ASTM D4692-01

Standard Practice for Calculation and Adjustment of Sulfate Scaling Salts (CaSO₄, SrSO₄, and BaSO₄) for Reverse Osmosis and Nanofiltration

SCOPE
1.1 This practice covers the calculation and adjustment of calcium, strontium, and barium sulfates for the concentrate stream of a reverse-osmosis system. The calculations are used to determine the need for scale control in the operation and design of reverse-osmosis installations. This practice is applicable for all types of reverse osmosis devices (tubular, spiral wound, and hollow fiber).  
1.2 This practice is applicable to both brackish waters and seawaters.

General Information

• Status: Historical
• Publication Date: 09-Jun-2001
• ICS: 71.120.99 - Other equipment for the chemical industry
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Replaces: ASTM D4692-87(1996) - Standard Practice for Calculation and Adjustment of Sulfate Scaling Salts (CaSO₄, SrSO₄, and BaSO₄) for Reverse Osmosis and Nanofiltration
• Effective Date: 10-Jun-2001
• Replaced By: ASTM D4692-01(2006)e1 - Standard Practice for Calculation and Adjustment of Sulfate Scaling Salts (CaSO₄, SrSO₄, and BaSO₄) for Reverse Osmosis and Nanofiltration
• Effective Date: 15-Dec-2006

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D 4692 – 01
Standard Practice for
Calculation and Adjustment of Sulfate Scaling Salts (CaSO ,
4
1
SrSO , and BaSO ) for Reverse Osmosis and Nanofiltration
4 4
This standard is issued under the fixed designation D4692; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 For definitions of terms relating to reverse osmosis,
1.1 This practice covers the calculation and adjustment of
refer to Test Methods D4194.
calcium, strontium, and barium sulfates for the concentrate
stream of a reverse osmosis or nanofiltration system. The
4. Summary of Practice
calculations are used to determine the need for scale control in
4.1 This practice consists of calculating the potential for
the operation and design of reverse osmosis and nanofiltration
scaling by CaSO , SrSO , and BaSO in a reverse osmosis or
4 4 4
installations.This practice is applicable for all types of reverse
+
nanofiltrationconcentratestreamfromtheconcentrationofCa
osmosis devices (tubular, spiral wound, and hollow fiber) and
++ ++ 5
+,Sr ,Ba , and SO in the feed solution and the recovery of
4
nanofiltration devices.
the reverse osmosis or nanofiltration system.
1.2 This practice is applicable to both brackish waters and
4.2 This practice also presents techniques to eliminate
seawaters.
++
scaling by decreasing the recovery, by decreasing the Ca ,
++ ++
2. Referenced Documents
Sr , and Ba concentrations in the feed water, and by
addition of scale inhibitors.
2.1 ASTM Standards:
2
D511 Test Methods for Calcium and Magnesium inWater
5. Significance and Use
2
D516 Test Method for Sulfate Ion in Water
2
5.1 In the design and operation of reverse osmosis and
D1129 Terminology Relating to Water
nanofiltrationinstallations,itisimportanttopredicttheCaSO ,
4
D3352 Test Method for Strontium Ion in Brackish Water,
3
SrSO , and BaSO scaling properties of the concentrate
Seawater, and Brines 4 4
stream.Becauseoftheincreaseintotaldissolvedsolidsandthe
D4194 Test Methods for Operating Characteristics of Re-
3
increase in concentration of the scaling salts, the scaling
verse Osmosis Devices
propertiesoftheconcentratestreamwillbequitedifferentfrom
D4195 Guide for Water Analysis for Reverse Osmosis
3
those of the feed solution.This practice permits the calculation
Application
ofthescalingpotentialfortheconcentratestreamfromthefeed
D4382 Test Method for Barium in Water, Atomic Absorp-
2
water analyses and the reverse osmosis or nanofiltration
tion Spectrophotometry, Graphite Furnace
operating parameters.
3. Terminology
5.2 Scaling by CaSO , SrSO , and BaSO will adversely
4 4 4
affect the reverse osmosis or nanofiltration performance. This
3.1 Definitions—For definitions of terms used in this prac-
practicegivesvariousproceduresforthepreventionofscaling.
tice, refer to Terminology D1129.
6. Procedure
1
++ ++ ++
This practice is under the jurisdiction ofASTM Committee D19 on Water and
6.1 Determine the concentrations of Ca ,Sr ,Ba , and
is the direct responsibility of Subcommittee D19.08 on Membranes and Ion
5
SO in the feed stream in accordance with Test Methods
4
Exchange Materials.
D511, D3352, D4382, and D516, respectively.
Current edition approved June 10, 2001. Published August 2001. Originally
published as D4692–87. Last previous edition D4692–87(1996).
2 NOTE 1—If H SO is used for control of CaCO scale, measure the
2 4 3
Annual Book of ASTM Standards, Vol 11.01.
5
3
SO after acid addition.
Annual Book of ASTM Standards, Vol 11.02. 4
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D4692–01
FIG. 1 K for CaSO versus Ionic Strength
sp 4
6.2 Determine the concentration of all major ions using the 7.4 Calculate the ionic strength of the concentrate stream as
appropriate methods given in Guide D4195. At a minimum, follows:
–
++ + −
the concentrations of Mg ,Na , HCO , and Cl must be
3 1
2
I 5 ( m¯ Z
determined. c i i
2
7. Calculation where:
I = ionic strength of concentrate stream,
c
7.1 Calculate the calcium concentration in the concentrate
m¯ = molal concentration of ion, i (moles/1000 g of
i
stream from the calcium concentration in the feed solution,
water) in the concentrate stream, and
from the recovery of the reverse osmosis or nanofiltration
Z = ionic charge of ion, i.
i
system, and from the calcium ion passage as follows:
NOTE 3—The molal concentration is calculated as follows:
1 2 Y ~SP !
Ca
Ca 5Ca 3
c f
1 2 Y C 1000 C
i i
m 5 5
i 6 6
10 2 TDS MW ~10 2 TDS!
i
where: 1000 MW
iF
...