ASTM D5526-94(2011)e1
(Test Method)Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under Accelerated Landfill Conditions
Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under Accelerated Landfill Conditions
SIGNIFICANCE AND USE
Decomposition of a plastic within a landfill involves biological processes that will affect the decomposition of other materials enclosed by, or in close proximity to, the plastic. Rapid degradation of the plastic has the ability to increase the economic feasibility of landfill-gas recovery, minimize the duration of after-care of the landfill, and make possible the recovery of the volume reduction of the waste due to biodegradation during the active life of the landfill. This procedure has been developed to permit determination of the anaerobic biodegradability of plastic products when placed in biologically active environments simulating landfill conditions.
As degradation occurs inevitably in a landfill, it is of immediate concern that the plastic materials do not produce toxic metabolites or end products under the various conditions that have the potential to occur in a landfill. The mixtures remaining after completion of the test method, containing fully or partially degraded plastic materials or extracts, can be submitted subsequently to ecotoxicity testing in order to assess the environmental hazards posed by the breakdown of plastics to varying degrees in landfills. This test method has been designed to assess biodegradation under optimum and less-than-optimum conditions.
Limitations—Because a wide variation exists in the construction and operation of landfills, and because regulatory requirements for landfills vary greatly, this procedure is not intended to simulate the environment of all landfills. However, it is expected to closely resemble the environment of a biologically active landfill. More specifically, the procedure is intended to create a standard laboratory environment that permits rapid and reproducible determination of the anaerobic biodegradability under accelerated landfill conditions, while at the same time producing reproducible mixtures of fully and partially decomposed household waste with plastic materials for ecotoxicological assessm...
SCOPE
1.1 This test method covers determination of the degree and rate of anaerobic biodegradation of plastic materials in an accelerated-landfill test environment. This test method is also designed to produce mixtures of household waste and plastic materials after different degrees of decomposition under conditions that resemble landfill conditions. The test materials are mixed with pretreated household waste and exposed to a methanogenic inoculum derived from anaerobic digesters operating only on pretreated household waste. The anaerobic decomposition occurs under dry (more than 30 % total solids) and static nonmixed conditions. The mixtures obtained after this test method can be used to assess the environmental and health risks of plastic materials that are degraded in a landfill.
1.2 This test method is designed to yield a percentage of conversion of carbon in the sample to carbon in the gaseous form under conditions that resemble landfill conditions. It is possible that this test method will not simulate all conditions found in landfills, especially biologically inactive landfills. This test method more closely resembles those types of landfills in which the gas generated is recovered or even actively promoted, or both, for example, by inoculation (codeposition of anaerobic sewage sludge and anaerobic leachate recirculation), moisture control in the landfill (leachate recirculation), and temperature control (short-term injection of oxygen and heating of recirculated leachate) (1-7).
1.3 This test method is designed to produce partially degraded mixtures of municipal solid waste and plastics that can be used to assess the ecotoxicological risks associated with the anaerobic degradation of plastics after various stages of anaerobic biodegradation in a landfill.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, asso...
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Designation: D5526 – 94 (Reapproved 2011)
Standard Test Method for
Determining Anaerobic Biodegradation of Plastic Materials
Under Accelerated Landfill Conditions
This standard is issued under the fixed designation D5526; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Reapproved with editorial changes throughout in February 2011.
1. Scope 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 Thistestmethodcoversdeterminationofthedegreeand
responsibility of the user of this standard to establish appro-
rate of anaerobic biodegradation of plastic materials in an
priate safety and health practices and determine the applica-
accelerated-landfill test environment. This test method is also
bility of regulatory limitations prior to use. Specific hazards
designed to produce mixtures of household waste and plastic
statements are given in Section 8.
materials after different degrees of decomposition under con-
ditions that resemble landfill conditions. The test materials are
NOTE 1—There is no known ISO equivalent to this standard.
mixed with pretreated household waste and exposed to a
2. Referenced Documents
methanogenic inoculum derived from anaerobic digesters op-
erating only on pretreated household waste. The anaerobic
2.1 ASTM Standards:
decomposition occurs under dry (more than 30% total solids)
D618 Practice for Conditioning Plastics for Testing
and static nonmixed conditions. The mixtures obtained after
D883 Terminology Relating to Plastics
this test method can be used to assess the environmental and
D1293 Test Methods for pH of Water
health risks of plastic materials that are degraded in a landfill.
