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Wastewater Purification: Aerobic Granulation in Sequencing Batch Reactors - Chapter 5

Nó xuất hiện từ các chương trước mà hầu như tất cả các nghiên cứu về hạt hiếu khí đã được thực hiện trong trình tự các lò phản ứng hạt nhân hàng loạt (SBRs), trong khi không có thành công hạt hiếu khí đã được quan sát thấy trong nền văn hóa của vi sinh vật liên tục. Như thể hiện trong chương 5, người ta tin rằng các hạt hiếu khí hình thành thông qua bất động tự của vi khuẩn khi áp lực chọn lọc phù hợp được cung cấp trong SBR. So sánh để liên tục vi sinh vật văn. | 5 Roles of SBR Volume Exchange Ratio and Discharge Time in Aerobic Granulation Zhi-Wu Wang and Yu Liu CONTENTS 5.1 Introduction.69 5.2 The Role of SBR Volume Exchange Ratio in Aerobic Granulation.70 5.3 Effect of Volume Exchange Ratio on Aerobic Granulation.71 5.4 Effect of Volume Exchange Ratio on Sludge Settleability.73 5.5 Effect of Volume Exchange Ratio on Production of Extracellular Polysaccharides.75 5.6 Effect of Volume Exchange Ratio on Calcium Accumulation in Aerobic Granules . 75 5.7 Volume Exchange Ratio Is a Selection Pressure for Aerobic Granulation.76 5.8 Effect of Discharge Time on Formation of Aerobic Granules.78 5.9 Effect of Discharge Time on Settleability of Bioparticles.79 5.10 Effect of Discharge Time on Cell Surface Hydrophobicity.82 5.11 Effect of Discharge Time on Production of Extracellular Polysaccharides.82 5.12 Conclusions.83 References.84 5.1 INTRODUCTION It appears from the preceding chapters among all the operation parameters that have been discussed so far only settling time can serve as an effective selection pressure for aerobic granulation. However a basic question to be addressed is if there are still other parameters that can also play the roles of selection pressure in aerobic granulation other than the identified settling time. The answer to such a question is essential for developing the design and operation strategy for rapid and stable aerobic granulation in both small- and large-scale sequencing batch reactors SBRs . This 69 2008 by Taylor Francis Group LLC 70 Wastewater Purification chapter looks into two other potential candidate parameters that may act as selection pressures in aerobic granulation in SBR namely SBR volume exchange ratio and discharge time. 5.2 THE ROLE OF SBR VOLUME EXCHANGE RATIO IN AEROBIC GRANULATION According to figure 5.1 the mixed liquor volume exchange ratio or volume exchange ratio for short is the volume of effluent that is withdrawn after a preset settling time divided by the total working .