Abstract:
This research aimed to study in-line coagulation and flocculation processes, using a static mixer and a 35-m hydraulic flocculator as a pre-coagulation integrating with a hybrid reactor. The hybrid reactor is a special designed reactor that combines a hydrocyclone, flocculation, flotation as well as separation in one reactor. For the study of the pre-coagulation, it was found that the treatment efficiencies were affected by raw water characteristics and fluid dynamic parameters (i.e. G, T and G.T). From this study, the optimal G, T and G.T values were 204.26 s-1, 106.37 s and 21,715.57 s/s, respectively. The highest turbidity removal was 94.25% operating under this optimal condition analyzed by sedimentation methods. For the study of the hybrid reactor that was operated continuously, it was found that the reactor could produce aerated floc with entrapped micro-bubbles inside. Furthermore, the results also showed that internal water recirculation, for the purpose of increasing velocity toward the top part of the reactor, could enhance treatment efficiency as well as separation efficiency between floc and treated water. The optimal conditions, particularly in this reactor, were 800 L/hr raw water flow rate, 80 L/hr pressurized water flow rate, internal water recirculation equal to raw water flow rate and air fraction of 0.0059. Under this optimal condition, the treatment efficiencies of turbidity and suspended solid were 64% and 61.59%, while separation efficiencies analyzing turbidity and suspended solid were 65.1 and 73.18, respectively.