E Instruction Manual

BOD-System Oxi700

Content

1. Thesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.1 Principleofthemethod. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.3 Illustrations/Equipmentsupplied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Themethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.1 Biochemicaloxygendemand(BOD). . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.2 BODsensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.3 Principleofmeasurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3. Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.1 Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.2 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.3 Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.4 Displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.5 InitialSetUp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.6 Switchingon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.7 Switchingoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.8 Readingstoredvalues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.9 Readingactualvalues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.10 Startingmeasurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.11 Parametermenu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.1 Settingdateandtime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.2 Autostart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.11.3 Autoduration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.11.4 Replacingbatteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.12 Datatransfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153.13 Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4. BODmeasurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.1 Samplevolume. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164.2 Preparingthewatersample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5. Interpretationofresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6. Checkingthemeasurementsystem . . . . . . . . . . . . . . . . . . . . . . . . 19

7. Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4

Content

8. Inductivestirringsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208.1 Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.1.1 Correctuse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.1.2 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.2 Safetyrequirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228.3 Equipmentdescriptionandfunction. . . . . . . . . . . . . . . . . . . . . . . . . . . 248.4 SetUp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248.5 Magneticstirringrods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258.6 Stirring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258.7 Maintenanceandcleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8 Troubleshouting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8.1 Thestirringrodrotatesunevenly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268.8.2 Thestirringrodswervesbackandforth . . . . . . . . . . . . . . . . . . . . . . . . 26

9. Technicaldata . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279.1 BODsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279.2 Inductivestirringsystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

10. Accessoriesandspareparts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5

1. TheSystem

1.1 Principleofoperation BOD ismeasuredby thepressuredifferencewithinaclosedsystem (respirometric

BOD).TheintegratedmemorysavesaBODvalueautomaticallyevery24hoursforatestperiodofmorethan3days.

1.2 Applications DeterminationofBOD5andBOD7,OECD301F/biologicaldegradability.

Otherbio-technologicalapplications.

1.3 Illustrations/Equipmentsupplied

■ 1xBODmeasuringdevicewithintegratedbottlerack

■ 6xBODsensor

■ 6xBODbottles

■ 6xsealcups(Gasket)

■ 6xmagneticstirringrods

■ 1xstirringsystemdrive

■ 1xstirringsystemcontroller

■ 1xnitrificationinhibitor(ATH)

■ 1xpotassiumhydroxidesolution(KOHsolution,45%)

■ 2xoverflowmeasurementflasks(157mland428ml)

■ 1xinstructionmanual

6

2. TheMethod

2.1 BiochemicalOxygenDemand(BOD) Thebiochemicaloxygendemand(BOD)ofwastewater,industrialeffluentsandsurface

waterisanexpressionfortheamountofoxygenconsumedbythedecompositionoforganicmatterinabiochemicalprocess.

2.2 PrincipleofMeasurement TheBODsystem,consistingofthesamplebottleandtheBODsensor,representsa

closedsystem.Inthebottle,abovethesampleitself,isadefinedvolumeofair.DuringtheBODmeasurement,thebacteriainthesampleconsumethedissolvedoxygeninthesample.Thisisreplacedbyoxygeninthebottleabovethesample.Thecarbondioxidereleasedatthesametimereactwiththepotassiumhydroxideinthesealgasket.Thisgeneratesadecreaseinpressurewithinthesystem.ThisismeasuredbytheBODsensoranddisplayedasaBODvalueinmg/lO2.

2.3 PreparingtheSample/BriefSummary• Estimatethemeasurementrangeandselectthevolumeforthesample(4.1).

• Carryoutnecessarypre-treatmentofthesample(e.g.,settingthepHvalue;filtering;etc.)(4.2).

• Measurethevolumeofthesampleprecisely,usingtheoverflowmeasurementflaskandtransferittotheBODbottle,withtheaidofafunnel.Ifnecessary,addnitrificationinhibitor(4.1).

• Insertthemagneticstirringrod.

• Place3-4dropsofKOHsolutionintothesealgasket.Theninsertthegasketintheneckofthebottle.

• ScrewtheBODsensorstothesamplebottles.

• Placethebottleinthebottlerack.

• Startthemeasurement(3.10).

• Incubatethesampleinaccordancewiththeinstructions(e.g.BOD5for5daysat20°C)

7

3. Operation

3.1 Keys

Key Functions

OnOff

• Switchestheunitonandoff(automaticswitchoffapprox.45secafterlastoperation)

• Quitssub-menus• Breaksoffoperations

START • SetUpofmeasurements

READ • Readingofacurrentvalueforaselectedposition(doesnotstorevalue!)

