Inclined plates (50°–60°) that shorten the settling distance of particles.
) : The total area available for particles to settle is calculated by multiplying the number of plates ( ) by the horizontal projection of each plate. : is plate length, is width, and is the inclination angle (typically 55∘55 raised to the composed with power 60∘60 raised to the composed with power
Only the horizontal projection of the inclined plates contributes to the settling area. The calculation for a single plate is:
In modern wastewater treatment, the (or inclined plate settler) is a cornerstone technology. Its primary appeal lies in its footprint; by using a series of inclined plates, it provides a massive settling area within a fraction of the space required by conventional circular clarifiers.
Removable individual plates are preferred to allow for cleaning while the unit remains operational. Lamella Clarifier Design Calculations | PDF - Scribd
( Re = \fracv \cdot d_h\nu ) ( d_h ) = hydraulic diameter ≈ ( 2 \times ) spacing (for parallel plates) Requirement: Re < 500 (laminar)
For detailed step-by-step calculations and templates, you can access these resources:
The core of lamella design is calculating the effective settling area, ensuring that the critical velocity is low enough for particles to settle within the plates. 2.1. Critical Velocity (
Rh=p⋅W2(p+W)≈p2 (when W≫p)cap R sub h equals the fraction with numerator p center dot cap W and denominator 2 open paren p plus cap W close paren end-fraction is approximately equal to p over 2 end-fraction (when cap W is much greater than p ) The velocity of the fluid parallel to the plates (
Collects settled solids at the bottom. The distance between the bottom of the plates and the sludge hopper must be sufficient to prevent re-entrainment.
This design yields a theoretical settling area of 189 m² within a very compact basin footprint.
Divide the total required effective area by the effective area of a single plate.
