Questions for Fall 2018

[ChingPangggg]

1. Balance reading, inconsistence measurement intervals
2. "Explore options for taking this technology to the field. Begin this exploration right away at the beginning of the semester."
3. When starting flow through system, we have to take down the reactor to get enough head to start the system. Is there a better way to do this?
4. Herrboldt thesis: natural organic matter and fluoride; aluminum sulfate, binding affinity as pH changes, comparison to PACl
5. Flow rate out of coagulant stock does not always equal the flow rate out of the coagulant constant head tank (same with fluoride). How can we account for this in order to measure the flow rate of coagulant into the system?
6. Fluoride Auto team assumed steady state at 1.5 hours, created isotherm based on readings taken at only 1.5 hrs.
7. Turbidity - is this a parameter we should be concerned about? Could be useful in determining optimal upflow velocity - adjust velocity until we get to a point where we see flocs.
8. Flocs? What should flocs look like vs. gel?
9. pH & temperature might affect fluoride readings? variability between samples during an experiment

[cheertsang]

"optimal pH for aluminum coagulant nanoparticle formation is between pH of 6.5 and 8.5" (AguaClara textbook)

• same as EPA secondary standards for drinking water

PACl is less mass, more cost-effective, consumes less alkalinity than alum (aluminum sulfate) (AguaClara textbook)

"velocity gradient is independent of viscosity (and hence temperature) for laminar flow. This is because the total amount of fluid deformation is simply based on geometry" (AguaClara textbook)

"Dissolved organic matter may slow the rate of coagulant nanoparticle transport by effectively increasing the size of the coagulant nanoparticles and thus reducing the diffusion rate" (AguaClara textbook)

"As turbidity increases the spacing between clay particles decreases and the time required for shear to transport coagulant nanoparticles to the clay decreases."

• "Increasing the shear also results in faster transport of the coagulant nanoparticles to clay surfaces. The times required are strongly influenced by the size of the coagulant nanoparticles because larger nanoparticles diffuse more slowly."

[ChingPangggg]

Meeting with Monroe (9/26)

Exploration: Make it small enough that we can ship it and explain the system operation; adjustment and maintenance are simple enough for others to process

Constant head tank flow rate--> is what matters (variability in the stock tank does not matter as much)

Measuring coagulant flow rate (in the field without a balance for the head tank)-> dripping somewhere? --> modify a float valve--> a long arm (low float high valve) A more sensitive float valve? for a low pressure environment? Adding a drip chamber after constant head tank? (see IV dripping system) (Assuming solution(coagulant) is close to water)

Head problem for sedtube: Use a suction bulb at the outlet to suck air-->water through (able to stop and start) or make the design easier to the sedtube to be taken down? A vacuum pump?

pH Can do sth about pH by measuring the pH throughout AguaClara Plat

Turbidity Meter would be helpful to see if flocs are coming out from effluent

Flocs Gel might be caused by bottom geometry Try to see what is happening at the bottom of the reactor

pH and temperature variability try temperature probe (calibrate it, first file on procoda) buy pH probe? try cole palmer probe without buffer on fluoride ionic strength or buffer? detailed description of what we are doing when we use the probe (to the container) have something the allow to hold the probe without us touching the probe? stir plate+ clamp??

[cheertsang]

Dehalococcoides - bacteria that reduced halogen compounds? maybe do some research on this, see how useful it could be in breaking down concentrated fluoride waste