ASTM D5975-96(2010)
(Test Method)Standard Test Method for Determining the Stability of Compost by Measuring Oxygen Consumption
Standard Test Method for Determining the Stability of Compost by Measuring Oxygen Consumption
SIGNIFICANCE AND USE
A measurement of compost stability is needed for several reasons. It aids in assessing whether the composting process has proceeded sufficiently far to allow the finished compost to be used for its intended application. A different compost stability may be required for different applications of the compost.
A measurement of compost stability also is needed to verify whether a composting plant is processing the waste to previously agreed levels of stability. This measurement is useful in the commissioning of composting plants and the verification of whether plant operators are satisfying permit requirements.
The level of compost stability also will indicate its potential to cause odors if the compost is stored without aeration, as well as the level to which it has been hygienized and how susceptible the compost is to renewed bacterial and possible pathogenic activity. Compost stability is an important parameter with regard to phytotoxicity and plant tolerance of the compost.
The determination of compost stability will allow the selection of well performing composting technologies, as well as the safe application of compost in its various markets. The method indicates a degree of stability, but does not necessarily indicate that one level is preferable over another level of stability.
SCOPE
1.1 This test method covers the stability of a compost sample by measuring oxygen consumption after exposure of the test compost to a well-stabilized compost under controlled-composting conditions on a laboratory scale involving active aeration. This test method is designed to yield reproducible and repeatable results under controlled conditions that resemble the end of the active composting phase. The compost samples are exposed to a well-stabilized compost inoculum that is prepared from municipal solid waste or waste similar to the waste from which the test materials are derived. The aerobic composting takes place in an environment where temperature, aeration, and humidity are monitored closely and controlled.
1.2 This test method yields a cumulative amount of oxygen consumed/g of volatile solids in the samples over a four-day period. The rate of oxygen consumption is monitored as well.
1.3 This test method is applicable to different types of compost samples including composts derived from wastes, such as municipal solid waste, yard waste, source-separated organics, biosolids, and other types of organic wastes that do not have toxicity levels that are inhibitory to the microorganisms present in aerobic composting systems.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 There is no similar or equivalent ISO method.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D5975 − 96 (Reapproved 2010)
Standard Test Method for
Determining the Stability of Compost by Measuring Oxygen
Consumption
This standard is issued under the fixed designation D5975; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the stability of a compost
D515 Test Method for Phosphorus In Water (Withdrawn
sample by measuring oxygen consumption after exposure of
1997)
the test compost to a well-stabilized compost under controlled-
D883 Terminology Relating to Plastics
composting conditions on a laboratory scale involving active
D1293 Test Methods for pH of Water
aeration.Thistestmethodisdesignedtoyieldreproducibleand
D1888 MethodsOfTestforParticulateandDissolvedMatter
repeatableresultsundercontrolledconditionsthatresemblethe
in Water (Withdrawn 1989)
end of the active composting phase. The compost samples are
D2908 Practice for Measuring Volatile Organic Matter in
exposed to a well-stabilized compost inoculum that is prepared
Water by Aqueous-Injection Gas Chromatography
from municipal solid waste or waste similar to the waste from
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
which the test materials are derived. The aerobic composting
D4129 Test Method for Total and Organic Carbon in Water
takesplaceinanenvironmentwheretemperature,aeration,and
by High Temperature Oxidation and by Coulometric
humidity are monitored closely and controlled.
Detection
1.2 This test method yields a cumulative amount of oxygen
D5338 Test Method for Determining Aerobic Biodegrada-
consumed/g of volatile solids in the samples over a four-day tion of Plastic Materials Under Controlled Composting
period. The rate of oxygen consumption is monitored as well. Conditions, Incorporating Thermophilic Temperatures
2.2 APHA-AWWA-WPCF Standards:
1.3 This test method is applicable to different types of
2540 D Total Suspended Solids Dried at 103°–105°C
compost samples including composts derived from wastes,
2540 E Fixed and Volatile Solids Ignited at 550°C
such as municipal solid waste, yard waste, source-separated
organics, biosolids, and other types of organic wastes that do
3. Terminology
not have toxicity levels that are inhibitory to the microorgan-
3.1 Definitions of terms in this test method appear in
isms present in aerobic composting systems.
Terminology D883.
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 4. Summary of Test Method
standard.
4.1 This test method consists of the following:
4.1.1 Selecting a compost sample for the determination of
1.5 There is no similar or equivalent ISO method.
the stability.
1.6 This standard does not purport to address all of the
4.1.2 Producing a fully stabilized compost from a similar
safety concerns, if any, associated with its use. It is the
waste stream under well-controlled laboratory conditions.
responsibility of the user of this standard to establish appro-
4.1.3 Exposing the compost test samples to the fully stabi-
priate safety and health practices and determine the applica-
lized compost under controlled composting conditions.
bility of regulatory limitations prior to use. Specific hazard
statements are given in Section 8.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This test method is under the jurisdiction of ASTM Committee D34 on Waste the ASTM website.
Management and is the direct responsibility of Subcommittee D34.03 on Treatment, The last approved version of this historical standard is referenced on
Recovery and Reuse. www.astm.org.
