TEST YOUR KNOWLEDGE
Reverse Osmosis Operation & Maintenance Training Level: Knowledgeable
To test your proficiency on the topics covered in this seminar, 20 questions are provided. The questions cover the major concepts participants learn in this seminar.
Contaminant Rejection
1. Which of the following pass(es) through a new, defect-free RO membrane the least?
a. Hydrogen ion, atomic weight of 1 b. Magnesium ion, atomic weight of 24 c. Potassium ion, atomic weight of 39 d. a., b. and c. pass through essentially the same amount e. a., b. and c. do not pass through
a. Hydrogen ion, atomic weight of 1
b. Magnesium ion, atomic weight of 24
c. Potassium ion, atomic weight of 39
d. a., b. and c. pass through essentially the same amount
e. a., b. and c. do not pass through
2. Which of the following pass(es) through a new, defect-free RO membrane the least?
a. Hydrogen gas, molecular weight of 2 b. Helium gas, molecular weight of 4 c. Oxygen gas, molecular weight of 32 d. a., b. and c. pass through essentially the same amount e. a., b. and c. do not pass through
a. Hydrogen gas, molecular weight of 2
b. Helium gas, molecular weight of 4
c. Oxygen gas, molecular weight of 32
3. Which of the following pass(es) through a new, defect-free RO membrane the least?
a. Butane, molecular weight of around 60 b. Sodium acetate, molecular weight of around 60 c. Isopropyl alcohol, molecular weight of around 60 d. a., b. and c. pass through essentially the same amount e. a., b. and c. do not pass through
a. Butane, molecular weight of around 60
b. Sodium acetate, molecular weight of around 60
c. Isopropyl alcohol, molecular weight of around 60
4. Which of the following pass(es) through a new, defect-free RO membrane the least?
a. Bacterium, 5 microns in diameter b. Clay particle, 1 micron in diameter c. Virus, 0.05 micron in diameter d. a., b. and c. pass through essentially the same amount e. a., b. and c. do not pass through
a. Bacterium, 5 microns in diameter
b. Clay particle, 1 micron in diameter
c. Virus, 0.05 micron in diameter
5. If the temperature of the RO feed water decreases and all flow rates stay the same (same feed, permeate and concentrate flow rates) the conductivity of the permeate will:
a. Decrease b. Increase c. Stay the same d. None of the above, the flow rates can’t stay the same
a. Decrease
b. Increase
c. Stay the same
d. None of the above, the flow rates can’t stay the same
Osmosis/Reverse Osmosis
Figure 1
6. Figure 1. In which direction will there be a net movement of water molecules due to osmosis?
a. Left to right b. Right to left c. Both direction equally d. Neither direction
a. Left to right
b. Right to left
c. Both direction equally
d. Neither direction
7. Figure 1. Referring to the illustration, approximately how much pressure, and applied to which side, would stop the net movement of water molecules (same number would pass in both directions)?
a. 1.5 psi (0.2 bar) on the left side b. 1.5 psi (0.2 bar) on the right side c. 15 psi (1 bar) on the left side d. 15 psi (1 bar) on the right side e. 150 psi (10 bar) on the left side f. 150 psi (10 bar) on the right side g. None of the above
a. 1.5 psi (0.2 bar) on the left side
b. 1.5 psi (0.2 bar) on the right side
c. 15 psi (1 bar) on the left side
d. 15 psi (1 bar) on the right side
e. 150 psi (10 bar) on the left side
f. 150 psi (10 bar) on the right side
g. None of the above
Figure 2
8. Figure 2. For this seawater RO unit, if there is no feed flow rate (upstream pumps are off) in which direction will there be a net movement of water molecules due to osmosis?
a. Feed to permeate b. Concentrate to permeate c. Permeate to feed d. None of the above
a. Feed to permeate
b. Concentrate to permeate
c. Permeate to feed
d. None of the above
9. Figure 2. Referring to the illustration, approximately how much pressure, and applied to which side of the membrane, would stop the net movement of water molecules (same number would pass in both directions)?
a. 150 psi (10 bar) on the feed side b. 150 psi (10 bar) on the permeate side c. 500 psi (34 bar) on the feed side d. 500 psi (34 bar) on the permeate side e. 750 psi (52 bar) on the feed side f. 750 psi (52 bar) on the permeate side g. None of the above
a. 150 psi (10 bar) on the feed side
b. 150 psi (10 bar) on the permeate side
c. 500 psi (34 bar) on the feed side
d. 500 psi (34 bar) on the permeate side
e. 750 psi (52 bar) on the feed side
f. 750 psi (52 bar) on the permeate side
Figure 3
10. Figure 3. Referring to the illustration, the high pressure pump has been turned on and the average pressure on the feed water side of a new, perfect membrane is shown. Which of the following will occur?