+ • Increasesparameter/figure

- • Reducesparameter/figure

ENTER• Confirmsinput• Switchestoothersectionsinmenus

• Headkey:selectsthepositionrequired

• Head LED : indicates the position which has been selected

1 2

3 45 6

8

3.3TechnicalTerms

Finishedhead Aheadwhichhascompleteditsseriesofmeasurements

FreeheadAheadwheretheseriesofmeasurementshasbeenfinishedandatleastonefigurehasbeendisplayedinread-outmode(see„Readingoutstoredvalues“).

Startvalue

BODmeasurementisbasedonadifferenceinpressure.Whenameasurementisstarted,theinitialpressureisstoredasthestartvalue.BODfiguresarethenobtainedbymeasuringcurrentpressurevaluesandcalculatingtheBODfromthedifferencebetweenthetwo.

DisplaymodeOperatingstatus,inwhichthe„Oxi700“displaysthelaststoredvalueandtheselectedmeasurementperiodforahead

Read-outmodeOperatingstatus,inwhichallthestoredvaluesforaheadcanbedisplayed,togetherwiththeassociatedtimeofmeasurement

Startmode Operatingstatus,inwhichmeasurementscanbestarted

BackgroundmodeThe„OxiDirect“carriesoutsporadicmeasurementsindependently.Theindicationisalineinthecentreoftheupperdisplay.Donotchangeanybottleswhilethisisinoperation.

3.2OperatingModes

9

3.4DisplaysandtheirMeanings

LEDs Meaning Actionrequired

LEDsIndicatethepostionwhichhasbeenactivated

LEDislit Measurementiscomplete

LEDflashes Measurementisnotyetcomplete

Dispay Meaning Actionrequired

LobAt

Batteryisnearlyempty• Changebatteries(see„Changing

theBatteries“-3.11.4)

LoAd„OxiDirect“hasnotfoundaheadatthisposition

• Checkwhetherthereisaheadattheselectedposition

• Checkcontactsbetweenheadandrack

xd

Theunitisin„displaymode“.Theupperdisplayshowstheselectedmeasurementperiod.Thelowerdisplayshowsthelastvaluewhichhasbeenstored

dx

hx

Theunitisin„read-outmode“andshowsthestoredvalueforday‚d‘/hour‚h‘(x=1...28daysor1...48hrs.)

UFLThevaluesarebelowthepermittedmeasurementrange(belowzero)

• Checkthattheflaskisfullysealedwiththemeasurementhead

• Checkthetemperature

OFLThevaluesareabovethepermittedmeasurementrange

• Checkthetemperature

10

Dispay Meaning Actionrequired

F1 Nomeasurementfigurepresent

F2No„start-value”present,sonoactualBODvaluecanbecalculated

see„Autostart“

F120 Anerrorhasoccurredon„Start“

Bottlesmustnotberemovedduringthe„start“process.Also,positionsmustnotbechangedduringthe„start“process

SetDAteDuringinitialsetuporafterpowersupplyfailsthetimeanddatemustbereset

See„SettingTimeandDate“(parametersmenu3.11.1)

SrtundLoAdTheunithasnotlocatedaheadatthepositionwhichhasbeenselected

• InsertabottlewithheadandpresstheOn/Offkey;or:

• Selectanotherposition.Theunitwillchangeto„DisplayMode“

SrtundDELThedatafortheheadattheselectedpositionhavenotyetbeenreadout.

• Tocontinuethe„start“process,pressthe„Enter“key.(NOTE:Alldataonthisheadwillbedeleted!)

• Toquitthe„start“process,presstheOn/Offkey.Theunitwillthenchangeto„DisplayMode“

EndundLiFE

Theelectronicsontheheadcannotstoreanymorevalues(thisshouldnotoccurinnormaluse).

Thevaluesmostrecentlystoredcanbereadout.Theheadmustbereplaced.

3.4DisplaysandtheirMeanings

11

3.5InitialSetUpThebatteriesarepackedseparatelywhentheunitisdelivered.Ifnecessary,removeallthebottlesfromtherack,turntherackandopenthebatterycompartment.Installthethreealkali-manganesebatteries(C/LR14)inthebatterycompartment(checkingforcorrectpolarity).Theunitshouldthenswitchonautomaticallyandthedisplaywillshow„SetDAte“.Ifnecessary,switchtheuniton.Setthedateandtime(seetheparametersmenu3.11.1).

3.6SwitchingonTheunitisswitchedonwiththeOn/Offkey.The„OxiDirect“willactivatetheleftpositioninthefront(position1)andwillindicatethisbytheLED,whichwillbepermanentlylit(=measurementiscomplete)orbyflashing(=measurementinprogress).

Ifthereisnoheadatthisposition,the„OxiDirect“willdisplay„LoAd“.

Whenitisswitchedon,the„OxiDirect“isin„DisplayMode“,inwhichthelaststoredvalueandtheselectedmeasurementperiodaredisplayed(oradisplayasshowninTable3.4).Forexample:

Meaning

Upperdisplay 5d days 5days‘BOD

Lowerdisplay 178 mg/l 178mg/lO2asthelaststoredvalue

3.7SwitchingoffTheunitisswitchedoffbypressingtheOn/Offkey.Iftheunitisnotin„DisplayMode“,theOn/Offkeymustbepressedseveraltimesinordertoswitchoff.

