NN31545.1227 *1227
oktober 1980
InstituutvoorCultuurtechniekenWaterhuishouding
Wageningen
IDENTIFICATIONOFORGANICCOMPOUNDSINTHELEACHATEOFAWASTETIP
J . Harmsen
BIBUOTVn i-tC
7
f..
>Ï'
X
Nota'svanhetInstituutzijninprincipeinternecommunicatiemiddelen, dusgeenofficiëlepublikaties.
Huninhoudvarieertsterkenkanzowelbetrekkinghebbenopeen
eenvoudigeweergavevancijferreeksen,alsopeenconcluderende
discussievanonderzoeksresultaten.Indemeestegevallenzullende
conclusiesechtervanvoorlopigeaardzijnomdathetonderzoeknog
nietisafgesloten.
Bepaaldenota'skomennietvoorverspreidingbuitenhetInstituut
inaanmerking.
CENTRALE LANDBOUWCATALOGUS
0000 0009 2219
SN
WU oc,2- oZ
C O N T E N T S
page
ABSTRACT
1
INTRODUCTION
I
ORGANICCONTAMINATIONOFTHELEACHATE
2
FREEVOLATILEFATTYACIDS
3
VOLATILEAMINES
5
HIGHMOLECULARCOMPOUNDS
6
ALIPHATIC,AROMATICANDPOLARCOMPOUNDS
8
ALIPHATICCOMPOUNDS
10
AROMATICCOMPOUNDS
11
POLAR,OXIDIZEDCOMPOUNDS
COMPLEXATIONOFHEAVYMETALSWITHORGANICCOMPOUNDS
14
15
ACKNOWLEDGEMENT
17
SUMMARY
17
LITERATURE
18
ABSTRACT
Twodifferenttypesofleachatefromawastetiphavebeenresearched.Forthatpurposesomeanalyticalmethodsweredeveloped.Thefirst
typeofleachatewassampledfromawastetipintheacidification
stage.Inthisleachatethelargerpartoftheorganicloadconsists
offreevolatileacids (95to100%oftheCOD).Volatileaminesand
ethanol (1.2%respectively 1%oftheCOD)werealsopresent.The
leachatewasextractedwithhexaneandtheextractwasanalyzedwith
infraredandnuclearmagneticresonancespectrometrieandagaschromatograph-mass spectrometer combination.Intheextractalcohols,
oil,esters,terpenesandphtalateshavebeenidentified.High
molecularcompoundswereonlypresentinalowconcentration.
Thesecond leachate,takenfromawastetipinthemethanefermentationstagecontainedmuchmorehighmolecularcompounds.About
32%oftheorganiccarbonconsistsofcompoundswithamolecularweight
over 1000.Inthiswaternoacids,aminesandalcoholscouldbedetected.Thismeansthattheorganiccompoundswereendproductsofdegradationprocesses.
Furthermore therewasaremarkabledifferenceinheavymetal
contentbetweenthetwoleachatetypes.
INTRODUCTION
IntheNetherlandsalargepartofthemunicipalrefuseisdepositedatwastetips.Thedumpedrefuseisleachedbypercolating
rainwaterandtheleachedcontaminantsmaypenetratethegroundwater
system.Thereforeitisimportanttoknowwhichcompoundsarepresent
intheleachate.Thepresenceoforganiccompoundsisofparticular
interestastheyplayaroleinthetransportofheavymetals:metal
ionsmaybecomeverymobileinthesoilwhentheyformwatersoluble
complexeswithorganicsubstances.
Inthepresentedresearch twotypesofleachatewereinvestigated.
Thefirstone (leachateI)wascollectedatanine-yearoldpartof
thewaste tipofAmbt-Delden,situated intheregionofTwentheinthe
easternNetherlands.Thewastetipisacontrolledone,i.e.therefuse
isdailycompactedandcoveredwithsand.Theleachatesampleshave
beentakenfromatiledrainagesystemjustbeneaththetip.
