作者:标准资料网 时间:2024-05-04 09:38:03   浏览:9835   来源:标准资料网

【英文标准名称】:StandardTestMethodforTotalOxygenDemandinWater
【原文标准名称】:水中总氧要求的标准试验方法
【标准号】:ASTMD6238-1998(2003)
【标准状态】:现行
【国别】:
【发布日期】:1998
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D19.06
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:试验室分析;生产线检测;总氧要求;需氧量;鳕鱼
【英文主题词】:BOD;COD;laboratoryanalyzer;onlinemonitor;oxygendemand;totaloxygendemand;TOD
【摘要】:Themeasurementofoxygendemandparametersiscriticaltothecontrolofprocesswastewaters.Biochemicaloxygendemand(BOD)andchemicaloxygendemand(COD)analyzershavelongtimecyclesandinthecaseofCODanalyzersusecorrosivereagentswiththeinherentproblemofdisposal.Totaloxygendemandanalysisisfaster,approximately3min,andusesnoliquidreagentsinitsanalysis.TODcanbecorrelatedtobothCODandBOD,providingeffectiveon-linecontrol.TODoffersseveralfeatureswhichmakeitamoreattractivemeasurementthancarbonmonitoringusingTotalCarbon(TC)orTotalOrganicCarbon(TOC)analyzers.TODisunaffectedbythepresenceofinorganiccarbon.TODanalysiswillalsoindicatenoncarbonaceousmaterialsthatconsumeorcontributeoxygen.Forexample,theoxygendemandofammonia,sulfiteandsulfideswillbereflectedintheTODmeasurement.Also,sincetheactualmeasurementisoxygenconsumption,TODreflectstheoxidationstateofthechemicalcompound(thatis,ureaandformicacidhavethesamenumberofcarbonatoms,yetureahasfivetimestheoxygendemandofformicacid).1.1Thistestmethodcoversthedeterminationoftotaloxygendemandintherangefrom100to100000mg/L,inwaterandwastewaterincludingbrackishwatersandbrines(see6.5).Largerconcentrations,orsampleswithhighsuspendedsolids,orboth,maybedeterminedbysuitabledilutionofthesample.1.1.1Sincetheanalysisisbasedonthechangeinoxygenreadingofthecarriergascomparedtothatwhenasampleisintroduced(see4.1),themeasurementrangeisafunctionoftheamountofoxygeninthecarriergas.Thehigherthedesiredconcentrationrange,themoreoxygenrequiredinthecarriergas.Underrecommendedconditions,thecarriergasconcentrationshouldbebetweentwotofourtimesthemaximumdesiredoxygendemand.1.1.2Thelowermeasurementrangeislimitedbythestabilityofthebaselineoxygendetectoroutput.Thissignalisafunctionofthepermeationsystemtemperature,carriergasflowrate,oxygendetectortemperature,andreferencesensorvoltage.Combined,thesevariableslimittheminimumrecommendedrangeto2to100mg/L.1.1.3Theuppermeasurementrangeislimitedbythemaximumoxygenconcentrationinthecarriergas(100%).Withtherecommendedconditionsofcarriergasconcentrationbeingtwotofourtimesthemaximumoxygendemand,thislimitsthemaximumpossibleoxygendemandtobetween250000to500000mg/L.However,asapracticalapplicationtowateranalysis,thistestmethodwillconsideramaximumrangeof100000mg/L.1.2Thistestmethodisapplicabletoalloxygen-demandingsubstancesundertheconditionsofthetestcontainedinthesamplethatcanbeinjectedintothereactionzone.Theinjectoropeninglimitsthemaximumsizeofparticlesthatcanbeinjected.Ifoxygen-demandingsubstancesthatarewater-insolubleliquidsorsolidsarepresent,apreliminarytreatmentmaybedesired.ThesepretreatmentmethodsaredescribedinAnnexA2.1.3Thistestmethodisparticularlyusefulformeasuringoxygendemandincertainindustrialeffluentsandprocessstreams.Itsapplicationformonitoringsecondarysewageeffluentsisnotestablished.ItsuseforthemonitoringofnaturalwatersisgreatlylimitedbytheinterferencesdefinedinSection6.1.4Inadditiontolaboratoryanalysis,thistestmethodisapplicabletoon-streammonitoring.SampleconditioningtechniquesforsolidspretreatmentapplicationsarenotedinAnnexA2.1.5ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicability......
【中国标准分类号】:Z16
【国际标准分类号】:13_060_50
【页数】:7P.;A4
【正文语种】: