ASTM D3739-06

Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis

SIGNIFICANCE AND USE
In the design and operation of reverse osmosis installations, it is important to predict the calcium carbonate scaling properties of the concentrate stream. Because of the increase in total dissolved solids in the concentrate stream and the difference in passages for calcium ion, bicarbonate ion, and free CO2, the calcium carbonate scaling properties of the concentrate stream will generally be quite different from those of the feed solution. This practice permits the calculation of the Langelier Saturation Index for the concentrate stream from the feed water analyses and the reverse osmosis operating parameters.
A positive Langelier Saturation Index indicates the tendency to form a calcium carbonate scale, which can be damaging to reverse osmosis performance. This practice gives various procedures for the adjustment of the Langelier saturation index.
The tendency to form CaCo3 scale can be suppressed by the addition of antiscalents or crystal modifiers. Suppliers of antisealents and crystal modifiers can provide information on the scale inhibition peformance of these types of chemical. Their use may be appropriate for reducing scale formation in RO systems. The RO system supplier should be consulted prior to the use of antisealents and crystal modifiers to ensure they will not have a negative impact on the RO system.
SCOPE
1.1 This practice covers the calculation and adjustment of the Langelier saturation index for the concentrate stream of a reverse osmosis device. This index is used to determine the need for calcium carbonate scale control in the operation and design of reverse osmosis installations. This practice is applicable for concentrate streams containing xx 10 to 10 000 mg/L of total dissolved solids. For concentrate containing over 10 000 mg/L see Practice D 4582.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 14-Dec-2006
• ICS: 07.030 - Physics. Chemistry
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Replaces: ASTM D3739-05 - Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• Effective Date: 15-Dec-2006
• Replaced By: ASTM D3739-06(2010) - Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis (Withdrawn 2019)
• Effective Date: 01-May-2010
• Referred By: ASTM D6161-19 - Standard Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes
• Effective Date: 15-Dec-2006
• Referred By: ASTM D4582-23 - Standard Practice for Calculation and Adjustment of the Stiff and Davis Stability Index for Reverse Osmosis
• 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:D3739–06
Standard Practice for
Calculation and Adjustment of the Langelier Saturation
1
Index for Reverse Osmosis
This standard is issued under the fixed designation D3739; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4582 Practice for Calculation and Adjustment of the Stiff
and Davis Stability Index for Reverse Osmosis
1.1 This practice covers the calculation and adjustment of
D6161 Terminology Used for Microfiltration, Ultrafiltra-
the Langelier saturation index for the concentrate stream of a
tion, Nanofiltration and Reverse Osmosis Membrane Pro-
reverse osmosis device. This index is used to determine the
cesses
need for calcium carbonate scale control in the operation and
design of reverse osmosis installations. This practice is appli-
3. Terminology
cable for concentrate streams containing xx 10 to 10 000 mg/L
3.1 For definitions of terms used in this practice, refer to
of total dissolved solids. For concentrate containing over
Terminology D1129 and Terminology D6161.
10 000 mg/L see Practice D4582.
3.2 Definitions of Terms Specific to This Standard:
1.2 This standard does not purport to address all of the
3.2.1 For descriptions of terms relating to reverse osmosis,
safety concerns, if any, associated with its use. It is the
refer to Test Methods D4194.
responsibility of the user of this standard to establish appro-
3.2.2 Langelier Saturation Index—an index calculated from
priate safety and health practices and determine the applica-
total dissolved solids, calcium concentration, total alkalinity,
bility of regulatory limitations prior to use.
pH, and solution temperature that shows the tendency of a
2. Referenced Documents water solution to precipitate or dissolve calcium carbonate.
2
2.1 ASTM Standards:
4. Summary of Practice
D511 Test Methods for Calcium and Magnesium In Water
4.1 This practice consists of calculating the Langelier Satu-
D1067 Test Methods for Acidity or Alkalinity of Water
ration Index for a reverse osmosis concentrate stream from the
D1129 Terminology Relating to Water
total dissolved solids, calcium ion content, total alkalinity, pH,
D1293 Test Methods for pH of Water
and temperature of the feed solution, and the recovery of the
D1888 Methods of Test for Particulate and Dissolved Mat-
3 reverse osmosis system.
ter in Water
4.2 This practice also presents techniques to lower the
D4194 Test Methods for Operating Characteristics of Re-
Langelier Saturation Index by decreasing the recovery, by
verse Osmosis and Nanofiltration Devices
decreasing the calcium content of the feedwater, or by chang-
D4195 Guide for Water Analysis for Reverse Osmosis and
ing the ratio of total alkalinity to free carbon dioxide in the
Nanofiltration Application
feedwater.
5. Significance and Use
1
This practice is under the jurisdiction of ASTM Committee D19 on Water and
is the direct responsibility of Subcommittee D19.08 on Membranes and Ion
5.1 In the design and operation of reverse osmosis installa-
Exchange Materials.
tions, it is important to predict the calcium carbonate scaling
Current edition approved Dec. 15, 2006. Published January 2007. Originally
properties of the concentrate stream. Because of the increase in
approved in 1978. Last previous edition approved in 2005 as D3739 – 05. DOI:
total dissolved solids in the concentrate stream and the differ-
10.1520/D3739-06.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ence in passages for calcium ion, bicarbonate ion, and free
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
CO , the calcium carbonate scaling properties of the concen-
2
Standards volume information, refer to the standard’s Document Summary page on
trate stream will generally be quite different from those of the
the ASTM website.
3
Withdrawn. feed solution. This practice permits the calculation of the
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1

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D3739–06
Langelier Saturation Index for the concentrate stream from the
Ca = calcium concentration in concentrate, as CaCO ,
c 3
feed water analyses and the reverse osmosis operating param-
mg/L,
eters.
Ca = calcium concentration in feed, as CaCO , mg/L,
f 3
5.2 A positive Langelier Saturation Index indicates the Y = recovery of the reverse osmosis system, ex-
tendency to form a calcium carbonate scale, which can be pressed as a decimal, and
SP = calcium ion passage, expressed as a decimal.
damaging to reverse osmosis performance. This
...