(Fun) Facts about Tube Floc
What is a floc?
Floc is an aggregation of dirty particles in water. Particles are moving at different speed in the tube (as shown in the figure below) and cause particle collisions, thus forming "flocs". Our goal is to form as many flocs as possible, so that they precipitate out in the sedimentation process.
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- Always check tube connections and make sure there is no clogging in the connections.
- Check the stock solutions. Make sure that there is no sedimentation occurring in clay and alum stock solutions.
- Check the influent turbidimeter. If it displays lower turbidity, then check the clay and alum stock solutions. Check if the flow coming out of the pumps . Check (You can check clay/alum flowrates flow rates with timer and graduated cylinder. ) Change in the process controller so that it will give correct value of clay/alum.
- Check bubbles in the flocculator and settling tubes, especially at the entrance of the settling column. Flocs could get trapped in the bubbles and get broken.
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Tube Flocculator is too dirty! How should I clean tube flocculator? (Credit to Monroe)
After you run many sets of experiments, the particles get attached and accumulate in the flocculator tubes, so it's harder to observe what's going on in the tubes and might break up flocs.
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- Turn the Process Controller OFF
- Prepare a small peg by the size of tube inner diameter by cutting the sponge
- Insert the peg at the starting point of the tube flocculator
- Press the pressure bottle (200kPa) to move the peg in
- Turn the Process Controller ON (State 2 - Clean Flocculator)
- Watch it does its magic
- Turn the Process Controller OFF when it almost reaches the end of tube.