SIST EN ISO 14855-2:2009
(Main)Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions - Method by analysis of evolved carbon dioxide - Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test (ISO 14855-2:2007)
Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions - Method by analysis of evolved carbon dioxide - Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test (ISO 14855-2:2007)
This part of ISO 14855 specifies a method for determining the ultimate aerobic biodegradability of plastic materials under controlled composting conditions by gravimetric measurement of the amount of carbon dioxide evolved. The method is designed to yield an optimum rate of biodegradation by adjusting the humidity, aeration and temperature of the composting vessel. The method applies to the following materials: - natural and/or synthetic polymers and copolymers, and mixtures of these; - plastic materials that contain additives such as plasticizers or colorants; - water-soluble polymers; - materials that, under the test conditions, do not inhibit the activity of micro-organisms present in the inoculum. If the test material inhibits micro-organisms in the inoculum, another type of mature compost or pre-exposure compost can be used.
Bestimmung der vollständigen aeroben Bioabbaubarkeit von Kunststoff-Materialien unter den Bedingungen kontrollierter Kompostierung — Verfahren mittels Analyse des freigesetzten Kohlenstoffdioxides - Teil 2: Gravimetrische Messung des freigesetzten Kohlenstoffdioxides im Labormaßstab (ISO 14855-2:2007)
Der vorliegende Teil von ISO 14855 legt ein Verfahren zur Bestimmung der vollständigen aeroben Bioabbaubarkeit
von Kunststoff-Materialien unter den Bedingungen kontrollierter Kompostierung durch gravimetrische
Messung der Menge des freigesetzten Kohlenstoffdioxides fest. Das Verfahren ist dafür ausgelegt, eine
optimale Geschwindigkeit des Bioabbaus durch Anpassung von Feuchte, Begasung und Temperatur des
Kompostiergefäßes zu erreichen.
Das Verfahren ist auf folgende Substanzen anwendbar:
- natürliche und/oder synthetische Polymere und Copolymere sowie Gemische aus diesen;
- Kunststoffe, die Additive, wie z. B. Weichmacher oder Farbstoffe, enthalten;
- wasserlösliche Polymere;
- Substanzen, die unter Prüfbedingungen die Aktivität der im Inokulum vorhandenen Mikroorganismen
nicht inhibieren.
Wirkt die Prüfsubstanz inhibierend auf die Mikroorganismen im Inokulum, kann eine andere Art von ausgereiftem
Kompost oder voradaptierter Kompost verwendet werden.
Détermination de la biodégradabilité aérobique ultime des matériaux plastiques dans des conditions contrôlées de compostage - Méthode par analyse du dioxyde de carbone libéré - Partie 2: Mesurage gravimétrique du dioxyde de carbone libéré lors d'un essai de laboratoire (ISO 14855-2:2007)
L'ISO 14855-2:2007 spécifie une méthode de détermination de la biodégradabilité aérobie ultime des matériaux plastiques, dans des conditions de compostage contrôlées, par mesurage gravimétrique de la teneur en dioxyde de carbone libéré. Cette méthode est conçue pour produire un taux de biodégradation optimal en ajustant l'humidité, l'aération et la température du récipient de compostage.
La méthode s'applique aux matériaux suivants:
polymères et copolymères naturels et/ou synthétiques, et mélanges des deux;
matériaux plastiques contenant des additifs tels que plastifiants ou colorants;
polymères solubles dans l'eau;
matériaux qui, dans les conditions d'essai, n'inhibent pas l'activité des micro-organismes présents dans l'inoculum.
