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Zhichao Wu - One of the best experts on this subject based on the ideXlab platform.

  • new insight into Sludge digestion mechanism for simultaneous Sludge Thickening and reduction using flat sheet membrane coupled aerobic digesters
    Chemical Engineering Journal, 2017
    Co-Authors: Wen Yi Yuan, Xinhua Wang, Zhichao Wu, Xuedong Zhang
    Abstract:

    Abstract Three identical pilot-scale flat-sheet membrane-coupled aerobic digesters for simultaneous Sludge Thickening and reduction (MSTR) were performed in parallel under a hydraulic retention time (HRT) of 14.6 h for 15 days. In the first 8 days, the stepwise destruction of waste activated Sludge (WAS) flocs, i.e., dispersion from the outer to inner part, was observed likely due to the variation of dissolved oxygen concentration (Step 1: from 7.0 to 2.5 mg/L, Step 2: from 2.5 to 0.5 mg/L). During the process, the concentration of extracellular polymeric substances (EPS) first decreased from about 170.0 to 140.8 mg/g volatile suspended solids (VSS), then from 140.8 to 67.7 mg/g VSS, resulting in the much higher concentration of soluble organic matters and small particles (1–20 μm) in Step 2. Meanwhile, the ratio of protein like substances to humic acids in the EPS first increased from 0.5 to 0.7, then decreased from 0.7 to 0.4. After 8 days, the regroupment of Sludge fraction and successive increase in fine particle could also correspond to the slight change of EPS concentration. Moreover, the degree of humification of the supernatant could well correspond to the reduction degree of the Sludge.

  • novel insights into destruction mechanisms in a hybrid membrane process for simultaneous Sludge Thickening and digestion by characterization of dissolved organic matter
    Chemical Engineering Journal, 2011
    Co-Authors: Xinhua Wang, Xiufen Li, Zhichao Wu
    Abstract:

    Abstract Three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy and gel filtration chromatography (GFC) were employed to characterize dissolved organic matter (DOM) in a hybrid membrane process for simultaneous Sludge Thickening and digestion (MSTD). The MSTD process was operated under a sequencing batch mode, and the operating time of each cycle was 15 d from the initial fresh Sludge to the final thickened and digested Sludge. Results showed that the molecular weight (MW) distribution of DOM in Sludge supernatant became broader after the MSTD process, and three main peaks including Peak A and Peak B related to protein-like substances and Peak C associated with humic acid-like substances could be identified from the EEM fluorescence spectra of all DOM samples in the MSTD process. The quantitative analysis of the fluorescence spectra of DOM in Sludge supernatant showed that the fluorescence intensity (FI) of Peak A and Peak B in Sludge supernatant correlated well with the concentration of soluble protein, MLSS destruction efficiency and mean particle size, suggesting that the variations of EEM fluorescence spectra of DOM in Sludge supernatant could be used to evaluate the floc destruction mechanisms of the MSTD process. It was also found that the FI of Peak A slightly increased before 8 d but rapidly went up after 8 d, and the FI of Peak B changed slightly before 8 d but increased after 8 d, which implied that the floc destruction mechanisms were varied in one cycle of the MSTD process.

  • temporal variations of membrane foulants in the process of using flat sheet membrane for simultaneous Thickening and digestion of waste activated Sludge
    Bioresource Technology, 2011
    Co-Authors: Zhichao Wu, Zhiwei Wang
    Abstract:

    Abstract Membrane foulants were extracted at different operation time in simultaneous Sludge Thickening and digestion reactors using flat-sheet membranes. Temporal variations of foulants were analyzed by three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy, gel filtration chromatography (GFC), particle size distribution (PSD) and attenuated total reflection–Fourier transform infrared (ATR–FTIR) spectroscopy. Results showed that during the first 4 days fouling was mainly assigned to internal membrane foulants (IMFs), and afterwards external membrane foulants (EMFs) increased dramatically. EEM analysis showed that both IMFs and EMFs changed during the operation. Cluster analysis demonstrated that the characteristics of IMFs were relatively similar; however, both quantity and properties of EMFs were changed. GFC analysis showed that EMFs contained more molecules with large molecular weight compared to IMFs. PSD analysis illuminated that particle size of EMFs gradually increased and was larger than that of IMFs. ATR–FTIR analysis indicated that the foulants on membranes consisted of polysaccharides and proteins.

