ASTM_D_3739_-_19.pdf

Designation:D373919Standard Practice forCalculation and Adjustment of the Langelier SaturationIndex for Reverse Osmosis1This standard is issued under the fixed designation D3739;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the calculation and adjustment ofthe Langelier saturation index for the concentrate stream of areverse osmosis(RO)device.This index is used to determinethe need for calcium carbonate(CaCo3)scale control in theoperation and design of RO installations.This practice isapplicable for concentrate streams containing 10 to 10 000mg/L of total dissolved solids.For concentrate containing over10 000 mgL,see Practice D4582.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D511 Test Methods for Calcium and Magnesium In WaterD1067 Test Methods for Acidity or Alkalinity of WaterD1129 Terminology Relating to WaterD1293 Test Methods for pH of WaterD1888 Methods Of Test for Particulate and Dissolved Matterin Water(Withdrawn 1989)3D4194 Test Methods for Operating Characteristics of Re-verse Osmosis and Nanofiltration DevicesD4195 Guide for Water Analysis for Reverse Osmosis andNanofiltration ApplicationD4582 Practice for Calculation and Adjustment of the Stiffand Davis Stability Index for Reverse Osmosis(With-drawn 2019)3D6161 Terminology Used for Microfiltration,Ultrafiltration,Nanofiltration,and Reverse Osmosis Membrane Processes3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminologies D1129 and D6161.3.1.2 For descriptions of terms relating to RO,refer to TestMethods D4194.3.2 Definitions of Terms Specific to This Standard:3.2.1 Langelier saturation index,nan index calculatedfrom total dissolved solids,calcium concentration,totalalkalinity,pH,and solution temperature that shows the ten-dency of a water solution to precipitate or dissolve calciumcarbonate.4.Summary of Practice4.1 This practice consists of calculating the Langelier satu-ration index for a RO concentrate stream from the totaldissolved solids,calcium ion content,total alkalinity,pH,andtemperature of the feed solution,and the recovery of the ROsystem.4.2 This practice also presents techniques to lower theLangelier saturation index by decreasing the recovery,bydecreasing the calcium content of the feedwater,or by chang-ing the ratio of total alkalinity to free carbon dioxide(CO2)inthe feedwater.5.Significance and Use5.1 In the design and operation of RO installations,it isimportant to predict the calcium carbonate scaling properties of1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.08 on Membranes and IonExchange Materials.Current edition approved July 1,2019.Published July 2019.Originally approvedin 1978.Last previous edition approved in 2010 as D3739 06(2010),which waswithdrawn January 2019 and reinstated in July 2019.DOI:10.1520/D3739-19.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 the concentrate stream.Because of the increase in totaldissolved solids in the concentrate stream and the difference inpassages for calcium ion,bicarbonate ion,and free carbondioxide,the calcium carbonate scaling properties of the con-centrate stream will generally be quite different from those ofthe feed solution.This practice permits the calculation of theLangelier