Laminar Tube Floc Team - Fall 2013

Flocculators are an integral part of the water treatment process. The occulation process turns the colloidal matter within water into ocs that will eventually be removed through the sedimentation process. The creation and eventual settling of ocs formed in the occulator results in cleaner, clearer water. According to Swetland et al.'s[3]hypothesis, ocs that reach a ceratin size are no longer e ective in removing colloids because the shear on the surface of the ocs becomes too high for the colloids to attach. Thus, by breaking large ocs, they may regrow and scavenge additional small colloids that are not able to settle out from the suspension. The purpose of this series of experiments was to test this hypothesis and, if valid, to determine the most e ective way to break up ocs in order to have the highest removal rate of colloidal particles. A base case was devised to serve as a control showing residual turbidity with varying coagulant doses. Clamps of varying size were used in subsequent experiments to break ocs, and the results were compared with the base case. Because variation in results had been a previous issue, experiments were replicated to ensure the extent of their variability was understood and quanti ed. Results from the base case showed that higher levels of coagulant dosage decrease the residual turbidity of the water. The data collected from clamp size experiments suggested that breaking up ocs once in the middle of the tubing arrangement can either improve or worsen the occulator performance depending on the clamp size used. Use of a 4mm clamp to break up ocs resulted in a higher residual turbidity than the base case while a 5mm clamp resulted in a lower residual turbidity than the base case. Only the 4mm clamp however, had results that were signi cantly di erent than the base case. The results found from this semester's experiments suggest further testing of clamp size on occulator performance.