Lamella Clarifier & Inclined Plate Settler Calculator

Q: How do lamella inclined plates reduce clarifier footprint?

Per Hazen sedimentation theory, clarification depends on surface settling area, not tank depth. By stacking closely spaced plates inclined at 55° to 60°, the projected horizontal area of each plate is added together. This allows a lamella clarifier to occupy 75% to 90% less land footprint than a conventional circular clarifier.

Q: Why is a 60-degree angle standard for lamella clarifiers?

An angle of 60 degrees provides the ideal balance between projected horizontal settling area (cos 60° = 0.5) and gravity self-cleaning. At 60°, settled sludge easily slides down the plate surface into the bottom hopper without clogging or requiring mechanical scrapers.

Q: What is the significance of the channel Reynolds number (Re)?

A low Reynolds number (strictly Re < 500, ideally Re < 250) confirms laminar flow between adjacent plates. Laminar flow prevents eddies and turbulence that would otherwise re-suspend settled floc and degrade effluent clarity.

Calculate total effective horizontal settling area, footprint space reduction percentage, plate pack hydraulic loading, and Reynolds flow stability for lamella plate clarifiers.

Influent Flow & Settling Velocity

Design Feed Flow Q (GPM):

Target Overflow Rate (GPM/ft²): Coagulated solids: 0.20 - 0.40

Plate Inclination Angle θ (degrees):

Plate Geometry & Pack Construction

Plate Length Lp (ft):

Plate Width Wp (ft):

Perpendicular Spacing w (inches): Standard: 2.0" (50 mm)

Flow Distribution Derate (η): Typical: 0.80 - 0.90

Plate Sizing & Clarifier Savings

Required Number of Lamella Plates

-- Plates

-- sq ft effective projected area

Basin Footprint Area

-- sq ft

vs -- sq ft conventional

Footprint Space Savings

--%

Area reduction factor

Effective Surface Overflow Rate: -- GPM/ft² (-- m/h)

Lamella Pack Dimensions: -- ft L x -- ft W x -- ft H

Channel Flow Velocity: -- ft/min

Channel Reynolds Number (Re): -- (Laminar < 500)

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Frequently Asked Questions

How do lamella inclined plates reduce clarifier footprint?

Per Hazen sedimentation theory, clarification depends on surface settling area, not tank depth. By stacking closely spaced plates inclined at 55° to 60°, the projected horizontal area of each plate is added together. This allows a lamella clarifier to occupy 75% to 90% less land footprint than a conventional circular clarifier.

Why is a 60-degree angle standard for lamella clarifiers?

An angle of 60 degrees provides the ideal balance between projected horizontal settling area (cos 60° = 0.5) and gravity self-cleaning. At 60°, settled sludge easily slides down the plate surface into the bottom hopper without clogging or requiring mechanical scrapers.

What is the significance of the channel Reynolds number (Re)?

A low Reynolds number (strictly Re < 500, ideally Re < 250) confirms laminar flow between adjacent plates. Laminar flow prevents eddies and turbulence that would otherwise re-suspend settled floc and degrade effluent clarity.