GB/T 22047-2008 PDF English
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Plastics -- Determination of the ultimate aerobic biodegradability in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved
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GB/T 22047-2008: PDF in English (GBT 22047-2008) GB/T 22047-2008
Plastics.Determination of the ultimate aerobic biodegradability in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved
ICS 83.080.01
G31
National Standards of People's Republic of China
GB/T 22047-2008/ISO 17556.2003
Final aerobic biodegradation of plastic materials in soil
Determination of the ability to measure a closed respirometer
Medium oxygen demand or method for determining released carbon dioxide
(ISO 17556.2003, IDT)
Released on.2008-06-18
2009-05-01 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Foreword
This standard is equivalent to the use of ISO 17556.2003 "the determination of the final aerobic biodegradability of plastic materials in soil by measuring the containment
The method of oxygen demand or determination of carbon dioxide released in the respirometer (English version), the technical content is exactly the same, only for the following editorial changes.
--- "This International Standard" is replaced by the word "this standard";
--- Replace the comma "," as a decimal point with a decimal point ".";
--- Removed the preface to the international standard.
Appendix A, Appendix B, Appendix C, Appendix D and Appendix E of this standard are informative annexes.
This standard was proposed by the China Light Industry Association.
This standard is under the jurisdiction of the National Plastics Standardization Technical Committee.
This standard is drafted by. Light Industry Plastics Processing Application Research Institute.
Participated in the drafting of this standard. Inner Mongolia Mengxi High-tech Group Co., Ltd., Zhejiang Huasheng Technology Co., Ltd., Shenzhen
Zhongjing Kelin Environmental Protection Plastic Technology Co., Ltd., Fujian Baishida Biomaterial Co., Ltd., Wuhan Gorgeous Environmental Protection Technology Co., Ltd., Bath
Fu (China) Co., Ltd., Ningbo Tianan Biomaterial Co., Ltd., Tianjin Sixiangli Degradable Plastic Co., Ltd., Shenzhen Hetian First Environmental Protection Division
Technology Co., Ltd., Fujian Pan Asia Technology Development Co., Ltd., National Plastic Products Quality Supervision and Inspection Center (Beijing), Sichuan University.
The main drafters of this standard. Weng Yunxuan, Zhang Xianbing, Zhang Ying, Wang Shihe, Shen Huafeng, Shen Liping, Xiang Hui, Chen Xuejun, Jia Weisheng, Ma Hongzhang,
Ye Xinjian, Li Ziyi, Wang Yuzhong, Mao Guoyu, Kong Li, Ding Shaozhong, Yu Runbao, Liu Caixia.
GB/T 22047-2008/ISO 17556.2003
introduction
As plastics increase, recycling and disposal have become a hot spot. Recycling should be a priority, but plastics should be completely
Recycling is difficult, such as plastic waste discarded by consumers at random, in addition to some difficult-to-recycle plastics such as fishing gear, agricultural mulch and water.
Soluble polymers, etc., these materials are discarded into the environment. The use of biodegradable materials is an effective way to solve such environmental problems.
One. International and national standards for the determination of final aerobic/anaerobic biodegradability of plastic materials under aqueous culture/composting conditions
It has been enacted, so it is important to develop a method for determining the ultimate aerobic biodegradability of these materials in the soil.
GB/T 22047-2008/ISO 17556.2003
Determination of final aerobic biodegradability of plastic materials in soil
Method for determining oxygen demand in a closed respirometer or measuring released carbon dioxide
WARNING. Wastewater, activated sludge, soil, and compost may contain potential pathogens, so appropriate precautions should be taken when handling.
Special care must be taken when handling toxicity test compounds or compounds of unknown nature.
1 range
This standard specifies the determination of plastic materials in soil by measuring the oxygen demand in a closed respirometer or measuring the amount of carbon dioxide released.
The final aerobic biodegradability. This standard adjusts the humidity of the test soil to obtain the best degree of biodegradability.
If unpre-exposed soil is used as an inoculum, this test only simulates the biodegradation process in a natural soil environment;
When using pre-exposed soil, this standard can be used to determine the potential biodegradability of the test material.
This standard applies to the following materials.
--- natural and/or synthetic polymers, copolymers or mixtures thereof;
--- Plastic materials containing additives such as plasticizers, pigments or other compounds;
---Water soluble polymer;
--- Under the test conditions, the material will not inhibit the activity of microorganisms in the soil, and the inhibition can be applied to the inhibition control.
