| 摘要: | 本研究是利用缺-好氧MBR系統處理來自台南安定飛灰掩埋場的垃圾滲出水，研究各程序下對薄膜阻塞的情形。系統由缺氧槽 (6L) 與MBR (12L) 所組成，總有效體積為18L。控制系統的水力停留時間 (HRT) 2天及污泥停留時間 (SRT) 50天。
研究分為3階段進行，第一階段無缺氧槽，第二階段缺氧-好氧MBR系統啟動，缺氧槽與MBR的迴流比為1Q，於缺氧槽添加碳源以供給脫硝作用所需。第三階段改變缺氧槽與MBR的迴流比為2Q。
系統添加糖蜜後，使得有機污染物開始減少。MLVSS對於有機污染物的去除效率有顯著的關係，在第二階段活性污泥於缺氧槽與MBR增長至4,550 - 9,100 mg/L 6,120 - 10,250 mg/L與，在第三階段活性污泥於缺氧槽與MBR增長至6,175 - 12,900 mg/L與6,125 -13,500 mg/L，由研究顯示，添加糖蜜後，對於TCOD、SCOD、氨氮與總氮的去除率可以達到88 %，86 %，100 % 與84%。
修正阻塞指標 (MFI) 是一種用於薄膜系統判定薄膜阻塞的指標。在MFI研究中發現，食微比 (F/M ratio)，胞外聚合物 (EPS)、懸浮固體物、顆粒粒徑分布、比阻抗 (α) 與薄膜孔徑之間的關係。由研究顯示，當MLSS大量附著於薄膜時，MFI會增加，比阻抗也隨之增加，使得出流水的流通量減少。當好氧-MBR處於低食微比、污泥粒徑較小、有較高EPS產生、有高濃度總有機碳時，也會造成MFI增加。本研究亦由Carmen-Kozeny 方程式、生物特性與操作特性來解釋MFI與幾個參數間複雜的關係。
An anoxic-oxic membrane bioreactor (MBR) process is presented to treating high contaminated landfill leachate from An-ding plant. The system operated with total working volume is equal to 18 L which separated into two tanks, the first tank is anoxic condition (6 L) and the second tank is oxic condition (12 L) respectively. Hydraulic retention time (HRT) was set at 2 days and sludge were discharged to maintain solid retention time (SRT) which are equal to 50 days.
The study consisted of three phases. The first phase was operated without anoxic bioreactor. For the second phase operated with anoxic-oxic MBR, 1Q recirculation rate and molasses was supplied in anoxic tank as an extra carbon source for denitrification. The third stage, system had changed the recirculation rate from 1Q to 2Q. At the initial start-up stage, the operation got some problems such as foaming, sludge washed out and poor removal efficiency of chemical oxygen demand (COD) and nitrogen compound which is consider as common operation problems for biological treatment of landfill leachate.
Successive reduction of organic pollutants were achieved after molasses addition, the average mixed liquor volatile suspended solids (MLVSS) and removal efficiency of organic pollutant increased obviously. The sludge in anoxic tank was increased up to the 4,550-9,100 mg/L and 6,175-12,900 mg/L on the second stage and the third stage respectivly. The sludge in oxic tank was increased up to 6,120-10,250 mg/L and 6,125-13,500 mg/L on the second stage and the third stage respectivly. The results of this study illustrated that the highest removal efficiencies of TCOD, SCOD, ammonia nitrogen (NH4+-N) and total nitrogen (TN) were 88%, 86%, 100% and 84%, respectively.
The relationship between foods per mass ratio (F/M ratio), extracellular polymeric substance (EPS) production, mixed liquid suspended solid (MLSS), particle size distribution, specific cake resistance (α) and membrane pore size with modified fouling index (MFI) were found. The MFI is method to measure fouling potential in membrane system. Factors effect to membrane fouling is too complex to explain by only one parameter. The results from this experiment found that, specific cake resistance was increased when MFI increased which results from high MLSS accumulated on membrane surface and may reduce permeate flux and system performance. Also at low F/M ratio, small particle size, high EPS production, high total organic carbon (TOC) concentration in oxic-MBR all are result in high MFI value. The complex relationship between several parameters and MFI was explained by Carmen-Kozeny equation, biomass characteristic and physical operation etc. |