D1888 Methods Of Test for Particulate and Dissolved
1.2 This test method is designed to yield a percentage of
Matter in Water
conversion of carbon in the sample to carbon in the gaseous
D2908 Practice for Measuring Volatile Organic Matter in
form under conditions that resemble landfill conditions. It is
Water by Aqueous-Injection Gas Chromatography
possible that this test method will not simulate all conditions
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
found in landfills, especially biologically inactive landfills.
D4129 Test Method for Total and Organic Carbon in Water
This test method more closely resembles those types of
by High Temperature Oxidation and by Coulometric De-
landfills in which the gas generated is recovered or even
tection
actively promoted, or both, for example, by inoculation (code-
E260 Practice for Packed Column Gas Chromatography
position of anaerobic sewage sludge and anaerobic leachate
E355 Practice for Gas Chromatography Terms and Rela-
recirculation), moisture control in the landfill (leachate recir-
tionships
culation), and temperature control (short-term injection of
2.2 APHA-AWWA-WPCF Standards:
oxygen and heating of recirculated leachate) (1-7).
2540D Total Suspended Solids Dried at 103°–105°C
1.3 This test method is designed to produce partially de-
2540E Fixed and Volatile Solids Ignited at 550°C
graded mixtures of municipal solid waste and plastics that can
212 Nitrogen Ammonia
be used to assess the ecotoxicological risks associated with the
3. Terminology
anaerobic degradation of plastics after various stages of an-
aerobic biodegradation in a landfill.
3.1 Definitions—For definitions of terms used in this test
1.4 The values stated in SI units are to be regarded as the method see Terminology D883.
standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and is the direct responsibility of Subcommittee D20.96 on Environmentally Standards volume information, refer to the standard’s Document Summary page on
Degradable Plastics and Biobased Products. the ASTM website.
Current edition approved Feb. 1, 2011. Published February 2011. Originally Withdrawn. The last approved version of this historical standard is referenced
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approved in 1994. Last previous edition approved in 2002 as D5526–94(2002) on www.astm.org.
5 th
. DOI: 10.1520/D5526-94R11E01. Standard Methods for the Examination of Water and Wastewater,20 ed.,
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof 1999, available from American Public Health Association, 800 I Street, NW,
this standard. Washington, D.C. 20001-3710, or http://www.standardmethods.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5526 – 94 (2011)
3.2 Definitions of Terms Specific to This Standard: 6. Apparatus
3.2.1 methanogenic inoculum—anaerobically digested or-
6.1 Pressure-Resistant Glass Vessels—Twenty-seven, each
ganic waste containing a high concentration of anaerobic
with a volume of 4 to 6 L, which can be closed airtight and
methane-producing microorganisms.
capable of withstanding an overpressure of two atmospheres.
The lids of the reactors are equipped with an overpressure
4. Summary of Test Method
valve (to prevent the overpressure from becoming higher than
4.1 Thistestmethoddescribedconsistsofthefollowing:(1)
2 bars), a manometer that provides a rough indication of the
selecting and analyzing material for testing; (2) obtaining a
overpressure,aseptumthatallowsonetotakegassamplesand
pretreated municipal-solid-waste fraction and a concentrated
measure the exact overpressure, and, finally, a valve to release
anaerobic inoculum from an anaerobic digester; (3) exposing
the overpressure (Fig. 1).
the material to an anaerobic static batch fermentation at more
6.2 Incubators, sufficient to store the vessels in the dark at
than 30% solids; (4) measuring total carbon in the gas (CO
35 6 2°C for the duration of the test.
and CH ) evolved as a function of time; (5) removing the
6.3 Pressure Transducer, connected to a syringe needle to
specimens for cleaning (optional), conditioning, testing, and
measure the headspace pressure in the test vessel.
reporting; (6) assessing the degree of biodegradability; and (7)
6.4 Gas Chromatograph, or other apparatus, equipped with
assessing the degree of biodegradability under less than opti-
a suitable detector and column(s) for measuring methane and
mum conditions.
carbon dioxide concentrations in the evolved gases.
