of producing SCAM in this study, using only CSH and water, is approximately NT$100 per kilogram(kg). In terms of carbon footprint, producing CSH generates a footprint of 0.06 kg CO2/kg. Therefore, the process of producing each kilogram of SCAM emits 0.06 kg CO2 but captures 0.16 kg CO2, resulting in a net capture of 0.1 kg CO2; (8)The SCAM is harmless. As CSH was added during the modification process, it can provide essential nutrients for crop growth. In the future, SCAM may be used as a soil backfill material to improve soil structure, increase permeability, and enhance aeration, while maintaining high microbial activity in the soil. This will help to increase organic matter content, improve soil fertility, and boost the carbon sink capacity of the soil; (9)This study utilizes innovative microbial immobilization and freeze-drying technologies, which allow methane-oxidizing bacteria to be prepared as immobilized particles or powders. This offers high activity, strong specificity, and tolerance (e.g., to pH, temperature, and toxic substances), as well as stable treatment effects, rapid decomposition rates, and improved transportability and application; (10)This study will combine both technologies into a unified system, integrating immobilized CH4-oxidizing bacteria particles with slow-release CO2 absorbent material, applying them in model field tests to achieve the simultaneous treatment of CH4 and CO2. Compared to other physical and chemical technologies, the biological transformation process stands out as a green, environmentally friendly, and sustainable technology. This technology combines microbial conversion of CH4 with the preparation of slow-release and long-lasting CO2 absorption materials to develop a green and net-zero system. This system is a greenhouse gas removal technology that is eco-friendly, energy-efficient, free from secondary pollution, cost-effective, and practical. It reduces greenhouse gas emissions and mitigates the impact of climate change. By addressing the global warming issues caused by CO2 and CH4 emissions, it supports the goals of low emissions, energy savings, high efficiency, and contributes to green, sustainable remediation, and achieving net-zero emissions by 2050. Keyword: greenhouse gas emission, methanotroph, CO2 adsorption, CH4, green absorption material, in situ remediation.