Duringtheswitching-offsequencetheupperdisplaywillshow„OFF“andalinewillthenappearinthemiddleofthedisplay.Duringthisperiod,donotremoveanybottlesfromtherack,orchangeplaces,oraddbottles,orpressanyotherkeys.Theswitching-offsequenceiscompletewhenboththedisplaysareblank.Atthispoint,waitafurther2secondsminimumbeforeswitchingonagain.

12

3.8ReadingoutstoredvaluesOncetheunitisswitchedon,pressthekeytoselectthepositionrequiredandconfirmbypressingthe„Enter“key.Theunitwillswitchto„DisplayMode“forthisposition.Theupperdisplaywillnowshowthemeasurementtimeandthelowerdisplaywillshowthevaluewhichhasbeenstored.

Theunitalwaysstartswiththefirstvalue–i.e.,withaBOD-5set-upitwillstartwithday1(d1),forexample:

Upperdisplay d1 days Valueofthefirstday

Lowerdisplay 147 mg/l 147mg/lO2asthevalueforthefirstday

The„+“and„-“keyscanbeusedtodisplayotherstoreddataforthisposition.

Theheadkeyscanbeusedtoselectanotherposition.Ifthispositionisvacanttheunitremainsin„read-out“modeandshows„LoAd“.Placeaheadinthispositionforreadingoutthestoredvaluesorselectanotherposition.

PressingtheOn/Offkeywillcausetheunittoquit„read-out“modeandgoto„displaymode“.

Forameasurementperiodofoneor2days(BOD-1andBOD-2)themeasurementtimeisstatedinhours.Formeasurementperiodsexceeding2days(BOD-3,BOD-4...)itisshownindays.Thehoursareshownintheformof„hxx“sothelatestfigureforaBOD-2,forexample:

Upperdisplay h1 hrs Valueofthefirsthour

Lowerdisplay 178 mg/l 178mg/lO2valueforthefirsthour

3.9ReadingoutthecurrentvaluesOncetheunitisswitchedon,pressthekeyforthepositionrequired.Thenpressthe„READ“key.Thecurrentvaluewillthenanddisplayed.

13

3.10Startingmeasurement

Startinganewmeasurementwilldeleteallstoreddatafromthehead!

Placeapreparedbottleinavacantpositionoftherack.Switchontheunitandpressthecorrespondingheadkeytoactivatethisposition.

Pressingthe„Start“keywillnowstartthemeasurementforthisbottle.Whenthe„Start“keyispressed,theunitchangesto„StartMode“andwilldisplaythelastselectedrangeusedforthishead,withthesamplevolumerequired(specialcasesaredescribedlaterinthissection).Thedisplaywillflash.Forexample:

Upperdisplay 157 ml 157ml(samplevolumerequiredforthemeasurementrange)

Lowerdisplay 400 mg/l Rangeupto400mg/lO2

Variousactionsarenowpossible:

• The„+“and„-“keyscanbeusedtochangethesamplevolumeandthemeasurementrange.

• Pressingthe„Enter“keywillselectthedisplayedsamplevolume/rangeandthe„start“processwillcontinue.

Theunitcheckswhether„Autoduration“isactive.Ifso,theunitwillautomaticallyselectthespecifiedmeasurementperiodandwillactivatethemeasurement.Themeasurementperiodisnotdisplayed.If„Autoduration“isnotactive,theunitwilldisplaythelastmeasurementperiodwhichwasused(thedisplaywillflash).Forexample:

Upperdisplay 5d ml 5days‘BOD(BOD-5)

Lowerdisplay Thelowerdisplayisblank

Variousactionsarenowpossible:

• The„+“and„-“keyscanbeusedtochangethemeasurementperiodinone-daysteps.

• Pressingthe„Enter“keywillselectthedisplayedmeasurementperiodtobeusedandtheunitwillstartthemeasurement.

Whiletheunitattemptstostartthemeasurement,thedisplayswillshow„0.0.0“and„0.0.0.0“(flashing).Timecanvary.

Whentheunithassuccessfullystartedthemeasurementthedisplayswillshow„000“and„donE“.

14

3.11ParametersMenuPressthe„ENTER“keyandholditdepressed.SwitchontheunitwiththeOn/Offkey.Allowthreedecimalpointsinthelowerdisplaytoflashfor3secondsandthenreleasethe„ENTER“key.Theunitisnowintheparametersmenu.The„+“and„-“keyscannowbeusedtoselectbetweentheDate/Time,„Autostart“,„Autoduration“and„ChangeBatteries“menus.Pressingthe„ENTER“keywillgiveaccesstothesub-menuwhichisselected.QuittheparametersmenuwiththeOn/Offkey.Theunitwillreturnto„DisplayMode“.

