This paper deals with optimisation and acceleration of the clarification process. It was established that both these objectives are closely inter-related and can be accomplished by the formation of aggregates with a high agitation intensity until the flocculation optimum is reached. This is a new method of formation of aggregates which is called the Inline High Density Suspension (IHDS) formation process. Further, under the IHDS process the aggregates are formed with a single root-mean-square velocity gradient