Design Challenges for Summer 2009

Subteam Leader: Heather Reed

Number of team members needed:

Total: 10
Additional needed: 8 to 9

Important team member skills:

• CEE 3310, or equivalent Fluid Dynamics course
• CEE 4540 co-requisite
• Student must be comfortable with coding
• Students should be familiar with the AguaClara design
• We are willing to train new members

Challenges

Ecuador Design Report

Work with Professor Hugo Castillo to provide all necessary documention for a demonstration plant. This needs to be a very high priority to ensure that this can be a success. He needs a detailed design that is carefully reviewed ASAP.
draft

Design Tool

• Check that all pieces are scaling properly
• Identify design errors and work with the team in Honduras to develop improved design algorithms
• Update the list of variables that are returned to the user to ensure that all relevant parameters are returned.
• eliminate variables in the VNG that aren't used.
• Determine what additional documentation should be returned to the user and develop a method of delivering multilingual support files. These support files could include select views of the plant in an easily viewable format (perhaps pdf), design disclaimer that requires an engineering review before construction, a design report, etc. Work with partner organizations to determine what resources we need to be providing. Ensure that the methods used to create this documentation can easily be extended to a multilingual platform. Develop a clear goal of what needs to be provided before beginning to make sure that we are creating the components that will fit together to provide a complete design package.

  Extend the Design

  There are many components of the water treatment plant that have not yet been fully designed. Develop a systematic approach to designing and drawing the additional components. We also need to develop methods for the inevitable transitions in design for components that don't scale smoothly. Examples of noncontinuous scaling include the transition from linear to nonlinear chemical dose controllers and the sedimentation tank inlet channel that that becomes so deep that it extends into the inlet manifold space.

  Entrance tank

  A first draft of this code has been created, but it has not yet been reviewed.

  Rapid mix components

  Requires review and possible upgrade to the first draft of the rapid mix design and then coding of the MathCAD to AutoCAD (MtA) code.

  Turbulent Flow (nonlinear) Chemical Dose Controller

  This code needs to be heavily edited and brought into compliance with the variable naming protocol.

  Chemical storage tanks

  These tanks need to be drawn. These may be an item that the onsite civil engineer will relocate to fit site conditions, but the design tool should show them at the correct elevation and in a reasonable location.

  Sedimentation tank drain valves

  Currently no valves are shown on the CAD drawings. The size of the valves is specified or could easily be specified, but no MtA code exists. We should determine the best way to add realistic drawings of these valves. It is possible that we could obtain a library of these valves so that we wouldn't have to create the AutoCAD drawings, but could simply copy them and possibly scale them. Also note that all of the flocculator and sed tank drain valves are to empty into a drain channel along the sed inlet end of the tanks.

  Floc hopper drain valves

  Flocculator drain system

  The flocculator drainage system needs to be designed now that we are using ferrocement baffles for larger plants. The two options for draining the flocculator were to

1. add some sort of check valves in the bottom of the baffles that would allow the compartments created by the baffles to drain
2. add a subfloor pipe network connecting to each compartment to a valve
   Of these options the 2nd one is preferable because the valves will be accessible whereas the check valves would be an inaccessible mechanical component that could easily fail. The flocculator drain system will involve adding either buried PVC pipes or constructing an underdrain false floor in the flocculator with channels connecting each compartment to a drain valve.

   Flocculation and Sedimentation Plant Flow Dump System

   The pipe weirs at the end of the sedimentation tank entrance and exit channels need to be connected to the plant drain channel. The connection could either be with a pipe or with an open channel

   Drain Channel

   The drain channel runs along the flocculation and sedimentation tanks at the end of the sed tank that contains the inlet channel. The drain channel should have a slope toward the sedimentation tank end and should be designed to handle the flow that would be generated from opening all of the drain valves for the floc and sed tanks.

   Sedimentation tank exit channel

   The sedimentation tank exit channel is currently a replicate of the entrance channel. The entrance channel size is based on the constraint of not breaking up flocs. This constraint causes the exit channel to be much larger than is necessary. The exit channel should be designed based on the constraint that the head loss in the open channel must be very small compared with the head loss in the launder orifices. This constraint ensures that the flow is uniformly distributed between sedimentation tank bays. The most sophisticated solution algorithm could use the direct step method and incorporate the changing flow through the channel. A simpler solution that would be conservative would be a simple friction slope calculation using the Darcy Weisbach equation adopted for flow in a rectangular channel. The friction slope times the length of the channel can be compared with the head loss in the orifices.

   Floc Hopper design

   The floc hopper fits nicely under the sed tank entrance channel for small plants, but for larger plants that space is reduced since the entrance channel is larger. We need a design for the floc hopper that accounts for the changing geometry of the entrance channel. The floc hopper also needs MtA code.

   Materials List

   Discuss the outputs of the current materials list with the AguaClara team in Honduras and determine what additional parameters should be returned to the user.

   Documentation

   Continue the documentation effort on the wiki. Evaluate possible methods for providing clear definitions of the variables in the VNG with links to graphic descriptions. Ideally it would be possible to link from the design tool or from the list of parameters returned with the design package to the variable definition on the wiki.

• Update AutoCAD documentation
• Add new pages for newly designed components (Floc Hopper, Rapid Mix, exit channel, flocculator drains, etc.)
• Update other pages as needed