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GB/T 39951-2021 PDF in English

GB/T 39951-2021 (GB/T39951-2021, GBT 39951-2021, GBT39951-2021)
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GB/T 39951-2021: PDF in English (GBT 39951-2021)

GB/T 39951-2021
ICS 85.010
Y 30
Evaluation method for degradability of disposable
paper products
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 4 
4 Principle ... 5 
5 Tests... 6 
6 Evaluation rules ... 17 
7 Test report ... 17 
Annex A (informative) Example of biodegradability test system ... 19 
Annex B (normative) Ecotoxicity test ... 20 
Evaluation method for degradability of disposable
paper products
WARNING - Personnel using this Standard shall have practical experience
working in a formal chemical laboratory. This Standard does not point out
all possible safety issues. The user is responsible for taking appropriate
safety and health measures and ensuring compliance with the conditions
stipulated by relevant national laws and regulations.
1 Scope
This Standard specifies evaluation methods for biodegradability, degree of
disintegration and ecotoxicity of disposable paper products under aerobic
composting conditions.
This Standard is applicable to evaluation for degradability of disposable paper
products and raw materials such as diapers (sheets, pads), sanitary napkins
(pads), wet wipes, paper cups, paper tableware, paper bags, paper boxes, pulp
molded products. It is also applicable to paper-based composite materials and
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.
GB/T 6682, Water for analytical laboratory use - Specification and test
GB/T 30903, Inorganic chemicals for industrial use - Determination of
impurity element - Inductively coupled plasma mass spectrometry (ICP-MS)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 compost
passing through the 2mm test sieve to the total dry solids.
During ecotoxicity test, the compost obtained after the disintegration of the
specimen is mixed with the reference culture soil in a precise ratio. Place in the
tray. Evaluate the ecotoxicity of the specimen by inspecting the number of
germination of seeds.
5 Tests
5.1 Biodegradability test
5.1.1 Reagents and materials
Unless otherwise specified, the reagents used in this Standard refer to
analytically-pure reagents. Microbiology reagents shall meet the requirements
of microbiology. Water: GB/T6682, grade three. Trace element solution: the solute concentrations are: boric acid:
500mg/L, potassium iodide: 100mg/L, ferric chloride: 200mg/L, manganese
sulfate: 400mg/L, ammonium heptamolybdate: 200mg/L, ferrous sulfate:
400mg/L. Mineral solution: Measure 1mL of calcium chloride solution with a
concentration of 0.1g/L, 1mL of sodium chloride solution with a concentration
of 0.1g/L, 1mL of trace element solution ( Weigh 1.0g of potassium
dihydrogen phosphate and 0.5g of magnesium sulfate. Use water to set volume
to 1000mL. Compost extract: Use the compost produced in the composting device
such as organic matter in municipal solid waste, garden and farmland waste to
add into water. The mass volume ratio is 1:5. Place for 30min. Use a filter screen
with a pore size of about 1mm or a medium-speed qualitative filter paper to filter
and remove the residue. Or use a centrifuge to centrifuge at 1000r/min for
15min. Or directly use commercial special inoculants for composting. Prepare
according to instructions for use. Inoculum: Measure 500mL of mineral solution ( and 500mL of
compost extract ( Mix well. Add 10.0g of peptone, 3.0g of beef dipping
powder, 5.8g of urea, 20.0g of corn starch, 20.0g of cellulose powder. Reference material: Use thin layer chromatography (TLC)
microcrystalline cellulose as a positive control reference material. The particle
size is less than 20μm. High-speed pulverizer: Speed is ≥8000r/min. pH meter: The reading is to the nearest of 0.1 or higher.
5.1.3 Specimen processing
Do not touch the specimen with hands. Wear clean powder-free protective
gloves when processing specimens.
Cut the specimen into small pieces of about 10mm×10mm with scissors. Mix
well. Use the high-speed crusher ( to crush the fragments into flocs.
Avoid specimen loss during crushing. Prepare three specimens. The weight of
each specimen is within 30g~70g. Try to ensure that each specimen contains
an integer number (pieces) of all the components of the specimen. If the mass
of a single (piece) specimen is greater than 70g, then take 30g~70g of
specimen. Ensure that the specimens taken are representative.
NOTE: Specimens also include powder, granular or other simple shapes.