3.11.1SettingtheDateandTimeConfirm„Set“„DAtE“bypressingthe„ENTER“key.Theunitwilldisplay„dA“andtheyearwhichiscurrentlyset.Pressthe„ENTER“key.Theunitdisplays„dA“andnowshowsthedatewhichiscurrentlysetintheformof„MM.TT“,where„MM“indicatesthemonthand„TT“indicatestheday.

Pressthe„ENTER“key.Theunitdisplays„ti“andthetimeintheformof„hh.mm“where„hh“indicatesthehoursand„mm“indicatestheminutes.Pressthe„ENTER“key.Theupperdisplayflashesandshows„JJ“andthelowerdisplayshowstheyearinfigures.Theyearcanbechangedwiththe„+/-“key.Pressthe„ENTER“key.

Inthiswayitispossibletoresetthefiguresforthemonth(thedisplayshows„Mo“),theday(thedisplayshows„dd“),thehour(thedisplayshows„hh“),thetensofminutes(thedisplayshows„M“)andthesingleminutes(thedisplayshows„m“).Eachentrymustbeconfirmedbypressingthe„ENTER“key.Finally,pressthe„ENTER“keyoncemoretoadoptthefigureswhichhavebeenset.Theunitsetstheinternalclocktothesefiguresand(providednomistakeshavebeenmade)willdisplay„iS“„Set“.Thedate/timemenucanbequittedatanytimebypressingtheOn/Offkey.

3.11.2AutostartUsingthe„Autostart“functiondoesnotreplacetemperingofthesampletotherequiredtemperaturebeforemeasurementisactivated.

If„Autostart“isactive,theunitwillwaitforpropertemperatureofthesample,indicatedbyadecreaseinpressure.Ittakesthispressureasthe„start“valueforthefollowingBODcalculations.However,themaximumwaitingtimeis3hours.Afterthistimetheunitwillautomaticallytakethecurrentpressureasthe„start“value,evenifnodecreaseinpressurehasbeendetected.Thiswillbeindicatedlaterbyflashingmeasurementvalues.

IfthetemperatureoftheBODsamplesissignificantlydifferentfromthespecifiedtemperature,achangeinpressurewillcauseerrorsindeterminingtheBODvalues.

The„Autostart“functioncanbeswitchedonandoff.Thesettingalwaysappliesfromthetimeitisdoneandappliestoalltheheadsontherack.

Confirm„Set“„Auto“withthe„ENTER“key.The„+“keyisusedtoswitchonthe„Autostart“function–“On“„Auto“andthe„-“keyisusedtoswitchitoff–„Off“„Auto“.Oncetheselectionhasbeenmade,thesub-menuisquittedwiththeOn/Offkey.

15

3.11.3AutodurationConfirm„Set““dur“withthe„ENTER“key.The„+“and„-“keyscanbeusedtosetfiguresbetween1and28,aswellas„OFF“.Figuresbetween1and28specifythemeasurementperiodindays,while„OFF“deactivatesthe„Autoduration“.With„Autoduration“deactivated,theunitwillaskfortherequiredmeasurementperiodinthe„StartMode“foreachsampleand/orrackposition.Theunitispresetbythemanufacturerforan„Autoduration“of5–thatis,for5days‘BOD.The„Autoduration“settingisretainedevenifthepowersupplyfailsandvalidalwaysforallpositions.

3.11.4ChangingtheBatteriesTochangethebatterieswithoutaffectingacurrentmeasurement,makesureyouhavethetoolrequiredtoopenthebatterycompartmentandhavethreereplacementalkali-manganesebatteries(C/LR14)ready.Gototheparametersmenuandselectthebatterychangemenu„Set“„bAt“(„+“key).Pressthe„ENTER“key.Theunitwilldisplay„bAt“.Pressthe„ENTER“keyagain.Theunitdisplaywillnowflash,showing„bAt“„chg“.Waituntilthedisplaydisappears–thismaytakeupto6minutes.Whenameasurementisactive,thebatterychangemustbecarriedoutwithin4minutesandtheunitmustnotbeleftwithoutpowerformorethanoneminutemaximum!Ifnecessary,removeallsamplesfromtheframe,rotatetheframeandopenthebatterycompartment.Takeouttheoldbatteriesandreplacethemimmediatelywiththenewones,checkingforcorrectpolarity.Closethecoverofthebatterycompartment,replaceallthesamples(theirpositionsarenotimportant)andswitchtheunitonagain.Iftheunitswitchesautomaticallytothedate/timemenuafterachangeofbatteries,thismeansthatthebreakinthepowersupplywastoolong.Itwillthenbenecessarytoresetthedateandtime.

