Laminar Tube Flocculator, Fall 2010

Tami Chung, Alexander O’Connell, Karen Swetland

Abstract

The Fall 2010 Tube Floc Team of aimed to better understand the development of rapid flocculation through a series of experiments and data analysis. In previous semesters, we had focused on the variation of flocculator length and alum dose. With the completion of these studies, we encountered more questions regarding the fundamental mechanisms involved in the process. As a result we chose to focus on characterizing the minimum coagulant dose needed to initiate rapid flocculation for two difference coagulants, alum and PAC. We hope to use this data in the future to develop a theoretical framework describing the onset of rapid flocculation. In order to accomplish this goal and to ensure the accuracy of our data we made a number of improvements and modifications to the FReTA apparatus this semester. We are currently in the process of collecting data and hope to complete our planned experiments by the end of the Fall 2010 semester.

Laminar Tube Flocculator, Fall 2012

Patience Ruijia Li

Abstract

According to the predictive occulation model proposed by Swetland et. al., 2012, large ocs do not signicantly contribute to turbidity removal  only small colloids can collide eectively and aggregate to a size that will be removed by sedimentation. Based on the hypothesis that large ocs are useless, a oc breakup procedure was devised. Results obtained using a coiled tube occulator and occulation residual turbidity analyzer (FReTA) shows that higher turbidity removal was achieved after breaking the ocs, comparing to results using the same method but without oc breakup. Therefore breaking ocs at regular intervals to maintain continuous growth will promote better performance of occulation. This research nding provided a good reference for future hydraulic occulator design.

Laminar Tube Flocculator - Summer 2013

Allan Brooks, Rivu Dey, William Pennock

Abstract:

Over the Summer of 2013, the Tube Flocculator team's overall goal was to further the understanding of floc breakup in order to heighten flocculator performance. Specifically, this was done by examining a single clamp's effect on flocculation, as well as finding the optimal orifice size while using multiple clamps. The effects of the clamps were predicted to increase overall colloid aggregation which would prove beneficial for the next step in AguaClara's process: sedimentation. Based on the results found over this summer, some conclusions can be made. One conclusion based on the end-clamp experiments is that larger orifice sizes display lower mean residual turbidities. Another is that, for a 28-meter-long flocculator, an evenly-spaced sixteen-clamp configuration appears to be better than using no clamps, depending on the clamp size used. The the eight-clamp configuration appears to not be any more effective than a no-clamp control, while a four-clamp configuration appears to show improved flocculator performance for certain clamp sizes. In future work, these findings can be applied to the full scale flocculator in hopes that floc breakup will prove useful for plant performance.

Laminar Tube Flocculator - Spring 2013

Margaret L. Fleming, Patience Ruijia L

Laminar Tube Flocculator - Summer 2014

Shreya Jain, Tanya Peifer, Nadia Shebaro, and Luke Zhu

Abstract:

Over the summer of 2014, the laminar tube flocculation team has worked to test AguaClara's new residual turbidity monitoring system, SWaT, as compared with prior teams that used FReTA. The group has also implemented PID control for the laminar tube flocculator to regulate the amount of clay added to the system. In order to achieve these goals, the laminar tubing system was simplified and reconfigured to eliminate the feedback loop with the turbidimeter. The team plans to continue optimizing the system and confirming the self regulating controls were working before starting experiments using varying dosages of coagulant.

Laminar Tube Flocculator - Spring 2014

Victoria Chou and Yining Dai

Abstract:

Flocculators are an integral part of the water treatment process. The􏱕focculation process turns the colloidal matter within water into flocs that will eventually be removed through the sedimentation process. The creation and eventual settling of flocs formed in the flocculator results in cleaner, clearer water. According to Swetland et al.'s hypothesis, flocs that reach a certain size are no longer effective in removing colloids be- cause the shear on the surface of the flocs becomes too high for the colloids to attach. Thus, by breaking large flocs, they may regrow and scavenge additional small colloids that were not able to settle out from the suspension. The purpose of this series of experiments is to continue testing the Floc Breakup Theory and, if valid, to determine the most effective way to break up flocs in order to have the highest removal rate of colloidal particles. The settled water turbidity analyzer (SWaT), a new turbidity measurement system, was designed and implemented for the Spring 2014 research, in which the effluent water first travels through an angled tube settler with continuous 􏱕ow before being analyzed by the effluent turbidimeter. A base case test was run to serve as a control showing residual turbidity with the new turbidity measurement system. Adjustments to the new setup were made to accommodate for issues that arose from the new turbidity measurement system.