Demo Plant

Motivation & Objective

To build realistic miniature AguaClara water treatment plants for outreach and education purposes.

Semester Research Goals

1. Finalize demo plant design, based on designs done in CEE 454.
2. Construct first demo plant.
3. Improve on design based on experience gathered from first demo plant.
4. Construct second demo plant.
5. Characterize performance characteristics of demo plant.
6. Publish scientific paper (and Wiki) on demo plant.

Past Research

The first few demo plants were built by Sara in Summer 2007. The design has since been improved and modified. The paper on the demo plant is available on the original CEE AguaClara website. In a nutshell, the demo plant is a transparent plastic miniature AguaClara water treatment plant. While the dimensions are not to scale with a real plant, the principles behind their operations are the same. The demo plant is gravity powered and fed by float valve-equipped flow control modules. The flocculator is vertical flow and sedimentation is done in an upflow lamella sedimentation tank.

In Fall 2007, the team researched the effect of introducing obstacles into the flow. Currently, the only sources of shear (and thus mixing and flocculation) are the 180° bends between the vertical flow channels. In the channels between those bends, there is very little shear - it is similar to pipe flow. There is therefore a large variance between the maximum shear (at the bends) and the average shear. That means the plant is not as space-time efficient as it can be. By introducing suitable obstacles (that create shear and mixing) into the vertical channels, the average shear is increased significantly without increasing the maximum shear.

The results of the experiments were mixed and inconclusive. While theoretically, the obstacles should improve the performance of the plant, the actual results did not show those trends. Many parameters, some of which are still unidentified, affect the performance of the plant. The team has yet to determine the limiting factors and the problems with the experiments.

This semester (Spring 2008), the team will go "back to basics" to characterize the performance of the demo plant without introducing obstacles. Aside from the plant to be built for demonstration only, the team should also build a plant for experimentation. It is hoped that the results of the performance tests will shed some light on the limitations of the plant and thus help explain the results of the experiments done last semester.