ISO INTERNATIONAL STANDARD 14851 Second edition 2019-03 Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium Method by measuring the oxygen demand in a closed respirometer Evaluation de la biodégradabilite aérobie ultime des materiaux plastiques en milieu aqueux - Méthode par détermination de la demande en oxygene dans un respirometre fermé Reference number IS0 14851:2019(E) ISO @ IS0 2019 IS0 14851:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ ISO 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below or Iso's member body in the country of the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 14851:2019(E) Contents Page Foreword ..iv Introduction. ..vi 1 Scope. 2 Normative references ..1 3 Terms and definitions 4 Principle ..3 5 Test environment. ..3 6 Reagents ..3 6.1 Distilled or deionized water ..4 6.2 Test medium .4 6.2.1 Standard test medium .4 6.2.2 Optimized test medium 6.3 Pyrophosphate solution .6 6.4 Carbon dioxide absorber. ..6 7 Apparatus ..6 8 Procedure .6 8.1 Test material ..6 8.2 Reference material ..7 8.3 Preparation of the inoculum 1 8.4 Test. .8 9 Calculation and expression of results ..9 9.1 Calculation 9 9.2 Expression and interpretation of results 10 10 Validity of results .10 11 Test report ..11 Annex A (informative) Theoretical oxygen demand (ThoD). ..12 Annex B (informative) Correction of BoD values for interference by nitrification ..13 Annex C (informative) Principle of a closed manometric respirometer ..15 Annex D (informative) Two-phase closed-bottle version of the respirometric test ..17 Annex E (informative) Example of the determination of a carbon balance .20 Annex F (informative) Example of a determination of the amount of water-insoluble polymer remaining at the end of a biodegradation test and the molecular mass of the polymer. .22 Annex G (informative) Example of the determination of the CO2 absorbed in the absorbent ..23 Bibliography .25 @ IS0 2019 - All rights reserved iii