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MK2 > Reverse Osmosis > Flashcards

Reverse Osmosis Flashcards

1
Q

The Village Marine Tec. (VMT) PW400 Seawater Desalinator is a ____

A

Single-pass fully transportable purification system that uses reverse osmosis (RO) as its method of seawater desalination

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2
Q

The Village Marine Tec. (VMT) PW400 Seawater Desalinator produces potable drinking quality water with salt concentrations of _____ from seawater with salt concentrations as high as _____

A

< 500 ppm

35000 ppm

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3
Q

Naturally occurring phenomenon in which a semi-permeable membrane separates a pure and a concentrated solution

A

Osmosis

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4
Q

Preferentially passes a particular substance

A

Semi-permeable membrane

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5
Q

This potential, referred to as osmotic pressure, increases in proportion relative to ____

A

Concentration of a solution

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6
Q

Every fluid has an ____ that is directly related to the type and amount of solids in solution

A

Inherent potential

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7
Q

A concentrated solution has an osmotic pressure that is ____ than that of a pure solution

A

Higher

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8
Q

In an osmotic system, the less concentrated solution will attempt to equalize the concentrations of both solutions by ____

A

Migrating across the semi-permeable membrane

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9
Q

Salt water is pressurized on one side of the semi-permeable membrane. The pressure must be high enough to exceed the ___ to cause reverse osmotic flow of water

A

Osmotic pressure

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10
Q

Product water

A

Pure water

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11
Q

Feed water

A

Concentrated solution

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12
Q

If the applied pressure is increased in an attempt to gain more product water, a point is reached at which the membrane becomes ____

A

Fouled by precipitated salts and other undissolved material from the water

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13
Q

This RO unit will produce permeate (product water) with a quality of ____ in accordance with World Health Organization (WHO) standards for drinking water

A

< 500 ppm TDS

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14
Q

Permeate

A

Drinking water

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15
Q

With constant salinity and pressure and increasing temperature, permeate TDS ____, Capacity ____

A

Increases

Increases

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16
Q

With constant temperature and pressure and increasing salinity, permeate TDS ____, Capacity ____

A

Increases

Decreases

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17
Q

With constant temperature and salinity and increasing pressure, permeate TDS _____, Capacity ____

A

Decreases

Increases

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18
Q

If feedwater salt concentration decreases, the product water flow rate should not be allowed to increase more than ___ above rated flow

A

20%

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19
Q

Feed pressure may need to be ___ to maintain rated flow in brackish water or fresh water applications

A

Lowered

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20
Q

Experience has shown that operating in waters such as the Chesapeake Bay, system pressure can be reduced from the normal ___ to ___

A

750-800 psi

350-550 psi

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21
Q

As the salinity of the water is lower, pressure can be ___

A

Decreased

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22
Q

Typical sea water contains about __ salinity whereas in a bay, it is about ___

A

33%

20%

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23
Q

The RO system can be adjusted to maintain a constant permeate output when feedwater temperature and salinity is other than nominal. This can be down by controlling system pressure manually via ___

A

The back pressure regulation valve located in the system brine piping

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24
Q

As permeate flow decreases, the operator can ____ to increase system pressure

A

Throttle the pressure regulation valve closed

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25
Q

Throttling the pressure regulation valve closed will ___

A

Increase the permeate output and mitigate the effect of a decrease in temperature or an increase in salinity

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26
Q

Operating the unit at more than 20% of rated capacity in low salinity water can ___

A

Damage the membranes

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27
Q

R/W temperature range (87)

A

33 - 113F (1 - 43C)

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28
Q

Minimum R/W inlet pressure (87)

A

Static suction pressure

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29
Q

Maximum R/W inlet pressure (87)

A

20 psi

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30
Q

Design RO element pressure (87)

A

800 psi

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31
Q

Max RO element pressure (87)

A

1000 psi

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32
Q

Max feedwater residual chlorine (87)

A

< 0.1 ppm

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33
Q

pH range (short term for cleaning) (87)

A

4 - 10 (3 - 11)

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34
Q

Membrane type (87)

A

Thing film composite

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35
Q

Minimum product water production (87)

A

8.3 gpm

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36
Q

Seawater that is ship piping supplied to the intake of the Village Marine Tec RO desalination unit will initially flow through the ____

A

Raw water strainer

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37
Q

Once through the strainer, the raw water is supplied to the ____ which ____ of the water in order to

A 
Lift pump (low pressure boost pump)
Raises the pressure  
Provide enough positive feed pressure to flow through the filtration system and into the suction of the high pressure pump
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38
Q

Path of seawater through RO

A 
Strainer
Lift pump
Pre-filter
High pressure pump
Membrane
Drinking water/Reject back to seawater
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39
Q

