改良式薄膜生物反應器對超濾薄膜積垢之量化影響

The Influence of Modified Membrane Bio-reactor System on Ultra-filtration Membrane Fouling

游禮轅(Li-Yuan You)

指導教授 ： 林正芳

國立臺灣大學/工學院/環境工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.02597

摘要

薄膜生物反應器(Membrane Bio-reactor, MBR)因具有污泥濃度高、廢棄污泥少及佔地面積較小等優點而廣為發展，然而，MBR系統雖在許多程序及設備方面改善了活性污泥法的缺點，但在其本身操作方面仍有許多問題，而薄膜積垢即為其中最廣為關心的阻礙。
傳統MBR的積垢問題來自生物反應槽之高污泥濃度，由固定化技術發展出的固定式生物處理法，擁有較長的污泥停留時間，產生的污泥量較少，若與薄膜結合成改良式MBR，應能有效減少傳統MBR的積垢問題。本研究主要目的為觀察此改良式MBR對薄膜積垢(UF薄膜)的量化影響，並在不同HRT (18小時、12小時、6小時)及曝氣型態(連續曝氣、1小時曝氣/1小時無曝氣、1小時曝氣/2小時無曝氣)下處理實廠工業廢水，比較其處理效率與積垢情形，以求得最佳操作參數，使此系統達到最佳的產水效率及降低積垢速率，延長薄膜壽命。
實驗結果顯示，較短的HRT(6小時)及階段性曝氣下，COD(初始濃度: 458~1007 mg/L)與NH4+-N(初始濃度: 6.3~12.8 mg/L)平均去除率較低，積垢速率較快，18小時HRT及連續曝氣下，能得到最佳的COD及NH4+-N去除率且大幅減少薄膜積垢，去除率分別為92.5 %及95.3 %，積垢試驗部分，維持固定通量(20 LMH)下透膜壓力(trans-membrane pressure, TMP)上升至最大值(55 kpa)所需時間為215分鐘，為傳統式MBR操作時間之3.8倍。
改良式MBR系統確實能有效改善傳統式MBR系統之積垢問題，因此改良式MBR在減緩薄膜積垢，增加產水效率方面具有取代現有之傳統式MBR的潛力。此系統之最佳操作條件為連續曝氣搭配18小時HRT之組合，HRT越長，曝氣持續越久，COD及氨氮處理效率與積垢延遲效果越好(18小時>12小時>6小時，連續曝氣>階段性曝氣)。

關鍵字

改良式MBR ； 固定式生物處理法 ； 薄膜積垢

並列摘要

Membrane bio-reactor (MBR) is the most popular biological treatment process because of its high mixed liquid suspended solid (MLSS), low production of sludge, stable and good effluent water, and a smaller footprint. However, membrane fouling has been the major problem that limiting the wide applications of MBR.
High sludge concentration of conventional MBR is referred as one of the major reason of membrane fouling. The fixed carrier biological system (FCBS) with longer sludge retention time (SRT) and low suspended solid (SS) believed to enable less membrane fouling. Thus, the influence of modified MBR system by combining FCBS with ultra-filtration membrane module on membrane fouling at various operating parameters such as HRT (18, 12 and 6h), continuous and interrupted aeration (1h aeration-1h non-aeration and 1h aeration-2h non-aeration) at room temperature was investigated and industrial wastewater was used throughout the experiment.
The result shows that HRT and aeration significantly influence the MBR performance. The shorter HRT (6h) with interrupted aeration results the lower COD (initial: 458~1007 mg/L) and NH+4-N (initial 6.3~12.8 mg/L) removal with higher membrane fouling. Whereas with continuous aeration at higher HRT (18h) higher removals of COD, NH+4-N and low effluent SS of 92.5 %, 93.7 % and 30.6 mg/L was achieved respectively and also results in less membrane fouling. The membrane fouling experiments at constant flux of 20 LMH, HRT of 12 h with continuous aeration shows that a maximum trans-membrane pressure (TMP) of 55 kpa was reached in 215 min which is 3.8 times delayed than the conventional MBR. From the results the best performance of the reactor operating conditions were found to be in the order of 18h>12h>6h HRTs and continuous aeration > interrupted aeration.
The conclusion it can be confidently stated that the modified MBR system really improve the MBR performance by decreasing fouling in comparison with conventional MBR system. Therefore, modified MBR have the potential for improvement or replacement of the existing conventional activated sludge process with regard to improving the effluent qualities by decreasing membrane fouling.

並列關鍵字

modified MBR ； fixed carrier biological system (FCBS) ； membrane fouling

參考文獻

Cho, E.S., Zhu, J. and Yang, P.Y. (2007) Intermittently aerated EMMC-Biobarrel (entrapped mixed microbial cell with Bio-barrel) process for concurrent organic and nitrogen removal. Journal of Environmental Management 84(3), 257-265.

Chae, S.R., Ahn, Y.T., Kang, S.T. and Shin, H.S. (2006) Mitigated membrane fouling in a vertical submerged membrane bioreactor (VSMBR). Journal of Membrane Science 280(1-2), 572-581.

Chang, I.S. and Kim, S.N. (2005) Wastewater treatment using membrane filtration - effect of biosolids concentration on cake resistance. Process Biochemistry 40(3-4), 1307-1314.

Cho, J.W., Song, K.G., Lee, S.H. and Ahn, K.H. (2005) Sequencing anoxic/anaerobic membrane bioreactor (SAM) pilot plant for advanced wastewater treatment. Desalination 178(1-3), 219-225.

Jeong, T.Y., Cha, G.C., Yoo, I.K. and Kim, D.J. (2007) Characteristics of bio-fouling in a submerged MBR. Desalination 207(1-3), 107-113.