I totally agree with Ademar. ...

I totally agree with Ademar. In practice it is difficult to identify the end of coagulation and the start of flocculation and there will probably be some overlap depending in the distribution of mixing energy. Coagulation happens  in the first few seconds after dosing the coagulant (with high mixing intensity with short duration) while some time (order of 10 minutes +- 5 min) is required for the subsequent flocculation step, largely depending on the intensity of flocculation/mixing energy which will be much less than the coagulation mixing intensity. Energy input and duration will depend largely on subsequent treatment step.