1、Designation: D 5511 02Standard Test Method forDetermining Anaerobic Biodegradation of Plastic MaterialsUnder High-Solids Anaerobic-Digestion Conditions1This standard is issued under the fixed designation D 5511; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the degreeand rate of anaerobic
3、 biodegradation of plastic materials inhigh-solids anaerobic conditions. The test materials are ex-posed to a methanogenic inoculum derived from anaerobicdigesters operating only on pretreated household waste. Theanaerobic decomposition takes place under high-solids (morethan 30 % total solids) and
4、static non-mixed conditions.1.2 This test method is designed to yield a percentage ofconversion of carbon in the sample to carbon in the gaseousform under conditions found in high-solids anaerobic digesters,treating municipal solid waste (1, 2, 3, 4).2This test methodmay also resemble some condition
5、s in biologically activelandfills where the gas generated is recovered and biogasproduction is even actively promoted, for example, by inocu-lation (codeposition of anaerobic sewage sludge, anaerobicleachate recirculation), moisture control in the landfill(leachate recirculation), and temperature co
6、ntrol (short-terminjection of oxygen, heating of recirculated leachate) (5, 6, 7).1.3 This test method is designed to be applicable to allplastic materials that are not inhibitory to the microorganismspresent in anaerobic digesters operating on household waste.1.4 The values given in SI units are to
7、 be regarded as thestandard.1.5 This test method is equivalent to ISO DIS15985.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and dete
8、rmine the applica-bility of regulatory limitations prior to use. Specific hazards aregiven in Section 8.2. Referenced Documents2.1 ASTM Standards:D 618 Practice for Conditioning Plastics for Testing3D 883 Terminology Relating to Plastics3D 1293 Test Methods for pH of Water4D 1888 Test Methods for Pa
9、rticulate and Dissolved Matter,Solids, or Residue in Water5D 2908 Practice for Measuring Volatile Organic Matter inWater by Aqueous-Injection Chromatography6D 3590 Test Methods for Total Kjeldahl Nitrogen in Water4D 4129 Test Method for Total and Organic Carbon in Waterby High-Temperature Oxidation
10、and by Coulometric De-tection4E 260 Practice for Packed Column Gas Chromatography7E 355 Practice for Gas Chromatography Terms and Rela-tionships72.2 APHA-AWWA-WPCF Standards:2540 D Total Suspended Solids Dried at 103105C82540 E Fixed and Volatile Solids Ignited at 550C8212 Nitrogen Ammonia82.3 ISO S
11、tandard:ISO DIS 15985 Plastics Determination of the UltimateAnaerobic Biodegradability and Disintegration UnderHigh-Solids Anaerobic-Digestion Conditions Methodby Analysis of Released Biogas93. Terminology3.1 Definitions Definitions of terms applying to this testmethod appear in Terminology D 883.3.
12、2 Definitions of Terms Specific to This Standard:3.2.1 methanogenic inoculumanaerobically digested or-ganic waste containing a high concentration of anaerobicmethane-producing microorganisms.4. Summary of Test Method4.1 This test method consists of selection and analysis ofmaterial for testing, obta
13、ining a concentrated anaerobic inocu-lum from an anaerobic laboratory-scale digester, exposing the1This test method is under the jurisdiction of ASTM Committee of D20 onPlastics and is the direct responsibility of Subcommittee D20.96 on Environmen-tally Degradable Plastics.Current edition approved A
14、ugust 10, 2002. Published October 2002. Originallypublished as D 5511 94. Last previous edition D 5511 94.2The boldface numbers is parentheses refer to a list of references at the end ofthe text.3Annual Book of ASTM Standards, Vol 08.01.4Annual Book of ASTM Standards, Vol 11.01.5Discontinued. See 19
15、91 Annual Book of ASTM Standards, Vol 11.01.6Annual Book of ASTM Standards, Vol 11.02.7Annual Book of ASTM Standards, Vol 14.01.8Standard Methods for the Examination of Water and Wastewater, 17th Edition,1989, American Public Health Association, 1740 Broadway, New York, NY 10018.9Available from Amer
16、ican National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.material to an anaerobic-static-batch fermentation at more than20 % solids, measuring total carbon
17、 in the gas (CO2and CH4)evolved as a function of time, and assessing the degree ofbiodegradability.4.2 The percentage of biodegradability is obtained by de-termining the percent of conversion of carbon from the testmaterial to carbon in the gaseous phase (CH4and CO2). Thispercentage of biodegradabil
18、ity will not include the amount ofcarbon from the test substance that is converted to cell biomassand that is not, in turn, metabolized to CO2and CH4.5. Significance and Use5.1 Biodegradation of a plastic within a high-solids anaero-bic digestion unit is an important phenomenon because it willaffect
