Water Facts Blog
Water Facts
Dewatering Equipment & Filter Presses

Deep Cone Clarifier vs. Rake Style Clarifier

Deep cone clarifier vs. rake style clarifiers is an important topic in wastewater treatment. There are advantages to each that are valuable for making decisions. Deep cone clarifier and rake style clarifiers are two of the main ways to recover water. It is a common assumption that they work the same way because they are both ‘clarifiers.’ However, the two processes have very distinct differences that make each one better in certain situations.

What is a Clarifier?

Deep cone and rake clarifiers are settling tanks built with mechanical means for continuous removal of solids as a result of sedimentation deposits. Generally, the purpose of a clarifier is to remove solid particulates or solids that suspend in liquid for clarification and/or thickening. The sludge is all the impurities that concentrate and discharge at the bottom of the tank.

Vertical Deep Cone Clarifier

A key distinction of the deep cone is its height. Because of that, people sometimes refer to it as a “vertical” deep cone. These decanters build on the principle of static decantation. Static decantation involves the natural precipitation of solid material. Isolating the particle components first using these processes may reduce the volume of downstream water treatment processes like filtration.


  1. In Matec silos, the solid particles sink down to the bottom of the structure.
  2. At the same time, the clean water overflows into the drainage system at the top of the silo.
  3. After, this water discharges into an area for clean water.

Inside the Deep Cone Clarifier:

  • The sedimentation of the solid material speeds up with the addition of polyelectrolyte (flocculant).
  • Simultaneously, the cone’s design creates a column of water that presses over the sludge which creates the perfect mud thickness.
  • Then, the reagents cause small particles in suspension to clump together and form larger and denser particles. The name for these particles are flocs. Flocs are quick to settle and more stable.
  • This allows the separation of the solids in the clarifier to easily and efficiently occur. This process helps the conservation of energy.
  • The cone’s incline perfects the thickening of mud and the upper cylinder can be used as extra storage space.
Vertical Deep Cone Clarifier
Matec Horizontal Deep Cone Clarifier

Horizontal Rake Style Clarifier

This style of clarifier is ideal for the largest water flows. Their shape limits the height but includes an upper sludge thickening system. We usually recommend this type of clarifier when deep cone height is potentially greater than nine meters.

Matec makes horizontal decanters with stainless steel in the mid-size versions, like the deep cone clarifiers. Matec also makes the larger horizontal decanters with concrete.

The decantation process is similar to the vertical clarifier. The difference is the precipitation aid isn’t in the design of a cone that uses pressure to force solids down.


  1. In the horizontal decanters, there is a rake mechanism that stirs the sludge through rotation.
  2. After, the rotation of the sludge pushes it to the bottom of the tank.

Inside the Horizontal Rake Style Clarifier:

  • Discharging is automatic and adjusts depending on the rake effort, to reach the correct thickness.
  • Next, sensors provide the opening input to the thickener discharge valve and the sludge will go through a flocculant station.