Or other appropriate method (see ISO 8192.1986) to measure. If the test material inhibits the activity of microorganisms in the soil
At the time of action, a lower concentration of test material, other inoculum or pre-exposed soil may be employed.
2 Normative references
The terms in the following documents become the terms of this standard by reference to this standard. All dated references, followed by all
Modifications (not including errata content) or revisions do not apply to this standard, however, parties to agreements based on this standard are encouraged to study
Is it possible to use the latest version of these files? For undated references, the latest edition applies to this standard.
ISO 8192.1986 Test for oxygen inhibition of water-activated sludge
ISO 10381-6.1993 Soil quality sampling - Part 6. Collection, treatment and storage of soil for aerobic biological processes in the laboratory
Tibetan technical guidance
ISO 10390.1994 Determination of pH of soil quality
ISO 10634.1995 Water quality for continuous determination of biodegradable capacity of organic compounds poorly soluble in water in aqueous culture solutions
Technical guidance for the preparation and treatment of liquids
ISO 10694.1995 Determination of total organic carbon after dry burning of soil quality (Elemental analysis method)
ISO 11266.1994 Technical guidance for laboratory tests of biochemical decomposition of organic chemicals in soil under aerobic conditions
ISO 11274.1998 Laboratory methods for the determination of soil quality water retention characteristics
ASTMD5988-1996 Method for determination of aerobic biodegradability of plastic residues in soil after composting
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Under aerobic conditions, organic compounds are decomposed by microorganisms into carbon dioxide (CO2), water (H2O) and mineralized inorganic salts of the elements contained therein.
GB/T 22047-2008/ISO 17556.2003
And new biomass.
3.2
Under certain conditions, the mass concentration of dissolved oxygen consumed by the test material in water due to aerobic biooxidation, in milligrams or grams
The number of milligrams of oxygen absorbed by the test material is expressed (mg absorbed oxygen/mg or g test material).
3.3
Dissolved in water, can not be separated by special phase separation method (such as 4000m·s-2 centrifugation for 15min or pore size 0.2μm～0.45μm
The organic carbon is separated by filtration through a filtration membrane.
3.4
The theoretical maximum value of oxygen required to completely oxidize the test material can be calculated from the molecular formula to absorb oxygen per milligram or gram of test material.
The number of milligrams of gas is expressed in mg (mg absorbed oxygen/mg or g test material).
3.5
The theoretical maximum value of carbon dioxide that can be generated when the test material is completely oxidized can be calculated from the molecular formula to test per gram or milligram.
The number of milligrams of carbon dioxide released by the material is expressed in mgCO2/g or mg of test material.
3.6
From the beginning of the test until the microorganisms adapt (or selected) the decomposition products, and the degree of biodegradation of the test materials has increased to the maximum
The number of days required for a biodegradation rate of 10%.
3.7
The number of days from the end of the lag phase to 90% of the maximum biodegradation rate.
3.8
In the test, the extent to which the test material no longer biodegraded during biodegradation is expressed as a percentage.
3.9
The number of days from the end of the biodegradation phase to the end of the trial.
3.10
Pre-incubation of the soil in the absence of chemical components or organic substances under the same conditions as the test conditions, in order to adapt the microorganisms
Test conditions should be used to improve the test results.
3.11
Pre-incubation of the soil in the presence of chemical components or organic materials under the same conditions as the test conditions, with the aim of adaptation and/or
Microorganisms are selected to enhance the biodegradability of the soil to the test material.
3.12
The mass of all volatile water when the soil is dried to constant weight at 105 ° C divided by the dry soil quality (ie the water quality and soil in the soil sample)
The ratio of particles).
GB/T 22047-2008/ISO 17556.2003
3.13
The mass of all volatile water in the water-saturated soil at 105 ° C to constant weight divided by the dry soil mass.
4 Principle
The method adjusts the humidity of the soil to obtain an optimum degree of biodegradability of the plastic material in the test soil.
Mix the plastic material with the soil as the sole source of carbon and energy. Place the mixture in an ampoule and determine the oxygen demand (BOD) or
The amount of carbon dioxide released. For example, measuring biochemical oxygen demand (BOD) can be achieved by measuring a constant volume in the flask in the respirometer
The volume of oxygen required by the gas or the change in volume or pressure (or both) measured automatically or manually. See the attached respiratory meter for an example.
Record A. For example, the carbon dioxide released can be measured, and the carbon dioxide-free air can be passed through the soil, and then the test material is released during biodegradation.
The amount of carbon dioxide. See Appendix B and Appendix C for examples of the above two methods.