  • a hybrid membrane process for simultaneous Thickening and digestion of waste activated Sludge
    Frontiers of Environmental Science & Engineering in China, 2010
    Co-Authors: Zhiwei Wang, Zhichao Wu, Qiaoying Wang, Xinhua Wang
    Abstract:

    A hybrid membrane process for simultaneous Sludge Thickening and digestion (MSTD) was studied. During one cycle (15 d) of operation under a hydraulic retention time of 1 d, the concentration of mixed liquor suspended solids (MLSS) continuously increased from about 4 g·L−1 to 34 g·L−1, and the mixed liquor volatile suspended solids (MLVSS) increased from about 3 g·L−1 to over 22 g·L−1. About 42% of the MLVSS and 39% of the MLSS reduction were achieved. The Thickening and digestion effects in the MSTD were further analyzed based on a mass balance analysis. Test results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the process. It was also found that the capillary suction time, colloidal chemical oxygen demand, soluble microbial products, viscosity, and MLSS had significant positive correlations with the membrane fouling rate, whereas extracellular polymeric substances, polysaccharides, and proteins extracted from biomass had negative impacts on membrane fouling.

  • Simulation and assessment of Sludge concentration and rheology in the process of waste activated Sludge treatment
    Journal of Environmental Sciences, 2009
    Co-Authors: Mingfang Xia, Xinhua Wang, Zhichao Wu, Zhen Zhou, Zhiwei Wang, Jilai Lu
    Abstract:

    The process of using flat-sheet membrane for simultaneous Sludge Thickening and digestion (MSTD) was employed. The variations of Sludge concentration and rheology were characterized and simulated. Based on mass balance analysis, mathematical models were developed and successfully used to predict and evaluate the variations of Sludge concentration and the digestion eficiency in the MSTD process. The apparent viscosity of Sludge could be modeled as functions of mixed liquor suspended solids and shear rates. The Sludge in the MSTD process showed both shear-thinning and viscoplastic behaviour, and under various shear rates different rheological models could be chosen to predict their flow behaviour. It was also found that Sludge concentration and viscosity had significant correlations with membrane fouling in the MSTD process. © 2009 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Zhiwei Wang - One of the best experts on this subject based on the ideXlab platform.

  • study on the membrane fouling of the process of using two layer flat sheet membrane for Sludge Thickening and water reuse
    Applied Mechanics and Materials, 2015
    Co-Authors: Ming Yuan Zhou, Zhiwei Wang, Wen Yi Yuan, Jie Guan
    Abstract:

    In this paper, the critical flux was applied to represent the tendency of membrane fouling. The response surface model was used to study different factors, such as Sludge concentration, space between membranes and aeration rate, affecting membrane fouling of the upper and lower layer membrane module. It was found that the model is fitting and significant, moreover, the Sludge concentration, space between membranes and aeration rate has a significant impact on the upper and lower membrane fouling. Meanwhile, it was also observed that the critical flux of both upper and lower layer membrane module sharply decreased with the increase of Sludge concentration. However, the different variation tendency of membrane fouling between upper and lower layer membrane module was detected due to the change of space between membranes and aeration rate, when it was under different Sludge concentrations. Finally, optimum operating parameters under different Sludge concentration simulated by response surface model were successfully applied to the process of using flat-sheet membrane for four-stage Sludge Thickening.

  • temporal variations of membrane foulants in the process of using flat sheet membrane for simultaneous Thickening and digestion of waste activated Sludge
    Bioresource Technology, 2011
    Co-Authors: Zhichao Wu, Zhiwei Wang
    Abstract:

    Abstract Membrane foulants were extracted at different operation time in simultaneous Sludge Thickening and digestion reactors using flat-sheet membranes. Temporal variations of foulants were analyzed by three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy, gel filtration chromatography (GFC), particle size distribution (PSD) and attenuated total reflection–Fourier transform infrared (ATR–FTIR) spectroscopy. Results showed that during the first 4 days fouling was mainly assigned to internal membrane foulants (IMFs), and afterwards external membrane foulants (EMFs) increased dramatically. EEM analysis showed that both IMFs and EMFs changed during the operation. Cluster analysis demonstrated that the characteristics of IMFs were relatively similar; however, both quantity and properties of EMFs were changed. GFC analysis showed that EMFs contained more molecules with large molecular weight compared to IMFs. PSD analysis illuminated that particle size of EMFs gradually increased and was larger than that of IMFs. ATR–FTIR analysis indicated that the foulants on membranes consisted of polysaccharides and proteins.