Thesecond type (leachateII)wascollectedatthewastetipof
WijsterinthenorthernpartoftheNetherlands.Therefuseatthe
samplingpointwasabouttwoyearsold.Onthistiptherefuseisnot
compactedandonlycoveredwithsand.Thesampleshavebeentakenin
thesamewayasinDelden.
Earlierresearchonorganiccompoundsinleachatesfromwastetips
wascarriedoutbyROBERTSONetal. (1), CHIANandDEWALLE (2)and
HARMSEN(3).
Theherepresentedresearchshowsthattherearelargedifferences
intheorganicloadofleachate,dependingonthefermentationstage
oftherefuse.Ingeneraltherearetwomaintypesofleachate.This
articledescribed thepresenceofdifferentorganiccompoundsinthese
twotypesofleachateandtheanalyticalmethodsused.
ORGANICCONTAMINATIONOFTHELEACHATE
Theorganicloadofthetwotypesofleachateiscompletelydifferent (Table 1).TheleachatefromDelden,furtheroncalledleachateI,
hasveryhighCOD (ChemicalOxygenDemand),TOC (TotalOrganicCarbon)
Table 1.COD,TOCandBODvaluesoftheleachates
LeachateI
COD mg.l -1 0 2
LeachateII
60,000
7000
1
20,000
2100
-1
30,000
50
TOC mg.l" C
BOD mg.l 0 9
andBOD (BiologicalOxygenDemand)values.For leachateIIfromWijster
thesevaluesaremuch lower,especially thelowBODvalueisremarkable.
Thisshowsthattheorganiccompoundsaremoreorlessendproductsof
thedegradation.
ResearchofHOEKSandBORST (4)hasindicated thattheorganic
loadofleachateIdrastically changedinasoilcolumnbymethane
fermentation.Theorganicloadoftheeffluentiscomparablewith
leachateII.Inawastetiptheprocessofmethanefermentationalso
takesplace.
LeachateIisproduced intheacidificationstageandleachateII
inthemethanefermentationstage.Thesestageshavebeendescribed
byFARQUHARandROVERS(5).
Intheacidificationstage,complexorganiccompoundsarefermented
anaerobically,yielding solubleorganicacids (freevolatilefatty
acids),aminoacidsandotherlowmolecularcompoundsandgaseslike
H„andCO».Inthemethanefermentationstagefreevolatileacidsare
fermentedyieldingCH,andC0„gasasendproducts.
Theorganicloadalsoinfluences thepH.InleachateIthepHis
5.7andinleachateIIabout7.AtthehigherpHthesolubilityof
theproducedC0„ishigher.ThebicarbonatecontentinleachateIis
17mg.l"1 HCO~andinleachateII 12,000mg.l _1 HC0~.
TheorganicloadofleachateIwasveryhigh,asappearedfrom
theCODwhichamounted toabout60,000mg.l
0„.Thelargerpartof
theseoxidizablecompoundscaneasilybedeterminedbygaschromatography.Thisisespecially trueforthefreevolatilefattyacids (C?
toandincluding C^). Inthiscasethewatersamplecandirectlybe
injected intothegasChromatograph (foraresultseeFig.1).
Aproblemwiththeanalysisoffattyacidsisthepollutionof
theinjectionpartoftheChromatograph,whichcausesso-calledghost
peakswhenwaterisinjectedafterwards.Becauseoftheirpolar
charactertheacidsareadsorbedintheinjectionport.Whenwateris
injectedtheacidsdesorbandgive'peaksatthesameplaceastheacids
1
detector
signal
acid
cid
•o
c
u
u
o
u
O
§ .y
y
*
n
o
io
aceti
propio
•D
10
1 *-
«
U
I
I
I
1_
10
20
time inmin.
I
i
1
i
1
Fig.1.GaschromatogramofC.-C,acids.Column3%Carbowax20M; 0.5%
HP0,onCarbopackB;6feetx1/8inchglass.CarriergasN
—
1
r\
40ml.min .Temp,column 170Cduring7min.;in1minuteto
210°C.Sample1]ilof0.01%ofeachacidin1%formicacid
tobeanalyzed.Theghostinglargelycanbeavoidedbyadding1mlof
formicacidtoa100mlsample.Theformicacidismorepolarthanthe
otheracidsandisthereforepreferently adsorbed,therebyreducing
theghostingtoanacceptable level (HARMSEN, 6).
Withthemethoddevelopedtheacids,aceticaciduptoandincludingcapronicacid,havebeenanalyzed.VANENGERS (7)hasalsodeterminedenanthicacid.TheresultsaregiveninTable2.Theaccuracy
oftheseanalysesisabout5to10%.ReferingtoTable2theconclusion
isthattheacidsrepresent95to100%ofthetotalCOD.
InleachateIInovolatileacidscouldbedetected.
Table2.FreevolatilefattyacidsinleachateI(COD65,000mg.l 0 2 )
-1
Conc^in
mg.lx
CODcaused
bytheacid
inmg.l 10„
11,000
11,730
17.9
3,760
5,690
8.7
520
950
1.4
9,890
17,980
27.4
2-methylbutyricacid
350
710
1.1
iso-valericacid
320
650
1.0
2,510
5,118
7.8
70
150
0.2
caproicacid
5,770
12,730
19.4
enanthicacid
5,200
12,160
18.5
Acid
aceticacid
propionicacid
iso-butyricacid
butyricacid
valericacid
iso-caproicacid
total
VOLATILEAMINES
Theaminesinleachatecanalsobedeterminedbygaschromatography
withoutconcentrating thembeforehand (MUYLAERT,8).Anexampleis
giveninFig.2.
Againghostingisaproblem,becausetheaminesarepolar.The
ghostpeakscanbereduced toanacceptablelevelbyadding 1gof
K0Hand20mlof25%ammoniato 100mlofsample.Resultsconcerning
leachateIaregiveninTable3.
Withthiscolumnethanolisalsodetermined.Theethanolconcentrationwas277ml.l ,whichrepresents 1%oftheCOD.InleachateII
noaminesandethanolweredetected.
Percentage
oftotalCOD
103.4
d«tector
signal
«- E?
•E e
E *o
° E >v
*• E S 5 o «>
Ê KM
0) E
•E E
BS
o >,
>.5
J^
_j^
«
i
yU u
Ui
i_
15
•time in min
10
Fig.2.Gaschromatogramofvolatileamines.Column4%Carbowax20M;
0.8%KOHonCarbopackB;6feetx 1/8inchglass.CarriergasN»
20ml.min ;temp.column70Cduring5min.;with4Cpermin.
to150°C.Sample0.5ylof0.01%ofeachaminein5%NH and
1%KOH
Table3.VolatileaminesintheleachateI (COD56,000mg.l 0 2 )
Amine
Cone,in
mg.l
COD caused by
the amines in
mg. L- 0 2
Percentage
of totalCOD
trimethylamine
6
83
9
201
t-butylamine
43
0.48
0.15
methylamine
sec-butylamine
102
114
268
iso-butylamine
32
83
total
HIGHMOLECULARCOMPOUNDS
Withmembranefiltrationandgelpermeationthepresenceofhigh
molecularcompoundscanbeestablished.ThiswasdonebyChianandDe
0.02
0.36
0.20
J.21
Walle.Usingmembranefiltrationtheyfound that 11.1%oftheTOChad
amolecularweightover 100,000.Withgelpermeationtheyfoundonly
6%oftheTOChavingamolecularweightofmorethan50,000.Theydid
notexplainthedifference.Fromtheheredescribedexperimentsit
appeared thatmembranefiltrationdidnotgivesatisfyingresultswhen
applied toleachateI,becausethefreevolatileacidsadsorbedinthe
filtersandthefilterhousing.Thisisthereasonwhythereduction
inCODafterfiltering cannotbeattributed tothepresenceofhigh
molecularcompounds (BEKER,9). PossibleChianandDeWallehavehad
thesameproblems,becauseintheirleachatevolatileacidswerealso
present.Probably theirresultswithgelpermeationwillbemorereliable.
