GB/T 19277.2-2013 PDF English
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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
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GB/T 19277.2-2013: PDF in English (GBT 19277.2-2013) GB/T 19277.2-2013
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
ICS 83.080.01
G31
National Standards of People's Republic of China
Final aerobic organisms under controlled composting conditions
Decomposition ability
Method of carbon dioxide Part 2. Weight
Analytical method for the determination of carbon dioxide under laboratory conditions
Release amount
evolvedcarbondioxide-Part 2. Gravimetricmeasurementof
(ISO 14855-2.2007, IDT)
2013-09-06 released.2014-01-31 implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
China National Standardization Administration issued
Foreword
GB/T 19277 "Determination of the final aerobic biodegradability of materials under controlled composting conditions using the method of determining the released carbon dioxide
The Law is divided into the following sections.
--- Part 1. General method;
--- Part 2. Determination of carbon dioxide emissions under laboratory conditions by gravimetric analysis.
This part is the second part of GB/T 19277.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This section uses the translation method equivalent to the ISO 14855-2.2007 "measurement of the final aerobic biodegradability of materials under controlled composting conditions"
Methods of determining the release of carbon dioxide - Part 2. Determination of carbon dioxide release under laboratory conditions by gravimetric method
the amount".
The documents of our country that have a consistent correspondence with the international documents referenced in this part are as follows.
---GB/T 19277.1-2011 Determination of the final aerobic biodegradability of materials under controlled composting conditions
Methods of carbon dioxide Part 1. General methods (ISO 14855-1.2005, IDT).
This part is under the jurisdiction of the National Biomaterials and Degradation Products Standardization Technical Committee (SAC/TC380).
This section drafted by. Suzhou Hanfeng New Materials Co., Ltd., Beijing Technology and Business University Light Industrial Plastics Processing Application Research Institute, Shenzhen City
Dajie Plastic Products Co., Ltd., National Plastic Products Quality Supervision and Inspection Center (Beijing).
The main drafters of this section. Yan Yujuan, Jiang Kai, Huang Xiangqiu, Chen Mingxing, Wei Wenchang, Li Ziyi.
introduction
Waste plastics management is a serious problem worldwide. Plastic recycling technology includes material recovery (mechanical recycling, chemical or
Crude recovery, biological or organic recovery) and energy recovery (thermal, steam or electrical energy as a substitute for fossil fuels and other fuel resources).
The use of biodegradable plastics is a valuable option for recycling (biological or organic recycling).
Some international standards for measuring the ultimate aerobic/anaerobic biodegradability of plastics have been published. In particular, ISO 14855-1 is adopted
The use of continuous infrared analysis, gas chromatography or titration to determine the amount of carbon dioxide released is a common test method. ISO 14855-
1.2005 has been equivalently adopted as China's standard GB/T 19277.1-2011. Compared with GB/T 19277.1-2011, this part makes
The ratio of compost inoculum to test sample used was 1.10. In order to ensure the activity of the compost inoculum, inert materials are mixed into the inoculum.
In order to give the mixture the same texture as the soil. The amount of carbon dioxide released from the experimental container is measured by a carbon dioxide absorption device,
The absorbent is then subjected to gravimetric analysis. ISO 14855 uses a closed system to collect the released carbon dioxide, which can be determined by isotope calibration
Research has obtained useful information, including the way in which the molecular structure of the copolymer is decomposed.
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.
Final aerobic organisms under controlled composting conditions
Decomposition ability
Method of carbon dioxide Part 2. Weight
Analytical method for the determination of carbon dioxide under laboratory conditions
Release amount
1 Scope
This part of GB/T 19277 specifies a test method for determining the discharge of a material under controlled composting conditions.
The amount of carbon dioxide is used to determine its ultimate aerobic biodegradability. This method regulates the humidity, aerobic concentration and temperature in the compost container
Equal conditions to achieve the best rate of biodegradation.
This section applies to the following materials.