  • a hybrid membrane process for simultaneous Thickening and digestion of waste activated Sludge
    Frontiers of Environmental Science & Engineering in China, 2010
    Co-Authors: Zhiwei Wang, Zhichao Wu, Qiaoying Wang, Xinhua Wang
    Abstract:

    A hybrid membrane process for simultaneous Sludge Thickening and digestion (MSTD) was studied. During one cycle (15 d) of operation under a hydraulic retention time of 1 d, the concentration of mixed liquor suspended solids (MLSS) continuously increased from about 4 g·L−1 to 34 g·L−1, and the mixed liquor volatile suspended solids (MLVSS) increased from about 3 g·L−1 to over 22 g·L−1. About 42% of the MLVSS and 39% of the MLSS reduction were achieved. The Thickening and digestion effects in the MSTD were further analyzed based on a mass balance analysis. Test results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the process. It was also found that the capillary suction time, colloidal chemical oxygen demand, soluble microbial products, viscosity, and MLSS had significant positive correlations with the membrane fouling rate, whereas extracellular polymeric substances, polysaccharides, and proteins extracted from biomass had negative impacts on membrane fouling.

  • Simulation and assessment of Sludge concentration and rheology in the process of waste activated Sludge treatment
    Journal of Environmental Sciences, 2009
    Co-Authors: Mingfang Xia, Xinhua Wang, Zhichao Wu, Zhen Zhou, Zhiwei Wang, Jilai Lu
    Abstract:

    The process of using flat-sheet membrane for simultaneous Sludge Thickening and digestion (MSTD) was employed. The variations of Sludge concentration and rheology were characterized and simulated. Based on mass balance analysis, mathematical models were developed and successfully used to predict and evaluate the variations of Sludge concentration and the digestion eficiency in the MSTD process. The apparent viscosity of Sludge could be modeled as functions of mixed liquor suspended solids and shear rates. The Sludge in the MSTD process showed both shear-thinning and viscoplastic behaviour, and under various shear rates different rheological models could be chosen to predict their flow behaviour. It was also found that Sludge concentration and viscosity had significant correlations with membrane fouling in the MSTD process. © 2009 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

  • application of flat sheet membrane to Thickening and digestion of waste activated Sludge was
    Journal of Hazardous Materials, 2008
    Co-Authors: Zhiwei Wang, Xinhua Wang, Zhichao Wu, Xingzhi Du
    Abstract:

    Abstract The feasibility of using flat-sheet membrane for waste activated Sludge (WAS) Thickening and digestion was studied in this paper. The characteristics of the processes including the Thickening efficiency, effluent water quality and filtration properties of the membrane for Sludge Thickening process (MST), digestion efficiency, effluent water quality and membrane permeability of the membrane for Sludge simultaneous Thickening and digestion process (MSTD) were investigated. Test results showed that good Sludge Thickening efficiency and superior effluent water quality were obtained in the MST process under hydraulic retention time (HRT) 0.26 and 2 d operation of each cycle, and the membrane fouling was mainly due to the increase of apparent viscosity of mixed liquors and the decrease of the cross-flow velocity (CFV) along membrane surfaces during one Thickening cycle. Membranes were also selected for the processes and M1 membrane of polyvinylidene fluoride (PVDF) material with pore size 0.2 μm demonstrated better permeability compared with other three membranes. About 80% MLSS destruction rate and 73% MLVSS destruction rate were achieved under HRT 1 d, dissolved oxygen (DO) concentration 0.5–1.5 mg/L, temperature 20–28 °C and 15 d operation for one cycle in MSTD process, and membrane fouling of MSTD process was attributed to not only the reason of MST process mentioned above, but also the change of Sludge properties such as the increase of soluble COD and microbial polymeric substances including EPS, carbohydrate and nucleic acids, etc. of the mixed liquors.

