The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep ...The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep bed filtration process were also studied theoretically. Through the comparison of the hydraulic and physicochemical forces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and the experimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoretical prediction was reasonably consistent with the experimental results under different conditions, which indicated that the regulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of the physicochemical interactions. Further theoretical and experimental research should be carried out to investigate the interaction mechanism and its application in the deep bed filtration and other cases.展开更多
The scanning electronic microscope and automated image analyzer are adopted to investigate the morphology of deposits formed during fiber bundle media filtration, which results in the discovery of the self—similarity...The scanning electronic microscope and automated image analyzer are adopted to investigate the morphology of deposits formed during fiber bundle media filtration, which results in the discovery of the self—similarity of the deposits. Then in this paper it is proposed that the deposits are a fractal structure. Moreover, the fractal dimension value is related to the filter performance. The higher the fractal dimension value, the higher the filtration efficiency, and the longer filtration cycle, but the development of the head loss is also faster.展开更多
Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration（DSMF）, with the goal of concentrating organic matters, is proposed as a pretr...Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration（DSMF）, with the goal of concentrating organic matters, is proposed as a pretreatment process in a novel sewage treatment concept. The concept of membrane-based pretreatment is proposed to divide raw sewage into a concentrated part retaining most organics and a filtered part with less pollutant remaining, so that energy recovery and water reuse, respectively, could be realized by post-treatment. A pilot-scale experiment was carried out to verify the feasibility of coagulant/adsorbent addition for membrane fouling control, which has been the main issue during this DSMF process. The results showed that continuous coagulant addition successfully slowed down the increase in filtration resistance, with the resistance maintained below 1.0 × 1013m^（-1） in the first 70 hr before a jump occurred. Furthermore,the adsorbent addition contributed to retarding the occurrence of the filtration resistance jump, achieving simultaneous fouling control and chemical oxygen demand（COD）concentration improvement. The final concentrated COD amounted to 7500 mg/L after 6 days of operation.展开更多
文摘The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep bed filtration process were also studied theoretically. Through the comparison of the hydraulic and physicochemical forces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and the experimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoretical prediction was reasonably consistent with the experimental results under different conditions, which indicated that the regulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of the physicochemical interactions. Further theoretical and experimental research should be carried out to investigate the interaction mechanism and its application in the deep bed filtration and other cases.
文摘The scanning electronic microscope and automated image analyzer are adopted to investigate the morphology of deposits formed during fiber bundle media filtration, which results in the discovery of the self—similarity of the deposits. Then in this paper it is proposed that the deposits are a fractal structure. Moreover, the fractal dimension value is related to the filter performance. The higher the fractal dimension value, the higher the filtration efficiency, and the longer filtration cycle, but the development of the head loss is also faster.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2012ZX07205-002)the Tsinghua University Initiative Scientific Research Program (No. 20121087922)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1152)
文摘Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration（DSMF）, with the goal of concentrating organic matters, is proposed as a pretreatment process in a novel sewage treatment concept. The concept of membrane-based pretreatment is proposed to divide raw sewage into a concentrated part retaining most organics and a filtered part with less pollutant remaining, so that energy recovery and water reuse, respectively, could be realized by post-treatment. A pilot-scale experiment was carried out to verify the feasibility of coagulant/adsorbent addition for membrane fouling control, which has been the main issue during this DSMF process. The results showed that continuous coagulant addition successfully slowed down the increase in filtration resistance, with the resistance maintained below 1.0 × 1013m^（-1） in the first 70 hr before a jump occurred. Furthermore,the adsorbent addition contributed to retarding the occurrence of the filtration resistance jump, achieving simultaneous fouling control and chemical oxygen demand（COD）concentration improvement. The final concentrated COD amounted to 7500 mg/L after 6 days of operation.
