COAGULATORS-FLOCULATORS

The Chemical -.Physical Treatment Plant

The treatment is based conceptually on the following stages:

FEI treatment is based conceptually on the following stages:

• • Equalizer tanks
  Provided by the client  or Fibra
• 
  

• Coagulation
  Coagulation is a process which consists of destabilizing colloidal particles through the neutralization of its charges, generally negative.
  
  Coagulation implies three stages:  addition of coagulant,  destabilization of colloidal particles and the formation of floccules. The addition of coagulant salts such as ferric chloride or aluminum sulphate, produces polymeric cations such as  (Fe3(OH)4)5+ whose positive charges neutralize the negative charges of the colloids, allowing the particles to unite forming small  agglomerates called floccules.

Figure 1: detail of  negative charges doing performing coagulation.

Flocculation and clarification.

The flocculation process consists in the agglomeration of destabilized particles so as to form floccules of a molecular weight sufficiently high that they float.  The design of the flocculation units, as well as the selection of the flocculants depends on the flow and characteristics of the industrial wastewater to be treated.

The grouping of these small floccules into bigger groups (flocculation) is done with the help of polyelectrolitic polymers which allow the settling at high rates of sedimentation. Due to the fact that coagulation and the immediate  stage of flocculation occur very rapidly, they are hard to detect in practice.

The tank for Flocculation – Clarification has a residence time of half an hour and also allows the flotation-sedimentation of the floccules that are formed.

Figure 2: Illustration with detail of charges in the floccules formed.