Clarification and storage

The water from the aggregate-washing process is laden with very fine particles (silts and clays, typically below 63–75 microns) which would settle very slowly without appropriate treatment.
Before entering the clarifier, the turbid wash water is collected in a dedicated tank. In more complex plants (such as Soil Washing or road sweeping), this initial tank is not a simple transit point: it functions as an agitated reaction tank, providing the contact time required for mixing with chemical reagents such as coagulants or pH correctors.

Clariflocculation then accelerates the process: flocculant is dosed into the turbid-water stream before it enters the clarifier. The reagent promotes the aggregation of the fine suspended particles into larger, denser flocs. The flocs then settle rapidly by gravity to the bottom of the clarifier cone. The clarified water rises at a velocity lower than the settling velocity of the solids and overflows at the surface, before being collected in a clarified-water storage tank and returned to the washing plant.

Our LEM (sludge-level monitoring) system automates the discharge of the thickened sludge at the bottom of the clarifier. The discharged sludge is then transferred to a dedicated sludge tank fitted with a sludge agitator to keep the sludge homogeneous and prevent solids from settling and compacting before it is pumped to the filter press.