ASTM D3739-06
Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis

Standard No.

ASTM D3739-06

Release Date

2006

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D3739-06(2010)

Latest

ASTM D3739-19

Scope

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.

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.

ASTM D3739-06 Referenced Document

• ASTM D1067 Standard Test Methods for Acidity or Alkalinity of Water
• ASTM D1129 Standard Terminology Relating to Water
• ASTM D1293 Standard Test Methods for pH of Water
• ASTM D1888 Methods of Test for Particulate and Dissolved Matter in Water
• ASTM D4194 Standard Test Methods for Operating Characteristics of Reverse Osmosis Devices
• ASTM D4195 Standard Guide for Water Analysis for Reverse Osmosis Application
• ASTM D4582 Standard Practice for Calculation and Adjustment of the Stiff and Davis Stability Index for Reverse Osmosis
• ASTM D511 Standard Test Methods for Calcium and Magnesium In Water
• ASTM D6161 Standard Terminology Used for Crossflow Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes

ASTM D3739-06 history

• 2019 ASTM D3739-19 Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• 2006 ASTM D3739-06(2010) Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• 2006 ASTM D3739-06 Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• 2005 ASTM D3739-05 Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• 2003 ASTM D3739-94(2003) Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis
• 1998 ASTM D3739-94(1998) Standard Practice for Calculation and Adjustment of the Langelier Saturation Index for Reverse Osmosis