...
Entire group met at plant along with Leah to review plant data from the weekend and discuss options for the Automated flow device. Also reviewed options for insulation and lighting on McMaster, and came up with potential options. Sara also described testing procedure to the rest of the group and Rebecca cleaned the turbiditymeters. Plant results were inconsistent, and the turbidity in the flocculator continues to be larger then the inflow water. Heavy condensation was noticed on the tubes connecting the tube settlers to the turbiditymeters, indicating a significant temperature difference between the water and the air. Pictures were taken of various components of the plant, and have been put on the Wiki.
Kevin brought a clear pipe and placed it down the side of the tank where upwelling is suspected to be a problem. Adjusting the pipe, the water in the pipe would rise up to two centimeters above the tank water level. Based on Bernoulli equations this shows that there is a significant velocity, and thus quantity of water bypassing flocculation. We concluded that this does not effect the turbiditimeters because they are placed upstream of the upwelling (the non-flocculated water is not going into the turbiditimeters), however upwelling does effect the flow rate. We must determine if this is significant.
February 21, 2008
Sara, Dave, Leah and Rebecca met at the plant today. The upwelling that Kevin measured previously was remeasured to confirm the significance of the bypass around the bottom panel. Today the height difference in the tube versus in the tank was 3/4". This was still considered significant enough that it was decided that the bottom of the tank would have to be caulked. The tank was was shut off drained and cleaned out to prepare for the caulking. A clear glass 400mL beaker and a large plastic 1000mL beaker were brought to the plant to test the sampling methods that will be used for the alternative method. The glass beaker was determined to be better. Rebecca calculated the time that the beaker sample would have to settle to be equivalent to the settling tubes. It was determined that instead of insulating the tube settlers to prevent the temperature change from affecting settling the tubes were submerged. The apparatus to keep the tubes submerged and at 60 degrees was also determined. They will be suspended off of a tube resting across the dividers. Strings will run down from the resting cross bar to the glass settling tube to hold it in place. To keep air in solution and keep it from bubbling out in the turbiditmeters and skewing data, the outlet from the turbidity meters is going to be raised to increase the pressure in the system and keep the air in solution. Dave is figuring out the necessary height to create enough pressure to keep the air in solution. Leah will also be implementing her entrance tank this upcoming week while the tank is off for caulking.