3.12DatatransferSwitchtheOxi700off.ConnecttheOxi700RS232interfacewiththeserialinterfaceofthecomputerusingthecable,whichispartofthedelivery.TransferingstoreddatafromtheOxiDirecttothecomputerrequiresatransferprogram,e.g.Hyperterminal(thisispartofstandardWindowssoftware).Pleasefinddetailedinformationonourhomepageinthedownloadarea.PresstheREADkeyandholditdepressed.SwitchtheunitonwiththeOn/Offkey.Allow3decimalpointsinthelowerdisplaytoflashfor3seconds,thanreleasetheREADkey.Theunitisnowtransferringallstoreddata.

3.13Notes• Ifabottlehasbeenaddedtotherackwhileameasurementisactive,theunitmustbe

switchedonagain,sothatthisnewflaskisdetectedandcorrectmeasurementcantakeplace.

• Ifabottlehasbeenremovedpermanentlyfromtheframe,theunitshouldbeswitchedononceandthenoffagain,sothatthesemissingbottlenolongercauseapowerconsumption.

• Theunitwillswitchoffautomaticallyifnokeyispressedforapprox.45seconds.However,toachievemaximumbatterylife,theunitshouldalwaysbeswitchedoffimmediately,ifnofurtheruseractionisrequired.Theunitwillswitchinbackgroundmodewhenmeasurementsarerequired,indicatedbyalineinthetheupperdisplay.Oncemeasurementiscomplete,theunitswitchesoffagain.

16

4. BODMeasurement

4.1 SampleVolume ThesamplevolumeisrelatedtotheexpectedBODvalue.TheOxi700isdesignedto

operatewiththefollowingrangesandsamplevolumes,allowingBODmeasurementupto0-4000mg/l,withoutanydilution.

Note

Theexpectedresultsshouldbeintheupperhalfoftherange.

FordomesticwasteitisgenerallyappropriatetoconsideraBOD5valuewhichisap-proximately80%oftheCODvalue.

RangeBODmg/l Samplevolumeinml DosageATH

0–40 428 10drops

0–80 360 10drops

0–200 244 5drops

0–400 157 5drops

0–800 94 3drops

0–2000 56 3drops

0–4000 21.7 1drops

4.2 PreparingtheWaterSample1. Check thepHvalueof theeffluentsample.TheoptimumpHvalue forbiochemical

oxidationisbetweenpH6.5and7.5.IfthepHvalueofthesampleishigherorlower,itshouldbepre-adjusted.AnysignificantdeviationwillresultinalowerBODvalue.IfthepHvalueistoohigh,itcanbereducedbyaddingdilutehydrochloricacid(1mol/l)ordilutesulphuricacid(1mol/l).IfthepHvalueislow,itcanbeadjustedwithasodiumhydroxidesolution(1mol/l).

2. Mixthewatersamplewellandallowtosettleforashortwhile.Itmayalsobeadvisabletofilterorhomogenisethesample.

3. Measurethesamplevolumeprecisely,usingtheappropriateoverflowmeasurementflaskandpourthesampleintothesamplebottle(itmaybehelpfultouseafunnelforthis).Ensurethatthesampleinthebottlecontainsarepresentativeportionofanysolidsinsuspension.Itisrecommendedthateachsampleshouldbetestedtwiceorthreetimes.

17

4. To inhibit nitrification, we recommend the addition of nitrification inhibitor B(=AllylThiourea,orATH).Thisisparticularlyimportantforthelowrange0-40mg/l(forexample,whencheckingdischargesfromeffluenttreatmentplants).TherightamountofnitrificationinhibitorBisrelatedtothemeasurementrange-see4.1.

Note Nitrifyingbacteriaalsoconsumeoxygen.Thisconsumptioncanoccurwithinthefirst5

daysandismorelikelywithsampleswithlowBODlevels.Asageneralrule,theBODmeasurementshouldnotincludetheoxygenconsumptioncausedbynitrifyingbacteriaandthiscanbeinhibitedbyusingnitrificationinhibitorB.Thisinhibitorsuppressestheactivityofthebacteriabyenzymaticinhibition,sothatonlythebreakdownoforganicsubstancesinthesamplewillbemeasuredastheBODvalue.

If it isdesired tomeasureoxygenconsumption resulting fromnitrification (N-BOD),carryoutmeasurementssamples,onewithandonewithoutnitrificationinhibitorandcomparetheresults.ThedifferencebetweenthetwoBODvalueswillrepresenttheoxygendemandofthenitrifyingbacteria.

5. Addacleanmagneticstirringrodtoeachsamplebottleandadd3-4dropsof45%potassiumhydroxidesolutiontothesealgasket(thiswillabsorbthecarbondioxide).Theninsertthesealgasketintheneckofthebottle.

Important The sample must never come into contact with the potassium hydroxide solution.

Neverusegreaseoranyotherlubricantsasanadditionalsealingagent,fortheBODsensorsorforthesealgasket.Productsofthiskindmaycontainsolventswhichwillattack thesensor, resulting inseveredamage to theplastichousingandeven toafailureofthesensor.Theuseofsealinggreasesandlubricantsisnotcoveredbyourguarantee!