Inthiscasegelpermeationhasgivengoodresults.Theleachates
weresupplied toagelpermeationcolumn (SephadexG-75).Theeffluent
wassampledbyafractioncollectorandthefractionswereanalyzed
forTOC.TheresultsaregiveninFig.3.Thefirstpeakiscausedby
highmolecularcompoundswithamolecularweightofmorethan50,000,
thelastpeakby lowmolecularoneswithamolecularweightofless
orabout 1000.Sinceasmallpartof theSephadexwasleachedfromthe
column,thebackgroundvalueoftheTOCwasabout 10mg.l C.
TOCmax=6000
TOC m g l ' 1
-,500
i
400
- 300
- 200
- 100
50
effluent inml.
F i g . 3 . TOC v a l u e s i n f r a c t i o n s of l e a c h a t e passed through a Sephadex
G-75 column (column dimension 60 x 1 cm; e l u a n t : d i s t i l l e d water
2 ml.hr
sample 1 ml, f r a c t i o n i n g every 30 minutes)
LeachateIcontainedonlyarelativesmallamountofhighmolecular
compoundscomparedwiththelowmolecularcompounds likeacidsandamines.
Thehighmolecularcompoundsrepresentedonly0.5%oftheTOC.About
0.8%oftheTOCwasattributabletocompoundswithamolecularweight
between 1000and50,000.TherestoftheTOCwasrelatedwithlow
molecularcompounds.
InleachateIIabout 12%oftheTOCcouldbeattributed tothe
presenceofcompoundswithamolecularweightofmorethan50,000and
20%tocompoundswithamolecularweightbetween 1000and50,000.The
remainingpartconsistedoflowmolecularcompounds.
Comparing leachateIandIIitcanbeconcluded thattheabsolute
amountofhighmolecularcompoundsisincreasedbyafactorof2.6,when
goingfromleachateItoII.Theabsoluteamountoflowmolecularones
isdecreasedbyafactorof10.
Theamountofhighmolecular compounds (50,000)intheleachate
asreportedbyChianandDeWalle,amountedto6%oftheTOC,while
thevolatileacidswerestillpresent.Thisindicates thattheleachate
investigatedbythemwasinafermentationstagesomewherebetweenthe
acidificationandmethanefermentationstage.
ThehighmolecularcompoundsinleachateIIwillbeofhumic
origin.Alsothelowmolecularcompoundswillpartly consistofhumic
andfulvicacids,since40%oftheCODprecipitateswhenthewateris
acified.At300°C75%isstillnon-volatile.
CHIAN (10)hasreportedsomemoredetailsonthemolecularweight
distribution.Heobserved thattheamountofvolatileacidsandhighmolecular
compoundsdecreasedwithtime,whencomparingwastetipsofdifferentages.
Hisresultsdonotcompletelyagreewiththeresultspublishedhere,becausetheseresultsshowthattheamountofhighmolecularcompoundsincreasedwithdecreasingamountofacids.Itis,however,likelythaton
thelongruntheamountofhighmolecularcompoundsalsowilldecrease.
Thereforenotonlythestageoffermentation,butultimatelyalsotheage
ofthewastetipwillinfluencetheamountoforganicsintheleachate.