Določanje končne aerobne biorazgradljivosti in razkroja polimernih materialov pod nadzorovanimi pogoji kompostiranja - Metoda z analizo sproščenega ogljikovega dioksida - 2. del: Gravimetrične metode za določevanje sproščenega ogljikovega dioksida v laboratorijskem merilu (ISO 14855-2:2007)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 14855-2:2009
01-oktober-2009
'RORþDQMHNRQþQHDHUREQHELRUD]JUDGOMLYRVWLLQUD]NURMDSROLPHUQLKPDWHULDORYSRG
QDG]RURYDQLPLSRJRMLNRPSRVWLUDQMD0HWRGD]DQDOL]RVSURãþHQHJDRJOMLNRYHJD
GLRNVLGDGHO *UDYLPHWULþQHPHWRGH]DGRORþHYDQMHVSURãþHQHJDRJOMLNRYHJD
GLRNVLGDYODERUDWRULMVNHPPHULOX ,62
Determination of the ultimate aerobic biodegradability of plastic materials under
controlled composting conditions - Method by analysis of evolved carbon dioxide - Part 2:
Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test (ISO
14855-2:2007)
Bestimmung der vollständigen aeroben Bioabbaubarkeit von Kunststoff-Materialien unter
den Bedingungen kontrollierter Kompostierung — Verfahren mittels Analyse des
freigesetzten Kohlenstoffdioxides - Teil 2: Gravimetrische Messung des freigesetzten
Kohlenstoffdioxides im Labormaßstab (ISO 14855-2:2007)
Détermination de la biodégradabilité aérobique ultime des matériaux plastiques dans des
conditions contrôlées de compostage - Méthode par analyse du dioxyde de carbone
libéré - Partie 2: Mesurage gravimétrique du dioxyde de carbone libéré lors d'un essai de
laboratoire (ISO 14855-2:2007)
Ta slovenski standard je istoveten z: EN ISO 14855-2:2009
ICS:
13.030.99 Drugi standardi v zvezi z Other standards related to
odpadki wastes
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 14855-2:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 14855-2:2009
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SIST EN ISO 14855-2:2009
EUROPEAN STANDARD
EN ISO 14855-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2009
ICS 83.080.01
English Version
Determination of the ultimate aerobic biodegradability of plastic
materials under controlled composting conditions - Method by
analysis of evolved carbon dioxide - Part 2: Gravimetric
measurement of carbon dioxide evolved in a laboratory-scale
test (ISO 14855-2:2007, including Cor 1:2009)
Détermination de la biodégradabilité aérobie ultime des Bestimmung der vollständigen aeroben Bioabbaubarkeit
matériaux plastiques dans des conditions contrôlées de von Kunststoff-Materialien unter den Bedingungen
compostage - Méthode par analyse du dioxyde de carbone kontrollierter Kompostierung - Verfahren mittels Analyse
libéré - Partie 2: Mesurage gravimétrique du dioxyde de des freigesetzten Kohlenstoffdioxides - Teil 2:
carbone libéré lors d'un essai de laboratoire (ISO 14855- Gravimetrische Messung des freigesetzten
2:2007, Cor 1:2009 inclus) Kohlenstoffdioxides im Labormaßstab (ISO 14855-2:2007,
einschließlich Cor 1:2009)
This European Standard was approved by CEN on 30 May 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14855-2:2009: E
worldwide for CEN national Members.
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SIST EN ISO 14855-2:2009
EN ISO 14855-2:2009 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 14855-2:2009
EN ISO 14855-2:2009 (E)
Foreword
The text of ISO 14855-2:2007, including Cor 1:2009 has been prepared by Technical Committee ISO/TC 61
“Plastics” of the International Organization for Standardization (ISO) and has been taken over as EN ISO
14855-2:2009 by Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2009, and conflicting national standards shall be withdrawn
at the latest by December 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 14855-2:2007, including Cor 1:2009 has been approved by CEN as a EN ISO 14855-2:2009
without any modification.
3
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SIST EN ISO 14855-2:2009
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SIST EN ISO 14855-2:2009
INTERNATIONAL ISO
STANDARD 14855-2
First edition
2007-08-15
Determination of the ultimate aerobic
biodegradability of plastic materials
under controlled composting
conditions — Method by analysis of
evolved carbon dioxide —
Part 2:
Gravimetric measurement of carbon
dioxide evolved in a laboratory-scale test
Détermination de la biodégradabilité aérobique ultime des matériaux
plastiques dans des conditions contrôlées de compostage — Méthode
par analyse du dioxyde de carbone libéré —
Partie 2: Mesurage gravimétrique du dioxyde de carbone libéré lors d'un
essai de laboratoire
Reference number
ISO 14855-2:2007(E)
©
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 3
5 Reagents . 3
6 Apparatus . 4
7 Procedure . 5
8 Calculation . 8
9 Expression and interpretation of results . 9
10 Validity of results . 9
11 Test report . 9
Annex A (informative) Basic principle of the test . 10
Annex B (informative) Example of an apparatus using an electrically heated composting vessel . 12
Annex C (informative) Derivation of the equation used to calculate the degree of biodegradation from
the amount of carbon dioxide evolved . 14
Bibliography . 15
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO14855-2 was prepared by Technical Committee ISO/TC61, Plastics, Subcommittee SC5, Physical-
chemical properties.
ISO 14855 consists of the following parts, under the general title Determination of the ultimate aerobic
biodegradability of plastic materials under controlled composting conditions — Method by analysis of evolved
carbon dioxide:
— Part 1: General method
— Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
Introduction
Management of plastics waste is a serious problem in the world. Plastics recovery technologies include material
recovery (mechanical recycling, chemical or feedstock recycling, and biological or organic recycling) and energy
recovery (heat, steam or electricity as a substitute for fossil fuels or other fuel resources). The use of
biodegradable plastics is one valuable recovery option (biological or organic recycling).