Xinhua Wang - One of the best experts on this subject based on the ideXlab platform.

  • new insight into Sludge digestion mechanism for simultaneous Sludge Thickening and reduction using flat sheet membrane coupled aerobic digesters
    Chemical Engineering Journal, 2017
    Co-Authors: Wen Yi Yuan, Xinhua Wang, Zhichao Wu, Xuedong Zhang
    Abstract:

    Abstract Three identical pilot-scale flat-sheet membrane-coupled aerobic digesters for simultaneous Sludge Thickening and reduction (MSTR) were performed in parallel under a hydraulic retention time (HRT) of 14.6 h for 15 days. In the first 8 days, the stepwise destruction of waste activated Sludge (WAS) flocs, i.e., dispersion from the outer to inner part, was observed likely due to the variation of dissolved oxygen concentration (Step 1: from 7.0 to 2.5 mg/L, Step 2: from 2.5 to 0.5 mg/L). During the process, the concentration of extracellular polymeric substances (EPS) first decreased from about 170.0 to 140.8 mg/g volatile suspended solids (VSS), then from 140.8 to 67.7 mg/g VSS, resulting in the much higher concentration of soluble organic matters and small particles (1–20 μm) in Step 2. Meanwhile, the ratio of protein like substances to humic acids in the EPS first increased from 0.5 to 0.7, then decreased from 0.7 to 0.4. After 8 days, the regroupment of Sludge fraction and successive increase in fine particle could also correspond to the slight change of EPS concentration. Moreover, the degree of humification of the supernatant could well correspond to the reduction degree of the Sludge.

  • novel insights into destruction mechanisms in a hybrid membrane process for simultaneous Sludge Thickening and digestion by characterization of dissolved organic matter
    Chemical Engineering Journal, 2011
    Co-Authors: Xinhua Wang, Xiufen Li, Zhichao Wu
    Abstract:

    Abstract Three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy and gel filtration chromatography (GFC) were employed to characterize dissolved organic matter (DOM) in a hybrid membrane process for simultaneous Sludge Thickening and digestion (MSTD). The MSTD process was operated under a sequencing batch mode, and the operating time of each cycle was 15 d from the initial fresh Sludge to the final thickened and digested Sludge. Results showed that the molecular weight (MW) distribution of DOM in Sludge supernatant became broader after the MSTD process, and three main peaks including Peak A and Peak B related to protein-like substances and Peak C associated with humic acid-like substances could be identified from the EEM fluorescence spectra of all DOM samples in the MSTD process. The quantitative analysis of the fluorescence spectra of DOM in Sludge supernatant showed that the fluorescence intensity (FI) of Peak A and Peak B in Sludge supernatant correlated well with the concentration of soluble protein, MLSS destruction efficiency and mean particle size, suggesting that the variations of EEM fluorescence spectra of DOM in Sludge supernatant could be used to evaluate the floc destruction mechanisms of the MSTD process. It was also found that the FI of Peak A slightly increased before 8 d but rapidly went up after 8 d, and the FI of Peak B changed slightly before 8 d but increased after 8 d, which implied that the floc destruction mechanisms were varied in one cycle of the MSTD process.

  • a hybrid membrane process for simultaneous Thickening and digestion of waste activated Sludge
    Frontiers of Environmental Science & Engineering in China, 2010
    Co-Authors: Zhiwei Wang, Zhichao Wu, Qiaoying Wang, Xinhua Wang
    Abstract:

    A hybrid membrane process for simultaneous Sludge Thickening and digestion (MSTD) was studied. During one cycle (15 d) of operation under a hydraulic retention time of 1 d, the concentration of mixed liquor suspended solids (MLSS) continuously increased from about 4 g·L−1 to 34 g·L−1, and the mixed liquor volatile suspended solids (MLVSS) increased from about 3 g·L−1 to over 22 g·L−1. About 42% of the MLVSS and 39% of the MLSS reduction were achieved. The Thickening and digestion effects in the MSTD were further analyzed based on a mass balance analysis. Test results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the process. It was also found that the capillary suction time, colloidal chemical oxygen demand, soluble microbial products, viscosity, and MLSS had significant positive correlations with the membrane fouling rate, whereas extracellular polymeric substances, polysaccharides, and proteins extracted from biomass had negative impacts on membrane fouling.

