1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 13975:2012Plastics Determinationof the ultimate anaerobicbiodegradation of plasticmaterials in controlled slurrydigestion systems Methodby measurement of biogasproductionB
2、S ISO 13975:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 13975:2012.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/21, Testing of plastics.A list of organizations represented on this committee can beobtained on request t
3、o its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 69419 6ICS 83.080.01Compliance with a British Standar
4、d cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 June 2012.Amendments issued since publicationDate Text affectedBS ISO 13975:2012 ISO 2012Plastics Determination of the ultimate anaerobic biodegr
5、adation of plastic materials in controlled slurry digestion systems Method by measurement of biogas productionPlastiques valuation de la biodgradabilit anarobie ultime des matriaux plastiques dans des systmes de digestion de boue contrls Mthode par mesurage de la production de biogazINTERNATIONAL ST
6、ANDARDISO13975First edition2012-05-01Reference numberISO 13975:2012(E)BS ISO 13975:2012ISO 13975:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
7、 means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyri
8、ghtiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 13975:2012ISO 13975:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 14 Principle . 35 Test and reference materials 36 Apparatus 37 Procedure 47.1 General
9、 . 47.2 Preparation of inoculum 47.3 Start-up of the test 47.4 Measurement of biogas produced (see Annex A) 57.5 Test duration . 57.6 Measurement of dissolved inorganic carbon (see Annex B). 58 Calculation and expression of results . 58.1 Amount of biogas produced . 58.2 Amount of dissolved inorgani
10、c carbon . 58.3 Calculation of percentage biodegradation . 69 Expression and interpretation of results 610 Validity of results . 611 Test report . 7Annex A (informative) Examples of test systems 8Annex B (informative) Example of apparatus for measurement of biogas dissolved in slurry 10Annex C (info
11、rmative) Example of a biodegradation curve 11Annex D (informative) Table of water vapour pressures at various temperatures .12Bibliography .13BS ISO 13975:2012ISO 13975:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
12、 member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, gover
13、nmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Di
14、rectives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bo
15、dies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 13975 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC
16、 5, Physical-chemical properties.iv ISO 2012 All rights reservedBS ISO 13975:2012ISO 13975:2012(E)IntroductionBiological recycling (biorecycling) is a viable option, together with mechanical recycling and chemical recycling, for the recovery of plastic waste. This International Standard specifies a
17、method of evaluating the anaerobic biodegradability of such waste in a controlled anaerobic slurry system. This is a representative anaerobic digestion test method and system for biodegradable plastic waste.The production of a biogas is observed under anaerobic conditions suitable for the growth of
18、thermophilic or mesophilic microorganisms. The biogas is collected in a bag under atmospheric pressure, and the biogas volume is measured with a syringe or a gas burette. The biodegradability of the test material is evaluated from the sum of the amount of carbon dioxide dissolved in the supernatant
19、and the cumulative quantity of evolved biogas. This International Standard is a biodegradation test method for plastic materials in a controlled anaerobic slurry system, and differs from ISO 15985 which uses high-solids anaerobic digestion conditions and ISO 14853 which uses an aqueous system in an
20、anaerobic environment. ISO 2012 All rights reserved vBS ISO 13975:2012BS ISO 13975:2012Plastics Determination of the ultimate anaerobic biodegradation of plastic materials in controlled slurry digestion systems Method by measurement of biogas productionWARNING Sewage sludge and other organic waste m
21、ight contain potentially pathogenic organisms. Therefore appropriate precautions should be taken when handling such materials. Digestion of organic materials produces flammable gases that present fire and explosion risks. These gases also contain toxic chemicals, including hydrogen sulfide and ammon
22、ia, in substantial concentrations. Appropriate safety measures, such as the use of a draft chamber, gas masks and/or well-ventilated laboratory facilities, should be taken. Toxic test chemicals and chemicals whose properties are not known should be handled with care and in accordance with safety ins
23、tructions. Care should be taken when transporting and storing quantities of organic matter undergoing digestion.1 ScopeThis International Standard specifies a method of evaluating the ultimate anaerobic biodegradability of plastic materials in a controlled anaerobic slurry digestion system with a so
24、lids concentration not exceeding 15 %, which is often found for the treatment of sewage sludge, livestock faeces or garbage. The test method is designed to yield a percentage and rate of conversion of the organic carbon in the test materials to carbon dioxide and methane produced as biogas.The metho
25、d applies to the following materials, provided they have a known carbon content: natural and/or synthetic polymers, copolymers or mixtures; plastic materials that contain additives such as plasticizers, colorants, or other compounds; water-soluble polymers.It does not apply to materials which exhibi
26、t inhibitory effects on the test microorganisms at the concentration chosen for the test.NOTE Inhibitory effects can be determined by an inhibition test (e.g. ISO 13641-1 or ISO 13641-2).2 Normative referencesThe following referenced documents are indispensable for the application of this document.