Biodegradation rate by the ratio of biochemical oxygen demand (BOD) to theoretical oxygen demand (ThOD) or the amount of carbon dioxide released and carbon dioxide
The ratio of theoretical release (ThCO2) is obtained and the results are expressed as a percentage. In the determination of BOD, consideration should be given to possible nitrification
The impact of the use. The test can be terminated when the biodegradation rate is constant or after the test time has elapsed for 6 months.
Unlike ISO 11266.1994, ISO 11266.1994 mainly measures various organic components, and this standard mainly measures materials.
Biodegradability.
5 test environment
The culture should be carried out in a dark or low-light confined space, which should have no steam that inhibits the growth of microorganisms, and keep the temperature at 20 °C~
Other suitable temperatures are selected at 25 ° C, depending on the medium used and the environment being evaluated.
6 materials
6.1 distilled or deionized water
Contains no toxic substances, dissolved organic carbon content (DOC) ≤ 2mg/L.
6.2 Carbon dioxide absorber
Soda lime granules or other suitable absorbent.
7 instruments
All utensils should be clean and free from any organic or toxic substances.
7.1 closed respirometer
Agitator and other test vessels (glass flasks) are required and placed in an incubator or thermostat (eg water bath)
See Appendix A for an example.
Note. Any respirometer that can accurately measure BOD can be used.
7.2 Apparatus for determining the amount of carbon dioxide released
7.2.1 Test flask
Glass containers (such as glass flasks) can be vented, shaken or stirred, and the connecting lines must not leak carbon dioxide. Test equipment
Place it in an incubator or in a thermostat (such as a water bath).
7.2.2 Air supply system without carbon dioxide
Provides a constant flow of carbon dioxide-free air to each test flask and maintains a constant flow rate with a deviation of ±10%
Within the scope (see Appendix B), the culture equipment specified in ASTM D5988-1996 is also applicable.
7.2.3 Analytical instrument for the determination of carbon dioxide
For the direct determination of carbon dioxide, or complete absorption with an alkaline solution, and then determine the dissolution of inorganic carbon (DIC) to calculate dioxide
Carbon content (see Appendix C). If you use a continuous infrared analyzer or gas chromatograph to directly measure the amount of carbon dioxide in the exhaust gas, you need to be precise.
GB/T 22047-2008/ISO 17556.2003
Control and measure air flow.
7.3 Analytical balance
8 procedures
8.1 Test materials
The test material should be of known quality and contain a sufficient amount of carbon, and the resulting biochemical oxygen demand (BOD) can be detected by the respirometer used. Yuhua
Calculate molecular formula or total organic carbon (TOC) by elemental analyzer, and calculate theoretical oxygen demand (ThOD) and theoretical release of carbon dioxide
Quantity (ThCO2) (see Appendix C and Appendix D).
Note 1. Although the elemental analyzer is used to measure substances with higher molecular weights, the accuracy of the substances with lower molecular weight is lower, but this precision is used for calculation.
It is acceptable to consider the amount of oxygen demand (THOD) or the theoretical amount of carbon dioxide released (ThCO2).
The quality of the test material should be such that the oxygen consumption or the amount of carbon dioxide released during the degradation is within the measuring range of the instrument, usually 100g~
300g to 300mg of test material can be added to 300g of soil to meet the requirements. The maximum amount of test material should be affected by the oxygen supplied to the test
The gas volume limit, except for the case where the soil contains a large amount of organic matter,.200 g of the test material is generally placed in.200 g of soil.
Note 2. In order to reduce the effects of soil respiration in the blank flask, the test material may be pre-aerated or inerted if necessary.
The test material is generally in the form of a powder, but it may be in the form of a film, a chip, or a shaped article.
Tests have shown that the final degree of biodegradation is almost independent of the shape and shape of the test material. But the speed of biological decomposition, and the test material
The shape and shape of the material are related. Therefore, if different plastic materials are compared during the same test period, the test materials should be the same.
Shape and shape. If the test material is in the form of a powder, particles with a known particle size distribution should be used. The recommended maximum particle size is
250 μm. If the test material is not in a powder form, the size of each test material shall not be greater than 5 mm x 5 mm. Test equipment size should
Compatible with the morphology of the test material. Make sure that there are no significant instrument deviations due to the design of the test instrument. Sample preparation process
(eg processing the mixture into a powder) should not significantly affect the degradation behavior of the material.
The contents of hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S) and their molecular masses of the test materials can be selectively determined. Test material
The material is preferably free of additives such as plasticizers. If the test material does contain such additives, the biocomponent of the polymeric material itself is evaluated.