a. Permeate production begins when the high pressure pump is turned on b. Good quality permeate is obtained when the high pressure pump is turned on c. Both a. and b. are correct in this situation d. Neither a. nor b. is correct in this situation
a. Permeate production begins when the high pressure pump is turned on
b. Good quality permeate is obtained when the high pressure pump is turned on
c. Both a. and b. are correct in this situation
d. Neither a. nor b. is correct in this situation
RO Unit Operation
11. Figure 4. What is the recovery rate?
Figure 4
a. 60% b. 64% c. 68% d. 72% e. 76% f. 80% g. You can’t calculate recovery rate from data shown
a. 60%
b. 64%
c. 68%
d. 72%
e. 76%
f. 80%
g. You can’t calculate recovery rate from data shown
12. Figure 5. What is the recovery rate?
Figure 5
a. 60% b. 64% c. 68% d. 72% e. 76% f. 80% g. You can’t calculate recovery rate from data provided
g. You can’t calculate recovery rate from data provided
13. Figure 6. Which system produces the most permeate (if permeate pressure the same for A & B)?
Figure 6
a. A b. B c. Both A & B produce the same amount of water d. Neither A nor B produce any permeate
a. A
b. B
c. Both A & B produce the same amount of water
d. Neither A nor B produce any permeate
14. Figure 7. Which system produces the most permeate (if permeate pressure the same for A & B)?
Figure 7
15. Figure 8. Which system produces the most permeate (if permeate pressure the same for A & B)?
Figure 8
Potential Problems
16. Figure 9. If the feed water to this RO unit contained 525 mg/L of dissolved substances, around what would be the concentration in the concentrate stream?
Figure 9
a. 1,310 mg/L b. 1,460 mg/L c. 1,640 mg/L d. 1,880 mg/L e. 2,190 mg/L f. 2,620 mg/L g. You can’t calculate even a “ballpark” concentration from data provided
a. 1,310 mg/L
b. 1,460 mg/L
c. 1,640 mg/L
d. 1,880 mg/L
e. 2,190 mg/L
f. 2,620 mg/L
g. You can’t calculate even a “ballpark” concentration from data provided
17. For a standard polyamide thin-film composite membrane system, what is the typical purpose of upstream acid injection?
a. Reduce biofouling potential b. Reduce colloidal fouling potential c. Reduce scaling by calcium sulfate d. Reduce scaling by barium sulfate e. Reduce scaling by strontium sulfate f. All of the above are correct g. None of the above is correct
a. Reduce biofouling potential
b. Reduce colloidal fouling potential
c. Reduce scaling by calcium sulfate
d. Reduce scaling by barium sulfate
e. Reduce scaling by strontium sulfate
f. All of the above are correct
g. None of the above is correct
18. A germicidal UV unit ahead of an RO unit inactivates 90% of the bacteria entering the unit. If around 50 bacteria enter the UV unit in each milliliter (mL), around how many bacteria enter the RO unit in each milliliter?
a. 0 b. 2 c. 5 d. 7 e. 10 f. 20 g. None of the above is correct
a. 0
b. 2
c. 5
d. 7
e. 10
f. 20
19. Chemically cleaning both stages of an RO unit at the same time:
a. Is the most efficient for moderate to severe biofouling b. Is the most efficient for moderate to severe colloidal fouling c. Is the most efficient for moderate to severe scale removal d. Both a. & b. are correct e. Both b. & c. are correct f. a., b. and c. are correct g. None of the above is correct
a. Is the most efficient for moderate to severe biofouling
b. Is the most efficient for moderate to severe colloidal fouling
c. Is the most efficient for moderate to severe scale removal
d. Both a. & b. are correct
e. Both b. & c. are correct
f. a., b. and c. are correct
20. What is the purpose of performing a high pH permeate flush right after a high pH chemical cleaning.
a. Kill bacteria b. Restore membrane functional groups c. Reduce scaling potential d. Both a. & b. are correct e. Both b. & c. are correct f. a., b. and c. are correct g. None of the above is correct
a. Kill bacteria
b. Restore membrane functional groups
c. Reduce scaling potential