用PTFE材料作為MBR系統中所使用的UF膜進而取活性污泥處理系統-研究PTFE作成的板式膜之積垢情形

Abstract

本研究利用新式PTFE薄膜應用於薄膜生物反應器處理養豬場厭氧消化出流廢水的研究。由本研究可了解MBR對於高碳高氮廢水的適應性、系統連續式操作結果以及新式PTFE薄膜的抗垢與耐受性。 本研究分為兩階段實驗，第一階段將PTFE及PVDF兩種薄膜置入容積25 L的小型MBR槽，倒入活性污泥，以冷藏於4℃冰箱的厭氧消化出流水為飼水，控制抽膜通量為10 LMH，進行連續71小時的抽膜實驗。 第二階段為實廠MBR模組，由一個沉澱槽與曝氣槽組成。啟動系統，待污泥馴養後設定SRT為20天，運轉開始通量維持於18 LMH，至第51天後通量急遽下降。啟動系統至監測結束共89天，實驗期間以PLC搭配人機介面操作，紀錄負壓及流量以供實驗結束後分析，此外第35天開始採薄膜出流水做水質分析，評估MBR對養豬廢水的處理效率結果，發現對COD與BOD的去除效率均有90 %以上。經由透膜壓力與通量 最後探討增設前處理系統去除水中鈣離子對於薄膜壽命之影響，研究結果顯示利用鈣離子與碳酸根離子易形成碳酸鈣沉澱(Ksp= 4.8×10-9)之原理，在含鈣廢水中添加碳酸鈉使其形成沉澱去除。pH亦須調整至10.5，使碳酸根 (pKa2= 10.3)以二價形式存在利於碳酸鈣沉澱。

From this study , we can understand the adaptability of treating high-carbon high-nitrogen wastewater by MBR , the continuous system operating results and the favorable resistance of new type PTFE. This research included two stage , in the first stage , fixing a PTFE membrane and a PVDF membrane in the reactor which volume is 25 L, then pooled into aerobic sludge and the reactor was fed with anaerobic digestion wastewater which was stored at 4℃. The flux was controlled at 10 LMH and started the experiment for 71 hours continuously. The second stage is a pilot scale experiment , it’s consisted of a sedimentation tank and an aeration tank. Started the system , and set SRT at 20 days after stabilizing sludge state. Maintained the flux at 18 LMH until 25 days , and the flux was dropped down. All the experiment from booted the system to the end was totally 89 days. The flux and TMP were recorded by PLC and computer in this experiment , and then analyzed the data. In addition, the effluent was started sampling after 35 days , and assessed the efficiency of treating anaerobic digestion swine wastewater by MBR. The COD and BOD removal rates were more than 90 %. PTFE was more durable than PVDF via the relationship of TMP and flux. Finally, we discuss additional pre-treatment system for the removal of calcium ions in the water affect the life of the film, the results show the use of calcium and carbonate ions easy to form of calcium carbonate (Ksp = 4.8×10-9) precipitation , It is the addition of sodium bicarbonate in water inside, and calcium ions to form a precipitate removed. need to control pH 10.5, that became a divalent carbonate type (pKa2= 10.3) , advantageously calcium carbonate precipitation.