Team Members - Spring 2008

Sara Schwetschenau #Gantt Chart - Sara
T. David McEvoy #Gantt Chart - Dave
Kevin Borden #Gantt Chart - Kevin
Rebecca Thompson#Gantt Chart - Rebecca
Narayana Pappu
Leah Buerman Automated Flow Control Info

Meeting Time:

Motivation & Objective

The main objective for the Spring 2008 semester was to create a reliable testing set-up that allows us to draw a conclusion about the efficiency of tapered flocculation in dynamic environments. The second main objective is to build and test a sedimentation tank in series with the flocculation tank. This will allow us to isolate what process needs to be improved. Does our flocculation model need to be improved or does our sedimentation design need alteration. It is also a goal to observe how these processes interact, how does flocculation affect sedimentation, especially how it affects sludge blanket formation.

Semester Research Goals

As the semester has progressed research for the pilot plant has sort of split into three separate sections, data analysis, tank testing, and sedimentation tank design and construction. Goals have been split-up into these sections.
Over View of Goals
1. Make Necessary Tank Modifications
2. Analyze and Alter Tank Testing Procedure Based on Collected Data
3. Design Sedimentation Tank
4. Build Sedimentation Tank
5. Analyze Sedimentation Tank Results to determine Design Viability

Flocculation Tank Modifications Made in Spring 2008

• Enlarged Port Holes - It was determined that the openings between the sections of the flocculator were too small
• Pressurized Turbidity Meters - Alter configuration of set-up drawing water from tube settlers to the turbidity meters. So that outlet is raised above the tank to ensure air stays in solution.
• Submerge Tube Settlers - to eliminate density gradients caused by temperature differences. This was causing the poor settling of flocs.
• Caulk Tank Bottom - to stop upflow surpassing the bottom panel of the tank
• Installation of Inline flow meter - to be used for comparison
• Install Inflow Bucket - Leah's flow measuring bucket required tank modifications
• Install Tank Light - Install submersibles light to provide better lighting in the tank

Tank Testing Procedure

• Our biggest goal is to establish a reliable experimental testing procedure. This method should include being able to visually analyze and classify, via a standardized reference, the flocculation in the tank. Week of March 28 A larger scale goal this smaller goal is of the testing is to develop a profile of floc formation along the length of the large-scale tapered flocculator - end of the semester.

• Development of Alternative Testing Procedure - In order to double check the validity of data from the tube settler and turbidimeter combination, we have developed an alternate testing procedure in which grab samples are taken near the inlet points of the tube settler and allowed to settle for a short period of time. Data using this procedure will be compared to data from the turbidimeters as a validity check. March 10 -development, March 28 implementation.

• Develop more detailed procedure for quantifying floc size in various parts of the sedimentation tank. This will be a combination of visual and data based analysis. If necessary, we may augment the turbidity level of the incoming water to simulate the higher turbidity levels found in Honduras.

Data Analysis

Data analysis techniques build off of work done by Carol Serna in previous semesters.  Data will be analyzed using MathCADD, and in some simple cases using Excel.  Data Analysis will begin March 31.

Comparative data of before and after tank improvements (cauking the tank, enlarging holes, and submerged tube settlers) is expected to be available.

Sedimentation Tank

This semester a sedimentation tank was constructed to follow the flocculation tank. It was design to run with just a sludge blanket. This tank was constructed and testing began at the end of the semester. A preliminary design for a sedimentation tank, with settling via lamella was designed as well, but this design is currently still under review.

Summary:
One of out main goals for the semester is to install an AguaClara style sedimentation tank in line with the pilot plant flocculator. We would like to utilize a sludge blanket in the sedimentation tank to hopefully get us closer to the 1 NTU goal. This will be particularly difficult because we have a limited amount of energy head to deal with along with limited space available to us at the water treatment plant. We plan to have siginifigant design work done by March 14th so that we can begin construction sometime this semester. We are also looking into the potential to add a second sedimentation tank with lamella instead of a sludge blanket to get a comparative look at the benefit of the sludge blanket. We will need to design a connection system between the flocculator and the sedimentation tank that has sufficiently low shear values so as to not break up the flocs formed in the floc tank.
The design will be reviewed the week after Spring Break and if the design is deemed plausible construction will begin the following week.

Past Research

In the Spring '07 semester, the pilot plant was designed and constructed.

in the Summer of '07, adjustments were made to the set-up and testing of the uniformly-spaced baffle design was done.  

In the Fall '07 semester, a tapered-baffle set-up was designed, constructed, and installed. 

History of past research and details of current research can be found on wiki page entitled Pilot Plant Construction and Past Research. Details of the Sedimentation Tank Research can be found on the wiki page entitled Pilot Plant- Sedimentation Tank.