Ideas
The AguaClara entrance tank needs to be redesigned to allow more space for the inlet pipe, for a system to reduce turbulence, and for a trash rack system that can easily be cleaned while preventing any debris from entering the plant during a storm event.
- incorporate ideas for reducing turbulence from the inlet pipe
- reduce turbulence in the flocculator generated by air entrainment by the LFOM.
- Alternative designs for the trash rack need to be explored that would make it easier for the operator to clean frequently during a storm event. Ensure that it is possible to clean without letting any trash get into the plant because the sedimentation tank diffusers will clog!
- Consider options for increasing the surface area of the trash rack by rotating the trash rack 90 degrees and adding a set of trash racks that act in parallel.
- Make sure that the head loss through the trash rack is acceptable.
- Evaluate the possibility of using trash racks that are made of bars so that the trash can be raked off of the rack.
- Consider the freeboard (currently set at 10 cm) and evaluate whether it is sufficient to prevent splashing (think about kinetic energy turning into an elevation!).
- Evaluate options to prevent air from being carried into the flocculator.
Design a CDC for flows above 100 L/s.
- Determine when a larger float valve is required for the constant head tank and locate an appropriate option.
- Identify the largest dosing tube that can practically be used. This will depend on the maximum length of straight wall that is at an appropriate location for the doser in a large plant.
- If not already done, update the CDC code to include the Reynolds number constraint. (see the FCM design challenge for musing on high flow CDC design)[https://colab.research.google.com/github/aguaclara/CEE4520/blob/master/DC/FCM_DC.ipynb#scrollTo=cCKDlukvG4F8]
- Determine the number of dosing tubes that will be required as a function of plant flow rate and estimate the maximum plant size for which the CDC is appropriate.
- Explore alternative dosing systems that will follow the plant flow rate and will not require electricity. Keep in mind that we are currently seeking a solution for a 430 L/s plant!
Vertical flow flocculators with limited channel width are unable to handle high flows see end of flocculation assignment. For higher flows the horizontal flow flocculator will work because He (horizontal distance between flow expansions) can be increased without limit to ensure that H/S is greater than 3 (remember He is now the channel width!). The flocculator can use masonry walls or other rigid material for the baffles. There may be other options to explore as well.
- Create the design algorithms to scale horizontal flow hydraulic flocculators. The algorithm should be able to handle flows from the maximum flow for vertical flow flocculators (around 180 L/s) to the largest flows required by cities. The equation that describes the transition from vertical to horizontal flow is
- Explore options for fabricating the baffles. We don't want any support structure (no pipes like are used with the polycarbonate baffles) that impedes walking through these large flocculators. Thus the baffles must be self supporting. Options included masonry and ferrocement.
For plants with flows above 120 L/s it will be very attractive to simplify the internal geometry of the sedimentation tanks. Devise a system that would ensure floc blanket formation, hydraulic sludge removal, and uniform flow through the sedimentation tank. Explore options for fabricating the bottom geometry that would start with a flat concrete tank floor. Draw your proposed design using Onshape and develop equations for the important dimensions using Python. This design will also be applicable to upgrades for facilities that have conventional sedimentation tanks. Consider designing an upgrade to the Cornell Water Filtration Plant to add floc blankets and tube settlers to their sedimentation tank. (See this capstone design for an example of the bottom geometry.)[https://github.com/AguaClara/CEE4520/blob/master/Previous%20Final%20Projects/2019S/LaMeraChimba_4L_per_S_sed_tank.md] The
- How will the operator turn off this sedimentation tank for maintenance or to divert poorly flocculated water?
- How will water be distributed to all of the inlet manifolds?
- Will you use a similar 4 channel control system or will that design need to change?
- What is the optimal size of floc hoppers?
- How many floc hoppers will needed to be controlled by the operator?
- Design for a deeper floc blanket (based on AguaClara pilot plant results - pending)
- Design for shallower tube settlers (based on AguaClara pilot plant results - pending)
The goal of this challenge is to help AguaClara develop designs for much larger flow rates than our largest current plant. This challenge builds on the previous challenges and provides guidance for the high level decisions about plant design.
- Optimal number (and minimum number) of
- Entrance tanks
- Chemical dosing points
- Flocculators
- Sedimentors
- Filters
- How will flow be controlled and distributed to parallel processes?
- What are the design constraints for sizing the channels that serve as manifolds?
- How will individual units be turned off for maintenance? Invent a simple gate similar to what is used for EStaRS filters.
- Bring all of the flow to a common header between unit processes for maximum flexibility
- How will the plant components be laid out to make efficient use of space AND to be easy for the operator? It should be possible to lay this out in Onshape.
- Pick a pesticide that is present in Honduran surface waters.
- Find information on the partitioning of this pesticide between activated carbon and aqueous phase
- Estimate the mass of activated carbon required per liter of water treated
- Compare options for powdered vs granular activated carbon and recommend the best option
- Estimate the cost per million liters of treated water
- Recommend either next steps for research or a design that could be piloted at Zamorano University
- Develop the design algorithm for UV disinfection units that takes into account UV absorbance of the water and target UV dosing.
- Determine the equivalent energy input in J/L and as meters of elevation
- Estimate the cost per million liters of treated water and compare with chlorine
- Compare performance based on expected public health outcomes.
- 10’ x 40’ container plant
- Design a compact AguaClara plant in a container. Consider fold out walkways and a tent style roof. This would be for the US market and for rapid deployment.