4.2 The percentage of biodegradability is obtained by de-
6.5 pH Meter, precision balance (60.1 g), analytical bal-
termining the percent of conversion of carbon from the test
ance (60.1 mg), thermometer, and barometer.
material to carbon in the gaseous phase (CH and CO ). This
4 2
6.6 Suitable Devices, for determining volatile fatty acids by
percentage of biodegradability will not include the amount of
aqueous-injection chromatography, total Kjeldahl nitrogen,
carbonfromthetestsubstancethatisconvertedtocellbiomass
ammonia nitrogen, dry solids (105°C), and volatile solids
and that is not, in turn, metabolized to CO and CH .
2 4
(550°C) concentrations.
5. Significance and Use
7. Reagents and Materials
5.1 Decomposition of a plastic within a landfill involves
7.1 Pretreated-Household Waste, derived from mixed mu-
biologicalprocessesthatwillaffectthedecompositionofother
nicipal solid waste or the organic fraction thereof, after
materials enclosed by, or in close proximity to, the plastic.
Rapid degradation of the plastic has the ability to increase the
economic feasibility of landfill-gas recovery, minimize the
duration of after-care of the landfill, and make possible the
recovery of the volume reduction of the waste due to biodeg-
radation during the active life of the landfill. This procedure
has been developed to permit determination of the anaerobic
biodegradability of plastic products when placed in biologi-
cally active environments simulating landfill conditions.
5.2 As degradation occurs inevitably in a landfill, it is of
immediate concern that the plastic materials do not produce
toxic metabolites or end products under the various conditions
that have the potential to occur in a landfill. The mixtures
remainingaftercompletionofthetestmethod,containingfully
or partially degraded plastic materials or extracts, can be
submittedsubsequentlytoecotoxicitytestinginordertoassess
the environmental hazards posed by the breakdown of plastics
to varying degrees in landfills. This test method has been
designed to assess biodegradation under optimum and less-
than-optimum conditions.
5.3 Limitations—Because a wide variation exists in the
construction and operation of landfills, and because regulatory
requirements for landfills vary greatly, this procedure is not
intended to simulate the environment of all landfills. However,
it is expected to closely resemble the environment of a
biologically active landfill. More specifically, the procedure is
intended to create a standard laboratory environment that
1 = Digester.
permits rapid and reproducible determination of the anaerobic
2 = Incubation chamber.
3 = Overpressure valve.
biodegradability under accelerated landfill conditions, while at
4 = Manometer.
the same time producing reproducible mixtures of fully and
5 = Septum.
partially decomposed household waste with plastic materials
6 = Valve.
for ecotoxicological assessment. FIG. 1 Setup of Accelerated Landfill
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D5526 – 94 (2011)
homogenizing, screening over a screen with holes of a diam- post-ferment anaerobically by itself. This is to ensure that
eterof40to80mm,andaerobicallystabilizedoveraperiodof large, easily biodegradable particles are degraded during this
2 to 4 weeks by blowing air into the material and maintaining period and also to reduce the background level of degradation
a dry-matter content of 50 6 5% and a temperature of 55 6 of the inoculum itself.
10°C. (Optional: the pretreated household waste can be re- 9.3 Thebiochemicalcharacteristicsoftheinoculumshallbe
placed by a similarly pretreated simulated solid waste.) as follows:
7.2 Anaerobic Inoculum, derived from a properly operating
9.3.1 pH—Between 7.5 and 8.5 (in accordance with Test
anaerobic digester with pretreated household waste as a sole Methods D1293);
substrate or a digester that treats predominantly household
9.3.2 Volatile Fatty Acids (VFA)—Below 1 g/kg wet weight
waste. (in accordance with Practice D2908); and
+
7.3 Cellulose, Analytical-Grade, for thin-layer chromatog-
9.3.3 NH -N—Between0.5and2g/kg(inaccordancewith
raphy as a positive control. APHATest 212 and Test Method D3590).