--- natural and/or synthetic polymers, copolymers and mixtures thereof;
---Plastics containing additives such as plasticizers and pigments;
---Water soluble polymer;
--- Materials that do not inhibit microbial activity in the inoculum under the experimental conditions.
If the test material has an inhibitory effect on the microorganisms in the inoculum, other types of compost compost or pre-exposure compost can be used.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.
Pieces. For undated references, the latest edition (including all amendments) applies to this document.
ISO 5663 Water quality-Determination
ISO 8245 Water quality-Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC) in water quality
ISO 14855-1 Determination of the ultimate aerobic biodegradability of materials under controlled composting conditions - Part 1. General method
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Compost compost
An organic soil conditioner obtained by biological decomposition of the mixture. The mixture consists mainly of plant residues and sometimes some organic materials.
Material and certain inorganic substances.
3.2
Composting composting
An aerobic treatment method that produces compost.
3.3
Total dry solids totaldrysolids
A known volume of material or compost is dried to a constant amount of solids at a temperature of 105 °C.
3.4
Volatile solid volatilesolids
The difference between the total dry solids of a known volume of material or compost minus the amount of residual solids obtained after incineration at a temperature of 550 °C.
Note. The volatile solids content is used to characterize the organic content of the material.
3.5
Ultimate aerobic biodegradation ultimateaerobicbiodegradation
Under aerobic conditions, organic compounds are decomposed by microorganisms into carbon dioxide (CO2), water (H2O) and mineralized inorganic salts of the elements contained therein.
And new biomass.
3.6
Theoretical release of carbon dioxide theoreticalamountofevolvedcarbondioxide
m(ThCO2)
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 mg/g or mg of test material.
3.7
Lag phase
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%.
3.8
Maximum biological decomposition rate maximumlevelofbiodegradation
In the test, the extent to which the test material no longer biodegraded during biodegradation is expressed as a percentage.
3.9
Biodegradation phase
The number of days from the end of the lag phase to 90% of the maximum biodegradation rate.
3.10
Stationary stage plateauphase
The number of days from the end of the biodegradation phase to the end of the trial.
3.11
Pre-exposure
In order to improve the ability of the inoculum to biodegrade test materials by adapting (selecting) microorganisms, docking in the presence of test materials in the test
The seeds are pre-cultured.
3.12
Pre-conditioning
In order to improve the test results of the microorganisms in the test environment, the inoculum is pre-tested in the absence of test materials in subsequent tests.
to cultivate.
3.13
Water holding rate water-holdingcapacity;WHC
The quality of water evaporated from water-saturated soil, ie the mass of water when the soil is dried at constant temperature at 105 ° C to constant weight divided by the dry soil
quality.
4 Principle
The method determines the biodegradation rate of the test material under the condition of composting compost by controlling the humidity, oxygen rate and temperature of the compost container
rate. The method is also directed to the use of a small reactor to determine the final biodegradability of the test material. By weighing sodium lime and sodium talc
The absorption device measures the amount of carbon dioxide released to periodically calculate the calculated decomposition rate.
The test material is a mixture of an inoculum from decomposed compost and an inert material such as sea sand. Sea sand in terms of moisturizing and maintaining biological activity
Play an active role. See Appendix A and Appendix B for examples of suitable test methods. Regularly weigh the amount of carbon dioxide released with an electronic balance for
The next method measures the carbon dioxide content. See Appendix C for the derivation formula for calculating the biodegradation rate from the amount of carbon dioxide released. In the method,
The biodegradation rate of the material is obtained by comparing the amount of carbon dioxide released with the theoretical release of carbon dioxide [m(ThCO2)] (in percentage table)
Show).
The test is terminated when the biodegradation reaches a stationary phase. The standard time for termination is 45d, but the trial can last up to 180d.
5 reagent
Use analytical grade reagents. Use deionized water.