Current edition approved Jan. 1, 2010. Published January 2010. Originally “Standard Methods for the Examination of Water and Wastewater,” 17th
approved in 1996. Last previous edition approved in 2004 as D5975–96(2004). Edition,1989,AmericanPublicHealthAssociation,1740Broadway,NewYork,NY
DOI: 10.1520/D5975-96R10. 19919.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5975 − 96 (2010)
4.1.4 Measuring the oxygen consumption rate and deter- 5.4 The determination of compost stability will allow the
mining the cumulative oxygen consumption. selection of well performing composting technologies, as well
as the safe application of compost in its various markets. The
4.2 Obtaining the level of stability from the cumulative
method indicates a degree of stability, but does not necessarily
oxygen consumption.
indicate that one level is preferable over another level of
stability.
5. Significance and Use
5.1 A measurement of compost stability is needed for
6. Apparatus
several reasons. It aids in assessing whether the composting
process has proceeded sufficiently far to allow the finished
6.1 Stabilized-Compost Inoculum Preparation Bin (see Fig.
compost to be used for its intended application. A different
1):
compost stability may be required for different applications of
6.1.1 Astabilized-compost inoculum preparation bin with a
the compost.
volume of 100 to 200 L, with insulation sufficient to maintain
5.2 A measurement of compost stability also is needed to composting temperatures of 50 to 65°C during a period of at
verify whether a composting plant is processing the waste to least two weeks when composting similar waste as the waste
previously agreed levels of stability. This measurement is
from which the samples were derived, and equipped with air
useful in the commissioning of composting plants and the
distribution plate, inlet and outlet, and airtight lid.
verification of whether plant operators are satisfying permit
6.1.2 Pressurized Air, provided to the composting bin at a
requirements.
precise and controllable rate up to 200 L/kg waste/day.
5.3 The level of compost stability also will indicate its
6.1.3 Thermometer, with temperature measurement up to
potential to cause odors if the compost is stored without
80°C (6 2°C).
aeration, as well as the level to which it has been hygienized
6.1.4 Suitable devices for measuring oxygen and CO
and how susceptible the compost is to renewed bacterial and
(optional) concentrations in the exhaust air of the composting
possible pathogenic activity. Compost stability is an important
bin, such as sensors or appropriate gas chromatography.
parameter with regard to phytotoxicity and plant tolerance of
the compost. 6.2 Composting Apparatus (see Fig. 2):
FIG. 1 Optional Set-Up Compost Preparation Bin
D5975 − 96 (2010)
FIG. 2 Optional Set-Up Using Gas Chromatograph (see also Test Method D5338)
6.2.1 A series of at least nine composting vessels (one test 8. Hazards
substance, one blank, one positive reference, all in three
8.1 This test method requires the use of hazardous chemi-
replicates) of 2 to 5 L of volume.
cals.Avoid contact with the chemicals and follow manufactur-
6.2.2 Incubators, water baths, or other temperature control-
er’s instructions and Materials Safety Data Sheets (MSDS).
ling means capable of maintaining the temperature of the
8.2 Thewastematerialsusedfortheproductionofstabilized
composting vessels at 58°C (6 2°C).
compost, or the compost samples may contain sharp objects.
6.2.3 Pressurized-Air System, providing H O-saturated air
Take care when handling.
to each of the composting vessels at the appropriate aeration
8.3 The composting vessels are not designed to withstand
rates.
high pressures. The system should be operated at close to
6.2.4 Suitable devices for measuring oxygen concentration
ambient pressure.
in the exhaust air of the composting vessels, such as specific
sensors or appropriate gas chromatography.
9. Stabilized Compost
6.3 Miscellaneous:
9.1 The stabilized compost, which serves as an inoculum
6.3.1 Balance (6 1 mg), to weigh sample and stabilized
and the test matrix, should be well-aerated compost two to four
compost.
months old, coming from the organic fraction of municipal
6.3.2 Scales (6 0.1 kg), to weigh composting waste for
solid waste or source-separated organics, and sieved over a
stabilized compost production.
screen of <10 mm. It is recommended that the stabilized
6.3.3 Normal laboratory glassware, equipment, and chemi-
compost control consumes 15 to 80 mg of oxygen/g of volatile
cals.
solids over the four-day test period. The stabilized compost
6.3.4 Suitable devices and analytical equipment for measur-
must have a total solids content between 50 and 60 % on wet
ing dry solids (at 105°C), volatile solids (at 550°C), volatile
weight, an ash content of less than 70 % on total solids, a pH
fatty acids by aqueous-injection chromatography, and total
between 7 and 8 and be free of volatile fatty acids (less than
Kjeldahl nitrogen.
100 mg/L as acetic acid). The C/N ratio should be between 10
and 20 and the C/P ratio between 30 and 60.
7. Reagents and Materials
9.2 The stabilized compost should be as free as possible of
7.1 Analytical-grade cellulose (microcrystalline, as used in larger inert materials (for example, glass, stones, metals).
thin-layer chromatography) with a particle size of less than 10 These items should be removed manually to produce a homo-
µm, for use as a positive control. geneous material.
D5975 − 96 (2010)
10. Test Samples the duration of the test. The incubation time may be extended
if the rate of oxygen consumption during the last 24 h is higher
10.1 The test sample must be represent
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