  • Simulation and assessment of Sludge concentration and rheology in the process of waste activated Sludge treatment
    Journal of Environmental Sciences, 2009
    Co-Authors: Mingfang Xia, Xinhua Wang, Zhichao Wu, Zhen Zhou, Zhiwei Wang, Jilai Lu
    Abstract:

    The process of using flat-sheet membrane for simultaneous Sludge Thickening and digestion (MSTD) was employed. The variations of Sludge concentration and rheology were characterized and simulated. Based on mass balance analysis, mathematical models were developed and successfully used to predict and evaluate the variations of Sludge concentration and the digestion eficiency in the MSTD process. The apparent viscosity of Sludge could be modeled as functions of mixed liquor suspended solids and shear rates. The Sludge in the MSTD process showed both shear-thinning and viscoplastic behaviour, and under various shear rates different rheological models could be chosen to predict their flow behaviour. It was also found that Sludge concentration and viscosity had significant correlations with membrane fouling in the MSTD process. © 2009 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

  • application of flat sheet membrane to Thickening and digestion of waste activated Sludge was
    Journal of Hazardous Materials, 2008
    Co-Authors: Zhiwei Wang, Xinhua Wang, Zhichao Wu, Xingzhi Du
    Abstract:

    Abstract The feasibility of using flat-sheet membrane for waste activated Sludge (WAS) Thickening and digestion was studied in this paper. The characteristics of the processes including the Thickening efficiency, effluent water quality and filtration properties of the membrane for Sludge Thickening process (MST), digestion efficiency, effluent water quality and membrane permeability of the membrane for Sludge simultaneous Thickening and digestion process (MSTD) were investigated. Test results showed that good Sludge Thickening efficiency and superior effluent water quality were obtained in the MST process under hydraulic retention time (HRT) 0.26 and 2 d operation of each cycle, and the membrane fouling was mainly due to the increase of apparent viscosity of mixed liquors and the decrease of the cross-flow velocity (CFV) along membrane surfaces during one Thickening cycle. Membranes were also selected for the processes and M1 membrane of polyvinylidene fluoride (PVDF) material with pore size 0.2 μm demonstrated better permeability compared with other three membranes. About 80% MLSS destruction rate and 73% MLVSS destruction rate were achieved under HRT 1 d, dissolved oxygen (DO) concentration 0.5–1.5 mg/L, temperature 20–28 °C and 15 d operation for one cycle in MSTD process, and membrane fouling of MSTD process was attributed to not only the reason of MST process mentioned above, but also the change of Sludge properties such as the increase of soluble COD and microbial polymeric substances including EPS, carbohydrate and nucleic acids, etc. of the mixed liquors.

Taihak Chung - One of the best experts on this subject based on the ideXlab platform.

  • performance of the Sludge Thickening and reduction at various factors in a pilot scale mbr
    Separation and Purification Technology, 2013
    Co-Authors: Taihak Chung
    Abstract:

    Abstract In this study, the performance of a Sludge Thickening and reduction system coupled with filtration using a flat-sheet membrane was investigated. The effects of various factors such as HRT, flux and addition of coagulant were determined. TMP was observed to increase as the HRT decreases and the operating flux increases. The operating condition was then determined and the selected HRT and flux were 6.7 days and 10.7 L/m 2  h, respectively. Different operating HRT indicated the variation of hydraulic loading rates for the organics and other nutrients affecting membrane fouling, while varying the flux showed the rate of decrease of the membrane permeability. When coagulant was added, the rate of increase of TMP was decreased, allowing the system to be operated for a longer period of time. It was observed that inorganic coagulant was more effective than organic coagulant based on the final TMP. It also suggests that membrane fouling was better minimized with the addition of inorganic coagulant. It was found that the most essential factor on membrane fouling was the addition of coagulant, while the effect of HRT was observed to be the least influential among the other factors considered.