5.1 Soda lime, used to absorb carbon dioxide, with a particle size of 2mm~4mm.
5.2 Anhydrous calcium chloride, used to absorb water, with a particle size of 2mm~3mm.
5.3 Talc powder filled with sodium hydroxide (commonly called sodium talc), used to absorb carbon dioxide, with a particle size of 2mm~3mm.
5.4 Silica gel (including hygrometer) for absorbing water with a particle size of 2mm~4mm.
5.5 Sea sand, particle size from 0.169cm to 0.224cm (20 mesh ~ 35 mesh).
5.6 Reference material. Thin-layer chromatography (TLC) microcrystalline cellulose was used as a positive control reference material with a particle size of less than 20 μm.
6 instruments
Make sure all the utensils are completely cleaned, especially if they are not attached to any organic or toxic substances.
6.1 Gas supply system
It is capable of delivering carbon dioxide-free, water-saturated air to each compost container. The air is compressed by air through the sodium and lime
Obtained after the carbon dioxide absorber and humidifier (see Appendix A and Appendix B for examples). Air flow is controlled by the flow meter to provide charge
The aerobic conditions of the points.
6.2 Compost container
A bottle or column container is used to ensure the supply of saturated water and carbon dioxide free air in the components. The optimum volume is 500mL. If you try
If the test requires the determination of the mass loss of the test material, the empty weight of each compost container shall be weighed.
6.3 Analytical instrument for the determination of carbon dioxide
The instrument can directly measure the amount of carbon dioxide according to the change in the mass of the carbon dioxide absorption device. Carbon dioxide absorption device is filled
A container of sodium lime, sodium talc and anhydrous calcium chloride. The container filled with calcium chloride is preferably divided into a container filled with sodium lime and sodium talc.
On (see Appendix A and Appendix B for examples). Between the compost container and the carbon dioxide absorption device, an ammonia absorption device (dilute sulfuric acid) and water suction are required.
Receiving device (silica gel and calcium chloride).
6.4 airtight tube
Used to connect compost containers with air systems and carbon dioxide measurement systems.
6.5 pH meter
Used to determine the pH of the test mixture. Its accuracy is not more than 0.1.
6.6 Analytical equipment
Used to determine dry solids (at 105 ° C), volatile solids (at 550 ° C) and total organic carbon (TOC) for elemental analysis of materials.
When necessary, it is also necessary to determine dissolved inorganic carbon (DIC), volatile fatty acids, air oxygen content, water content, and total nitrogen content.
6.7 balance
Used to periodically measure the mass of the carbon dioxide absorber (to measure the amount of carbon dioxide released), as well as to hold compost and test materials
The quality of the compost container. It is recommended to use an electronic balance with a top loading display accuracy of 10 mg and a range of 500 g.
6.8 thermostatic control unit
It is used to ensure that the temperature of the compost container is controllable during the test (see Appendix A and Appendix B for examples). The temperature of the compost container should be maintained at a constant
The setting is ±2 °C.
6.9 Compost bioreactor
Covered boxes of polypropylene or other materials can be used as compost bioreactors, and the box size should be such as to facilitate agitation of the components. Use with cover
The box avoids excessive evaporation of water. Three holes with a diameter of 10 mm were struck at equal intervals along the center line of the cover. Through these 3 holes, the cabinet can be made
The outside gas is exchanged and excess water is gradually evaporated.
7 test steps
7.1 Preparation of inoculum
A fully aerated compost produced by a normally operating aerobic composting unit can be used as an inoculum. The inoculum should be uniform and free of large inertia
Substances such as glass, stone, and metal. After removing these impurities by hand, the compost was screened with a sieve having a pore size of 3 mm.
Composting can be obtained as follows. Use shavings, sawdust, mushroom beds, chaff or straw as a carbon source. Adding livestock manure as a compost
And mineralized inorganic salt nutrient sources. The above materials were placed in a container having a volume of about 1 m3 and mixed well. Carbon to nitrogen ratio required for composting
(C/N) is 15, and the carbon to phosphorus ratio (C/P) is 30. When the phosphorus content is insufficient, it can be supplemented with calcium superphosphate. Add water to make the moisture content 65%.
