Journal ArticleDOI
Parameters affecting steady-state floc blanket performance
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TLDR
In this paper, a laboratory-scale reactor was used to simulate a water treatment process sequence of rapid mix, hydraulic flocculation, upflow clarification with a floc blanket, and lamellar sedimentation to accomplish removal of colloidal particles.Abstract:
A laboratory-scale reactor was used to simulate a water treatment process sequence of rapid mix, hydraulic flocculation, upflow clarification with a floc blanket, and lamellar sedimentation to accomplish removal of colloidal particles. This study focused on variables affecting performance of the floc blanket including: provision of hydraulic flocculation, raw water turbidity, coagulant dose, upflow velocity through the floc blanket, and bulk density and solids concentrations of the floc blanket. An upflow clarifier velocity between 1.0 and 1.3 mm s -1 produced the best floc blanket performance for turbidities studied between 10 and 200 NTU while an upflow velocity between 0.6 and 0.8 mm s -1 produced the best floc blanket performance at 500 NTU. The results show that overall particle removal efficiency improved with increasing hydraulic flocculator residence time and energy dissipation rate. Particle removal efficiency improved with increasing floc blanket depth for floc blanket depths between 15 and 75 cm. Lamellar sedimentation with a capture velocity of 0.12 mm s -1 is a key component in improving clarifier performance when utilizing a floc blanket.read more
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Journal ArticleDOI
Flocculation model and collision potential for reactors with flows characterized by high Peclet numbers.
TL;DR: A mechanistically-based model is developed to characterize flocculation in the context of flow regimes with high Peclet numbers such as would occur in serpentine flow reactors, which is shown to be a better predictor of flocculator performance than the conventional product of θ and the velocity gradient.
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Floc Roll-Up and Its Implications for the Spacing of Inclined Settling Devices
Michael J. Adelman,Matthew W. Hurst,Monroe L. Weber-Shirk,Tanya S. Cabrito,Cosme Somogyi,Leonard W. Lion +5 more
TL;DR: In this article, the authors show that the fluid velocity gradient at the tube or plate surface is the limiting constraint for spacing, and for very small spacing, particles that settle on the solid surface are carried up the incline.
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Revisiting Hydraulic Flocculator Design for Use in Water Treatment Systems with Fluidized Floc Beds
TL;DR: In this article, laminar flow flocculculators varying in velocity gradient (G) and residence time (θ) were tested in a laboratory scale water treatment system with a floc blanket.
Journal ArticleDOI
Apparatus for Observation and Analysis of Floc Blanket Formation and Performance
TL;DR: In this paper, a 1.3 cm-thick section of a floc blanket was constructed under simulated raw water conditions of 100 nephelometric turbidity units (NTU), an alum coagulant dose of 45 mg/L (4.1 µm/L as Al), and at sedimentation tank upflow velocities ranging from 0.4 to 1.8 µmm/s.
Journal ArticleDOI
Influence of alum coagulant dose and influent turbidity on floc blanket growth rate, steady-state suspended solids concentration, and turbidity removal.
TL;DR: In this paper, floc blankets were formed in the laboratory at an upflow velocity of 1.2m/s and at varying alum coagulant dosages with influent turbidities of 10 nephelometric turbidity units (NTU), 100 NTU, and 500 NTU.