Lamella clarifier

[4] Their all-steel design minimizes the chances that part of the inclined plate will chip off and be carried over into the membrane, especially compared to tube settlers, which are made of plastic.

The system therefore requires no energy input except for the influent pump and has a much lower propensity for mechanical failure than other clarifiers.

Lamella clarifiers are unable to treat most raw feed mixtures, which require some pre-treatment to remove materials that could decrease separation efficiency.

The feed requires initial processing in advanced fine screening and grit and grease removal to ensure the influent mixture is of an appropriate composition.

[8] The layout of the clarifier creates extra turbulence as the water turns a corner from the feed to the inclined plates.

[3] Additionally, poorly maintained plates can cause uneven flow distribution and sacrifice the efficiency of the process.

Typical lamella clarifier design consists of a series of inclined plates inside a vessel, see first figure.

Above the inclined plates all particles have settled and clarified water is produced which is drawn off into an outlet channel.

Some possible design characteristics include: Lamella clarifiers can handle a maximum feed water concentration of 10000 mg/L of grease and 3000 mg/L of solids.

For these settling rates, the retention time in the clarifier is low, at around 20 minutes or less,[7] with operating capacities tending to range from 1–3 m3/hour/m2 (of projected area).

Inclined angle of plates allows for increased loading rate/throughput and decreased retention time relative to conventional clarifiers.

Higher values for turbidity removal efficiency correspond to less particulates remaining in the clarified stream.

The underflow stream is often put through a dewatering process such as a thickener or a belt press filter to increase the density of slurry.

For example, if the fluid being put through the lamella clarifier comes from a heavy industrial plant it may require post-treatment to remove oil and grease especially if the effluent is going to be discharged to the environment.

In either of these cases the overflow requires post-treatment such as an anthracite-sand filter to prevent the algae from spreading downstream of the lamella clarifier.

[7] One variation on the standard design of a lamella clarifier being developed is the way the effluent is collected at the top of the inclined plates.

Obviously this design only works for relatively clean effluent streams as the orifices would quickly become blocked with deposits which would severely reduce the efficiency of the unit.

[20] Another design variation, which improves the efficiency of the separation unit is the way the effluent enters the lamella clarifier.