C/N, C/P and moisture content can be adjusted to appropriate values based on seasonal variations and climate differences. Composting from the container every week
Remove and refill the compost and replenish it as needed before refilling the compost into the container and continuing the test. The best time to use compost is
60d~120d.
Unexposed inoculants are generally used, especially in standard trials that simulate biodegradation behavior in real composting equipment.
Sometimes pre-exposure compost can also be used depending on the purpose of the test, as long as it is clearly stated in the test report (eg percentage of biodegradation =
X%, using pre-exposure compost), and the pre-exposure method is detailed in the test report.
The total amount of total dry solids and volatile solids in the compost inoculum was determined. The total dry solids should be 35% to 55% of the amount of wet solids.
The amount of volatile solids exceeds 30% of the dry solids. If necessary, add water before using compost, or perform proper drying (such as drying)
The air is aerated to the compost to adjust the moisture content appropriately.
Prepare a mixture of 1 part of inoculum and 5 parts of deionized water, and shake them thoroughly to measure the pH immediately. The value should be 7.0~
9.0.
In order to further characterize the inoculum, some suitable parameters, such as total organic, can be selectively determined at the beginning and at the end of the experiment.
Carbon, total nitrogen or fatty acid content.
The inoculum activity was tested by biodegrading the reference material during the test and then measuring the carbon dioxide released from the blank container. Trying
At the end of the test, the reference material should be decomposed by at least 70%. Within 10 days of the start of the test, the inoculum in the blank container is relatively volatile per gram.
The carbon dioxide produced by the body is about 50mg~150mg. If the amount of carbon dioxide released is too high, the compost should be aerated for a few days and reused for new
Test.
7.2 Preparing the sea sand
Soak the sea sand in tap water. Remove floating impurities by precipitation, fully rinse the sea sand, drain the water and keep it at around 105 °C
Dry it.
Note. Sea sand is an inert substance with a SiO2 content of more than 90%. It plays an important role in maintaining proper moisture content and supporting microbial growth.
7.3 Preparation of test materials and reference materials
Determination of total organic carbon (TOC) of test materials and reference materials in accordance with ISO 8245, grams of total organic carbon per gram of total dry solids
To represent. Alternatively, if the material does not contain inorganic carbon, its carbon content can be determined by elemental analysis. The test material should contain enough
Machine carbon to produce the carbon dioxide needed for the determination. Typically 10 g of total dry solids per container contains at least 4 g of total organic carbon.
The test material is preferably in the form of a powder, but it is also possible to use a small piece of film or a fragment of a shaped article. The recommended maximum particle size is
250 μm.
7.4 Start the test
Prepare at least the following number of compost containers.
a) 2 test containers (VT) containing the test mixture;
b) 2 blank containers (VB);
c) Two containers (VR) for testing the activity of the inoculum with reference material.
The amount of test mixture of test material and inoculum depends on the nature of the test material and the size of the compost container. Total stem of inoculum
The total dry solids ratio of solid to test material was approximately 6.1. If an inert material is added, the ratio is not considered. The test mixture should have
Have the same moisture content as the inoculum. The moisture content of the test mixture should be set at 80% of the water content of the test mixture (WHC)~
90%. An inoculum of the same amount of total dry solids should be placed in each test vessel.
In a typical test, prepare a 500 mL container with a lid, weigh the inoculum containing 60 g of total dry solids, and add enough water to make the water
The content is 65%. Mix well and place the compost at room temperature for 24 h. Weigh 320g of sea sand and add water to make it have a moisture content of 15%.