Several ISO standards for determining the ultimate aerobic/anaerobic biodegradability of plastic materials have
been published. In particular, ISO 14855-1 is a common test method that measures the amount of carbon
dioxide evolved using methods such as continuous infrared analysis, gas chromatography or titration.
Compared with ISO 14855-1, the amounts of compost inoculum and test sample used in this part of ISO 14855
are one-tenth the size. In order to ensure the activity of the compost inoculum, inert material that gives the
mixture the same texture as soil is mixed into the inoculum. The carbon dioxide evolved from the test vessel is
determined by absorbing it in a carbon dioxide trap and carrying out gravimetric analysis of the absorbent. The
method described in this part of ISO 14855, which uses a closed system to capture the carbon dioxide evolved,
can also be used to obtain valuable information, by means of isotopic-labelling studies, on the way in which the
molecular structure of co-polymers degrades.
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SIST EN ISO 14855-2:2009
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vi
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SIST EN ISO 14855-2:2009
INTERNATIONAL STANDARD ISO 14855-2:2007(E)
Determination of the ultimate aerobic biodegradability of plastic
materials under controlled composting conditions — Method by
analysis of evolved carbon dioxide —
Part 2:
Gravimetric measurement of carbon dioxide evolved in a
laboratory-scale test
WARNING—Sewage, activated sludge, soil and compost may contain potentially pathogenic
organisms. Therefore appropriate precautions should be taken when handling them. Toxic test
compounds and those whose properties are unknown should be handled with care.
1Scope
This part of ISO 14855 specifies a method for determining the ultimate aerobic biodegradability of plastic
materials under controlled composting conditions by gravimetric measurement of the amount of carbon dioxide
evolved. The method is designed to yield an optimum rate of biodegradation by adjusting the humidity, aeration
and temperature of the composting vessel.
The method applies to the following materials:
— natural and/or synthetic polymers and copolymers, and mixtures of these;
— plastic materials that contain additives such as plasticizers or colorants;
— water-soluble polymers;
— materials that, under the test conditions, do not inhibit the activity of micro-organisms present in the
inoculum.
If the test material inhibits micro-organisms in the inoculum, another type of mature compost or pre-exposure
compost can be used.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 5663, Water quality — Determination of Kjeldahl nitrogen — Method after mineralization with selenium
ISO 8245, Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved
organic carbon (DOC)
ISO 11721-1, Textiles — Determination of resistance of cellulose-containing textiles to micro-organisms — Soil
burial test — Part 1: Assessment of rot-retardant finishing
ISO 14855-1, Determination of the ultimate aerobic biodegradability of plastic materials under controlled
composting conditions — Method by analysis of evolved carbon dioxide — Part 1: General method
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
compost
organic soil conditioner obtained by biodegradation of a mixture principally consisting of various vegetable
residues, occasionally with other organic material and having a limited mineral content
3.2
composting
aerobic process designed to produce compost
3.3
total dry solids
◦
amount of solids obtained by taking a known volume of test material or compost and drying at about 105 C to
constant mass
3.4
volatile solids
amount of solids obtained by subtracting the residue of a known volume of test material or compost after
◦
incineration at about 550 C from the total dry solids of the same sample
NOTE The volatile-solids content is an indication of the amount of organic matter present.
3.5
ultimate aerobic biodegradation
breakdown of an organic compound by micro-organisms in the presence of oxygen into carbon dioxide, water
and mineral salts of any other elements present (mineralization) plus new biomass
3.6
theoretical amount of evolved carbon dioxide
ThCO
2
maximum theoretical amount of carbon dioxide evolved after completely oxidizing a chemical compound,
calculated from the molecular formula and expressed as milligrams of carbon dioxide evolved per milligram or
gram of test compound
3.7
lag phase
time, measured in days, from the start of a test until adaptation and/or selection of the degradation micro-
organisms is achieved and the degree of biodegradation of a chemical compound or organic matter has
increased to about 10 % of the maximum level of biodegradation
3.8
maximum level of biodegradation
degree of biodegradation, measured as a percentage, of a chemical compound or organic matter in a test,
above which no further biodegradation takes place during the test
3.9
biodegradation phase
time, measured in days, from the end of the lag phase of a test until about 90 % of the maximum level of
biodegradation has been reached
3.10
plateau phase
time, measured in days, from the end of the biodegradation phase until the end of the test
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
3.11
pre-exposure
pre-incubation of an inoculum in the presence of the chemical compound or organic matter under test, with the
aim of enhancing the ability of the inoculum to biodegrade the test material by adaptation and/or selection of the
micro-organisms
3.12
pre-conditioning
pre-incubation of an inoculum under the conditions of the subsequent test in the absence of the chemical
compound or organic matter under test, with the aim of improving the test by acclimatization of the micro-
organisms to the test conditions
3.13
water-holding capacity
WHC
◦
mass of water that evaporates from soil saturated with water when the soil is dried to constant mass at 105 C,
divided by the dry mass of the soil
4 Principle
This method is designed to yield the optimum rate of biodegradation of a plastic material in mature compost by
controlling the humidity, aeration ratio and temperature in the composting vessel. It also aims to determine the
ultimate biodegradability of the test material by using a small-scale reactor. The degradation rate is periodically
measured by determining the mass of the evolved carbon dioxide using an absorption column filled with soda
lime and soda talc on an electronic balance.