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
Lab litt
heating m a n t l e
energy r e g u l a t o r unit
destination b o t t l e 3 1
d e s t i n a t i o n collumn
thermometer
cooler
teflon v a l v e
inlet tube hexane
sample flask 20-t
magnetic s t i r r e r ( w a t e r p o w e r )
r e t u r n t u b e w i t h w a t e r seal
all glas connections NS 2 9
unless stated else
Fig.4.Apparatusforcontinuousextractionofwatersamples
ALIPHATIC,AROMATICANDPOLARCOMPOUNDS
Theremainingcompoundshavebeeninvestigatedbyextractingthe
leachatewithhexane.Tothispurposeanapparatusforcontinuousextractionwasconstructed (seeFig.4).Asimilarapparatushasbeen
usedbyMEIJERSandVANDERLEER (11).
Thehexanesolutionisconcentratedbyevaporationandtheacids
andbasesareremovedbyextractionwithdilutedHClandNaOH.Next
theextractisadded toacolumnofsilica-gel (Fisher S662).The
aliphaticcompounds (oil)areelutedwithhexane,thearomaticones
withbenzeneand thepolarcompounds (theso-called 'oxys')with
chloroform-methanol (1:1).
Table4.Withhexaneextractablecompoundsintheleachateinmg.l
LeachateI
LeachateII
aliphaticcompounds
0.64
0.09
aromaticcompounds
1.21
0.38
oxys
12.5
4.38
Theelutedfractionshavebeeninvestigatedbygaschromatography.
TheresultsaregiveninTable4.Sincehexaneonlypoorlyextractsthe
morepolarcomponents,theactualconcentrations intheleachate,as
farasaromaticcompoundsandoxysareconcerned,willbehigherasreportedhere.
ALIPHATICCOMPOUNDS
Thealiphaticsareeasily identified inthechromatogram.They
couldbenamedwiththeaidofstandards.Thechromatogramofleachate
I isgiveninFig.5.Fromthisfigureitappears thatthealiphatics
mayoriginatefromlighttoheavygasoil(C.^-C^r)andlubricantsand
waxes (COS-COQ)•
ThechromatogramofleachateIIiscompletely identical,indicating
thatthesamealiphaticsarefound.Only thetotalamountofaliphatics
ismuchsmallerinleachateI(Table 4).Thismaybecausedbythe
highamountofvolatileacidsinleachateI,becausethesolubility
ofhydrocarbons israisedbythepresenceoftheseacids.
10
n- 30 29 26 24 22 20 18
16
14
Fig.5.Gaschromatogramaliphaticcompounds inleachateI
AROMATICCOMPOUNDS
Thearomaticsinthegaschromatogramscannoteasilybenamed.
Fortheidentificationofthesecompoundsotherdetectionmethodsare
needed.Inthisresearchthearomaticfractionswereinvestigatedby
infraredspectrometryandnuclearmagneticresonance.Thespectraof
leachateIaregiveninFigs.6and 7.ForleachateIItheconcentrationsweretoolowtogiveclearpeaks.IntheNMRspectrumonlya
peakforaromaticsandintheIRspectrumapeakfortheC=0group
wastobeseeninthehexaneextractoftheleachate.Becauseofthe
littleinformationsgotfromthespectra,thespectraofleachateII
arenotpresented.
IntheNMRspectra6-IIIand6-IVthepeaksarefoundatsomewhat
lower6-value(0.1ppm)becauseoftheeffectofthebenzenesolvent.
Thepeakat 1.6ppminspectrum5-IIIindicatestheexistenceofa-C=
C-H«group,thepeakat2.1ppmreferstoa-C-CH^-C=Cgroupand
theoneat2.2ppmtoCH„substituted toanaromaticring.Thepeaks
11
é iti nuit
100
90
SO
"T
Fig.6.NMRspectraofleachateI.I,withhexaneextracted compounds; II,
afterremovingacidsandbases;III,aromaticcompounds;IV,oxys
4000
m —i
3000
1000
2000
Fl
I • • • • I • • • I I I • • • I I I I I I I t 1 1 I • I
4000
3000
wave-number inem"1
2000
•
'
'
•
'
'
1000
Fig.7.InfraredspectraofleachateI.I,extractafterremoving
acidsandbases;II,aromaticcompounds;III,oxys
12
« Tl
E '
1 *°
m <M
•*%•
u
0
\
30
time in min
Fig.8.