7.4 Polyethylene (optional), as a negative control. It needs
9.4 Analyses are performed after dilution of the inoculum
to be in the same form as that in which the sample is tested:
with distilled water on a ratio of distilled water to inoculum of
film polyethylene for film samples, pellets of polyethylene in
5 to 1 on a weight-over-weight basis.
case the sample is in the form of pellets, etc.
10. Test Specimen
8. Hazards
10.1 The test specimen needs to be of sufficient carbon
8.1 This procedure involves the use of inoculum and mu-
content, analyzed in accordance with Test Method D4129,to
nicipalsolidwastecontainingbiologicallyandpossiblychemi-
yield carbon dioxide and methane volumes that can be mea-
cally active materials known to produce a variety of diseases.
sured accurately by the trapping devices described. Add more
Avoidcontactwiththesematerialsbywearingglovesandother
testspecimenwhenlowbiodegradabilityisexpected,upto100
appropriate protective equipment. Use good personal hygiene
g of dry matter of the test specimen.
to minimize exposure.
10.2 It is acceptable for the test specimen to be in the form
8.2 It is possible that the solid waste mixture will contain
of films, powder, pellets, or formed articles, or in the form of
sharpobjects.Takeextremecarewhenhandlingthismixtureto
a dog bone and in accordance with Practice D618. The test
avoid injury.
setup needs to be capable of handling articles that are 100 by
8.3 This test method includes the use of hazardous chemi-
50 by 4 mm thick.
cals. Avoid contact with the chemicals and follow the manu-
facturer’s instructions and material safety data sheets.
11. Procedure
8.4 The methane produced during the procedure is explo-
11.1 Preparation of the Mixtures:
sive and flammable. Upon release of the biogas from the
11.1.1 Determinethevolatilesolids,drysolids,andnitrogen
gas-collection system, take care in venting the biogas to the
content of the pretreated household waste and the inoculum in
outside or to a hood.
accordance with Test Methods D1888, D3590, and APHA
2540D and 2540E.
9. Inoculum
11.1.2 Determine the volatile solids, dry solids, and carbon
9.1 The inoculum can be derived either from a laboratory-
content of all test substances in accordance withAPHA2540D
scale or full-scale continuous digester or batch digester, oper-
and 2540E and Test Method D4129.
ating at 35°C and functioning with an organic fraction of
11.1.3 Weigh and combine the components and adjust the
household waste as the predominant substrate. In case the
drymattercontentofthefinalmixtureswithwatertoreachthe
inoculum is derived from a continuous laboratory-scale or
desired dry-matter content for each vessel. Roughly weigh out
full-scale digester, the digester must be operating for a period
600gonadry-weightbasisofpretreatedhouseholdwaste,and
of at least one month on the organic fraction of household
mix it with 100 g on a dry-weight basis of mesophilic
waste, with a maximum retention time of 30 days under
anaerobic inoculum from a continuously operating digester or
mesophilic conditions (35 6 2°C). Gas production yields must
150 g on a dry-weight basis of anaerobic inoculum from a
be at least 15 mL at standard temperature and pressure of
batch digester. Add 60 to 100 g of dry matter of the test
biogas/gramofdrysolidsinthedigesterandperdayforatleast
substance. Add water until the appropriate final dry matter
7 days. In case the inoculum is derived from a batch digester,
content is reached. (In order to reach 60% dry matter content
the gas production rate must have exceeded 1 L/kg waste/day,
in the mixture, it is necessary, in some cases, to have water
and the methane concentration of the biogas being produced
removed prior to combining the different components of the
must be above 60%.
mixture. This can be accomplished by drying the pretreated
9.2 The prepared inoculum needs to undergo a short meso-
household waste or centrifuging the anaerobic inoculum.) Mix
philic post-ferment
...
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