The test material is mixed with an inoculum derived from mature compost and with an inert material such as sea
sand. The sea sand plays an active part by acting as a holding body for humidity and micro-organisms.
Examples of suitable test arrangements are presented in Annexes A and B. The amount of carbon dioxide
evolved is measured at intervals on an electronic balance and the carbon dioxide content is determined using
the following method. The derivation of the equation used to calculate the degree of biodegradation from the
amount of carbon dioxide evolved is given in Annex C. In this method, the degree of biodegradation, expressed
as a percentage, is calculated by comparing the amount of carbon dioxide evolved with the theoretical amount
(ThCO ).
2
The test is terminated when the plateau phase of biodegradation has been attained. The standard time for
termination is 45 days, but the test could be continued for up to six months.
5Reagents
Use only analytical-grade reagents. Use only deionized water.
5.1 Soda lime, particle size between 2mm and 4mm, for CO absorption.
2
5.2 Anhydrous calcium chloride, particle size between 2mm and 3mm, for water absorption.
5.3 Sodium hydroxide on a talc support (commonly known as soda talc), particle size between 2mm and
2mm, for CO absorption.
2
5.4 Silica gel (with moisture indicator), particle size between 2mm and 4mm, for water absorption.
5.5 Sea sand, particle size between 20 mesh and 35 mesh.
5.6 Reference material: TLC (thin-layer chromatography) grade microcrystalline cellulose with a particle size
of less than 20µm, for use as the reference material in the positive control.
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
6 Apparatus
Ensure that all glassware is thoroughly cleaned and, in particular, free from organic or toxic matter.
6.1 Air-supply system
The air-supply system shall be capable of supplying each composting vessel with carbon-dioxide-free, water-
saturated air. The air can be prepared by supplying compressed air through a carbon dioxide trap and a
humidifier (see examples in Annexes A and B), i.e. columns filled with soda lime and water, respectively. The air
flow rate shall be controlled with a flow controller so that it is high enough for aerobic conditions.
6.2 Composting vessels
Use bottles or columns that ensure a supply of water-saturated, carbon-dioxide-free air to the contents. A
suitable volume is 500 ml. If the loss in mass of the test material is to be determined, weigh each composting
vessel empty before starting the test.
6.3 System for the determination of carbon dioxide
This system shall be capable of determining carbon dioxide directly from the change in mass of a carbon
dioxide trap. The carbon dioxide trap shall consist of columns filled with soda lime, soda talc and anhydrous
calcium chloride. The calcium chloride should preferably be in a separate column from the soda lime and soda
talc (see examples in Annexes A and B). An ammonia trap (dilute sulfuric acid) and a water trap (silica gel and
calcium chloride) are required between the composting vessel and the carbon-dioxide-absorbing column.
6.4 Gas-tight tubes
These tubes are used to connect the composting vessels to the air supply and the carbon dioxide measurement
system.
6.5 pH-meter
The pH-meter is used for measurement of the pH of the test mixture. It shall be accurate to 0,1 pH-units or
better.
6.6 Analytical equipment
◦ ◦
This equipment is used for the determination of the dry solids (at 105 C), volatile solids (at 550 C) and total
organic carbon (TOC), for elemental analysis of the test material and, if required, for the determination of
dissolved inorganic carbon (DIC), volatile fatty acids, oxygen in the air, water content and total nitrogen.
6.7 Balance
The balance is used to periodically measure the mass of the carbon-dioxide-absorbing column, in order to
determine the amount of carbon dioxide evolved, and also to measure the mass of the composting vessel
containing compost and test material. A top-loading electronic balance with a display reading down to 10 mg
and a capacity greater than 500 g is preferred.