5.1.4 Test steps Method A: Aerobic composting method Determination of total organic carbon content Total organic carbon content of specimen
According to the instructions for use of the total organic carbon analyzer
(, preheat and calibrate. Prepare another specimen according to 5.1.3.
Use a balance to take 50mg~100mg (depending on the test range and accuracy
of the instrument), to the nearest of 0.1mg. Put it into the high temperature
resistant specimen cup for testing. Test for 10 times in total. Take the average
of 10 test results as the total organic carbon content of the specimen. The result
is rounded to 0.0001g/g. Total organic carbon content of reference material
Refer to to test the total organic carbon content of the reference
material ( Test twice in total. Take the average value as the total organic
carbon content of the reference material. The result is rounded to 0.0001g/g. Test preparation stage Preparation of activated vermiculite
Mix the vermiculite ( with the inoculum ( at a ratio of 1:3 (mass :
volume). Place it in the vermiculite activation reactor ( Incubate at
(50±2)°C for 3d~4d. If necessary, use water to make up to the initial mass by
required moisture content by adding water or draining water, passing in wet air
or dry air. If adjustments are made, the amount of carbon dioxide emitted shall
be closely monitored. Compost cultivation until the specimen reaches the
maximum level of biodegradation. The composting cycle generally does not
exceed 6 months. If obvious biological decomposition can be observed, then
the test period shall be extended to the constant plateau stage. If the plateau
stage occurs earlier, that is, when the level of biodegradation no longer
increases, then it can shorten the test cycle and stop the test.
NOTE: If the pH is lower than 7.0, it is because the easily decomposed sample quickly
decomposes to acidify the compost, which will inhibit the biological decomposition of the
material. To prevent acidification, it can increase the amount of compost in all compost
containers. Or decrease the specimen, increase the compost, and repeat the test. Carbon dioxide emission test
During the test, regularly use the carbon dioxide analysis equipment (
to measure the carbon dioxide content in the exhaust gas of each compost
container. Calculate the cumulative amount of carbon dioxide released. The
number of measurements depends on the method used, the accuracy of the
required biodegradation curve, and the biodegradability of the specimen. If the
measurement method of carbon dioxide analysis instrument is used, measure
at least 2 times a day in the biodegradation stage. In the steady phase, measure
at least once a day. The gas flow rate at the outlet shall be accurately measured.
If the measurement method of sodium hydroxide absorption and release of
carbon dioxide is used, then measure dissolved inorganic carbon once a day in
the biological decomposition stage; in the stationary phase, measure 2 times a
week. Method B: Component analysis method
For multi-component products, the level of biodegradation of the product shall
be calculated based on the level of biodegradation of each component
(material). For components with unknown level of biodegradation, then use
method A ( to determine the level of biodegradation of each component.
Calculate the level of biodegradation of the sample according to, of
which the mass of each component is accurate to 0.001g.
5.1.5 Calculation and presentation of results Calculation of level of biodegradation of aerobic composting Level of biodegradation of specimen
Calculate the level of biodegradation of specimen according to formula (1):
5.2 Disintegration degree test
5.2.1 Instruments and equipment Compost container
The volume of the compost container shall be large enough (the smallest
volume is 140L), so as to ensure that natural heating can occur. The material
shall be made of strong, high-temperature resistant, and non-biodegradable
materials. Does not affect the composting process or the quality of compost
when used.
The bottom layer of the compost container has at least a 5cm thick drip plate to
form a drainage system. Use suitable air supply system to provide adequate
and continuous ventilation conditions for each compost container. Temperature measuring equipment
The reading is to the nearest of 0.1°C. pH meter
The reading is to the nearest of 0.1 or higher. Oxygen test equipment
The reading is to the nearest of 0.1%. Sieve
Use a test sieve with a suitable shape and 2mm mesh.
5.2.2 Test steps Test preparation stage Preparation of biomass waste
Use the used biomass waste as carrier substrate. Try to take samples from the
inputs of composting equipment that mainly treats municipal waste. The sample
can also be directly sourced from biomass waste from households or grocery
NOTE: The typical artificial biomass waste containing the following ingredients can be
- Fresh fruit and vegetable mixed waste;
- Rabbit feed (seeds and extruded dried vegetable pellets);
four weeks, conduct once a week. Conduct once every two weeks after that
until the test ends. If a specimen grid is used, open the grid and turn the
ingredients inside. Ventilation
Regularly measure the oxygen content of composted materials or the air
consumed. Measure at least once every working day during the first month of
the test. Conduct once a week thereafter. The oxygen content in the composted
material shall be higher than 10%. If the oxygen content is less than 10%,
ventilate the biomass waste. The air flow rate per kilogram of total dry solids
shall be less than 15L/h.