The compost is then mixed evenly with the sea sand as an inert material. 10 g (dry weight) of the test material was added to the mixture and mixed well. Touch gently
I feel the feeling of soil. If necessary, measure the WHC of the test mixture according to ISO 11721-1, add water or dry air
Aeration treatment to adjust the moisture content of the mixture to about 90% of the WHC. The mixture is placed in a compost container. If you use meteorites
Inert material, prepared in accordance with ISO 14855-1.
When using composted compost stored in a cold storage as an inoculum, the compost needs to be pretreated before use. In a typical test, it will contain
60g of total dry solids composted compost is loaded into the compost bioreactor, and the water content of the compost is about 110% of the water holding capacity by adding water. Mixed
After homogenization, it was allowed to stand at room temperature for 24 h and then at 58 ° C for 24 h. Add the same volume of sea sand as the composted compost (dry weight
320g), evenly mixed. The moisture content of the sea sand was adjusted to 15% (the water holding capacity of the sea sand) before the addition. Add 10g of six water if necessary
Magnesium ammonium phosphate is used as a nitrogen source. The mixture was loaded into a compost bioreactor and incubated at 58 ° C for one week. To maintain aeration conditions and allow excess water
The mixture was evaporated and the mixture was stirred several times a day for 10 min. After one week, the moisture content of the mixture was adjusted to 90% of the water holding capacity. Mixed
The final mass of the compound should be 550g, but the final quality may change due to the use of compost (the different composting water holding capacity)
Chemical. 10 g of the test material (dry weight) was added to the mixture and uniformly mixed, and placed in a compost container.
When performing the ISO 14855-1 biodegradation test, composted compost with a moisture content of approximately 50% should be used in accordance with ISO 14855-1.
Each compost container was filled with 120 g of decomposed compost containing 60 g of total dry solids. Add 10g test material (dry weight) to the compost compost
And mix well. The mixture is placed in a compost container. If the test mixture dries too quickly, the aqueous inert material together with the mixture
Load the container. However, the aqueous material cannot be mixed with the test mixture.
The organic carbon content can be calculated from the total organic carbon (TOC) of the inoculum and the test material. A representative sample of the test mixture can be used
The total nitrogen content was determined (determined by the Kjeldahl method according to ISO 5663).
The compost container was placed in a test environment at 58 ° C ± 2 ° C, and aerated with water saturated with carbon dioxide. These bars
The parts can be satisfied by passing air through a carbon dioxide absorber containing sodium and lime and a humidifier containing water (see Appendix A and Appendix).
Record B). The air flow through each compost container was adjusted by adjustment and was between 10 mL/min and 30 mL/min.
A sufficiently large air flow should be used to ensure that each compost container maintains aeration conditions throughout the test period. Should be fixed
Check the air flow rate of each outlet with a bottle or soap bubble flow meter.
The method of treating the reference material is the same as that of the test material. The blank container contains only inoculum and sea sand. Blank container and test
The amount of inoculum and sea sand in the material container should be equal.
7.5 Determination of carbon dioxide emissions
1 mol/L of sulfuric acid was charged into the ammonia absorption bottle to remove ammonia from the composting container. Loading silica gel and anhydrous calcium chloride separately
Two water removal devices. The carbon dioxide absorber and the water absorbing agent are separately charged into the carbon dioxide absorbing device and the water removing device. Carbon dioxide absorption
The charge is preferably a mixture of the same amount of sodium lime and sodium talc. The water absorbing agent is preferably anhydrous calcium chloride. Use an electronic day with an accuracy of 10mg
The mass of the absorption device was measured flat (two devices were measured together). The amount of carbon dioxide released was determined based on the increase in mass of the device.
When the absorption amount of the reagent in the carbon dioxide absorbing device and the water absorbing device reaches 80% of its absorption capacity, the reagent is replaced. 80g equivalent
The mixture of soda lime and sodium talc has the ability to absorb approximately 15 g of carbon dioxide.
7.6 Inoculation stage
The amount of carbon dioxide in the exhaust gas of each compost container was measured during the test using the change in mass of the carbon dioxide absorber. Alive
The decomposition phase is measured at least once a day. In the stationary phase, measure at least once every two days.