6.8 Thermostatic-control unit
This unit is required to maintain the temperature of the composting vessels at a controlled temperature during
the test (see examples given in Annexes A and B). It shall be capable of maintaining the temperature of the
◦
composting vessels constant to within ± 2 C.
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SIST EN ISO 14855-2:2009
ISO 14855-2:2007(E)
6.9 Composting bioreactor
A composting bioreactor is a box, made from polypropylene or another suitable material, having a size that
allows the contents to be stirred easily with a spatula. The box shall be provided with a tightly fitting lid to avoid
excessive water loss. Three holes with a diameter of about 1cm shall be made at equal distances along the
centreline of the lid. These holes allow air to enter and gases to leave the box, as well as the gradual
evaporation of excess water.
7 Procedure
7.1 Preparation of the inoculum
Well-aerated compost from a properly operating aerobic composting plant shall be used as the inoculum. The
inoculum shall be homogeneous and free from large inert objects such as glass, stones or pieces of metal.
Remove such items manually and then sieve the compost on a screen of about 3mm mesh.
Compost can be made as follows. Wood shavings, sawdust, used mushroom beds, chaff or rice straw is used
as the carbon source. Livestock excrement is added as a source of composting micro-organisms and mineral
3
salt nutrients. This is placed in a container with a volume of about 1m and mixed well. It is recommended that
the compost be adjusted to a carbon/nitrogen (C/N) ratio of 15 and a carbon/phosphorous (C/P) ratio of 30.
Insufficient phosphorous levels can be supplemented using calcium superphosphate. Water is added to reach
a water content equal to 65 %. The C/N, C/P and water-content values may also be adjusted to other values,
determined by experience, depending on seasonal variations and climatic differences. The compost should be
removed from the container once a week to turn it and add water if necessary, before returning it to the
container to continue the composting process. The age of the compost should preferably be between two and
four months.
Normally, non-exposed inoculum is preferred, especially in the case of standard tests simulating biodegradation
behaviour in real composting facilities. Depending on the purpose of the test, however, pre-exposed compost
may be used, provided that this is clearly stated in the test report (e.g. percent biodegradation = X%, using
pre-exposed compost) and provided the method of pre-exposure is detailed in the test report.
Determine the total dry solids and volatile-solids content of the compost inoculum. The total dry solids should be
between 35 % and 55 % of the wet solids and the volatile solids more than 30 % of the dry solids. Adjust the
water content, if necessary, before the compost is used by adding water or drying gently, e.g. by aerating the
compost with dry air.
Prepare a mixture of 1 part of inoculum to 5 parts of deionized water. Mix by shaking and measure the pH
immediately. It should be between 7,0 and 9,0.
For further characterization of the inoculum, suitable parameters such as the content of total organic carbon,
total nitrogen or fatty acids can optionally be determined at the beginning and the end of the test.
Check the activity of the inoculum during the test by means of a biodegradable reference material and by
measuring carbon dioxide evolution in the blank vessels. The reference material shall be degraded by 70 % or
more at the end of the test. The inoculum in the blank should produce between 50 mg and 150 mg of carbon
dioxide per gram of volatile solids over the first 10 days of the test. If the production of carbon dioxide is too high,
stabilize the compost by aeration for several days before using it in a new test.
7.2 Preparation of the sea sand
Dip the sea sand in tap water. After removing floating impurities by decantation, rinse the sand sufficiently, drain
◦
off the water and dry the sand at about 105 C.
NOTE Sea sand is a inert product that contains more than 90 % of SiO . It plays an important role, however, in maintaining
2
an appropriate water content and as a support for microbial growth.
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7.3 Preparation of test material and reference material
Determine the total organic carbon (TOC) of the test material and the reference material using e.g. ISO 8245
and report it preferably as grams of TOC per gram of total dry solids. Alternatively, provided that the materials
do not contain inorganic carbon, it is possible to determine the carbon content by elemental analysis. For this,
the test material has to contain sufficient organic carbon to yield carbon dioxide in an amount suitable for
determination. Normally, a minimum of 10 g of total dry solids containing 4g of TOC is required per vessel.
The test material should preferably be used in powder form, but it may also be introduced as small pieces of
films or as fragments of shaped articles. A maximum particle size of 250µm in diameter is recommended.
7.4 Starting up the test
Provide at least the following numbers of composting vessels:
a) two test vessels for the test mixture (symbol V );
T
b) two vessels for blank controls (symbol V );
B
c) tw
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