  • enhancing filterability of flat sheet membrane by addition of cationic polymer for Sludge Thickening system
    Desalination and Water Treatment, 2010
    Co-Authors: Ramon Christian Eusebio, Taihak Chung
    Abstract:

    The efficiency of coagulation-coupled membrane filtration as an alternative process for Sludge Thickening was evaluated using various parameters that could influence the thickened Sludge, such as mixed liquor suspended solids (MLSS) concentration, viscosity, critical flux and soluble microbial products. Dead-end filtration experiment and determination of critical flux were conducted to investigate the change in permeation across the membrane after addition of coagulant. PVDF flat-sheet membrane with 0.08 mm pore size was used in the experiment. Two separate submerged systems were run in parallel, one with coagulant and the other served as the control. A significant difference between the transmembrane pressures (TMPs) of the two systems was observed. It was found that an increase in soluble microbial products (SMPs) concentration decreases filtration flux, which in turn increases TMP. PSD analysis confirmed that larger flocs were formed after addition of coagulant. Confocal laser scanning microscopy (CLSM...

  • dynamic process response to Sludge Thickening behaviors in the anaerobic sequencing batch reactor treating high solids content waste
    Journal of Bioscience and Bioengineering, 1999
    Co-Authors: Duk Chang, Taihak Chung
    Abstract:

    Solid-liquid separation and its type greatly affected the stability and performance of the anaerobic sequencing batch reactor (ASBR) for municipal Sludge digestion. Flotation Thickening occurred in mesophilic ASBR, while solid-liquid separation in thermophilic ASBR followed a gravity Thickening. The hydraulic retention time (HRT) and cycle period as well as the type of Thickening were key parameters governing Sludge thickenability and critical solids accumulation. Thickened Sludge volume was a critical operating variable in the ASBR with the gravity Thickening, which had a poor performance because of the loss of thickened solids, and Sludge interface disruption or instability of Sludge bed due to internal gas evolution. A cyclic mutual effect between thickened volume and gas production was a serious in the gravity Thickening, whereas it was insignificant in the flotation Thickening.

  • Significance of pressure and recirculation in Sludge Thickening by dissolved air flotation
    Water Science and Technology, 1997
    Co-Authors: Taihak Chung
    Abstract:

    An experimental study was conducted to identify the effect of each operating variable on the liquid-solids separation efficiency using a bench scale batch flotation system and waste activated Sludge. Interpretation of the experimental results was performed by use of the characteristic constants of an empirical equation proposed. Minimum A/S ratio for reliable operation of dissolved air flotation should be greater than 0.009. However, unstable Sludge rising took place at the initial clarification stage due to excessive shear and turbulence when the pressure was high in spite of high A/S ratio. The efficiency increased as the A/S ratio increased except a case of high pressure coupled with high A/S ratio. High recirculation flow with a saturator pressure less than 5 atm is recommended for stable and efficient operation. The pore size of a diffuser did not affect the Thickening efficiency significantly. Concentration gradient of the float solids became larger as flotation continued. Skimming of a top layer or a long skimming interval is desirable for high Thickening efficiency.

N. Tambo - One of the best experts on this subject based on the ideXlab platform.

  • Pilot study of a fluidized-pellet-bed technique for simultaneous solid/liquid separation and Sludge Thickening in a sewage treatment plant
    Water Science and Technology, 2004
    Co-Authors: Xiaochang Wang, H. L. Yuan, E. R. Wang, N. Tambo
    Abstract:

