Numerical simulation of mechanical flocculation in water treatment

Zhan, Minshu; You, Minghao; Liu, Lingling; Zhang, Yilin; Fang, Yuan; Guo, Bin; Cheng, Guojian; Xu, Wei

doi:10.1016/j.jece.2021.105536

Cited by 23 publications

(9 citation statements)

References 27 publications

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“…The flocs are separated by the solid-liquid separation process as filtration or sedimentation to decrease turbidity and color using flocculation chemicals. Meanwhile, the phosphorous or organic matters adsorbed by the flocs are removed (Zhan et al 2021).…”

Section: Analysis Of Purification Bathing Wastewater Mechanism In Dsl...mentioning

confidence: 99%

Purification of bathing wastewater by double suspended layer fluidized bed reactor

Ban

2022

Water Science and Technology

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An external radial magnetic field and built-in stainless steel balls formed a magnetic suspended layer (MSL), as observed in this study. Under the condition of crossflow inflow, the flocculating agent and coagulant aids form a flocculated particles suspension layer (FPSL). Thus a double suspended fluidized bed reactor was constructed to treat bathing wastewater. Using a Particle image velocimetry device to detect flow patterns, analyze the flocculation conditions. The results showed that under the condition of crossflow inflow, at the same time,the flooding water was 0.023–2.101 m3/h, and the dosage of poly aluminum chloride (PAC) and Polyacrylic Amide (PAM) was 90 mg/L and 1.5 mg/L, respectively, removed rates of Turbidity, Chemical Oxygen Demand (CODCr) and linear alkylbenzene sulphonates (LAS) reached more than 99, 90,and 80%. Filtration, grid flocculation and particle interception were functions of the MSL. Meanwhile, the crossflow input created additional vortexes, increasing the likelihood of flocculation particle collision, improving the flocculation condition, and cleaning the MSL. The reactor aids in the development of the initial flocculated particles suspension layer, flocculation strengthening, chemical dosage reducting, effluent qualities improvement, and effluent stability maintenance.

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Section: Analysis Of Purification Bathing Wastewater Mechanism In Dsl...mentioning

confidence: 99%

Purification of bathing wastewater by double suspended layer fluidized bed reactor

Ban

2022

Water Science and Technology

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“…The dissolved substances such as metal ions interact with polyelectrolytes that clump together forming flocs that can be separated by sedimentation or filtration processes . This process not only decreases turbidity and color but also helps improve water quality and reduce membrane fouling . The flocculation process is fast, straightforward, and cost-effective .…”

Section: Introductionmentioning

confidence: 99%

“…1 This process not only decreases turbidity and color but also helps improve water quality and reduce membrane fouling. 15 The flocculation process is fast, straightforward, and cost-effective. 4 The flocculant used in this study, C8030, is a water-soluble cationic polyacrylamide (PAM) with a high molecular weight (8−10 million g mol −1 ).…”

Section: Introductionmentioning

confidence: 99%

Integrating Ultrafiltration Membranes with Flocculation and Activated Carbon Pretreatment Processes for Membrane Fouling Mitigation and Metal Ion Removal from Wastewater

Matebese

Moutloali

2023

ACS Omega

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The presence of metal ions in an aqueous medium is an ongoing challenge throughout the world. Processes employed for metal ion removal are developed continuously with the integration of these processes taking center stage. Herein, an integrated system consisting of flocculation, activated carbon (AC), and an ultrafiltration (UF) membrane was assessed for the removal of multiple metal ions contained in wastewater generated from a university chemistry research laboratory. The quality of the wastewater was established before and further determined after treatment with inductively coupled plasma optical emission spectrometry (ICP-OES) for metal content, total dissolved solids (TDS), turbidity, electrical conductivity (EC), and pH. Assessing the spent AC indicated minimal structural changes, indicating a potential for further reuse; for instance, the BET for both the pristine and spent AC exhibited type I isotherms with a mesoporous structure, indicating no major structural changes due to metal complexation. The relative performance of the integrated system indicated that the use of flocculation improved the water quality of metal-laden wastewater for safe disposal. The integrated treatment systems exhibited high removal efficiencies between 80 and 99.99% for all the metal ions except for Mn (<0.008 mg L–1) and Cr (<0.016 mg L–1) both at ca. 70%, indicative of the positive influence of the polyelectrolyte in the treatment process. The fabricated UiO-66-NH2@GO membranes (Z4 and Z5) exhibited high fouling resistance and reusability potential as well as relatively high pure water flux. Consequently, the integrated process employed for the treatment of laboratory metal-containing wastewater is promising as a generic approach to improving the quality of metal-containing wastewater to meet the standards of discharging limits in South Africa.

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“…Floc characteristics in flocculation and sedimentation are limited by the small scale of flocculators (Saxena et al 2020;Sun et al 2020). However, flask conditions differ from those in actual water utilities (Zhan et al 2021). There are few concerns on the effect of hydrodynamic conditions on the evolution of floc characteristics in a continuous flocculation and sedimentation process.…”

Section: Introductionmentioning

confidence: 99%

Effect of hydrodynamic breakage on floc evolution and turbidity reduction in flocculation and sedimentation processes

et al. 2021

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Coagulation and sedimentation process is one of the most popular processes in drinking water treatment. Hydrodynamic breakage has a significant impact on the evolution of floc characteristic and the efficiency of turbidity removal. In this work, the effects of hydrodynamic breakage on floc size, fractal dimension, and floc morphology were investigated with an in-situ recognition system. The experiments were conducted in a continuous flocculation and sedimentation reactor equipped with perforated plates to provide different hydrodynamic breakage conditions. The experimental results indicated that the hydrodynamic conditions significantly influenced the floc destabilization and restructuring processes. A low hydrodynamic shear forces provided by P1 led to the increase of both bigger sized flocs but accompanied with small particles (0–10 μm). Excessive velocity gradient provided by P3 produced smaller and looser flocs. An appropriate velocity gradient (i.e., the flow velocity through the perforated plate P2 at 18.9 × 10−3m s−1) was conducive for the formation of larger and more compact structures, with higher average floc size and fractal dimension. This flocculation condition in turn resulted in effective improvements in the turbidity removal efficiency. Floc evolution models were described based on the mechanism of the breakage and restructuring process.

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Numerical simulation of mechanical flocculation in water treatment

Cited by 23 publications

References 27 publications

Purification of bathing wastewater by double suspended layer fluidized bed reactor

Purification of bathing wastewater by double suspended layer fluidized bed reactor

Integrating Ultrafiltration Membranes with Flocculation and Activated Carbon Pretreatment Processes for Membrane Fouling Mitigation and Metal Ion Removal from Wastewater

Effect of hydrodynamic breakage on floc evolution and turbidity reduction in flocculation and sedimentation processes

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