Inclined plate settler

A lamella clarifier or inclined plate settler (IPS) is a type of settler designed to remove particulates from liquids.

They are often employed in primary water treatment in place of conventional settling tanks. They are used in industrial water treatment. Unlike conventional clarifiers they use a series of inclined plates. These inclined plates provide a large effective settling area for a small footprint. The inlet stream is stilled upon entry into the clarifier. Solid particles begin to settle on the plates and begin to accumulate in collection hoppers at the bottom of the clarifier unit. The sludge is drawn off at the bottom of the hoppers and the clarified liquid exits the unit at the top over a weir.

Lamella clarifiers can be used in a range of industries including mining and metal finishing, as well as used to treat groundwater, industrial process water and backwash from sand filters. Lamella clarifiers are ideal for applications where the solids loading is variable and solids sizing is fine and are more common than conventional clarifiers at many industrial sites due to their smaller footprint.

One specific application is as pre-treatment stage for effluent entering membrane filters. Lamella clarifiers are considered to be one of the best options for pre-treatment ahead of membrane filters. Their all steel design means there is a low chance that part of the inclined plate will chip off and be carried over into membrane, especially when compared to tube settlers which are constructed of plastic. Further lamella clarifiers are able to maintain the required water quality to the membrane without the use of chemicals. This is a cost saving measure both in purchasing chemicals and limiting damage to the membrane, as membranes do not work well with the large particles contained in flocculants and coagulants.

Lamella clarifiers are also used in the municipal wastewater treatment processes. The most common wastewater application for lamella clarifiers is as part of the tertiary treatment stage. Lamella clarifiers can be integrated into the treatment process or stand-alone units can be used to increase the flow through existing water treatment plants. One option for integrating lamella clarifiers into existing plants is for conventional or sludge blanket clarifiers to be upgraded by attaching a bundle of inclined plates or tubes before the overflow in the so-called "clear water zone". This can increase the settling area by two-fold resulting in a decrease in the solids loading in the overflow.

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