Clean and filtered R/W

A

Feedwater

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40
Q

The high pressure pump raises feedwater pressure to between ___

A

800 - 1000 psi

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41
Q

Nominal pressure range required or optimal system recovery

A

800 - 1000 psi

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42
Q

As the pressurized feedwater flows across the membrane it is divided into two streams

A

Permeate

Brine

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43
Q

High purity product stream

A

Permeate

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44
Q

Increasingly concentrated reject stream

A

Brine

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45
Q

After exiting the membrane array, the brine flows through the ___

A

Back pressure regulator valve

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46
Q

Used to control the back pressure through the membrane array

A

Back pressure regulator valve

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47
Q

Membrane array back pressure is directly related to ___

A

System pressure

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48
Q

After passing through the back pressure regulator, the brine flows through the ____ and exits the RO unit

A

Reject flow meter

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49
Q

Provides the operator a means for removing performance degrading organic foulants and scale deposits from the RO membranes

A

Membrane cleaning system

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50
Q

How often should the RO unit be cleaned during constant use?

A

Approximately every 30 days

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51
Q

Components of the membrane cleaning system

A

5 micron filter housing, LP boost pump, HP pump, cleaning valve, HP bypass valve

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52
Q

The filter housing in the membrane cleaning system also functions as a ___

A

Mixing tank

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53
Q

Size of the filter in the membrane cleaning system

A

5 micron

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54
Q

Provides a signal to the Water Quality Monitor

A

Conductivity sensor

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55
Q

TDS

A

Total Dissolved Solids

56
Q

Permeate TDS > 500 ppm indicates ___

A

Poor quality water

57
Q

If permeate TDS is > 500 ppm, a signal is sent to a ____ which will ____

A

3-way product diversion valve

Divert the water away from the tanks to the reject stream

58
Q

If permeate TDS is < 500 ppm a signal is sent to the product diversion valve to ___

A

Re-position which directs the permeate to a flow meter and then on to the tanks

59
Q

If your product system backpressure approaches ___, you may be unable to deliver rated amounts of product to P/W tanks

60
Q

If the product system backpressure approaches 40 psi, it may be necessary to ___

A

Adjust the setpoint of the pressure relief valve

61
Q

Adjusting the setpoint of the pressure relief valve should only be performed by __

A

Factory trained service representative

62
Q

Monitors and displays permeate salinity, temperature and accumulated unit operating hours

A

Water Quality Monitor

63
Q

Provides operational mode control of the system product valve

A

Water Quality Monitor

64
Q

Water Quality Monitor pushbuttons

A

Temperature
Salinity alarm set point
Mode

65
Q

Alloys the operator to display permeate temperature

A

Temperature pushbutton

66
Q

By adjusting the ___ the temperature can be displayed in F* and C*

A

Control knob located on the back of the monitor

67
Q

The display normally displays ___

A

Permeate salinity display

68
Q

How to adjust the salinity alarm set point

A

Salinity alarm pushbutton and the control knob located on the back of the monitor

69
Q

Allows the operator to bypass the normal automatic operation and manually activate (dump) product valve

A

Mode pushbutton

70
Q

During normal operation a ___ light is illuminated

71
Q

During dump/cleaning operation a ___ light is illuminated

72
Q

The salinity alarm displays a ____ light

A

Red flashing light

73
Q

Illuminated when the product valve is energized and permeate is flowing through the product valve

A

Green light

74
Q

Illuminated when the product valve is de-energized and the product valve is closed

A

Yellow light

75
Q

Indicates that permeate quality is above the salinity set point

A

Red flashing light on the salinity alarm

76
Q

Provides centralized control and monitoring of all important unit functions and operating parameters

A

Master Control Center

77
Q

When unit is in standby mode it will display ___

A

STANDBY MODE

78
Q

When LP boost pump is running (only) it will display ___

A

LP PUMP ONLY

79
Q

When HP pump is running (only) it will display __

A

NOTE: HP PUMP ON ONLY (NO LP PUMP)

80
Q

When both low and high pressure pumps are running it will display ___

81
Q

When automatic fresh water flush it will display ___

A

0 FLUSH 2

««««<

82
Q

When unit has high salinity it will display ___

A

CHECK PRODUCT WATER

83
Q

When unit has low inlet pressure it will display ___

A

CHECK FILTRATION

84
Q

After every 500 hours of operation it will display ___

A

CHANGE HP PUMP OIL

85
Q

After every 2000 hours of operation it will display ____

A

CLEAN MEMBRANES

86
Q

After every 50 freshwater flushes it will display ___

A

CHANGE FLUSH FILTER

87
Q

Accumulated operating hours for membrane cleaning should be multiplied by ___ to get actual hours

88
Q

Master Control Center pushbuttons

A

LP pump
HP pump
Flush
Reset

89
Q

Controls the operation of the LP pump and energized a light that indicates when the pump is running

90
Q

When the raw water pump is running the ___ signals the MCC to display the message LP PUMP ON

91
Q

Controls the operation of the HP pump and energizes a light that indicates when the pump is running

92
Q

When only the HP pump is running, ___ signals the MCC to display the message NOTE: HP PUMP ON ONLY. NO LP PUMP

93
Q

Opens the automatic flush valve. Activates an internal time that will automatically run the LP and HP pumps for every 2 minutes.

