Information
 Types of Membranes
 Temperature Effect
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 Bacterial Removal
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 Troubleshooting

 

Reverse Osmosis Information

Troubleshooting

 

 

 

 A

B

 

ELEMENT
PERFORMANCE

 REJECTION =

REJECTION LOW

 1 

FLUX =

GOOD

OXIDATION
RECOVERY TOO HIGH
SEAL REVERSED
 2 

FLUX LOW

FOULED

FOULED
OVER PRESSURE

 3 

FLUX HIGH

TEMPERATURE VARIATION
PRESSURE VARIATION

OXIDATION

BACTERIA ATTACK
 

 

   PERFORMANCE CONDITION DESCRIPTION  RESPONSE  ACTION
A1  REJECTION =  FLUX =  GOOD   Element performing within specifications    
A2  REJECTION =  FLUX LOW  FOULED  Organic fouling more likely than inorganic  CLEAN  Chlorinate / UV, change carbon
TEMPERATURE
 VARIATION		 Cold feed water temperature greatly lowers flux. Standard = 77°F (25°C)   Use higher productivity element
PRESSURE
VARIATION 		 Low pressure will give lower flux. Standard is 60 psi., residential-225 psi, commercial    Increase pressure
A3 REJECTION =  FLUX HIGH  EMPERATURE
VARIATION		 Warm feed water temperature raises flux. Maximum is 110°F (43.3°C)    Increase feed flow, cool feed water
PRESSURE
VARIATIONS		 High pressure increases flux    Check gauges
B1 REJECTION LOW  FLUX = OXIDATION Chlorine or other oxidizers not adequately removed. Damage is accumulative and progressive REPLACE Change precarbon or chemical treatments
RECOVERY TOO
HIGH 		 Average feed concentration much higher than expected  CLEAN  Lower recovery
SEAL REVERSED  Part of feed bypasses the element-fouling is very likely if not corrected quickly  CLEAN  Reverse element
B2 REJECTION LOW  FLUX LOW  FOULED #1 mode of element failure. Inorganic or organic material coats membrane surface  CLEAN  Lower recovery, add softener, use chemical feed additives
OVER PRESSURE  Exceeding maximum pressure or allowing water hammer stretches membrane which opens up rejection layer and compresses support layer  REPLACE  Lower pressure and vent any air prior to start up
B3   REJECTION LOW  FLUX HIGH  OXIDATION  2nd common mode of failure. Chemical burn of membrane destroys rejection layer  REPLACE  Increase precarbon size
BACTERIA  Rarely happens, but membrane can be attacked  REPLACE  Use UV or chlorine pretreatmen