27、For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 14853:2005, Plastics Determination of the ultimate anaerobic biodegradation of plastic materials in an aqueous system Method by measureme
28、nt of biogas production3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1ultimate anaerobic biodegradationbreakdown of an organic compound by microorganisms in the absence of oxygen into carbon dioxide, methane, water and mineral salts of any othe
29、r elements present (mineralization) plus new biomassINTERNATIONAL STANDARD ISO 13975:2012(E) ISO 2012 All rights reserved 1BS ISO 13975:2012ISO 13975:2012(E)3.2digested sludgemixture of the settled sewage and activated sludge which has been incubated in a mesophilic or thermophilic anaerobic digeste
30、r to reduce the biomass and odour and to improve the dewaterability of the sludgeNOTE 1 to entry: Digested sludge contains an association of anaerobic fermentative and methanogenic microorganisms producing carbon dioxide and methane.3.3slurrywatery mixture of insoluble matterNOTE 1 to entry: The sus
31、pended-solids concentration of a slurry might be as high as around 15 %, but slurry is fluid and pumpable.3.4dissolved inorganic carbonDICcarbon dioxide dissolved in water or transformed into carbonic acid, hydrogen carbonate ion and carbonate ion3.5total dry solidsamount of solids obtained by takin
32、g a known volume of test material or inoculum and drying at about 105 C to constant mass3.6volatile solidsamount of solids obtained by subtracting the residue of a known volume of test material or inoculum after incineration at about 550 C from the total dry solids of the same test portionNOTE 1 to
33、entry: The volatile-solids content is an indication of the amount of organic matter present.3.7theoretical amount of evolved biogasThBiogasmaximum theoretical amount of biogas (CH4+ CO2) which will evolve after complete biodegradation of an organic compound under anaerobic conditionsNOTE 1 to entry:
34、 ThBiogas is calculated from the molecular formula and expressed as litres of biogas evolved per gram of test material under the standard conditions.3.8lag phasetime from the start of an anaerobic digestion test until adaptation and/or selection of the degrading microorganisms is achieved and the de
35、gree of biodegradation of a chemical compound or organic matter has increased to about 10 % of the maximum level of biodegradationNOTE 1 to entry: It is measured in days.3.9biodegradation phasetime from the end of the lag phase of a test until about 90 % of the maximum level of biodegradation has be
36、en reachedNOTE 1 to entry: It is measured in days.3.10plateau phasetime from the end of the biodegradation phase until the end of the testNOTE 1 to entry: It is measured in days.2 ISO 2012 All rights reservedBS ISO 13975:2012ISO 13975:2012(E)3.11maximum level of biodegradationdegree of biodegradatio
37、n of a chemical compound or organic matter in a test, above which no further biodegradation takes place during the testNOTE 1 to entry: It is measured in percent.4 PrincipleThis test method is designed to determine the biodegradability of plastic materials under anaerobic conditions in a slurry syst
38、em. The methanogenic inoculum is obtained from an anaerobic digester operating on sewage sludge or, alternatively, on organic waste such as livestock faeces or garbage. The test material mixed with the inoculum is anaerobically incubated in a test vessel at a pre-selected temperature for a period no
39、rmally of 60 days. The test period may be shortened or extended until a plateau phase is reached, but the total period shall not exceed 90 days. The digestion temperature shall be (55 5) C in order to simulate thermophilic anaerobic digestion. Alternatively, the digestion temperature may be set at (
40、35 3) C in order to simulate mesophilic anaerobic digestion.The volume of the gases produced in the test vessel, carbon dioxide (CO2) and methane (CH4), is measured. A considerable amount of CO2will also be dissolved in the digested sludge or dissociated to hydrogen carbonate ion and carbonate ion u
41、nder the conditions of the test. This dissolved inorganic carbon (DIC) is measured at the end of the test. The amount of biogas produced is calculated from the volume of biogas collected and the amount of DIC formed in excess of blank values.The percentage biodegradation is calculated as the ratio o
42、f the sum of the net increase of produced biogas and DIC to the theoretical amount of evolved biogas (ThBiogas). The biodegradation curve can be followed by making intermediate measurements of biogas production.5 Test and reference materials5.1 Test material: The test material is normally added dire
43、ctly as solids to give a concentration of volatile solids in the range of 7 g/l to 10 g/l. The test material should preferably be used in powder form or as film.5.2 Reference material: TLC (thin-layer chromatography) grade microcrystalline cellulose with a particle size 70 % after 15 days;b) the dif
44、ference between the percentage biodegradation of the reference material in the different vessels is 20 % at the end of the test.6 ISO 2012 All rights reservedBS ISO 13975:2012ISO 13975:2012(E)11 Test reportThe test report shall contain at least the following information:a) a reference to this Intern
45、ational Standard;b) all information necessary to identify the test and reference materials, including their organic carbon content, ThBiogas, chemical composition and formula (if known), shape, form, and amount/concentration in the samples tested;c) the concentration of the test material in the test
46、 vessels;d) details of the way in which the amount of biogas produced was measured (e.g. type of volume-measuring system used) and of the carbon analyser used to measure the DIC;e) information on the inoculum used, such as source, age, date of collection, storage, handling, any adaptation to the tes
47、t material, any other pre-incubation, total dry solids, volatile solids, pH of the suspension, total nitrogen content and volatile fatty acids, as appropriate;f) the results obtained for the biogas evolution and percentage of biodegradation for each digestion vessel and the averages, in tabular form
48、 and graphically, as well as the final percentage of biodegradation for the test material and the reference material and the activity of the inoculum;g) the incubation temperature;h) the pH and DIC of the test suspensions at the end of the test;i) the duration of the lag phase and the degradation ph
49、ase, and the duration of the test;j) the reasons for rejection of any test results. ISO 2012 All rights reserved 7BS ISO 13975:2012ISO 13975:2012(E)Annex A (informative) Examples of test systemsKey1 incubator2 digester3 inoculum4 gas outlet5 leak valve6 bag for gas collection7 biogas8 syringe9 dischargeFigure A.1 Example of a test system using a syringe to measure the volume of biogas produced8 ISO 2012 All rights reservedBS ISO 13975:2012ISO 13975:2012(E)Key1 thermostatically controlled bath2 digester3 valve4