6. Beforemeasurementbegins, thepreparedsamplemustbebrought to thedesiredtemperature(e.g.BOD5,20°C).Thiscanbeachievedbyplacingthesampleinather-mostaticallycontrolledcabinet,whilestirringthesamplecontinuouslywiththeinductivestirringsystem.

TheOxi700hasanoptional“Auto-Start”function,whichenablesittostartwithsamplesattemperaturesfrom15°to20°C.Whenthis“Auto-Start”functionisswitchedon,thesystemchecksinspecificintervalswhethertherehasbeenadecreaseofthepressureintheBODbottleandwillnotstartthetimeruntilapressuredecreaseisdetected(latest,thetimerwillstart3hoursaftertheBODsensorhasbeenstarted).

7. PlacetheBODsensorsonthesamplebottlesandtightencarefully.Thisisextremelyimportant–thesystemmustbecompletelyair-tight.ThenplacetheBODbottle,withthesensorscrewedinposition,intothebottlerack.Thiscanbedoneinthethermo-staticallycontrolledcabinetitself.

Alternatively,becauseoftheuser-friendlydesignoftheOxi700,youcanremovetheentireBODunit,withitsintegralbottlerack,fromthethermostaticallycontrolledcabinet,whileleavingtheinductivestirringsysteminthecabinet.Thereisnoneedtodisconnectthecabling.OncetheBODbottleshavebeenplacedintherack,thesystemispositionedovertheinductivestirringsystemsothatthe4adjustmentscrewsfitintheassociatedrecessesofthestirringsystem.

8. Startthemeasurementprocess(seeSection3.10).9. Incubatethesampleinaccordancewiththeinstruction(e.g.BOD5for5daysat20°C).

18

5. InterpretingtheResults

Start 1. Day 2. Day 3. Day 4. Day 5. Day

300

250

200

150

100

50

0

1. TheBODvalueonanyparticulardaymustbehigherthantheoneofthepreviousday.

2. BODvaluesdonotincreaseinalinearmanner.Theincreaseisalwayssmallerthantheoneofthepreviousday.

3. IftheBODresultsincreaseinalinearmanner,thesamplehasahigherBODvaluethanexpected.

4. IfBODresultsincreasedsuddenlyduringthemeasurement,thismaybetheresultofnitrification.

5. IfBODresultsdecreasesuddenlyduringthemeasurement,thismayindicatesleakageofthesystem.

Theinformationgivenreferstonormalsamples(municipalwastes)andthenormalcir-cumstancesofaBODmeasurement.However,deviationarealwayspossible,dependingonthesamples.Forexample,ifthereisareadingofzeroafter5days,thismaybeasignofsevereinhibitionoroxidizingofthesample.

Inthecaseofindustrialeffluents,samplesmaycontaintoxicsubstances.Thesemustberemoved,orthesamplemustbediluted.Inaddition,nutrients(nitrogen;phosphate)andtraceelements(suchasiron)mustbepresentinsufficientconcentrations;otherwisebacterialgrowthmaybelimitedandartificiallylowBODvaluesmayberecorded.Whereproblemsofthiskindoccur,eachindividualcasemustbeconsidered.

Forfurtherinformation,pleaseaskforourapplicationreports.

19

6. CheckingtheMeasurementSystem

TestSet(Ordercode:L418328) Thetestsetenablesacheckofall thecomponentsof theOxi700.Usingaspecialreagenttablet,adefinedunderpressureisgeneratedinthesealedBODbottle.

7. Maintenance

High-qualitymetalalloysareusedforthecontactsbetweentheBODsensorsandthebottlerack.Ifnecessary,thecontactsmaybecleanedcarefullywithasoftcloth.

TocompensateforanyirregularitiesandtoensureoptimumcontactbetweentheBODsensorandthebottlerackaswellasinsuringproperstirring,theBODmeasurementsystemhas4levellingscrewsonitsbase.

Ifnecessary,theBODbaseunit(includingthebottlerack)andtheBODsensorscanbecleanedcarefullywithasoftcloth.

Allpartswhichcomeintocontactwiththesample(BODbottles;sealcups;magneticstirringrod)mustbecleanedthoroughlyaftereachmeasurement.Thebottlesmustbeemptiedcompletelyandwashedseveraltimesinhotwater.

Whenanycleaningagents,dish-washingliquids,etc.,areused,allpartsmustberinsedthoroughlyafterwards!TheresiduesofsuchagentscaninterferewithBODmeasure-ments.

20

8. InductiveStirringSystem

Fig.1:Inductivestirringdrivewithstirringcontroller

Å Stirringplace

Ç Stirringdevice

É Controller

Ñ Plug

Ö Cable

Ñ

É

Ö

Ç

Å

21

8.1 Instructions

8.1.1 Correctuse

ThisinductivestirringsystemhasbeendesignedforstirringliquidsinBODbottles.