94
Q

Completion of each successful flush cycle will be recorded on the ___

A

Flush counter

95
Q

What is considered a long term shutdown?

96
Q

What valves must be open to turn on the RO unit?

A 
Sea chest
Supply to RO unit
Brine OVBD discharge
RO unit discharge
Discharge to tank
97
Q

What valve must be closed to turn on the RO unit?

A

RO unit flush water cut off

98
Q

How to start the RO

A 
Verify valves
Verify power
Start the LP pump
Start the HP pump
When flow through the reject discharge flow meter is free of air bubbles, place the high pressure bypass valve in the RO position
99
Q

Pressure on the HP gauge should never exceed ___

100
Q

After starting the unit, if the green lamp does not light within ___, sample the product water

101
Q

Normally a drop of ___ in the product water product water production rate indicates the need for RO membrane cleaning

102
Q

The product flow meter indicates in ___

A

Gallons per hour

103
Q

When the water product quality reaches ___, the green lamp will light

A

500 ppm TDS

104
Q

The brine flow meter indicates in ___

A

Gallons per minute

105
Q

Short term shutdown procedure

A

Release pressure by turning high pressure bypass valve to Cleaning position
Secure HP pump
Secure LP pump
Perform fresh water flush

106
Q

Bacterial contamination of the RO unit can be avoided by ___

A

Flush with non-chlorinated fresh water for 2 minutes weekly
Flush the RO unit by operating the system for 5 minutes every 7 days
Flush with a preservative solution every 3 months

107
Q

Flush the unit with ___ water only

A

Non-chorinated fresh

108
Q

Do not exceed ___ flushing water pressure

109
Q

The ___ must be in place while flushing

A

Carbon filter

110
Q

The drive belt should not deflect more than 1/2” when a force of ___ is applied

111
Q

Adjust the ___ to obtain proper belt tension

A

Base plate

112
Q

When flushing with preservative, allow the chemical solution to circulate for ___

A

10 minutes

113
Q

What chemical is used for flushing?

A

Preservative chemical #3

114
Q

Preservative chemical #3 is a ____

A

Food-grade preservative

115
Q

The preservation procedure should be repeated every ___. In colder climates, the interval between preservation may be ___

A

3 months

6 months

116
Q

The filter should be replaced when ___

A

The inlet pressure gauge reading drops below 0 psi

117
Q

The PW400 uses a ____ filter

A

Single 5 micron, 30 ft2 filter

118
Q

Filters can be washed and reused ___ times

A

2 - 3 times

119
Q

VMT filter cartridges are specifically designed for RO applications and constructed from ____

A

An oil attractive sulfone

120
Q

HP pump plungers should have ___ applied to them any time it is inspected or installed

A

Ceramic lubricant

121
Q

How much oil does the HP pump take?

A

Approximately 32 oz

122
Q

Basic cleaning used to remove oil, grease, biological matter, and grime from the surface of the RO membranes

A

Cleaning chemical #1 Alkaline detergent

123
Q

Used to remove mineral scale deposits

A

Cleaning chemical #2 Acid cleaner

124
Q

Used to prevent formation of microbiological slimes

A

Cleaning chemical #3 Food grade preservative

125
Q

How much of each chemical is used in cleaning the membranes

A

1 cup #1
3/4 cup #2
1/6 cup #3

126
Q

___ may need to be added during the duration of the cleaning cycle to maintain the pH = 2

A

Cleaning chemical #2

127
Q

R/W temperature range (87)

A

33 - 113 degrees F

128
Q

Minimum R/W inlet pressure (87)

A

Static suction pressure

129
Q

Maximum R/W inlet pressure (87)

130
Q

Design RO element pressure (87)

131
Q

Maximum RO element pressure (87)

132
Q

Maximum feedwater residual chlorine (87)

133
Q

pH range (short term for cleaning) (87)

A

4 - 10 (3 - 11)

134
Q

Membrane type (87)

A

Thin film composite

135
Q

Minimum product water production (87)

MK2 (4 decks)

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