We have two indications that small flocs are needed to aggregate with colloids. The flocculation model based on the physics of the aggregation process only fits the data if we assume that large flocs are no longer reactive. A preliminary experiment using the tube flocculator and FReTA shows a significant reduction in settled water turbidity when the flocculator had 6 floc breakup flow constrictions. Although all of our experimental work is based on laminar flow tube flocculators, the results are quite similar to full scale hydraulic flocculator performance and the flocculation model explains the need for the 1000 second retention time. Thus we should begin to explore the implications of our new understanding of the flocculation process on full scale hydraulic flocculators. | 