Lamella Clarifier Design Calculation Pdf | Downloadl Better

A lookup table for spacing based on sludge type (e.g., 50 mm for light floc, 75 mm for heavy grit). 2.5. Reynolds Number (Re) per Channel Laminar flow is mandatory. For flow between parallel plates:

[ N_plates = \frac\textWidth of clarifier tank\textPlate spacing + \textplate thickness ] lamella clarifier design calculation pdf downloadl better

Industrial plant discharges 400 m³/day of wastewater (peak hour = 30 m³/h). TSS = 200 mg/L, particle density = 1.2 g/cm³, water at 20°C. Desired effluent TSS < 50 mg/L. A lookup table for spacing based on sludge type (e

Spacing = 50 mm, plate length = 1.5 m, width = 1.0 m, angle 55°. Each plate projected area = 1.5 × 1.0 × sin(55°) = 1.23 m². Number of plates needed = 3.15 / 1.23 ≈ 2.6 → use 3 plates (4 channels). Wait – this seems too few! This reveals the problem with a too-simple PDF. Most designs use 20-100 plates. What went wrong? We forgot that the actual channel velocity must be reasonable and that Vs is only for discrete particles—flocculent settling requires a 3-5x reduction in assumed Vs. A better PDF would flag this and recommend a design Vs of 1-2 m/h for flocculent solids. For flow between parallel plates: [ N_plates =

[ V_s = \fracg (d_p)^2 (\rho_p - \rho_w)18 \mu ]

Area = Flow rate / Vs = 30 m³/h / 14.3 m/h = 2.10 m² (ideal). Add safety factor 1.5 → 3.15 m²

Where (\theta) is the inclination angle (typically 50–60° from horizontal).