Typical Membrane Element Rejections/Passages - GE Osmonics E4H Series Operation And Maintenance Manual

SALTS
CATIONS
Percent Passage Concentration
Name Symbol Rejection
Sodium Na + 94-96
Calcium Ca +2 96-98
Magnesium M g 96-98
+2
Potassium K +1 94-96
I r o n Fe +2 98-99
Manganese M n 98-99
+2
Aluminum A l +3 99+
Ammonium N H +1 88-95
4
Copper Cu 98-99
+2
Nickel N i 98-99
+2
Zinc Zn +2 98-99
Strontium S r 96-99
+2
Hardness Ca & Mg 96-98
Cadmium Cd +2 96-98
S i l v e r Ag 94-96
+1
Mercury Hg 96-98
+2
ANIONS
Chloride C l - 1 94-95
Bicarbonate H C O - 1 95-96
3
Sulfate S O - 2 99+
4
N i t r a t e N O 85-95
- 1
3
Fluoride F 94-96
- 1
S i l i c a t e SiO - 2 80-95
2
Phosphate P O - 3 99+
4
Bromide Br - 1 94-96
Borate B O 35-70**
- 2
4 7
Chromate CrO - 2 90-98
4
Cyanide C N - 1 90-95**
S u l f i t e S O - 2 98-99
3
Thiosulfate S O 99+
- 2
2 3
* Must watch for precipitation; other ion controls maximum
concentration
* * Extremely dependent on pH; tends to be an exception to the
r u l e
The following are typical rejections and passages for various salts and
fi
organics using the SEPA -HR membrane at 400 psig (27.6 bar) operat-
ing pressure. Modules made with this membrane, such as the OSMO
HR, can be expected to give these same passages. As can be seen,
multivalent ions tend to have less passage than do monovalent ions. If
monovalent ions are combined with multivalent ions to form a salt, the
passage will be controlled by the multivalent ion. In RO all ions must be
combined as the salt form before passages can be considered.
For estimating purposes, to obtain the expected permeate quality when
handling a solution of salts , take a simple average of the feed concentra-
tion and the
concentrate concentration and multiply this figure by the average per-
cent passage to calculate the average concentration of the
permeate.Salts or organics that are complexed with organics of large
molecular weights will tend to act like the organics with which they are
complexed.
NOTE: The actual permeate water quality will vary with the inlet water quality and can only be veri-
fied by actual analysis of the permeate stream.
Figure 1.2
Typical Membrane Element
Rejections/Passages
Percent Maximum
(Avg) Percent
5 5-10
3 *
3 *
5 5-10
2 *
2 *
1 10-20
8 3-8
1 10-20
1 10-20
1 10-20
3 -
3 *
3 10-20
5 *
3 -
4 5-8
4 5-10
1 5-15
10 3-6
5 5-8
10 -
1 10-20
5 5-8
- -
6 8-12
- 4-12
1 5-15
1 10-20
fi
-
To estimate passage of salts for membrane elements other than SEPA-
HR, take the passage for the SEPA-HR and multiply by the factor for the
passage for the particular membrane element. The factors are:
S E PA-SR is 1.6 times SEPA-HR passage
S E PA-PR is 2.5 times SEPA-HR passage
Operation of the SEPA-HR membrane element at pressures over 400 ps i g
(27.6 barg) will reduce salt passage slightly. Operation at 200 psig (13.8
bar) will increase the passage of monovalent ions by approximately 2.0
times and the passage of multivalent ions will increase by 1.5 times the
400 psig (27.6 bar) passage.
For SEPA membrane elements with larger pores than the SEPA - P R i t i s
recommended that actual tests be run prior to estimating the permeate
q u a l i t y.
The maximum concentrations given in the table are the approximate
concentrations resulting in an osmotic pressure of 500 psi (34.5 barg)
f o r t h e s o l u t i o n .
Compounds such as CaSO
controlled with proper addition of dispersants. Check with the factory for
more information on Osmonics special line of dispersants .
ORGANICS
Molecular
W eight
Sucrose Sugar 342
Lactose Sugar 360
Protein 10,000 Up
Glucose 180
Phenol 94
Acetic Acid 60
Formaldehyde 30
Dyes 400 to 900
Biochemical
Oxygen Demand (BOD)
Chemical
Oxygen Demand (COD)
Urea 60
Bacteria & Vi r u s 50,000 to
500,000
Pyrogen 1,000
to 5,000
* * * Permeate is enriched in material due to preferential pas-
sage through the membrane.
GASES, DISSOLVED
Carbon Dioxide C O
2
Oxygen O
2
Chlorine C l
2
9
which have specific solubility limits can be
4
Maximum
Percent Concentration
Rejection Percent
99.9 30-35
99.9 30-35
99.9 50-80
99.0 15-20
* * *
* * *
* * *
99.9
90.0-99.9
99.9
40-60 Reacts s i m i l a r t o
a s a l t
99.9+
99.9+
30-50%
Enriched in permeate
30-70%
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