Lamella Clarifier
Inclined plate settler technology for high-rate, compact clarification — achieving the settling performance of a much larger conventional clarifier within a fraction of the footprint
Overview
What is Lamella Clarifier?
A lamella clarifier (also known as an inclined plate settler or tube settler) uses arrays of closely spaced inclined plates or tubes to dramatically increase the effective settling surface area within a compact vessel. By inclining the settling surfaces at 45 to 60 degrees to the horizontal, the vertical settling distance for particles is reduced to the perpendicular distance between adjacent plates — typically just 50–100 mm — while the tank itself may only be 1–2 metres deep. The result is a clarification capacity many times greater than a conventional open clarifier of equivalent plan area.
The fundamental principle is the same as conventional gravity sedimentation: particles denser than water settle downward under gravity. However, in a lamella clarifier, the short distance to the nearest settling surface means particles reach that surface and are removed from the water column very quickly, regardless of their settling velocity. Particles slide down the inclined plate surface under gravity into the sludge collection hopper below the plate pack, while clarified water rises between the plates and overflows at the top.
Lamella clarifiers are available in fully fabricated metallic (steel or stainless steel) designs for smaller capacities, and in larger civil tank configurations with FRP (fibre-reinforced plastic) plate pack internals for major municipal or industrial installations. A mechanical sludge scraper or suction header at the hopper bottom removes accumulated sludge continuously or on a timed cycle.
Process
How a Lamella Clarifier Works
Influent Entry & Flow Distribution
Wastewater enters the clarifier below the inclined plate pack through an inlet distribution system or baffle that spreads flow uniformly across the full width and depth of the plate array, preventing channelling or short-circuit flow paths.
Upward Flow Through Inclined Plates
Wastewater flows upward through the channels between the inclined plates. The flow velocity in each channel is maintained low enough that particles can settle faster than the upward water velocity — enabling particle capture even at high overall tank flow rates.
Particle Settling to Plate Surface
Suspended particles settle across the short perpendicular distance between adjacent plates, quickly reaching the lower plate surface. Once on the plate surface, gravity pulls them downward along the incline toward the sludge collection zone.
Sludge Slide-Down & Collection
Settled solids slide down the inclined plate surfaces under gravity and accumulate in the hopper or sludge blanket below the plate pack. A scraper mechanism, suction headers, or periodic hydraulic flushing removes settled sludge to a sludge pump for dewatering or disposal.
Clarified Water Overflow
Clarified water, freed of its suspended particle load as it passes through the plate pack, rises above the plate pack and overflows a collection launder or weir at the top of the tank. The overflow is collected and directed to the next treatment stage.
Benefits
Key Advantages
- Compact footprint: equivalent settling capacity to a conventional clarifier at 3–5 times smaller plan area
- High hydraulic loading rates — suitable for upgrading existing plants without expanding civil structures
- Fast solids removal: short settling distances ensure rapid particle capture even for fine particles
- Available in steel/stainless steel fabricated units for smaller capacities and FRP plate packs for large civil installations
- Suitable for retrofitting inside existing clarifier tanks to increase capacity without demolition
- Low construction cost per unit of settling area compared to conventional circular clarifiers
- Simple operation with minimal moving parts in the separation zone
- Effective for both primary and post-biological secondary clarification
- Handles a wide range of suspended solids concentrations and particle types
- Compatible with upstream coagulation/flocculation for chemical precipitation applications
Applications
Industries & Use Cases
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