RO

Question 1

What is the desired temp for a calorifier?

Answer 1

• 66°c
• Doesnt burn people

Question 2

How do you adjust the calorifier?

Answer 2

• Screwdriver
• Or appropriate tool to adjust bimetallic strip

Question 3

What do you look for when inspecting plumbing?

Answer 3

• Physical damage
• Vibration damage
• Noise shorts

Question 4

Explain the conductivity meter

Answer 4

• 2 electrodes placed a distance apart
• Current applied
• Too much salt will allow current to light the lamp

Question 5

Why is preservation carried out?

Answer 5

Prevent biological growth

Question 6

When is preservation carried out?

Answer 6

When plants are shutdown for 2-30 days

Question 7

What solution is used for preservation?

Answer 7

Sodium metabisulphate 1% with chlorine free water

Question 8

What happens if you fail to preserve the plant?

Answer 8

permanent damage to membranes due to biological growth

Question 9

List the control & protection devices fitted & their parameters

Answer 9

• LP switch <1bar falling
• HP switch >69 bar rising
• Permeate line HP 3-4 bar rising
• Concentrate line HP 4-6 bar rising

Question 10

Describe chemets procedure

Answer 10

• Take water sample
• Snap chemets vial in water sample
• compare colour with chart

Question 11

What is the principle of reverse osmosis?

Answer 11

• Apply pressure to sea water
• force through membranes
• Remove 99% of TDS & bacteria

Question 12

Why do we de-acidify the water & what are the advantages of using it?

Answer 12

• Raise ph from 6.5 to 7.5
• Stops corrosion in pipework

Question 13

What is the consumption rate of dolomite?

De-acidifier

Answer 13

20g per tonne

Question 14

What is inside a de-acidifier?

Answer 14

Dolomite which is calcium rich

Question 15

Name 4 steps for reducing stagnation onboard

Answer 15

1. No dead legs
2. Aeration
3. Locking sounding tubes
4. Chlorine injection

Question 16

What are the prohibited locations for using RO?

Answer 16

1. Esturies
2. Harbour
3. Contaminated location
4. Bays

Question 17

What is used for chlorination?

Answer 17

Sodium hypochlorite

Question 18

What is the chlorine solution strengths for
1. F/W in storage tanks
2. F/W from taps

Answer 18

1. 0.8 ppm
2. 0.5 ppm

Question 19

When is superchlorination carried out?
(50PPM)

Answer 19

1. Commissioning
2. After tank cleaning or painting
3. if tank is suspected to be contaminated

Question 20

Hazards & precautions of RO?

Answer 20

1. HV / isolate power
2. HP / check fittings
3. Chemicals / fumes use ppe

Question 21

State the rules for mixing acid & water

Answer 21

1. Always add acid to water
2. never with S/W or hot water

Question 22

When is chemical cleaning of RO carried out?

Answer 22

When output drops 10-15%

Question 23

When cleaning RO what is used?

Answer 23

1. RO A
2. RO C

Question 24

How does increase in sea temp affect rejection rate?

Answer 24

• Higher output due to membranes becoming softer
• Worse quality water

Question 25

How does increase in pressure on the membranes affect rejection rate?

Answer 25

* More output as more water is forced through membranes * better rejection rate

Question 26

What is anti-scalant dosing?

Answer 26

* continual injection of anti scalant into RO plant

Question 27

What does **anti - scalant** do?

Answer 27

* Stops salt buildup in membranes * Must only use chlorine free water

Question 28

What if you dont use **anti-scalant?**

Answer 28

* Membrane failure due to salt build up

Question 29

On Pall plant when is anti-scalant done?

Answer 29

* Above 15c s/w temps * high silt density

Question 30

What are the precautions when preparing anti-scalant dosing chemicals?

Answer 30

Use only chlorine free water so it doesnt destroy plant