Information on the biodegradability of the additive is also required when solving the capacity.
For details on the treatment of compounds that are poorly soluble in water, see ISO 10634.1995.
8.2 Reference material
Use known biodegradable polymers (such as microcrystalline cellulose powder, ashless cellulose filter paper or poly-β-hydroxybutyrate) as positive control
The reference material, the total organic carbon content (TOC), shape and size are as close as possible to the test material.
A non-biodegradable polymer (such as polyethylene) having the same shape as the test material can be selected as the negative control reference material.
8.3 Preparation of test soil
8.3.1 Soil collection and sieving
The natural soil used is collected from the soil surface of the field and/or forest, or has been pre-exposed. Sift the soil to obtain a small size
In 2mm particles, and remove obvious plant material, stones and other inert materials.
Note 1. Organic solids such as straw are removed as much as possible because these materials will decompose during the test.
Note 2. The soil can be pretreated, but the soil that has been pre-exposed can not be used, especially when simulating the biodegradation behavior in the natural environment.
Pre-exposure the soil. However, the use of pre-exposure soil for general testing purposes should be clearly stated in the test report (eg biodegradation)
Percentage = 狓%, using pre-exposure soil), and the method of pre-exposure is detailed in the test report. Pre-exposed soil can be passed differently
Under suitable conditions, it can be obtained by suitable biodegradation tests in the laboratory, or in places with similar environmental conditions (such as contaminated sites or industries).
Collected in the waste disposal site).
Record the location, location, proportion of plants or previous crops, sampling time, sampling depth, and if possible, record soil for planting
The use of fertilizers and pesticides in the process.
8.3.2 Measurement of soil properties
Soil characteristics were determined according to the following criteria.
GB/T 22047-2008/ISO 17556.2003
Determination of total water retention capacity according to ISO 11274.1998;
Determination of the pH of the soil according to ISO 10390.1994;
The content of organic matter was determined according to ISO 10694.1995.
Regulate the soil by adding an appropriate amount of water to the soil or by exposing the soil to a shaded area after adding the appropriate amount of water.
Wet content to a value suitable for the test. Adjust the pH of the soil to 6.0 to 8.0.
Note 1. The optimum moisture content of the test soil depends on the test material and is usually between 40% and 60% of the total water retention capacity.
Note 2. In order to ensure a good biodegradation process, the ratio of organic carbon to soil nitrogen of the test material or reference material (C.N ratio) is recommended to be adjusted to at least
40.1, this can be achieved by adding nitrogen, such as an aqueous solution of ammonium chloride or the like.
8.3.4 Treatment and storage of soil
The soil was stored in an insulated container at 4 ° C ± 2 ° C before the test. Avoid any treatment that inhibits microbial activity in the soil.
Use ISO 10381-6.1993 to confirm that soil activity is not affected by sampling.
8.4 Test procedure
Prepare the following number of flasks (test bottles).
a) two flasks (FT) containing test materials;
b) two for the blank test flask (FB);
c) two flasks (FC) using a reference material for the detection of soil activity;
Also, if needed.
d) a flask (FS) for checking for possible non-biodegradable or non-microbial changes such as hydrolysis;
e) A flask (FI) for checking the possible inhibition of microbial activity by the test material.
Place between 100g and 300g of soil at the bottom of each flask (see 8.3), the thickness should not exceed 3cm, as shown in Table 1, add
Test materials (see 8.1) or reference materials (see 8.2) into the soil. The mass of each flask containing the test mixture was recorded.
Table 1 Final distribution table of test materials and reference materials
Flask test material reference material medium
FT test + - +
FT test + - +
FB blank - - +
FB blank - - +
FC soil activity test - + +
FC soil activity test - + +
FS non-biodegradable test bottle (optional) + - -
FI suppression control bottle (optional) + + +
Note 1. The test material should be evenly mixed with the soil. If the test material is a powder, disperse it into the soil as much as possible; if the test material is a film, it should be used as much as possible.
The test material can be brought into contact with the soil. It is also possible to scrape the surface of the sample with a spatula to increase the contact between the test material and the microorganisms in the soil.
Note 2. Two test bottles are also available for every three test bottles for test materials, blank test and soil activity check.
The flask was placed in a constant temperature test environment, the sealed test bottles were attached, placed in a respirometer, and the stirrer was turned on. Connected well
Start the culture with a respirometer or a carbon dioxide-free air supply system.
If it is to measure the consumption of oxygen, record the necessary readings on the meter (such as manual) and check if the oxygen-consuming recorder is running correctly.
Often (automatic respirometer) (see Appendix A).
