1、Designation: D5511 12Standard Test Method forDetermining Anaerobic Biodegradation of Plastic MaterialsUnder High-Solids Anaerobic-Digestion Conditions1This standard is issued under the fixed designation D5511; the number immediately following the designation indicates the year oforiginal adoption or
2、, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 bi
3、odegradation 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 sta
4、tic 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 conditions i
5、n biologically activelandfills where the gas generated is recovered and biogasproduction is actively promoted by inoculation (for example,codeposition of anaerobic sewage sludge, anaerobic leachaterecirculation), moisture control (for example, leachate recircu-lation), and temperature control (for e
6、xample, 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 Claims of performance shall be lim
7、ited to the numericalresult obtained in the test and not be used for unqualified“biodegradable” claims. Reports shall clearly state the percent-age of net gaseous carbon generation for both the test andreference samples at the completion of the test. Furthermore,results shall not be extrapolated pas
8、t the actual duration of thetest.1.5 The values given in SI units are to be regarded as thestandard.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 heal
9、th practices and determine the applica-bility of regulatory limitations prior to use. Specific hazards aregiven in Section 8.NOTE 1This test method is equivalent to ISO 15985.2. Referenced Documents2.1 ASTM Standards:3D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to Pl
10、asticsD1293 Test Methods for pH of WaterD1888 Methods Of Test for Particulate and DissolvedMatter in Water4D2908 Practice for Measuring Volatile Organic Matter inWater by Aqueous-Injection Gas ChromatographyD3590 Test Methods for Total Kjeldahl Nitrogen in WaterD4129 Test Method for Total and Organi
11、c Carbon in Waterby High Temperature Oxidation and by Coulometric De-tectionE260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Rela-tionships2.2 APHA-AWWA-WPCF Standards:2540 D Total Suspended Solids Dried at 103105C52540 E Fixed and Volatile Solids Igni
12、ted at 550C5212 Nitrogen Ammonia52.3 ISO Standard:6ISO 13641-1 Water qualityDetermination of inhibition ofgas production of anaerobic bacteriaPart 1: General testISO 15985 PlasticsDetermination of the ultimate anaero-bic biodegradability and disintegration under high-solids1This test method is under
13、 the jurisdiction of ASTM Committee of D20 onPlastics and is the direct responsibility of Subcommittee D20.96 on Environmen-tally Degradable Plastics and Biobased Products.Current edition approved May 1, 2012. Published June 2012. Originallypublished as D5511 94. Last previous edition D5511 11. DOI:
14、 10.1520/D5511-12.2The boldface numbers is parentheses refer to a list of references at the end ofthe text.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the stand
15、ards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.5Standard Methods for the Examination of Water and Wastewater, 17th Edition,1989, American Public Health Association, 1740 Broadway, New York, NY 10018.6Availa
16、ble from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.anaerobic-digestion conditionsMethod by analysis ofreleased bioga
17、s3. Terminology3.1 DefinitionsDefinitions of terms applying to this testmethod appear in Terminology D883.3.2 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
18、. Summary of Test Method4.1 This test method consists of selection and analysis ofmaterial for testing, obtaining a concentrated anaerobic inocu-lum from an anaerobic laboratory-scale digester, exposing thematerial to an anaerobic-static-batch fermentation at more than20 % solids, measuring total ca
19、rbon 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 biodegrad
20、ability 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 willaf
21、fect the decomposition of other waste materials enclosed bythe plastic and the resulting quality and appearance of thedigestate after an anaerobic digestion process. Biodegradationof plastics could allow for the safe disposal of these plasticsthrough aerobic and anaerobic solid-waste-treatment plant
22、s.This 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 digestate from municipal solid waste.5.2 LimitationsBecause there is a wide variation in thecons
23、truction 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-soli
24、ds anaerobic-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 In
25、verted Graduated 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
26、 gas tubing, 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 e
27、volvedgases.6.3 Incubator, or hot-water bath capable of maintaining thetest bottles at 37C (62C) or 52C (62C) for the duration ofthe 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, precis
28、ion balance (60.1 g), 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 Material
29、s7.1 Anaerboic Inoculum, 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 (optional). It isoptimal if it is in the same f
