生物處理為處理廢水中重要的程序之一，在處理過程中所遇到最大的問題是污泥膨化現象，當污泥膨化發生時，沈澱池中污泥不易沈降，造成出流水水質惡化，除了解決污泥膨化問題外，加以找出污泥膨化發生的原因。
本研究主要使用活性污泥法並結合生物浮動床處理技術(MBBR)原理來操作，在不同操作條件之下探討污泥膨化現象。
實驗分為六個階段，第一階段為污泥馴養期進流水COD為653mg/L，第二階段進流水COD為1000mg/L，第三階段進流水COD為2000mg/L，第四階段進流水COD為3000mg/L，第五階段進流水COD為3000mg/L及設定污泥停留時間20天，第六階段進流水COD為3000mg/L及設定污泥停留時間10天，提升有機負荷後經由生物浮動床處理技術（MBBR）操作下，平均COD去除率90%以上，有良好的去除效率。
根據第二到第三階段研究結果顯示，食微比在0.06~0.15(Kg COD/Kg MLVSS-day)之間時會發澎污泥膨化現象。比較未排泥、SRT20及SRT10，增加排泥不會降低污泥膨化現象，反而使系統中絲狀菌快速生長，出流水MLSS濃度增加，SVI的提升使污泥不易沈降，因此SRT10則無法使污泥膨化現象更加反更為嚴重。 Biological treatment is one of the most popular procedures in wastewater treatment process. The biggest problem encountered in the process of sludge is bulking phenomenon. When the bulking occurs, the sludge in sedimentation tank will not be able to settle easily and will result in the deterioration of water quality. The objectives of this study are to solve the problem of sludge bulking and to find out the reasons for the occurrence of sludge bulking.
In this study, a Moving Bed Bio-film Reactor (MBBR) was used as a treatment system which is the synthetic sewage combined with the activated sludge method together with various operating conditions to study the sludge bulking to enhance the organic loading and to reduce the sludge bulking.
The study was separated into six phases. The first to fourth phase was operated through influent COD of 653 mg/L, 1000mg/L, 2000mg/L and 3000mg/L, respectively. The fifth phase was operated through influent COD of 3000mg/L and sludge residence time (SRT) of 20 days. The sixth phase was operated through influent COD of 3000mg/L and SRT of 10 days.
The results show that average COD removal rate was more than 90% with good removal efficiency. During the second and third phases, DO in MBBR was 4.5 mg/L and the average DO at the sedimentation tank was 0.17mg/L. Comparing non-sludge withdrawal operation with SRT of 20 and 10 days, the decrease of sludge age cannot reduce the sludge bulking phenomenon. On the other hand, the rapid growth of the filamentous bacteria was discovered in the system. The increase of MLSS concentration in the effluent and the improvement of SVI caused the difficult settlement of the sludge.
