PSS Team Future Challenges and Task List (For Summer 2010 and onward)
The team's future challenges include: finishing the planned velocity gradient experiments using the clay stock and current reservoir system; reviewing settling velocity experiment calculations, setting up and running the experiment; and rerunning the velocity gradient experiments using natural organic matter instead of clay. Following this, the team should organize and prepare documents for publication of the results.
Tasks Accompanying Planned Experiments
Velocity Gradient Experiments with clay stock:
This experiment seeks to differentiate the effects of velocity gradients from capture velocity on plate settler deterioration. The capture velocity is set to 10 m/day (the value used in AguaClara plants). A range of diameters (5/8", 1/2", 3/8", and 1/4") were chosen to reflect relevant AguaClara spacing. Every tube diameter will be tested at upflow velocities of 1 mm/s, 2 mm/s, and 5 mm/s with different lengths of tubing for each to achieve appropriate capture velocities. Failure is not expected to occur at a 1 mm/s upflow velocity, so the team plans to use this set of tubes as a control experiment to show success. For higher upflow velocities, failure is expected to occur. (See the excel file: "Materials List Velocity Gradient Experiments, PSS 5-12-10" for expected failures that is, Pi-V ratio of less than 1)
Tasks
1. Review the calculation methodology in the MathCAD (titled "spring 2010 new mathcad file, 510" in the PSS_Spring2010 folder under AguaClara team folders.
2. Make sure the materials list (titled "Materials List Velocity Gradient Experiments, PSS 5-12-10") for the velocity gradient experiments match up with the MathCAD calculations
3. Prepare tubes, fittings, and manifolds for the experiment
4. Verify/make necessary alterations to the Process Controller Method (titled "Constant Vc 5-4-10 Vup 1mm-s.pcm") under the folder "PSS_Spring2010\Constant Vc Experiments"
5. Run experiments, ensuring 3 residence times of the tube settler, manifold, reservoir, turbidimeter system
6. Analyze and summarize results
Settling Velocity Experiments:
The team plans to perform this experiment in order to determine the settling velocity distribution of particles in the floc blanket. This information will hopefully allow the team to predict the magnitude of failure based on the capture velocity and predicted failure particle size. Furthermore, this test will determine whether different floc blankets produced by the system have similar characteristics. This experiment is performed using a single tube whose dimensions are detailed in the MathCAD file spring 2010 new mathcad file, 510" in the PSS_Spring2010 folder under AguaClara team folders. The capture velocity will be ramped by adjusting the flow rate through the system. Details on the required flow rates are in the MathCAD file.
Tasks
1. Review calculation methodology in the MathCAD file (titled "spring 2010 new mathcad file, 510" in the PSS_Spring2010 folder under AguaClara team folders) to ensure correctness and verify needed materials
2. Order required tubing and make any necessary alterations to the experimental setup
3. Program the necessary Process Controller Method
4. Run experiments, analyze and summarize results
Velocity Gradient Experiments with natural organic matter (NOM)
This experiment is aimed at testing the effects of natural organic matter on plate settler failure. The team will use a natural organic matter (humic acid) in place of a clay stock and rerun the original velocity gradient experiments. NOM tends to produce flocs that are less dense than clay flocs. This leads the team to believe that failure will happen at lower velocity gradients and thus at larger tube diameters. The team hopes that this experiment will provide some justification for larger plate settler spacings.
Tasks
1) If possible, model the effects of NOM on floc formation
2) Create a MathCAD file similar to the velocity gradient experiments with clay stock but for NOM
3) Review the required materials and setup, ensuring that the procedure is adequate.
4) Run the experiment, analyze and summarize results, compare to the clay velocity
Documentation
The team wants to ultimately be able to provide length and flow rate recommendations for all spacings tested that correspond to effluent turbidities below 1 NTU. The documentation should include supporting evidence from at least the Velocity Gradient Experiments with Clay. The subsequent two experiments detailed above will provide supplementary information.
Tasks
1. Review all MathCAD modeling and results from experiments
2. Appropriately format and organize the information
3. Write the paper and review for correctness