柳橙廢棄物於微生物燃料電池產電之研究

Abstract

微生物燃料電池係兼具處理有機污染物與產生電能之一項技術，對於環境的永續有相當重要的價值。一般的微生物燃料電池主要組成包含電極、反應槽、曝氣裝置、基質、導電中介質、質子交換膜與菌種。本研究採用空氣陰極式微生物燃料電池，以碳布為電極的材料，不使用質子交換膜，但利用陰極與陽極適度的距離以阻隔氧氣進入；菌種來自養豬廠廢水處理系統之厭氧汙泥，經過煮沸前處理後，再以固定化技術固定菌種於醋酸纖維中，而基質除了人工廢水外，也使用柳丁榨汁廢棄物為基質料源。本研究之目的在於以食品廢棄物做為微生物燃料電池之產電基質，找出適宜的操作方式並評估其產電效能。 本實驗之操作變因主要分為兩大類：1. 有無添加石墨粉；2. 三種不同的基質組成 (100 %人工廢水、50%人工廢水與50%柳丁廢水、100 %柳丁廢水)。同時也評估以柳丁廢棄物為基質的三種不同有機負荷時(4 g/L/d、15.44 g/L/d及42.75 g/L/d) 的產電效能。 實驗結果顯示在操作條件為：無添加石墨粉、pH為5、有機負荷4 g/L/d、基質為100 %人工廢水時效能最好，其COD去除率達84.84± 2.09 %，最大功率密度1.47 mW/m2，電流密度為20.65 mA/m2，以及庫倫效率為0.370 %。在加入柳丁廢棄物基質後，則以有機負荷4 g/L/d時混合等比例人工廢水效果最好，其COD去除率為88.36± 2.50 %，最大功率密度0.26 mW/m2時，電流密度為4.55 mA/m2，庫倫效率為0.186%。此外，在固定化微生物有無添加石墨粉的比較試驗，在有機負荷同為15.44 g/L/d時，以沒有添加的試驗組有較好的電池效能，其COD去除率可達73.91± 8.33 %，最大功率密度為0.016 mW/m2、電流密度為0.84 mA/m2，以及庫倫效率為0.005 %。

Microbial fuel cell (MFCs) is a technology which possesses functions of pollution control and electricity production, with significant value in sustainability to our environment. The typical MFC consists of electrodes, reactor, aerator, substrate,mediator, proton exchange membrane (PEM) and inoculum. The configuration of MFC used in this study was an air-cathode, single-chambered MFC, in which carboncloth was used as electrode and to block the diffusion of oxygen with proper layout of electrodes, so that PEM was not applied in this study. Inoculum, the anaerobic sludge, was obtained from a swine wastewater treatment system. After boiling pretreatment, the sludge was entrapped with cellulose acetate. Besides synthetic wastewater, orange waste from juice shop was also used as substrate in this study. The purpose of this study is to find out the proper operational methods for using the food waste as the substrate of MFC and to evaluate its performance of electricity production. Two groups of operational parameters were tested in this study: 1. with or without addition of graphite powder for immobilized cells, and 2. three different substrate compositions for reactor feeding (100% artificial wastewater, 50% artificial wastewater and 50% orange waste, 100% orange waste). Performance of electricity production at three different organic loading rates (4 g/L/d、15.44 g/L/d及42.75 g/L/d) of using orange waste as substrate were evaluated. Experimental results showed at the operational condition: without addition of graphite powder in immobilized cells, pH 5, 4 g/L/d organic loading rate, 100% artificial wastewater as substrate, the system had the best performance. It was observed that 88.84