19、 the decomposition of other waste materials enclosed bythe plastic and the resulting quality and appearance of thecompost after an anaerobic digestion process. Biodegradationof plastics could allow for the safe disposal of these plasticsthrough aerobic and anaerobic solid-waste-treatment plants.This
20、 procedure has been developed to permit the determinationof the rate and degree of anaerobic biodegradability of plasticproducts when placed in a high-solids anaerobic digester forthe production of compost from municipal solid waste.5.2 LimitationsBecause there is a wide variation in theconstruction
21、 and operation of anaerobic-digestion systems andbecause regulatory requirements for composting systems vary,this procedure is not intended to simulate the environment ofany particular high-solids anaerobic-digestion system. How-ever, it is expected to resemble the environment of a high-solids anaer
22、obic-digestion process operated under optimumconditions. More specifically, the procedure is intended tocreate a standard laboratory environment that will permit arapid and reproducible determination of the anaerobic biode-gradability under high-solids digestion conditions.6. Apparatus6.1 Inverted G
23、raduated Cylinder or Plastic Column,inwater or other suitable device for measuring gas volume. Thewater in contact with the gas must be at a pH of less than twoduring the whole period of the test to avoid CO2loss throughdissolution in the water. The gas-volume-measuring device, aswell as the gas tub
24、ing, shall be of sufficient quality to preventgas migration and diffusion between the system and thesurrounding air (see Fig. 1).6.2 Gas Chromatograph, (optional) or other apparatus,equipped with a suitable detector and column(s) for measuringmethane and carbon dioxide concentration in the evolvedga
25、ses.6.3 Incubator, or hot-water bath capable of maintaining thetest bottles at 52C (62C) for the duration of the test.6.4 Erlenmeyer Flasks, with sufficient capacity for theexperiment and openings of at least 7-cm diameter, set up sothat no loss of gas occurs.6.5 pH Meter, precision balance (60.1 g)
26、, analytical bal-ance (60.1 mg), thermometer, and barometer.6.6 Devices, suitable for determining volatile fatty acids byaqueous-injection chromatography, total Kjeldahl nitrogen,ammonia nitrogen, dry solids (105C) and volatile-solids(550C) concentrations.7. Reagents and Materials7.1 Anaerboic Inocu
27、lum, derived from a properly operatinganaerobic digester with pretreated household waste as a solesubstrate.7.2 Analytical-Grade Cellulose, for thin-layer chromatogra-phy as a positive control.7.3 Polyethylene, as a negative control. It should be in thesame form as the form in which the sample is te
28、sted (forexample, film polyethylene for film samples, pellets of poly-ethylene if the sample is in the form of pellets, etc.).8. Hazards8.1 The procedure given in this test method involves the useof an inoculum composed of biologically and possibly chemi-cally active materials known to produce a var
29、iety of diseases.Avoid contact with these materials by wearing gloves and otherappropriate protective garments. Use good personal hygiene tominimize exposure.8.2 The solid-waste mixture may contain sharp objects.Take extreme care when handling this mixture to avoid injury.8.3 The biological reactor
30、is not designed to withstand highpressures; operate it at close to ambient pressure.8.4 This test method includes the use of hazardous chemi-cals. Avoid contact with the chemicals and follow the manu-facturers instructions and Material Safety Data Sheets.8.5 The methane produced during this procedur
31、e is explo-sive and flammable. Upon release of the biogas from thegas-collection system, take care in venting the biogas to theoutside or to a hood.9. Inoculum9.1 The inoculum must be derived from a properly operat-ing anaerobic digester functioning with a pretreated householdwaste as a sole substra
32、te. The pretreated household wasteshould come from an existing waste treatment facility treatingmunicipal solid waste, where through sorting, shredding,sieving, or other means, a fairly homogeneous organic fractionis produced of less than 60 mm. The digester should beoperating for a period of at lea
33、st four months on the organicfraction, with a retention time of a maximum of 30 days underFIG. 1 Test SetupD5511022thermophilic conditions (52 6 2C). Gas-production yieldsshould be at least 15 mL at standard temperature and pressureof biogas per gram of dry solids in the digester and per day onthe a
34、verage for at least 30 days.9.1.1 The inoculum should be derived preferably from adigester operating under dry (20 % total solids) conditions, orcan be derived from a wet fermentation whereby the anaero-bically digested sludge is dewatered through centrifugation,with a press or through drying at a m
