Sedimentation
As the critical first stage in the water purification process, clarifiers remove large quantities of suspended and organic matter from your supply water. There are three main types of clarifiers: Coagulators, Cold-Lime Softeners, and Lamella Clarifiers. The difference in quality between the raw, untreated water and your post-clarification water determines the chemical storage and feed equipment needed for disinfection, coagulation, pH adjustment, coagulation enhancement and floc (waste sludge) formation.
When do you need it?
Coagulator Clarifiers are used to treat surface water with high suspended solids levels. Coagulants are introduced into the clarifier, agglomerating suspended materials and absorbing some of your process water’s alkalinity. Coagulated materials are then flushed out of the system as sludge. This prevents a build-up of suspended solids at the filtration stage, reducing filter maintenance and chemical use at later stages. Cold-Lime Softening Clarifiers are used when the surface water is “hard”, or has a high lime and mineral content, and high suspended solids levels. Lamella Clarifiers are small, low-flow-rate coagulator clarifiers. Coagulants are introduced and the water is flocculated before allowing agglomerated materials to settle to the bottom of the clarifier. Agglomerated materials are then flushed out of the system. Clarifiers are normally followed by gravity filters.
| Chosing A Clarifier | Raw Water Characteristics | Flow Rate |
| Coagulator Clarifier | - | - |
| Cold-Lime Softening Clarifier | High Hardness | - |
| Lamella Clarifier | - | Low Flow |
