ASTM_D_1291_-_17.pdf

Designation:D129117Standard Practice forEstimation of Chlorine Demand of Water1This standard is issued under the fixed designation D1291;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 provides a means of estimating the quan-tity of chlorine required to be added to a unit volume of waterto accomplish a predetermined treatment objective or tocompletely react with all chlorine reactable substances in thewater,or both.1.2 Temperature,pH,and initial chlorine dosage are allvariables in estimating the optimum chlorination practice.Theeffects of these variables can be evaluated using this practice.1.3 Chlorine residual is determined using Test MethodD1253.1.4 This practice is applicable to all types of water in whichthe stated treatment objective can be evaluated or residualchlorine can be measured,or both.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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 and health practices and determine the applica-bility of regulatory limitations prior to use.For a specifichazard statement,see 7.5.1.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1253 Test Method for Residual Chlorine in WaterD1293 Test Methods for pH of WaterD3370 Practices for Sampling Water from Closed Conduits3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,seeTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 chlorine demand,nthe amount of chlorine that mustbe added to a unit volume of water under specified conditionsof pH,temperature,and contact time to completely react withall chlorine-reactable substances in the water.3.2.1.1 DiscussionIt is defined as the difference betweenthe amount of chlorine applied and the amount of free chlorineremaining at the end of the contact period.3.2.2 chlorine requirement,nthe amount of chlorine thatmust be added to a unit volume of water under specifiedconditions of pH,temperature,and contact time to achieve theobjectives of chlorination.4.Summary of Practice4.1 Known amounts of chlorine are added to a series of 500mL aliquots of sample.The treated sample aliquots arepermitted to stand for a specified contact time(or a variety ofdifferent specified contact times)under specified conditions ofpH and temperature.At the end of the contact time,the samplealiquots are either analyzed for chlorine content by TestMethod D1253 or subjected to whatever evaluative techniqueis required to establish accomplishment of the treatmentobjective,or both.5.Significance and Use5.1 Chlorine is added to potable water,waste water,andindustrial water for a variety of purposes.Some of thesepurposes are:5.1.1 To eliminate or reduce the growth of microorganismsin water,5.1.2 To destroy or modify decomposable organic sub-stances so as to reduce the biochemical oxygen demand of thewater,5.1.3 To eliminate or reduce taste,odors,and color in thewater,5.1.4 To separate grease in waste water by eliminating theprotective colloidal effect of proteins present,and5.1.5 To destroy or modify substances in the waste waterthat react directly by oxidation,such as ammonia,cyanates,1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits,Analysis of Water for Power Generation and Process Use,On-Line Water Analysis,and Surveillance of Water.Current edition approved Feb.1,2017.Published February 2017.Originallyapproved in 1953.Last previous edition approved in 2016 as D1291 16.DOI:10.1520/D1291-17.2For 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.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 cyanides,ferrous iron,nitrites,phenol,phosphorus,sulfides,sulfites,thiocyanates,and other oxidizable constituents.5.2 It is important to avoid over-chlorination in order tominimize chemical consumption,meet restrictions specified byregulatory agencies,and minimize equipment