Water Clarification in Water Re-Use

Materials:

Roles:

Safety:


Instructions:

  1. Read these instructions completely and ask any questions if you are not clear on what you will be doing.
  2. AGITATORS: put on safety gloves and glasses.
    TIMERS: make sure you know how to use your stopwatches.
  3. AGITATORS: bring your cylinders and stoppers to the Waste Water station, fill them to the FILL line, and insert the stopper. Carefully bring the filled cylinders back to your station and place them upright in the spill pan.  You should always keep the cylinders within the spill pan to help with clean-up.
  4. AGITATORS: Hold the cylinder at each end with your hand over the stopper and practice agitating the cylinders with a smooth, inverting motion, and then back again.  One inversion cycle counts as 1.  Practice doing 3 inversion cycles.
  5. TIMERS:  Record the total volume (in mL) of Waste Water to be treated in the cylinder. Get in position and ready to record the settling time between the RED and BLACK lines.
  6. AGITATORS: when ready, remove the stopper and have the Polymer Supplier inject the desired quantity of Coagulant into the waste water.  Re-insert the stopper and agitate (as practiced) the specified number of inversion cycles.  Place the cylinder upright in the spill pan so your TIMERS can see it.
  7. TIMERS: start your timers when the settling front is at the RED line, and stop it when the front is at the BLACK line.  Record the time to settle for the given dosage and number of inversions.  Record Turbidity of water and Sludge Thickness after 5 minutes of settling.
  8. AGITATORS: after all the data has been recorded, carefully bring the cylinder to the Waste Disposal area and empty the cylinder.  Throw away your gloves, return your safety glasses, and leave the wet area and wash your hands!
  9. TIMERS:
  1. Calculate the settling rate in mm/s:  Settling Rate = 60 mm / (recorded time)
  2. Calculate the Operating Cost using the formula below
  1. TIMERS:  Record your chosen operating conditions and your results as below

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Optimal operation:

Dosage: _______ (mL)                        Agitations: ________

Turbidity: ______ (FNU)                        Settling Rate: _______ (mm/s)

Sludge Thickness: ______ (mm)                Operating Cost: ____________ ($)

Operating Cost = (Agitations) x $5.00 + (Dosage) x $5.00 + (Sludge Thickness) x $0.10 + (Turbidity) x $0.02