If it is to measure the released carbon dioxide, according to the rate of carbon dioxide released, the amount of carbon dioxide, in a certain interval, use
A suitable, sufficiently accurate method (see Appendix B and Appendix C) determines the amount of carbon dioxide evolved from each flask.
If the rate of biodegradation is slowed due to soil drying during the test, the measurement should be stopped, from the respirometer or without carbon dioxide supply.
GB/T 22047-2008/ISO 17556.2003
The flask was removed from the system. The flask was weighed and an appropriate amount of water was added to the soil to bring the moisture content to the initial value. Reconnect the flask to the system,
Measure oxygen consumption or carbon dioxide release. These operations should not inhibit the activity of soil microorganisms and will not affect oxygen consumption or
The measurement of the amount of carbon dioxide released is clearly stated in the test report.
When the measured BOD value or the amount of released carbon dioxide reaches a stable level (reaching the stationary phase), and no further biological points are expected
At the time of solution, the test is considered to have ended. The test period is up to 6 months. If the test needs to be extended, the sealing of the system should be checked regularly.
Make sure the system is leak free.
At the end of the test, the flasks were removed and weighed to check the reduced moisture content of the test soil. Residual test materials can be used if needed
Extract from the soil with a suitable solvent and weigh.
9 Calculation and representation of results
9.1 Calculation
9.1.1 Calculating the percentage of biodegradation from oxygen consumption
Use an appropriate respirator to read the oxygen consumption of each flask according to the method indicated by the instrument.
The biochemical oxygen demand (BODS) of the unit test material is calculated according to formula (1).
ρT
(1)
In the formula.
BODS---BOD value of unit test material, expressed in milligrams per gram of test material, in milligrams per gram of test material
(mg/g);
ρT—The concentration of the test material in the reaction mixture of the flask FT in milligrams per gram of test soil (mg/g).
(2)
Calculate the BOD value and the percentage of biodegradation of the reference material flask FC in the same manner, and then calculate the abiotic decomposition correction value flask.
FS, inhibition control flask FI's BOD value and percentage of biodegradation. See Appendix A for the method of ThOD.
9.1.2 Calculating the percentage of biodegradation from the amount of carbon dioxide (CO2) released
9.1.2.1 Theoretical release of carbon dioxide from test materials
The theoretical release of carbon dioxide (ThCO2) is calculated according to formula (3) in milligrams (mg).
(3)
In the formula.
ωC---the carbon content in the test material, determined by the chemical formula or calculated by elemental analysis, expressed in %;
44 and 12---represent the molecular mass of carbon dioxide and the atomic weight of carbon, respectively.
The same method was used to calculate the theoretical release of carbon dioxide from the reference material and the mixture of test material and reference material in the test flask FI.
9.1.2.2 Percentage of biodegradation
ThCO2 ×
100 (4)
In the formula.
GB/T 22047-2008/ISO 17556.2003
ThCO2---The theoretical release of carbon dioxide from the test material in milligrams (mg).
The same method was used to calculate the percentage of biodegradation of the reference material in the soil activity test bottle FC.
9.2 Expression and interpretation of results
The BOD value or the amount of carbon dioxide and the percentage of biodegradation for each measurement cycle of each flask were compiled into a table. For each flask, at the time
A plot of BOD or carbon dioxide emissions and percent biodegradation is plotted on the abscissa. For double flasks, if you want to get a comparison result,
An average biodegradation curve can be made.
Characterizing the biodegradation of the test material by determining the maximum value of the biodegradation rate from the average or highest value of the stationary phase of the biodegradation curve
degree.
The hygroscopicity and shape of the test material may affect the test results, so the test uses plastic materials of similar structure whenever possible.
To compare.
Data on the toxicity of the test materials can help explain why the results of the biodegradation test are low.
10 Effectiveness of the results
Only if the test meets the following requirements can it be considered valid.
The percentage of biodegradation of the reference material is >60% during the stationary phase or at the end of the test;
At the stationary stage or at the end of the test, the relative deviation of the BOD value or the amount of carbon dioxide released from the two blank test flasks is not exceeded.
Over 20%.
If the above requirements are not met, the test is repeated using another pretreated or pre-exposed soil.
11 test report
a) according to the standard;
b) all information indicating the test and reference materials, including their organic carbon content (TOC), chemical composition, molecular formula
(if known), theoretical oxygen demand (ThOD), theoretical release of carbon dioxide (ThCO2), shape, state, quantity, and concentration, aid
Agent content (if known);
c) all information on the soil used, including source, time of collect......
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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