35、aximum temperature of55C to a dry-solids content of at least 20 %.9.2 The prepared inoculum should undergo a short post-fermentation of approximately seven days at the same operat-ing temperature from which it was derived. This means that theinoculum is not fed but allowed to post-ferment anaerobica
36、llyby itself. This is to ensure that large easily biodegradableparticles are degraded during this period and also to reduce thebackground level of degradation of the inoculum itself.9.2.1 The most important biochemical characteristics of theinoculum shall be as follows:9.2.1.1 pHBetween 7.5 and 8.5
37、(in accordance with TestMethods D 1293),9.2.1.2 Volatile Fatty Acids (VFA)Below 1 g/kg wetweight (in accordance with Practice D 2908), and9.2.1.3 NH4+-NBetween 0.5 and 2 g/kg wet weight (inaccordance with APHA Test Method 212 and Test MethodD 3590).9.3 Analyses are performed after dilution of the in
38、oculumwith distilled water on a ratio of distilled water to inoculum of5 to 1 on a weight over weight basis.10. Test Specimen10.1 The test specimen should be of sufficient carboncontent, analyzed in accordance with Test Method D 4129,toyield carbon dioxide and methane volumes that can be accu-rately
39、 measured by the trapping devices described. Add moretest specimen when low biodegradability is expected, up to 100g on a dry weight basis of the test specimen.10.2 The test specimen may be in the form of films, powder,pellets, formed articles, or in the form of a dog bone andconforming to Practice
40、D 618. The test set-up should be able tohandle articles that are 100 by 50 by 4 mm thick.11. Procedure11.1 Inoculum Medium:11.1.1 Remove enough inoculum (approximately 15 kg)from the post-fermentation vessel and mix carefully andconsistently by hand in order to obtain a homogeneousmedium.11.1.2 Test
41、 three replicates each of a blank (inoculum only),positive control (thin-layer chromatography cellulose), nega-tive control (polyethylene), and the test substance beingevaluated.11.1.2.1 Manually mix 1000 g wet weight (at least 20 % drysolids) of inoculum in a small container for a period of 2 to 3m
42、in with 15 to 100 g of volatile solids of the test substance orthe controls for each replicate. (Determine dry solids andvolatile solids in accordance with APHA Standards D 2540,E 2540, and Test Method D 1888).11.1.2.2 For the three blanks containing inoculum only,manually mix 1000 g of the same ino
43、culum in a small containerfor a period of 2 to 3 min with the same intensity as was donefor the other vessels containing test substance or controls.11.1.2.3 Determine the weight of the inoculum and testsubstance added to each individual Erlenmeyer flask accu-rately.11.1.2.4 If formed plastic article
44、s are added, a specificnumber of articles may be added and retrieved at the end of thedigestion period.11.1.3 Add the mixtures to a 2-L wide-mouth Erlenmeyerflask and gently spread and compact the material evenly in theflask to a uniform density.11.1.4 After placing the Erlenmeyer flask in a water b
45、ath orincubator, connect it with the gas-measurement or gas-collection device.11.1.5 Record room temperature and atmospheric pressureprior to turning on the heating system of the incubator or waterbath.11.2 Incubation:11.2.1 Incubate the Erlenmeyer flasks in the dark or indiffused light at 52C (62C)
46、 for a period of normally 15 days.The incubation time may be extended until no significant gasproduction in excess of the blank has been recorded during oneweek or until the positive reference has been degraded for morethan 70 %, depending on the methanogenic activity of theinoculum.11.2.2 Control t
47、he pH of the water used to measure biogasproduction to less than two by adding HCl.11.3 Analytical Measurements:11.3.1 Make a sufficient number of measurements of gasvolume in order to establish the gas production as a function oftime. More frequent readings in the early stages may berequired, with
48、less frequent readings needed as timeprogresses.11.3.2 Determine methane and carbon dioxide concentra-tion by using analytical devices suitable for the detection andquantification of these gases, such as a gas chromatograph withan appropriate detector, in accordance with Practices E 260 andE 355.11.
49、3.3 Verify the quality of the inoculum by analyses forpH, volatile fatty acids, and total Kjeldahl nitrogen (in accor-dance with Test Methods D 1293 and D 3590 and PracticeD 2908).11.4 At the end of the digestion period, allow the setup tocool to room temperature for 8 h and determine the followingparameters:11.4.1 Total gas-volume production produced during thetest,11.4.2 Gas composition at the end of the test,11.4.3 Weight loss of each vessel, and11.4.4 Room temperature and atmospheric pressure at theend of the test.12. Calculation12.1 By using the total carbon