NOTE: Air flow can control the temperature and moisture content of the compost container.
The air flow to ventilate the compost container shall be consistent with the actual
composting equipment. If an excessively high air flow rate is used in practical applications,
the amount of ammonia lost with the air can be supplemented by adding some substances
(such as urea). Moisture content and pH
After turning, take specimens from each test series to measure moisture
content and pH. If the moisture content (mass fraction less than 40%) is too low,
it will not be conducive to the normal progress of the composting process. Water
shall be added at this time. Temperature
Measure the temperature in the middle of the compost, at least once every
working day. Termination of test Cycle
The cultivation cycle is 3 months. Residual material
Use a 2mm mesh sieve to sieve all materials. Use running water to wash
carefully as much as possible. The washed pellets are dried to constant weight
at 105°C (materials with a melting point lower than 105°C is at 40°C). Determine
the total dry solids of fragments larger than 2mm.
5.2.3 Calculation
Weigh the mass of the specimen collected in fragments larger than 2mm.
Compare with the mass of the starting specimen ( Calculate the
5.4.2 Test methods
When fluorine content is measured, the specimen is calcined in a high-
temperature furnace at 1000°C for 15min under the condition of water vapor
and oxygen. Collect condensate. Then use ion chromatograph to test.
Other elements are tested according to GB/T 30903.
6 Evaluation rules
6.1 If the product needs to provide proof of biodegradability (degradation)
performance, a biodegradability test shall be carried out.
6.2 If the product needs to provide a certificate of compostability, it shall carry
out biodegradability test, disintegration test and ecotoxicity test. The content of
heavy metals, toxic and harmful substances in the product shall meet the
requirements of Table 1.
7 Test report
The test report shall contain the followings:
a) Reference to this Standard;
b) Source of vermiculite and compost extract in the biodegradability test;
c) Total organic carbon content of the reference material in the
biodegradability test and its biodegradation rate in 45d;
d) Total organic carbon content of the specimen in the biodegradability test
and its maximum level of biodegradation;
e) Source of the biomass waste in the disintegration test and the results of
all the analyses performed at the beginning of the test;
f) Degree of disintegration of the specimen in the disintegration test;
g) Source of reference culture soil in the ecotoxicity test;
h) Germination rate of blank compost in the ecotoxicity test;
i) Ratio of germination number between compost specimen and blank
compost in the ecotoxicity test;
j) Content of heavy metals, toxic and harmful substances;
Annex B
Ecotoxicity test
B.1 Simulation of reference culture soil
Any soil that can make seeds germinate and plants grow normally can be used
as a reference cultivation soil. No additional fertilizer shall be added to the
reference culture soil.
B.2 Sample preparation
Use 50% (mass fraction or volume fraction, stated in the report) compost and
reference culture soil to prepare a mixture (sample). The "compost sample" is
a mixture of the final product obtained after the disintegration of the specimen
and the reference culture soil. The "blank compost" is the reference culture soil
without adding the specimen after disintegration.
B.3 Plant species
Use mung bean and wheat in plant species to conduct eco-toxicity test
B.4 Test steps
Take at least 12 trays to test mung bean and wheat separately. Each plant
requires 3 to hold compost samples and 3 to hold blank compost. Each tray is
filled with at least 200g of sample (B.2). Add at least 100 seeds (B.3) on the
upper surface. Use thin layer of inert material to cover seeds, such as silicate
sand or perlite. Conduct three sets of parallel tests for each sample. Add water
to 70%~100% of the water retention capacity. Regularly replenish the water lost
due to evaporation throughout the test period.
NOTE: Tray size is about 30cm×20cm×5cm (length × width × height). During germination,
place the tray in a dark place or cover it.
B.5 Result evaluation
Check the number of sprouts of compost samples and blank compost. Use the
number value of plant germination to calculate the ratio of the number of sprouts
between the compost sample and the blank compost, expressed in percentage.
B.6 Validity of results
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.