ASTM_D_1291_-_06_2011.pdf

Designation:D129106(Reapproved 2011)Standard 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 Note 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 of Terms Specific to This Standard:3.1.1 chlorine demandthe amount of chlorine that must beadded to a unit volume of water under specified conditions ofpH,temperature,and contact time to completely react with allchlorine-reactable substances in the water.It is defined as thedifference between the amount of chlorine applied and theamount of free chlorine remaining at the end of the contactperiod.3.1.2 chlorine requirementthe 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.3.2 DefinitionsFor definitions relating to this practice,seeTerminology D1129.4.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 May 1,2011.Published June 2011.Originallyapproved in 1953.Last previous edition approved in 2006 as D1291 06.DOI:10.1520/D1291-06R11.2For 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 States1 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 degradation.6.Apparatus6.1 All of the apparatus listed in Test Methods D1293 andD1253 may be required.Any other apparatus necessary tocarry out the final evaluation of the effects of chlorination willbe required.7.Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indica