Page History

...

Design

The design team challenges are available in a separate google doc. The design team will consist of 4-8 students that will work on these tasks individually or in pairs. Desired (but not necessary) skills: Mathcad, AutoCAD, 4540, fluids, Spanish fluency, and engineering design experience.

...

• Correct elevation errors** Coagulant constant head tank is higher than the discharge elevation of the coagulant into the drop tube
  • Drop tube long enough so that the bottom of the drop tube is always full of coagulant
  • Determine the correct tubing lengths for flow control of water and coagulant and appropriate head loss from entrance tank to flocculator
• Zero doser (zero flow through plant lever is horizontal)
• Add counterweight to lever so that dose can be adjusted without the lever falling on the float side
• Calibrate doser (put a percent scale on the lever as we are proposing for the new doser) and label the maximum dose.
• Label chem stock tank with concentration of coagulant
• Add stabilizing feet to flocculator
• better method for mixing up coagulant and clay (single scoop per liter of water)
• O-rings on seal system for top of sed tank wear quickly. Design a better system.
• Develop protocol for setting up and backwashing filter that methodically remove air from the tubing and filter.

Chemical Doser

The chemical doser is one of the key AguaClara technologies and it is critical for successful plant operation. The 

1. Build another prototype possibly working with Hancock Precision who anodized and engraved it. They said they could build the whole thing for us but it would be rather expensive. Alternately work with the CEE shop to fabricate a new unit.
2. Figure out a good way to do the constant head tank for larger flow rates. It requires a bigger float/float valve.
3. Better Float. Some of the floats in Honduras move around excessively because of a lack of a heavy enough counterweight and because of poor entrance tank design. Explore options for better floats including buoys and floats that are shallow (more like a cake pan).
4. Anodizing didn't work great, because it was turning purple. Either figure out why it changed color so it can be prevented or paint it. Assess the durability of the anodized surface in a wet environment.
5. Develop a better method to zero the constant head tank - minor height adjustments to the lever or constant head tank were difficult and cumbersome.
6. The lever arm is big and might not fit in all the plants (This may be fixed by the better entrance tank geometry in the future)
7. Figure out if we can build the dosing tubes directly to specifications and expect them to work. This would minimize calibration time. The main concern is the dosing tube length
8. Create a better manifold system that is chemical resistant.
9. Document how all of this is to be done in clear concise product data sheets. Right now this knowledge is in David, Andrea, Rudy, Tim and Paul's heads' not written down anywhere. This could include documentation for fabrication and calibration.
10. Figure out retrofits for existing plants.
11. Determine how the doser systems should be fabricated in the future. Should they be produced and then sold by AguaClara LLC or should they be produced locally in each country?
12. Further performance testing.