ISO INTERNATIONAL STANDARD 9408 Second edition 1999-08-01 Water quality Evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium by determination of oxygen demand in a closed respirometer Qualité de I'eau- [ Evaluation, en milieu aqueux, de la biodégradabilite aérobie ultime des composés organiques par détermination de la demande en oxygene dans un respirometre fermé Tso Referencenumber ISO 9408:1999(E) y IHS under I without license from IHS Not for Resale ISO 9408:1999(E) Contents Page 1 Scope 2 Terms and definitions 3 Principle 4 Test environment.. .3 5 Reagents 6Apparatus 5 7 Procedure. .5 8 Calculation and expression of results. 9 Validity of results 10 10 Test report . Annex A (informative) Example of calculation of theoretical oxygen demand.. 12 Annex B (informative) Correction of oxygen uptake for interference by nitrification... ..14 Annex C (informative) Example of a biodegradation curve ... .16 Annex D (informative) Closed respirometer, Bibliography.... @ISO1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 · Switzerland Internet [email protected] Printed in Switzerland ational Organization for Standardization from IH Not for Resale @ ISO ISO 9408:1999(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through isO technical 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/lEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. SC 5, Biological methods. This second edition cancels and replaces the first edition (IsO 9408:1991), which has been technically revised. ili Not for Resale