Mixing intensity governs whether coagulant disperses and whether flocs grow or shear apart. It is quantified by the velocity gradient G and the Camp number Gt, the master variables of flocculator design.
The physical chemistry behind every coagulant dose, from zeta potential to the Camp number.
DAF, clarification and chemical conditioning systems for solids and oil removal.
Dissolved air flotation for coagulated solids, fats and oils.
Mixing intensity in coagulation and flocculation is quantified by the velocity gradient G (in s⁻¹) and, combined with retention time, by the dimensionless Camp number Gt. Rapid mix needs a high G — typically 300–1,000 s⁻¹ — to disperse coagulant in seconds, whereas flocculation needs a much lower G of 20–75 s⁻¹ over several minutes to grow flocs without tearing them apart. Too much energy shears the floc; too little leaves coagulant poorly mixed or flocs under-grown — both carry solids into the clarifier. Reynolds & Bauhm calculate the required G and Gt for each stage and select mixers and flocculators that reliably deliver them at your design flow.
The root-mean-square velocity gradient G, with units of reciprocal seconds, measures the shear rate that drives particle collisions.
The dimensionless product of G and residence time integrates the total collision opportunity and is the primary design variable.
Smoluchowski kinetics show the particle count falling exponentially with Gt, explaining why Gt, not G alone, sets performance.
High G (500 to 1,500 per second) for under a minute disperses coagulant before hydrolysis completes.
G is tapered downward through successive stages to grow flocs without shearing the mature ones.
Maximum stable floc size scales inversely with the square root of G, capping floc growth at high shear.
Required mixer power follows from the target G and the tank volume and viscosity.
Multiple flocculation stages with decreasing G optimise the collision yield.
Tank volume sets residence time and, with G, the achievable Camp number.
Reynolds & Bauhm delivers this scope as part of an integrated, single-point engagement matched to your project, programme and regulatory regime.
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