| 摘要: | 衛生掩埋為當今處理生活垃圾最普遍的方式。但衛生掩埋場依其不同的垃圾組成而產生複雜難處理之垃圾滲出水。垃圾滲出水若收集處理不當，將會污染土壤與水體。
本論文利用類芬頓-活性碳生物濾床處理垃圾場滲出水，以類芬頓法為前處理單元，評估活性碳生物濾床為後處理單元之可行性。主要實驗變數為pH值、起始三價鐵濃度與過氧化氫濃度，研究類芬頓法、類芬頓-混凝以及類芬頓-混凝-活性碳生物濾床對COD與色度之去除效能，評估類芬頓法與類芬頓-混凝程序對後續活性碳生物濾床生物生物降解之影響。除此之外，本研究利用statistical design-expert 軟體，針對實驗數據，進行最佳反應條件之模擬。
在類芬頓法部分，以實驗條件pH 2，起始三價鐵濃度40mM及過氧化氫濃度800mM時之效能最佳。數據模擬結果顯示，降低pH值或三價鐵濃度與過氧化氫濃度有助於處理效率的提昇。類芬頓法處理垃圾滲出水之反應速率式如下：
在類芬頓-混凝部分，數據模擬結果顯示，pH 2條件下有最高之COD去除率（64%），pH 4條件下有最高之色度去除率（97%）。
實驗結果亦顯示，利用類芬頓法處理垃圾場滲出水，有助於提升後續之生物降解。活性碳生物濾床實驗結果顯示，活性碳於實驗4天後達飽和，後續對滲出水處理之主要機制為生物降解作用。
Nowadays the most common way to eliminate municipal and industrial solid wastes is sanitary landfill. In spite of many advantages, the generation of landfill leachate is significant variations in both volumetric flow and the chemical compositions, it was become of drawback. Landfill leachate contains a lot of toxic and organic substances. Therefore, untreated leachate can contaminate in soil, surface water and groundwater. In this study the treatment efficiency of landfill leachate by Fenton-like oxidation, Fenton-like and coagulation and combination system between Fenton-like process and GAC-biofilter were investigated. The effect of pH, initial concentration of ferric ions and hydrogen peroxide were examined. The efficiency of Fenton-like processes was measured by removal of COD, color degradation and the improvement of biodegradability (BOD5/COD ratio). In addition, the experimental results were analyzed by using statistical design-expert software (version 7.0, trial version). The pH, initial concentration of ferric ions, and initial concentration of Hydrogen peroxide were selected as the independent variables while COD removal, color removal and biodegradability (BOD5/COD ratio) were considered as the response surface functions.
In Fenton-like oxidation, the COD degradation rate was observed to find the optimum pH. The results show that the highest COD degradation rate of 83 mg/l•min was obtain at the condition of pH 2. For statistical analysis, the results indicate that the three independent variables affect COD degradation. The highest COD removal efficiency of 62% was obtained at pH 2, initial concentration of ferric ions and Hydrogen peroxide were 40and 800 mM, respectively. In additional, pH gives the negative effect to the Fenton-like processes. For the kinetic of Fenton-like processes, it also show that the COD removal efficiency increased with increasing the concentration of ferric ions and Hydrogen peroxide. Overall rate equation that obtained in this study is:
For Fenton-like and coagulation processes, COD removal efficiency, color removal efficiency and biodegradability improvement were examined and the results show that the highest COD removal efficiency was 64 % at the condition of pH 2. For color removal efficiency, the highest removal efficiency of 97 % was obtained at pH 4 with the initial concentration of ferric ions and hydrogen peroxide of 40 and 800 mM, respectively. And biodegradability was improved from 0.3 to 0.5 at the condition of pH 3. The almost experimental data that obtained from this study are consistent with the model which provided by Design Expert Software (Trial version 7).
To evaluate the improvement of biodegradation, GAC-biofilter was used in this study. The result showed that after the GAC was exhausted in 4 day, by calculation. The biological activity could be established on the GAC surface and it indicated that a pretreatment by Fenton-like can enhance and improve the biodegradability in biological process. |