GaschromatogramofthearomaticcompoundsinleachateI,mentioningthosethathavebeenidentifiedbyGC-MS.ColumnOV17;5
feetx1/4inchglass.CarriergasHe30ml.min ;temp,column
70-200°C;8°C.min-1.DetectionwithVGMicromass70-70
at4.0ppmrefertobothestersandethers.Thepresenceofestersis
confirmedbythepeakat1700cm intheinfraredspectrum7-II.
Fig.6alsoshowsthatafterremovingacidsandbases,thepeak
-..C *-l-~ ^ V A _ . M ^ ^ n n
OJL
Luc
d i. u m c t L.±.L-o
„j- ~7 A —,«*w V n » *->-»~ ^ r-*——11^ ~ T«- •*»..n4- V.« r*r\r\••*1 *"^f\A
ÖL.
/ . u
L>L/UI U C L U U C O
D i u a i i c L • x L. I U U O I . u o
L U U ^ i u u c u
thereforethataromaticbasesoracidsarepresentintheleachate.
ThearomaticfractionofleachateIhasalsobeeninvestigated
withtheaidof
agasChromatographmass-spectrometer combinationVG
Micromass 70-70.TheresultsaregiveninFig.8.Atypicalproblemwas
metinthemass-spectraofseveralpeaksinthechromatogram.Theyall
hadincommonmasspeaksat99and117.Thesespectrabelongtoester
ofcaproicacid.
InFig.8smallaromaticcompoundsdetectedbygaschromatography
arementioned.Theeluatewhichwasobtainedbypercolating thesilicagel
columnwithbenzenewasreferredto
asthearomaticfraction,because
thearomatichydrocarbonsarepresentinthisfraction.Ofcoursealso
othernon-aromaticcompoundswithapolaritycomparabletothearomatics
maybepresent.ThisisquiteclearfromthechromatograminFig.8.
13
AstheexperimentswithNMRandIRdidshowaromaticcompoundsthey
willbepresentintheextract,butprobably theycannotbedetermined
withthegaschromatographicmethodused.Capillaryorliquidchromatographywillmostprobably givebetterresults.
Unfortunately therewasnoopportunity toanalyzeleachateIIwith
mass-spectrometry,sinceatthetimeoftheexperiments theGC-MSwas
notavailable.
POLAR,OXIDIZEDCOMPOUNDS
Theoxyshavealsobeeninvestigatedwithinfraredspectrometry,
NMRandmass-spectrometry.SincemethanoldoesinfluencetheIRand
NMRspectra,theoxyswereelutedwithchloroforminsteadofchloroformmethanol.Thischangeineluantdidnotinfluencethechromatogram.
In'theIRandNMRspectrathebenzenesolventisalsovisible.
TheresultsofleachateIarepresentedinFigs.6and 7.TheNMRpeaks
at4.0ppmrefertoestersandethers,at3.5ppmtoalcohols(-CH„-0H
or-CH-OH),at2ppmtodoubleboundsandthepeaksat0.9and 1.5ppm
to-CEL-and-CFL.Thepeakofthe-OHgroupcanbefoundatabout
0.5ppm.This6-valueisvery low,becauseofthelowconcentration
ofthe-OHgroups.Athigher-OHconcentration therewillbeinteraction
betweendifferentOHgroups,resultinginahigher6-value.Thepresence
ofestersandalcoholsisconfirmedbytheIRspectrum7-IIIbecause
ofthepresenceoftheC=0peakat 1700cm andthe-OHpeakat
3400cm"1.
Asalreadymentioned theNMRandIRspectraofleachateIIare
notpresentedherebecausetherewereonlyafewpeakspresent.The
absenceoftheOHpeakintheIRspectrumindicates thatalcoholsare
notpresentinleachateII.
Inbothleachatesn-butylphtalateandiso-octylphtalatecouldbe
identifiedwhichisinaccordancewith thepresenceoftheC=0peak
intheIRspectra.
ThepxysinleachateIwereinvestigatedwithGC-MS.Theresults
arepresented inFig.9.
14
.30.
timein m m
Fig.9.GaschromatogramoftheoxysinleachateI,mentioning those
identifiedbyGC-MS.ColumnSilar5C;5feetx 1/4inchglass,
CarriergasHe30ml.min .Temp.
Temp,(column80-250°C;8°C.min
DetectionwithVGMicromass70-70
C0MPLEXATI0NOFHEAVYMETALSWITHORGANICCOMPOUNDS
Therewasaremarkabledifferenceinheavymetalcontentbetween
thetwotypesofleachate(Table 5). Thisdifferenceisrelatedtothe
organicloadintheleachate.
Table5.Heavymetalsintheleachatesinmg.l
LeachateI
Fe
1120
Mn
53
-1
LeachateII
40
0.24
Cd
0.01
0.02
Cu
0.65
0.20
Ni
1.04
0.40
Pb
0.17
1.0
Zn
54
1.6
15
During theacidificationstageinthewastetip (leachateI)the
metalsarekeptinsolutionbycomplexationwith thefreevolatile
acids.Inthemethanefermentationstage (leachateII)theacidsdisappearandthereisonlyarelativesmallamountoforganiccompounds
leftwithdifferingcomplexingfeatures.Thisgivesachangeinthe
metalconcentrations.Leadforinstanceisknownasametalwhichforms
verystablecomplexeswithhumicacidsandthismaybethereasonthat
leadispresentinahigherconcentrationinleachateII.Moredetails
aboutthebehaviouroftheheavymetalsarepublishedbyHOEKSand
BEKER (12).
TheeffluentoftheSephadexcolumnwhichwasusedtostudythe
molecularweightdistributioninleachateII,isalsoinvestigated
withrespecttoafewheavymetals.TheresultsaregiveninFig.10.
Pbmg r'
O 35
Fe mg-l
10 r
Znmg-r
0.60 r
mol wght 41000
TOC m g . r '
160
0.30
!\
8 -
120
0.40
0.25
0.20
80
020
0.15
0.10
- 40
O05
o t-
...... .-L
40
effluent (ml)
Fig. 10.HeavymetalsinfractionsofleachateIIpassed througha
SephadexG75column (columnandeluantasinFig.3,sample
0.5ml,fractioningevery30minutes)
Itisclearthatironandleadhaveformedcomplexesmainlywith
thehighmolecularcompounds,whilezincisassociatedwiththelow
molecularones.
Moreaboutthissubjectwillbepublished infuture.
16
0
ACKNOWLEDGEMENT
Itisgratefullyacknowledged thatforIR,NMRandGC-MSanalyses
usewasmadeofthefacilitiesoftheDepartmentofOrganicChemistry
oftheAgriculturalUniversity inWageningen.Inparticulartheauthor
wishestothankDr.M.PosthumusforhisaidwiththeGC-MScombination.
SUMMARY
Twocharacteristic typesofleachatesofawastetiphavebeen
investigatedwithrespecttoorganiccompounds.Forthatpurposesome
analyticalmethodsweredeveloped.
Thefirsttypeofleachatewascollectedfromawastetipinthe
acidificationstage.Thelargerpartoftheorganicsinthisleachate,
95to 100%oftheCOD^appearedtoconsistoffreevolatilefattyacids.
Theacidshavebeenanalyzedbygaschromatography.Ghostingwasa
problem,butthiscouldlargelybeeliminatedbytheadditionofformic
acid.
Thevolatileaminescouldbeanalyzedinasimilarwayasthe
acids.Theyrepresentabout 1.2%oftheCOD.Ethanol,1%oftheCOD,
couldalsobeanalyzedwiththecolumnusedforamines.
TheremainderpartoftheCODwasinvestigatedbyextractingthe
leachatewithhexane.Theextractwasseparatedintoanaliphatic,an
aromaticandamorepolarfractionbycolumnchromatography.These
fractionswereanalyzedbygaschromatography,IR,NMRandalsobya
gasChromatographmass-spectrometer combination.Severalcompoundshave
beenidentified,amongwhichoil,alcohols,esters,terpenesand
phtalates.
Itwasnotpossibletoestablishthepresenceofhighmolecular
compoundswithmembranefilters,because theacidswereadsorbedinthe
filters.Gelpermeationgavemorereliableresults.About0.5%ofthe
TOChadamolecularweightmorethan50,000and0.8%between 1000and
50,000.
Inthesecond leachate,takenfromawastetipinthemethane
fermentationstage,about 12%oftheTOChadamolecularweightofmore
17
than50,000and20%between 1000and50,000.
Inthisleachatenovolatileacids,aminesandalcoholscouldbe
identified.Theorganicloadwasrelatively lowandbecauseofthe
remarkablelowBOD-value (highC0D/B0Dratio)itisconcludedthat
theorganiccompoundspresentaremoreorlessendproductsofthe
degradationprocess.Probablymostoftheorganicsconsistofhumic
andfulvicacids.
Notonlythenatureoftheorganiccompoundsinthetwotypesof
leachatediffers,butalsotheamountofheavymetalscomplexedby
thesecompounds.Thiscanbeexplainedbydifferentcomplexingfeatures
oftheorganiccompounds.Withgelpermeationitisshownthatsome
metalsarebettercomplexedbyhighmolecularcompoundsandsomeby
lowmolecularones.
LITERATURE
(1) ROBERTSON,J.M.,L.R.TOUSSAINTandM.A.JARQUE. 1974.Organic
compoundsenteringgroundwaterfromalandfill.Environmental
ProtectionTechnologySeriesEPA660/2-74-077.47pp.
(2) CHIAN,S.K.andF.B.DEWALLE. 1977.Characterizationofsoluble
organicmatterinleachate.Environ.Sei.Technol.10:158-163.
(3) HARMSEN,J. 1977.Analysisofdissolved organiccompounds inthe
leachateofthewastetipAmbt-Delden.Nota 1010ICW,Wageningen.29pp (inDutch).
(4) HOEKS,J.andR.J.BORST. 1980.Anaerobicdigestionoffree
volatilefattyacidsinsoilsbelowwaste tips.Water,Airand
SoilPoll, (inpress).
(5) FARQUHAR,G.J.andF.A.ROVERS.1973.Gasproductionduringrefuse
decomposition.Water,AirandSoilPoll.2:483-495.
(6) HARMSEN,J. 1977.Gaschromatographicanalysisoffreevolatile
fattyacidsinwater.Nota980ICW,Wageningen. 18pp(in
Dutch).
(7) ENGERS,L.E.VAN. 1976.Mineralisationoforganicmatterbelowa
wastetip.SVA/1849,Amersfoort (inDutch).
(8) MUYLAERT,J.M. 1979.Gaschromatographic analysisofvolatile
aminesinwater.Nota 1120ICW,Wageningen. 19pp (inDutch).
18
(9) BEKER,D. 1977.Personalinformation
(10)CHIAN,E.S.K. 1977.Stabilityoforganicmatterinlandfill
leachates.WaterResearch 11:225-232.
(11)MEUERS,A.P.andR.Chr.VANDERLEER. 1976.Theoccurrenceof
organicmicropollutantsintheriverRhineandtheriverMaas
in 1974.WaterResearch 10:597-604.
(12)HOEKS,J.andD.BEKER. 1980.Behaviourofinorganicionsand
heavymetalsinsoilsbelowwastetips (inpress).
19