8.1.2 Symbols

Thefollowinginstructionsymbolsareusedinthisoperatingmanual:

DANGER! Thissignreferstodangerousvoltages

DANGER! Thissignreferstohazardoussituations. Riskstohumanlifeareindicatedbytheterm”LIFEHAZARD”

y CAUTION! Thissignindicatesriskstoequipmentandmachinery

i INFORMATION Thissignindicateseasierworkingpractices

22

8.2 SafetyRequirements Foryourownsafety,youshouldobservethefollowingwarnings.

Thesafetywarningsindicateapossiblesourceofdanger.Atthesametimetheygiveinformationhowtoavoiddamage.Youwillalwaysfindthesesignswheredangercanoccur.

DANGER! Magnetism. Magneticormetallicparts(e.g.datacarriers,pacemakers,watches...)canbeaffectedbymagneticfields. Keepsuchpartsawayfromthemagneticstirrer(2)andthemagneticstirringrods

DANGER! Voltageandfrequencymustbewithintherangespecifiedforthecontrolunit(3)

y CAUTION! Donotuseinhazardouslocations

y CAUTION! Generalambientconditions: Stirringdrive(2):-10to+56°Cat100%humidity. Controlunit(3):0to+40°Catmax.80%humidity. Avoidextremetemperaturechanges. Thecontrolunit(3)mustnotbeusedinareasofhighhumidityorinareaswherewatermaysplash!

23

y CAUTION!

Donotplacehotsamplesontopofthemagneticstirrer(2). Maximumtemperature:56°C.

y CAUTION! Incaseofrepair,theequipmentmustonlybeopenedbyanauthorisedservicetechnician.Disconnectfrommainsbeforeopening!

y CAUTION! Donotallowthemagneticstirringrodtorestinanalternatingmagneticfield.Donotplacethemagneticstirringrodinastronginversemagneticfield.Thismayresultindestructionofthemagneticfieldofthestirringrod.

i INFORMATION Thelengthofthemagneticstirringrodmustnotexceed40mm. Donotuseellipticalstirringrodswitharoundcross-section.

24

8.3 EquipmentDescriptionandFunction ThestirringsystemhasbeendesignedforstirringliquidsinstandardBODbottles.The

ultra-slimstirringdrive(2)has6stirringareas(1)andaseparatecontroller(3).Bottlescanberemovedfromtherackwithoutstoppingthestirringdrive(2).

The inductivestirringdrivehasnomotorand isthereforewear-free. It isparticularlydesignedforcontinuousstirringinaincubator.Itishermeticallysealed(fullyprotectedagainstsplashingwater)andcanbeusedevenintheroughestenvironments.Thewidespacebetweenthestirringareas(1)ensuresgoodventilationofthebottles,speciallyinanincubator.Thestirringdrive(2)isdrivenbyacontroller(3)withapre-setspeed.Whenturnedon,thesoftstartfeatureensuresauniformstartofthemagneticstirringrodsathalfspeed.

Every40seconds,thecontrollerreducesthestirringspeedby50%,re-centringthemagneticstirringrodinthemiddleofthebottle.

Themagneticstirringrodsaredrivensynchronously,preventingpracticallyanyinterfe-rencebetweenthem.

8.4 SetUp

DANGER!

Voltageandfrequencymustbewithintherangespecifiedforthecontrolunit(3)

DANGER! Magnetism.Magneticormetallicparts(e.g.datacarriers,pacemakers,watches...)canbeaffectedby

magneticfields.Keepsuchpartsawayfromthemagneticstirrer(2)andthemagneticstirringrods.

y CAUTION! Donotuseinhazardouslocations

y CAUTION! Generalambientconditions: Stirringdrive(2):-10to+56°Cat100%humidity. Controlunit(3):0to+40°Catmax.80%humidity. Avoidextremetemperaturechanges. Thecontrolunit(3)mustnotbeusedinareasofhighhumidityorinareaswherewatermaysplash!

Thecontrolunit(3)doesnothaveanyswitch.Itisreadyforuseassoonasitispluggedin:Connectthecable(5)fromthestirringdrive(2)withthesocket(4)ofthecontrolunit(3)andfixit.Plugthecontrolunit(3)intothemainssocket.Toensureproperstirringthefourscrewsatthebottomoftherackcanbeusedtooptimizethedistancebetweenstirringdriveandmagneticstirringrod.

25

8.5 Magneticstirringrods WerecommendtheuseofPTFE-coatedmagneticstirringrods.

i INFORMATION

Thelengthofthemagneticstirringrod(8)mustnotexceed40mm.

8.6 Stirring

y CAUTION! Donotplacehotsamplesonthemagneticstirrer(2). Maximumtemperature:56°C.

Fillthebottleswiththesample.

Placeamagneticstirringrodintoeverybottle.