The composting container oscillates once a week to prevent squashing and to ensure adequate contact of the microorganisms with the test material.
Visual inspections should be performed frequently to ensure proper humidity in the test mixture in the compost container without any free water or block. General, heap
There is no condensate on top of the fertilizer container to indicate that the system is dry. The moisture content can be measured with an appropriate instrument and kept at approximately
The test mixture holds 80% to 90% of the water. Use humid air or dry air to adjust the system to the desired moisture content. From the air intake
Water or water can cause significant changes in moisture content.
When the compost container is oscillated weekly and at the end of the test period, visual observations of composting properties such as structure, moisture content, and color should be recorded.
Ze, mold production, odor of exhaust gas and degree of disintegration of test materials.
The composting cycle does not exceed 180d and the temperature is maintained at 58 °C ± 2 °C. If the test material can be observed after 180d, there are obvious creatures.
Decomposition, the test period should be extended to a constant stationary phase. If the stationary phase occurs early, the test cycle can be shortened.
During the test, if necessary, an equal amount of compost may be added to each test container to re-inoculate it. The test report should clearly identify the heap
Fertilizer source and date of re-inoculation.
After the start of the test, the pH should be measured periodically.
If the pH is lower than 7.0, it is because the test material which is easily decomposed rapidly decomposes and acidifies the compost, which inhibits the bio-division of the material.
solution. At this time, it is recommended to measure the volatile fatty acid content and check the acidification of the components in the compost container. If every kilogram of total dry solids is produced
If the volatile fatty acid content exceeds 2 g, the test must be considered ineffective because acidification and microbial activity are inhibited. To prevent acidification,
Increase the amount of compost in all compost bins, or reduce test materials, increase compost or pre-exposure compost, and repeat the test.
7.7 Termination of the test
If the mass loss of the test material is to be determined, re-weigh each fill mixture (compost, sample and inert) at the end of the test
Composting containers for sexual materials such as sea sand. The mixture was taken from each container and the total dry solids and volatile solids were determined.
8 calculation
8.1 Theoretical release of carbon dioxide from test materials
Calculate the theoretical release of methane (ThCO2) produced by the test material in each compost container according to formula (1), expressed in grams (g).
m(ThCO2)=m×wC×44/12 (1)
In the formula.
m --- the mass of the test material in the test vessel, in grams (g);
wC --- The carbon content of the test material, derived from chemical formula or elemental analysis, expressed as mass fraction;
44 and 12---represent the molecular weight of carbon dioxide and the atomic weight of carbon, respectively.
The theoretical carbon dioxide emissions of the reference material in each vessel were calculated in the same manner.
8.2 Percentage of biodegradation
Calculate the biodegradation of the test material in each test vessel VT according to the amount of accumulated carbon dioxide released by equation (2) during each measurement period.
Percentage Dt (%).
Dt=∑m
(CO2)tT-∑m(CO2)tB
m(ThCO2) ×
100 (2)
In the formula.
∑m(CO2)tT --- The cumulative amount of carbon dioxide emitted by each test vessel VT at the start of the test, in grams (g);
∑m(CO2)tB --- The average amount of carbon dioxide released by each blank container VB from the start of the test to time t (two sets of empty
Average of white containers) in grams (g);
m(ThCO2) --- The theoretical release of carbon dioxide produced by each container of test material in grams (g).
9 Results representation and explanation
Fill out the daily table of measured and calculated values for test materials, reference materials, and blank materials.
When the cumulative amount of carbon dioxide released from each compost container and blank compost container containing test materials and reference materials is relative
The intercropping curve is used to make a biodegradation curve (percentage of biodegradation versus time) between the test material and the reference material. If each
If the deviation of the measured values does not exceed 20%, the average value is used, otherwise, the biodegradation curve of each compost container is made.
If a plateau ...
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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