Abstract
This thesis assesses the influence of hydrodynamic mixing regimes on floc formation and treatment efficiency in the coagulation–flocculation process. Experiments were carried out with the bentonite–sapropel composite coagulant and a polymer flocculant system, varying the rapid-mix velocity gradient G, the slow-mix gradient and the Camp number (Gt). The optimal rapid-mix gradient was G ≈ 350–500 s⁻¹, ensuring rapid reagent distribution and completion of charge neutralisation; an excessive gradient broke the flocs and lowered efficiency. In slow mixing, an optimum of G ≈ 20–40 s⁻¹ and Gt ≈ (3–4)·10⁴ produced the largest (d₅₀ ≈ 700 μm) and strongest flocs. Under the optimal regime turbidity removal reached 96.3 %. The results show that management of mixing energy is a key factor governing floc structure and treatment efficiency.
References
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