The study and control of the flocculation or coagulation process can be carried out by monitoring the evolution of the particles chord size distribution on real time, which is obtained by a Focused Beam Reflectance Measurement probe (FBRM). The methodology, developed by the Cellulose and Paper Research Group of UCM, gives information about the size and concentration of the particles in the dispersion.

This technology does not require manipulating the suspension and it is applicable to study any flocculation process, independently of the aggregation mechanism or the suspension nature. The measurement interval of this technique is from 0.5 μm to 2000 μm. It can be used to select the best flocculant or coagulant, and the best dosage, and to optimize the flocculation conditions. This allows decreasing the operation costs by optimizing the efficiency of flocculants or coagulants and thus, avoiding their excess load. It also minimizes the flocculant or coagulant concentration in the effluents and therefore, reduces the problems that their presence could originate.

                                                                            
                                                                                           FBRM probe

When this technology is used for controlling flocculation, it is possible to detect any alteration in the process before it affects the downstream and, because of that, it possibilities to carry out the pertinent action in the most efficient way. Therefore, the quality of the treated wastewater is expected to increase as a consequence of the optimization of the flocculation system and the better and more sensitive flocculation control technology.
 

• Colloidal material is stable in dispersion because of its high specific area, which allows it to interact with the solvent. The stability of the colloidal material is due to the electrical double layer, which generates electrostatic repulsive forces, which impair their agglomeration.
• Flocculation process is affected by many variables related to the flocculant, the water to treat and the process conditions; all of them influence each other. Factors related to the flocculant are its nature, its structure and its molecular weight and charge density, which determine the flocculation mechanism. However, flocculant dosage and polymer chain conformation are also critical factors.
• The traditional methodologies, based on the measurement of the surface charge of the particle, are appropriate to study the aggregation process only when it implies the modification of these properties, but not when the flocculation is carried out by other mechanisms, as bridging with neutral polymers, for example.