PlacebottlesintheBODrack.

Thecontrolunit(3)ispresettooperateat320rpm.Every40secondsthespeedisreducedto200rpm,whichwillre-centerthenagneticstirringrod,ifnecessary.

Ifyouwanttostopthestirringprocess:

Disconnectthecontrolunit(3)fromthemainssocket.

26

8.7 MaintenanceandCleaning Thestirringdrive(2)ismaintenance-free.

Themagneticdriveisembeddedinasyntheticresinandiscompletelywatertight.Cleanthesurfaceofthestirringdrive(2)inregularintervalsusingacleaningoradisinfectantsolutionsuitableforuseonPVC.Cleanthesurfaceofthestirringcontroller(3)usingdrycloth.

y CAUTION! Incaseofrepair,theequipmentmustonlybeopenedbyanauthorisedserviceagent.Disconnectfrommainsbeforeopening!

8.8 Troubleshooting

8.8.1 Themagneticstirringrodrotatesunevenly:

Overtime,someageingof thestirringrodcannotbeavoided.Thismayreduce itsmagnetisation.

y CAUTION! Donotallowthemagneticstirringrodtocometorestinanalternatingmagneticfield(e.g.inanunfilledstirringvesselwhenthestirringormixingmodeisselected).Donotsubjectthemagneticstirringrodtoastronginversemagneticfieldortostrongimpactshocks(e.g.bydroppingit).Thismayresultindestructionofthemagneticstirring

rod.Replaceitbyanewone.

8.8.2 Thestirringrodswervesbackandforth:

Swervingmovementsofthestirringrodmaybecausedbyirregularshapedbottomofthebottle.Replacethebottlebyanewone.

27

9. TechnicalData

9.1 BODSystem

Type Oxi700

Measurementprinciple Manometric;mercury-free;electronicpressuresensor

Ranges 0-40,0-80,0-200,0-400,0-800,0-2000,0–4000mg/l[mg/lO2]

Applications BSB5,BSB7,OECD301F...

Resultdisplay BSB[mg/l];4-digits;7-segmentLED

Measurement BOD-range,volume,duration,displaytimeofmeasurementparameterdisplay

Measurementperiod User-selectable,between1and28days

Autoresultstorage upto28results,dependingonmeasurementperiod

Storageinterval –hourly(1day); (formeasurementperiodof...) –every2hours(2days); –daily(3-28days)

Automaticstartfunction –automaticstartafterpressuredecrease –canbeswitchedoff

Powersupply 3alkaline-manganesebatteries

Batterylife 1year(normaluseasBOD5meter–max.onereadingaday); Low-Batt-Indication

Clock Real-timeclock

Protectionclass IP54(sensorhead)

Dimensions 375x195x230mm (LxWxH) includingstirringunit

Housing ABS

Approval CE

28

9.2 InductiveStirringSystem

Type InductiveStirringSystem

Stirringvolume 6BODbottles

Stirringpower 7W

Rotationspeed 320rpm (reducedto200rpmevery40s)

Dimensions(WxDxH) 270x180x25mm

Distancebetween 88mm stirringpoints

Weight(stirringdrive) 1800g

Housingmaterial PVC

GeneralAmbientConditions -10to+56°Cat100%humidity

Operatingvoltage 20Vmax.

Controlcable 2m

Protectionclass IP68(DIN40050)

Stirringcontroller 230Vversion 220–240V/10V/50-60Hz,protectionclassII, thermalfuse,CE 115Vversion 110–120V/10V/50-60Hz,protectionclassII, thermalfuse,CE Permanentambientconditions 0to+40°Catmax.80%humidity Protectionclass IP20(DIN40050)

29

10. AccessoriesandSparePartsList

Article Ordercode

ReplacementBODsensor L2444430

ReplacementBODbaseunit L444433

Stirringcontroller L444413

Inductivestirringdrive L444411

TestSet L418328

Potassiumhydroxidesolution(50ml) L2418634

NitrificationinhibitorB(50ml) L2418642

BODsamplebottle L418644

Sealcup(gasket) L418636

Diagrampad L418663

Magneticstirringrod L418637

Magneticstirringrodremover L418638

Overflowmeasuringflask,428ml L418660

Overflowmeasuringflask,360ml L418659

Overflowmeasuringflask,244ml L418658

Overflowmeasuringflask,157ml L418657

Overflowmeasuringflask,94ml L418656

Overflowmeasuringflask,56ml L418655

Overflowmeasuringflask,21.7ml L418664

Completesetoverflowflasks L418654

Thermostaticallycontrolledincubators seegeneralcatalogue

Thermostaticallycontrolledincubatorswithglassdoor seegeneralcatalogue

Orbeco-HelligeInc.,185MarineStreet,Farmingdale,NY11735

Phone:631-293-4110,Fax:631-293-8258,service@orbeco.com,www.orbeco.com