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This semester I have been working on the FCM Chlorine Precipitation team. So far this semester, I have been involved in designing our various experimental setups. I, as well as the rest of team, have done research using the emails from those in Honduras and past experiments to determine the desired flow range, concentrations of Calcium Hypochlorite solution, and other parameters for our experiments. I have performed most of the calcium carbonate settling tests and vacuum filtrations and have been slowly compiling the data from those experiments. I have also spent time trying to understand the chemistry behind the precipitate forming and what (such as alkalinity) leads to an increase in precipitate formation, although Scott has definitely taken the lead in that.
A lot of what our team did for the first part of the semester involved extensive planning of our goals and future plans and familiarizing ourselves with all aspects of the Demo plant (because 3 out of 4 of our members are new). I learned how to run the plant, the purpose of each individual part of the plant, and how it all relates to the efficiency at which the plant reduces the turbidity of the water. More recently though, we have been working more on the design aspects of the plant and I've become a lot more familiar with the Engineering behind it all, such as how head loss, flow rate, and other aspects of the flow control relate to each other.
I performed the flocculation efficiency experiment with Taylor at the start of the design process, in which we observed the point at which the flocs reached their maximum size. Then, by relating it to our current MathCAD program, we found a more accurate efficiency value, as well as a better horizontal flocculator length for the design of the new plant. I've also contributed to the design of the new sedimentation tank that will distribute equal amounts of water through each lamella column.
In the last portion of the semester, our team really accomplished a lot more of our concrete goals. Once we became familiar with the Demo Plant and it's previous construction we were able to design and build 2 new Sedimentation Tanks, 2 new identical flocculators, and 2 new identical flow control modules.
With the new Demo Plant I, as well as the other Demo Plant Spring 2008 members, ran experiments at various flow rates, logging how turbidity changes with time at each flow.
I helped to analyze the data shown in the Results and Discussion section of the Demo Plant Performance Tests, and to compare the G-theta values calculated with and without the frictional losses in the vertical columns of the lamella. From this data analysis and calculations we together concluded that the frictional losses, accounting for a 5 times greater shear in the Demo Plant, cannot be neglected as previously assumed. We also concluded that a 50 mL/min flow rate appears to yield the lowest turbidity values and largest flocs. We believed this to be due to the high shear at larger flows leading to floc breakup.
Throughout the semester I have also helped to create and edit the following pages: