IS/ISO 14853: Determination of ultimate aerobic diodegradability of plastic materials in and aqueous medium - Method by Measurement of biogas production

2005·10.9 MB·English

by  Bureau of Indian Standards

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IS/ISO 14853 (2005): Determination of ultimate aerobic
diodegradability of plastic materials in and aqueous medium
- Method by Measurement of biogas production [PCD 12:
Plastics]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

ISIISO 14853 : 2005

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Indian Standard
PLASTICS - DETERMINATION OF THE ULTIMATE
ANAEROBIC BIODEGRADATION OF PLASTIC
MATERIALS IN AN AQUEOUS SYSTEM - METHOD BY
MEASUREMENT OF BIOGAS PRODUCTION
ICS 83,010,01
e
SIS 2009
BUREAU OF IND IAN STANDARDS
MANAK SHAVAN. 9 SAHADUR SHAH ZAFAR MARG
NEWDELHI110002
January 2009 PriceGroup10
Plastics SectionalCommittee.PCD 12
NATIONALFOREWORD
This Indian Standard which is identical with ISO 14853 :2005 'Plastics - Determination of the ultimate
anaerobicbiodegradation ofplastic materials inanaqueoussystem- Methodby measurementofbiogas
production'issuedbytheInternationalOrganization forStandardization(ISO) wasadoptedbytheBureauof
IndianStandardsontherecommendationofthePlasticsSectionalCommitteeandapprovaiofthePetroleum,
CoalandRelatedProductsDivisionCouncil.
The text of ISO Standard has been approved as suitable for publication as an Indian Standard without
deviations. Certainconventions are, however, not identical to thoseused in Indian Standards.Attentionis
particularlydrawn tothe following:
a) Whereverthewords'InternationalStandard'appearreferringtothis standard,theyshouldbe readas
'IndianStandard'.
b) Comma(,)has been used as adecimal markerwhile inIndian Standards,the currentpractice isto
use apoint(.)as the decimal marker. .
Thetechnicalcommitteeresponsibleforthepreparationofthisstandardhas reviewedthe provisionsofthe
following lnternational Standardsand has decided that they are acceptablefor use inconjunction with this
standard:
InternationalStandard Title
ISO8245:1999 Waterquality- Guidelinesforthedeterminationoftotal organiccarbon(TOC)
and dissolvedorganic carbon(DOC)
ISO 13641(allparts) Water quality - Determination of inhibition of gas production of anaerobic
bacteria
In reporting the results of a test or analysis made in accordance with this standard, if the final value.
observed or calculated, is to be rounded off, it shall be done in accordance with IS 2 : 1960 'Rules for
roundingoffnumericalvalues(revised)',
ISIlSO 14853: 2005
Indian Standard
PLASTICS - DETERMINATION OF THE ULTIMATE
ANAEROBIC BIODEGRADATION OF PLASTIC
MATERIALS IN AN AQUEOUS SYSTEM - METHOD BY
MEASUREMENT OF BIOGAS PRODUCTION
WARNING- Sewage and activated sludge may contain potentially pathogenic organisms. Therefore
appropriate precautions should be taken when handling them. Digesting sewage sludge produces
flammable gases which present fire and explosion risks.Care should be taken when transporting and
storing quantities of digesting sludge. Toxic test chemicals and those whoso properties are not
known should be handled with care and in accordance with safety instructions. The pressure meter
and microsyringes should be handled carefully to avoid needle stick injuries. Contaminated syringe
needles should be disposed ofinasafemanner.
1 Scope
ThismternationalStandard specifies amethodforthe oeterrmnanon ofthe ultimateanaerob.cbl()degradablhty
of plastics by anaerotnc rmcroorqarusms The condrnons described In trus rntemauonat Standard do not
necessanly correspond to the opt.mum condrnons for Ihe maximum degree of biodegradation 10 occur The
lest calls for exposure of the test material to sludge for a penod of up to 60 days. which .s longer than the
normal sludge retention lime (25 10 30days) In anaerobic digesters.though digesters at Industnal sites can
have muchlongerretentrontimes
Themethod applies tothe follOWingmatenals
Naturaland/or synthehcpolymers.copolymers ormixtures thereof.
Plasticmaterialswhich containadditives such as ptasnozers.colorantsorothercompounds:
Water-solublepolymers,
Matenals which. under the test conditions. do not Inhibit the microorganisms present 10 the inoculum
lntubrtorveffectscan be determined uSIOganmhlbltlon control or byanotherappropnate method (seeeg
ISO 13641) Ifthe test matenat ISmhlbltory to the Inoculum,a lowertest concentration,another Inoculum
orapre-exposed Inoculumcan beused
2 Normative references
The following referenced documents are indispensable for the apphcation of trus document FOf dated
references. only the edition Cited apphes. For undated references. the latest edit,on 01 the referenced
document(indudlngany amendments)applies
ISO8245, Water quality - Guidetmes for the determmatton of total organic carbon (TOG) and dissotve<1
organiccarbon (DOC)
ISO 13641 (allparts).Waterquality - Detemxnstiot:ofinhIbitionofgasproductton ofanaerobicbactena

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ISIISO 14853: 2005
3 Terms and definitions
Forthe purposesofthisdocument,the followingterms anddefinitions apply.
3.1
ultima..anaerobic: biodegradation . .
breakdownofanorganiccompoundby microorganismsinthe absenceofoxygen tocarbon dioxide.methane.
water andmineralsaltsof any other elementspresent (mineralization)plus newbiomass
3.2
primaryanaerobicbiodegradation
structural change (transformation) of a chemical compound by microorganisms, resulting in the loss of a
specificproperty
3.3
diges1IIdsludge
mixtureofsettledsewage and activatedsludge which have been incubated in an anaerobic digesterat about
35·C toreduce the biomassand odourandtoimprovethe dewaterabilityofthe sludge
NOTE Digested sludge contains an associationof anaerobic fermentative and methanogenic bacteria producing
ca1bondioxideandmethane
3.4
cor....nb.tIonofsuspendedsolidsIn digestedsludge
amount of solids obtained by filtration or centrifugation of a known volume of activated sludge and drying at
about105·Ctoconstantmass
3.5
d6se0fvedorganiccarbon
DOC
organiccarbon inthe waterphase which cannot be removed by specified phase separation, for example by
centrifugation at40000 ms-2for 15min or by membranefiltration using membranes with pores of 0,2 IJmto
0,045~diameter
3.'
inorganiccarbon
IC
Il'lOfganiccarbonwhich is dissolvedor dispersedinthe aqueousphaseofa liquid and is recoverablefrom the
supernatantliquid aft8fthe sludgehas beenallowed to settle
3.7
total drysolids
!he amount of solids obtained by taking a known volume of test material or inoculum and drying at about
l05·Ctoconstantmass
U
theoreticatamountofevolvedbiogu
ThbIoplI
maximl.m theoretical amount of biogas (CH. + CO2) evolved after complete biodegradation of an organic
malllriel under anaerobic oonditions, calculated from the molecular formula and expressed as millilitres of
biogasewMldpermilligramoftestmaterialun<l8fstandardconditions
U
thecntIAIamountofevolwdcarbon dioxide
~
maxml.m ttleon!ticaI amount of carbon dioxide evotvedafter complete oxidation of an organic rnatenal.
cak:'II.....d fromthe molecular formula and expressed as milligrams of carbon dioxide per mHligram of test
material

II
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ISIISO 14853: 2005
3.10
theoreticalamountofevolvedmethane
ThCH"
maximum theoretical amount of methane evolved after complete reduction of an organICmatenal,calculated
fromthemolecularformula and expressedasmilligramsofmethaneevolvedper milligramoftestmatenal
3.11
lagphase
lag period
time, measured in days, from the start of a test until adaptation and/or selection of the degrading
microorganismsisachievedand the degreeof biodegradation of a chemical compound or organicmatterhas
increasedtoabout 10%ofthe maximumlevel ofbiodegradation
3.12
plateauphase
time, measuredindays, from the end ofthebiodegradationphaseuntil the end ofthetest
3.13
biodegradationpha..
time, measured in days, from the end of the lag phase of a test until about 90 0,4of the maximum level of
biodegradationhas been reached
3.14
maximumlevelofbiodegradation
degree of biodegradation, measured in percent. of a chemical compound or organic matter in a test. above
whichnofurtherbiodegradationtakesplace duringthe test
4 Principle
The biodegradability of a plastic material is determined using anaerobic conditions in an aqueous system
Test material with a concentration of 20mgll to 200 mgll organic carbon (OC) is incubated at (35 t 2)·C In
sealed vessels together with digested sludge for a period normally not exceeding 60 days Before use. the
digestedsludge iswashed so that it containsvery low amounts ofinorganic carbon (IC) and dilutedto 1gJllo
3giltotal solids concentration.The increaseinheadspacepressureor the volumetricIncrease(dependingon
the method used for measuring biogas evolution) in the test vessels resulting from the productton of carbon
dioxide (C02) and methane (CH,,) is measured. A considerable amount of CO2will be dissolved in water or
transformed to bicarbonate or carbonate under the conditIOnS of the test. This inorganIc carbon (IC) IS
measured at the end of the test. Theamount of microbiologicaHy produced biogas carbon is calculated from
thenet biogas production and the net IC formation in excessof blank values.The percentage biodegradatton
is calculated from the total amount of carbon transformed to biogas and IC and the measured or calculated
amount of carbon added as test material. The course of biodegradation can be followed by making
intermediate measurements of biogas production.As additional information.the pnmary biodegradability can
be determinedbyspecificanalysesatthe beginning and end of the test
This test methodisdesignedtodetermine thebiodegradabilityof plasticmaterials underanaerobiccondmons
Optionally,the assessmentofthe recoveryrate mayalso beofinterest(see AnnexG)
5 Reagents and materials
5.1 Distilledordeionizedwater,free oftoxic substances.containinglessthan 2mgllofDOC.
5.2 Testmedium.preparedusingonly reagentsofrecogniZedanalyticalgrade
Prepare the test mediumto containthe followlng constituents10thestatedamounts
Anhydrouspotassiumdihydrogenphosphate 0.27g

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ISilSO 14853 :2005
Orsoounn hydrogen phosphatedodecahydrate Na2HP04·12Hp 1,12 9
Ammoniumchloride NH4CI 0,539
Calcium chloride dihydrate CaCI22H20 0,0759
Magnesium chloridehexahydrate M9CI26H20 0,109
Iron(lI)chloride tetrahydrate FeCI24H20 0,029
Resazurin(oxygenindicator) 0,0019
Oisodium sulfide(see note) 0,19
Stock solution oftrace elements(optional) 10 ml
Stocksolutionsofvitarnlns (optional) Vitamin solution No. 0,5ml
Vitaminsolution NO.2 O,Gml
Addwater(5.1)(oxygen-free)to 1I
Adjust the pH ofthemediumwith dilutemineralacidoralkali.ifnecessary,to 7±0,2.
Toensureo~en-freeconditions,purge thewaterwith nitrogenfor about20 minimmediatelybeforeuse.
Use freshlyprepared sodium sulfide,orwash and dry it before use.to ensure sufficient reductive capacity.In
ordefto ensure strictly anaerobic conditions,it is recommended that a small amount of sodium dithionite be
added to the medium after it has been prepared until it becomes colourless.Do not use more than 10mgll.
becausehigherconcentrationsmayproduce inhibitory effects.
5.3 T~ntsolution (optional).
It is recommended that the test medium be supplemented with the following trace elements to improve the
anaerobicdegradationprocess,especiallyiflowinoculum concentrationsare used:
Manganesechloridetetrahydrate MnCI2·4H2O 0.059
Boricadd H3B03 0,005g
Zincchloride ZnCI2 0,005g
Copperchloride CuCI2 0.003g
Disodiummotybdatedihydrate Na2Mo04·2H20 0,001 9
Cobaltchloridehexahydrate CoC12·6H2O 0.19
Nickelc:Noridehexahydrate NiC~·6H20 0,01 9
0iI0dUn .... ~3 0,0059
0iI0diumtungIIaIe Na2W04·2H2O O,002g
Add....(5.1)(oxygenfree)to 1I
lIM10mIoftracHllementsotution perlitreottestmedium.
1511SO 14853: 2005
5.4 Vitamin solutions(optional)
5.4.1 Vitamin solution No.1
4-Amlnobenzolcacid 40 mg
10mg
Dissolve inhotwater (5 1) SOOml
Allow tocool andadd
D-Pantothenicacid.calcium salt 50mg
Pyridoxaminedihydrochloride ,50mg
Thiaminedichloride 100mg
Filter the solution through a membrane filter (pore size 0.45pm) tnat neither adsorbs nor releases organic
carbon insignificantamounts.and store inthedark at4 ·C
Use0.5mlofvitamin solutionperlitre oftestmediurn.
5.4.2 Vitamin solution No.2
Cyanocobalamin(vitaminB12) 10mg
Dissolve inwater (51) 100ml
Filter the solution through a membrane filter (pore size 0.45urn) that neither ad50rbs nor releases organic
carbon in significantamounts.and store inthedark at4·C.
Use0.5ml ofvitamin solutionper litre oftestmedium
5.5 Barriersolution
NaCI 200 9
Dissolve inwater (5 1) 1000ml
Acidify with citricacid 5g
Add apH·Indicator such as bromophenolblue or methyl orange In order to be able to verify that the solution
remainsacidduringthe test
5.6 Testmaterial
The test material is usually added directly as solid to give a concentration of 20mgl1to 200mg.o1 organIC
carbon Thetest material (plastic) should be used inpowdered form ifpoSSible
The biodegradability of plasticmaterials which are not inhibitory to microorganisms can be determined using
concentrations higherthan 200 mgllorganiccarbon.tnthis case,ensurethat the buffercaPaCItyand mtneral
saltcontentofthemediumaresufficient
5.7 Referencematerial.
Use a well-defined anaerobically biodegradable polymer. eg poty-13·hydroxybutyrate. cellulose or
poly(ethyleneglycorJ400 asareferencematerial Ifpossible. the form, size. solubilityand concentrahon ofthe
reference materialshould be comparable10that ofthetest material.

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