Coagulation-sedimentation-rapid filtration

Fig. 10. Plots of particle size distribution in effluent of one-layer rapid sand filtration after coagulation-sedimentation ...

Usually, in a conventional coagulation-filtration process for arsenic removal, the addition of the coagulant is followed by a short rapid-mix step followed by a slow-mix step for flocculation. Flocculation is usually followed by sedimentation and filtration. To do away with the multitude of steps required in the conventional process, the authors designed and tested a simplified iron coagulation-direct mi-croflltration process, as described below (3,4). 

The system includes rapid water and coagulant mixing, slow mixing (flocculation), sedimentation in Sedimentation Tanks and filtration by sand Filters (Fig. 2). 

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