Set up bench system

[cheertsang]

Set up fluoride bench system, compare flow rate out of sed tube to gravity powered setup.

• Determine fluoride stock solution
• Determine PACl stock solution
• Determine pump speeds for fluoride and PACl
• Calculate necessary water pump speed for 1.5 mm/s upflow velocity in sed tube
• Write Python code for all of the above

[cheertsang]

Determine fluoride stock Literature shows highest reported levels of fluoride in groundwater are up to 21 mg/L.

• start with 5 mg/L
• 10 mg/L
• 15 mg/L
• 20 mg/L Target range of fluoride is: 0.6 to 1.5 mg/L (should reduce fluoride concentration to this amount) (Karthikeyan and Lakshmanan, 2011) Fluoride solution: 10,000 ppm C1V1 = C2V2
• 2.0 mL fluoride solution per 1 L of water - yields 19.96 mg/L fluoride stock
• 1.5 mL fluoride solution per 1 L of water - yields 14.925 mg/L fluoride stock
• 1.0 mL fluoride solution per 1 L of water - yields 9.95 mg/L fluoride stock
• 0.5 mL fluoride solution per 1 L of water - yields 4.975 mg/L fluoride stock

[cheertsang]

June 8, 2018 Started calibrating fluoride probe. Measured fluoride probe voltage with solution of 50 mL DI water, 50 mL TISAB solution, and 1 mL 1000 (?) mg/L fluoride solution. E1 = 0.06657, E2 = 0.009. Slope = -0.05757. Slope was within the range of -0.056 V, indicating probe was working correctly.

Table for calibration

[cheertsang]

June 12, 2018 Need to calculate pump speeds for fluoride concentrations we want through the system. Switch to yellow-blue tubing, conversion = 0.149 mL/rev.

[cheertsang]

June 12, 2018 Experiment setup Vary fluoride stock concentration, keep pump speed constant. Fluoride pump speed = 20 rpm Fluoride stock:

• 10,000 ppm solution
• 4 mL F- solution per 1 L water
• yields fluoride stock concentration of 39.84 mg/L

QsysCsys = QstockCstock

• Qsys = 1.013 mL/s
• Qstock = 0.000049667 L/s
• Cstock = 39.84 mg/L
• Concentration of fluoride in system = 19.53 mg/L

Repeat calculations for 3, 2, 1 mL F- solution per 1 L water

[ChingPangggg]

Calibration of Fluoride pump

[cheertsang]

June 20, 2018

Measured actual flow rates through system. Coagulant pump: 2 mL/ 5 min 58 s = 0.005586592179 mL/s

• Set points on ProCoDA: Flow rate of coagulant = 0.0009719 mL/s, 0.019 mL/s
• Pump running at 14 rpm
• Actual pump speed on ProCoDA = 0.031 mL/s

Verified actual flow rate by using graduated cylinder and timing flow rate per volume: Ran coagulant pump manually at 6 rpm

• 1.9 mL/ 12 min 53.51 s = 0.002456335406 mL/s
• Target flow rate = 0.0019 mL/s Ran coagulant pump manually at 40 rpm
• 4 mL/4 min 0.15 s = 0.01665625651 mL/s
• Target flow rate = 0.01267 mL/s

[cheertsang]

June 20, 2018

Changed out 6-600 rpm pump to 1.6-100 rpm pump for coagulant for better accuracy at low flow rates.

• Measured flow rate = 1 mL/9 min 55 s = 0.001680672269 mL/s
• Target flow rate = 0.001583 mL/s (5 rpm)

Verified water pump speed.

• Measured flow rate = 9.6 mL/10.3 s = 0.932038835 mL/s
• 9 mL/10.37 s = 0.8678881389 mL/s
• Target flow rate = 0.7601 mL/s (57 rpm)

Changed water pump speed set point: 0.6601 mL/s

• Measured flow rate = 8.2 mL/11.64 s = 0.704467354 mL/s

Changed water pump speed set point: 0.7001 mL/s

• Measured flow rate = 9.6 mL/11.61 s = 0.826873385

Changed water pump speed set point: 0.6801 mL/s

• Measured flow rate = 9 mL/11.85 s = 0.7594936709 mL/s - Pump speed at 51 rpm

[cheertsang]

Verified flow rates through water pump, fluoride pump, and coagulant pump. Adjusted flow through water pump as necessary to obtain upflow velocity of 1.5 mm/s.