How a Lamella Clarifier Works: A Step-by-Step Guide

Water pumped from an excavation, or runoff from exposed soil, often carries silt and other suspended solids. A lamella clarifier removes them using gravity and a stack of inclined plates, so the water leaving the site is cleaner. This guide walks through how it works.

What is a lamella clarifier?

A lamella clarifier is a gravity-based unit that removes suspended solids and settleable matter from water. Effective gravity separation requires the largest possible settling area and optimal hydraulic flow. Holland Pump's lamella clarifiers use lamella plate technology to keep ideal settlement conditions inside each unit, so particles settle well in a minimum footprint.

How it works, step by step

Inlet flow passes through a feed channel to the base of the plates, then is distributed diagonally upwards, in parallel to the lamella plates. Particles settle on the plates and are retained in the sludge storage area of the unit, while treated water discharges by gravity.

1. Water is pumped into the clarifier.

2. A stilling chamber directs the flow downwards.

3. Flow is distributed between the plates.

4. Solids travel down the plates as water moves upwards.

5. The outlet design maintains flow even if the unit is not level.

6. Sludge is stored in the hopper.

Operating notes: Make sure treated water does not scour the ground at the point of exit.

Emptying the sludge hopper

The sludge hopper can be emptied through drain ports and valves, for example by vacuum truck, or by manual or mechanical means. Hopper-bottomed units can be fitted, on request, with an automatic sludge removal system, which makes operation virtually maintenance-free. The plates are easy to clean, with no blockages and no backwashing required.

What a lamella clarifier can and can't do on its own

Gravel, sand, and silt settle by gravity, so a lamella clarifier is the most efficient way to remove them. Clay particles are too fine to settle under gravity alone, even in a lamella clarifier at normal flow rates. Water containing clay needs chemical pre-treatment first: a coagulant, then a flocculant.

Where lamella clarifiers are used

Typical applications include:

• Surface water runoff

• Groundwater treatment

• Excavation dewatering

• Drilling and mining

The units are skid-mounted, compact and modular, so they suit sites with limited access, restricted space and temporary projects. They can run singly or in parallel, and can be supplied as a complete packaged solution with lids, covers, walkways, flow meters, chemical dosing, sludge pumps and sludge storage.

Choosing a unit

Holland Pump offers two sizes: the LC220 (220 GPM) and the LC330 (330 GPM). See specifications and options on our lamella clarifier rental page.