30、orm as the form in which thesample is tested (for example, film polyethylene for filmsamples, pellets of polyethylene if the sample is in the form ofpellets, etc.).8. Hazards8.1 The procedure given in this test method involves the useof an inoculum composed of biologically and possibly chemi-cally a
31、ctive materials known to produce a variety of diseases.Avoid contact with these materials by wearing gloves and otherappropriate protective garments. Use good personal hygiene tominimize exposure.8.2 It is possible that the solid-waste mixture contains sharpobjects. Take extreme care when handling t
32、his mixture to avoidinjury.8.3 The biological reactor is not designed to withstand highpressures; operate it at close to ambient pressure.FIG. 1 Test SetupD5511 1228.4 This test method includes the use of hazardous chemi-cals. Avoid contact with the chemicals and follow the manu-facturers instructio
33、ns and Material Safety Data Sheets.8.5 The methane produced during this procedure 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 a
34、naerobic digester functioning with a pretreated householdwaste as a sole substrate. The pretreated household waste shallcome from an existing waste treatment facility treating munici-pal solid waste, where through sorting, shredding, sieving, orother means, a fairly homogeneous organic fraction is p
35、ro-duced of less than 60 mm. The digester shall be operating fora period of at least four months on the organic fraction, with aretention time of a maximum of 30 days under thermophilicconditions (52 6 2C). Gas-production yields shall be at least15 mLat standard temperature and pressure of biogas pe
36、r gramof dry solids in the digester and per day on the average for atleast 30 days.9.1.1 It is preferable to derive the inoculum from a digesteroperating under dry (20 % total solids) conditions, but it isacceptable to derive it from a wet fermentation whereby theanaerobically digested sludge is dew
37、atered through centrifuga-tion, with a press or through drying at a maximum temperatureof 55C to a dry-solids content of at least 20 %.9.2 The prepared inoculum shall undergo a short post-fermentation of approximately seven days at the same operat-ing temperature from which it was derived. This mean
38、s that theinoculum is not fed but allowed to post-ferment anaerobicallyby 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 characteristi
39、cs of theinoculum shall be as follows:9.2.1.1 pHBetween 7.5 and 8.5 (in accordance with TestMethods D1293),9.2.1.2 Volatile Fatty Acids (VFA)Below 1 g/kg wetweight (in accordance with Practice D2908), and9.2.1.3 NH4+-NBetween 0.5 and 2 g/kg wet weight (inaccordance with APHA Test Method 212 and Test
40、 MethodD3590).9.3 Analyses are performed after dilution of the inoculumwith 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 shall be of sufficient carbon content,analyzed in accordance with Test Method D4129, to
41、 yieldcarbon dioxide and methane volumes that can be accuratelymeasured by the trapping devices described. Add more testspecimen when low biodegradability is expected, up to 100 gon a dry weight basis of the test specimen.10.2 It is acceptable if the test specimen is in the form offilms, powder, pel
42、lets, formed articles, or in the form of a dogbone and conforming to Practice D618. The test set-up shall beable to handle articles that are 100 mm by 50 mm by 4 mmthick.11. Procedure11.1 Inoculum Medium:11.1.1 Remove enough inoculum (approximately 15 kg)from the post-fermentation vessel and mix car
43、efully andconsistently by hand in order to obtain a homogeneousmedium.11.1.2 Test 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 (
44、at least 20 % drysolids) of inoculum in a small container for a period of 2 to 3min 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 , , and TestMethod D1888).11.1.2.2 For the three
45、 blanks containing inoculum only,manually mix 1000 g of the same inoculum 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 indivi
46、dual Erlenmeyer flask accu-rately.11.1.2.4 If formed plastic articles are added, it is possiblethat a specific number of articles be added and retrieved at theend of the digestion period.11.1.3 Add the mixtures to a 2-L wide-mouth Erlenmeyerflask and gently spread and compact the material evenly in
47、theflask to a uniform density.11.1.4 After placing the Erlenmeyer flask in a water bath 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 Incubatio
48、n:11.2.1 Incubate the Erlenmeyer flasks in the dark or indiffused light at 52C (62C) for thermophilic conditions, or37C (62C) for mesophilic conditions for a period of nor-mally 15-30 days.11.2.1.1 For the test to be considered valid, the positivecontrol must achieve 70 % biodegradation within 30 da
49、ys.11.2.1.2 The incubation time shall be run until no net gasproduction is noted for at least five days from both the positivecontrol and test substance reactors.11.2.1.3 The test substance and the positive control shall berun for the same duration.11.2.2 Control the pH of the water used to measure biogasproduction to less than two by adding HCl.11.3 Analytical Measurements:11.3.1 Make at least five measurements of gas volume perweek in order to establish the gas production as a function oftime.11.3.2 Determine methane and carbon dioxide concentra-tion