    A fluidized-pellet-bed separator with movable Sludge hoppers was applied in pilot scale for the separation and Thickening of activated Sludge mixture liquid. Under the condition of suspension SS around 4,000 mg/L, polymer (CJX103, cationic, MW 5 × 10 6 ) dose at a dry solid ratio of 0.003 and upward flow rate at 5.4 m/hr, the fluidized pellet bed performed solid/liquid separation and Sludge Thickening well. The SS concentration of the treated water was about 5 mg/L on average and the moisture content of the Sludge after screening for 5 min was less than 94%, which is much lower than that after conventional settling and Thickening and easy to be finally disposed. At a higher upward flow rate of 7.2 m/hr, similar results could also be obtained but higher polymer dose (solid ratio of 0.004) was required. The morphological characteristics and density-size relationship of the granular particles formed in the fluidized pellet bed were also investigated by image analysis and settling velocity measurement of individual particles. The two-dimensional fractal dimension was evaluated to be 1.6-1.8, showing a good quasi-spherical morphology of the granular particles with their density much higher than the conventional flocs. The results of the pilot study indicate a possible way to innovate the conventional secondary settling and gravitational Thickening processes for solid/liquid separation and Sludge handling, especially for small scale wastewater treatment plants to reach the goal of space saving and higher treatment efficiency. Keywords Activated Sludge; fluidized pellet bed; organic polymer; solid/liquid separation; Thickening

  • pilot study of a fluidized pellet bed technique for simultaneous solid liquid separation and Sludge Thickening in a sewage treatment plant
    Water Science and Technology, 2004
    Co-Authors: Xiaochang Wang, H. L. Yuan, E. R. Wang, N. Tambo
    Abstract:

    A fluidized-pellet-bed separator with movable Sludge hoppers was applied in pilot scale for the separation and Thickening of activated Sludge mixture liquid. Under the condition of suspension SS around 4,000 mg/L, polymer (CJX103, cationic, MW 5 × 10 6 ) dose at a dry solid ratio of 0.003 and upward flow rate at 5.4 m/hr, the fluidized pellet bed performed solid/liquid separation and Sludge Thickening well. The SS concentration of the treated water was about 5 mg/L on average and the moisture content of the Sludge after screening for 5 min was less than 94%, which is much lower than that after conventional settling and Thickening and easy to be finally disposed. At a higher upward flow rate of 7.2 m/hr, similar results could also be obtained but higher polymer dose (solid ratio of 0.004) was required. The morphological characteristics and density-size relationship of the granular particles formed in the fluidized pellet bed were also investigated by image analysis and settling velocity measurement of individual particles. The two-dimensional fractal dimension was evaluated to be 1.6-1.8, showing a good quasi-spherical morphology of the granular particles with their density much higher than the conventional flocs. The results of the pilot study indicate a possible way to innovate the conventional secondary settling and gravitational Thickening processes for solid/liquid separation and Sludge handling, especially for small scale wastewater treatment plants to reach the goal of space saving and higher treatment efficiency. Keywords Activated Sludge; fluidized pellet bed; organic polymer; solid/liquid separation; Thickening

  • Pilot study of a fluidized-pellet-bed technique for simultaneous solid/liquid separation and Sludge Thickening in a sewage treatment plant
    Water Science and Technology, 2004
    Co-Authors: X.c. Wang, P. K. Jin, H. L. Yuan, E. R. Wang, N. Tambo
    Abstract:

    A fluidized-pellet-bed separator with movable Sludge hoppers was applied in pilot scale for the separation and Thickening of activated Sludge mixture liquid. Under the condition of suspension SS around 4,000 mg/L, polymer (CJX103, cationic, MW 5 x 10(6)) dose at a dry solid ratio of 0.003 and upward flow rate at 5.4 m/hr, the fluidized pellet bed performed solid/liquid separation and Sludge Thickening well. The SS concentration of the treated water was about 5 mg/L on average and the moisture content of the Sludge after screening for 5 min was less than 94%, which is much lower than that after conventional settling and Thickening and easy to be finally disposed. At a higher upward flow rate of 7.2 m/hr, similar results could also be obtained but higher polymer dose (solid ratio of 0.004) was required. The morphological characteristics and density-size relationship of the granular particles formed in the fluidized pellet bed were also investigated by image analysis and settling velocity measurement of individual particles. The two-dimensional fractal dimension was evaluated to be 1.6-1.8, showing a good quasi-spherical morphology of the granular particles with their density much higher than the conventional flocs. The results of the pilot study indicate a possible way to innovate the conventional secondary settling and gravitational Thickening processes for solid/liquid separation and Sludge handling, especially for small scale wastewater treatment plants to reach the goal of space saving and higher treatment efficiency.