BNQ, 2004 Working Draft WD 0413-220-2 Organic Soil Conditioners Composts Determination of Oxygen Uptake Respirometric Method Amendements organiques Composts Détermination du taux d assimilation d oxygène Méthode respirométrique Copyright notice This document of the Bureau de normalisation du Québec (BNQ) is a working draft and is copyright-protected by Canadian laws and international treaties. While the reproduction of working drafts in any form for use by participants in the BNQ standards development process is permitted without prior permission from BNQ, neither this document nor any extract from it may be reproduced, stored or transmitted in any form for any other purpose without prior written permission from BNQ. Requests for permission to reproduce this document for the purpose of selling it should be addressed to BNQ. Reproduction for sales purposes may be subject to royalty payments or a licensing agreement. Violators may be prosecuted. Warning This document is not a standard of the Bureau de normalisation du Québec. It is distributed for review and comment. It is subject to change without notice and may not be referred to as a standard. Descriptors: compost, organic matter, organic soil conditioner, oxygen uptake, respirometry. ICS: ICS: 19.020; 65.080
NOTICE DISCLAIMER OF RESPONSIBILITY This document was developed as a reference document for voluntary use. It is up to users to verify if legislation or regulations make application of this document mandatory, or if trade regulations or market conditions stipulate its use in, for example, technical regulations, inspection plans originating from regulatory authorities and certification programs. It is also up to the user to consider limitations and restrictions specified in the Purpose or Scope chapters of the document, or both. INTERPRETATION In this document, the use of the following expressions, verbal forms and of notes and informative annexes shall be interpreted by the reader as follows: The verb shall is used to express a mandatory requirement in order to comply with this document. The verb should, or the equivalent expressions it is recommended that and ought to, are used to indicate a useful, but not mandatory, suggestion, or to provide the most appropriate meaning in order to comply with this document. With the exception of the normative notes indicated as such in the lower part of the figures and tables that contain requirements, all other notes are informative and provide useful information pertaining to the understanding or intent of a requirement, or to add some clarification or precision. Informative annexes provide additional information intended to assist the understanding or use of elements of this document or to clarify its implementation, but contain no requirements to be complied with. BNQ, 2004
FOREWORD This document was prepared by the following persons: CANTIN, Sophie PETITCLERC, Odette ALLARD, Sylvain Centre de recherche industrielle du Québec (CRIQ) Centre de recherche industrielle du Québec (CRIQ) Bureau de normalisation du Québec (BNQ) This document was approved by the Standards-Writing Committee on composts, whose members were: ANTLER, Susan BERMAN, Laura BRYDEN, Jack CANTIN, Pascale CANTIN, Sophie FRY, Rodney J. GAMBLE, Scott GARDINER, Ian HÉBERT, Marc HENNESSEY, Tom Composting Council of Canada (CCC) Foodshare Toronto B.C. Ministry of Water, Land and Air Protection Ministère de l Agriculture, des Pêcheries et de l Alimentation du Québec (MAPAQ) Centre de recherche industrielle du Québec (CRIQ) Envirem Technologies Inc. Earth Tech (Canada) Inc. Canadian Food Inspection Agency (CFIA) Ministère de l Environnement du Québec (MENV) Miller Composting Corporation BNQ, 2004
HOLE, Jim KIDNIE, Rod PATTERSON, Greg POTVIN, Denis Hole s Greenhouses & Gardens Ltd. All Treat Farms Ltd. A&L Canada Laboratories East Inc. Association québécoise des industriels du compostage (AQIC) ALLARD, Sylvain (coordinator) Bureau de normalisation du Québec (BNQ) BNQ, 2004
CONTENTS Page INTRODUCTION 1 1 PURPOSE 1 2 SCOPE 1 3 NORMATIVE REFERENCES 1 3.1 GENERAL 1 3.2 NORMATIVE DOCUMENTS 2 4 DEFINITIONS 2 5 PRINCIPLE 2 6 MATERIAL AND REAGENTS 3 7 APPARATUS 3 8 SAMPLES 4 8.1 SAMPLING 4 8.2 STORAGE OF SAMPLES 4 9 PROCEDURE 4 9.1 SAFETY MEASURES 4 9.2 CALIBRATION 4 9.3 TEST PREREQUISITES 4 9.4 PREPARATION OF THE TEST PORTION 5 9.5 TEST 5 10 CALCULATION AND PRESENTATION OF RESULTS 6 BNQ, 2004
11 TEST REPORT 9 ANNEX A RESPIROMETER-PRINCIPLE OF OPERATION 10 FIGURE A.1 DIAGRAM OF A RESPIROMETER 10 BNQ, 2004
ORGANIC SOIL CONDITIONERS COMPOSTS DETERMINATION OF OXYGEN UPTAKE RESPIROMETRIC METHOD INTRODUCTION This standard presents a respirometric method that was adapted from a method developed by the Centre de recherche industrielle du Québec (CRIQ) and presented under the title Mise au point d une méthode respirométrique pour l'évaluation de la stabilité des composts at the fourth annual meeting of the Composting Council of Canada held on June 13-14, 1994 in Toronto. The method uses a respirometer to determine the amount of oxygen consumed by the metabolic activity of aerobic micro-organisms in a compost sample over a period of time, which permits an estimate of the biological activity of the compost. As the biological activity of compost diminishes as the composting process nears completion, oxygen uptake decreases and may be used to provide an indication of compost maturity. 1 PURPOSE This standard specifies a method for the determination of oxygen uptake of compost by respirometry. 2 SCOPE This method applies to compost from different sources used as organic soil conditioners. 3 NORMATIVE REFERENCES 3.1 GENERAL In this standard, a dated normative reference means that this specific edition shall be used, while a non-dated normative reference means that the last edition of this reference shall be used. For the purpose of this document, the following reference documents contain necessary requirements and are referred to in appropriate places in the text. page 1 BNQ, 2004
3.2 NORMATIVE DOCUMENTS BNQ (Bureau de normalisation du Québec) CAN/BNQ 0413-200 Organic Soil Conditioners Composts. (Amendements organiques Composts.) ASTM (American Society for Testing and Materials) ASTM D 2974 Test Method for Moisture, Ash, and Organic Matter of Peat and Other Organic Soils. ISO (International Organization for Standardization) ISO 3310-1 Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. (Tamis de contrôle Exigences techniques et vérifications Partie 1 : Tamis de contrôle en tissus métalliques.) 4 DEFINITIONS The terms used in this document are defined in Standard CAN/BNQ 0413-200, except for the terms below that are defined as follows: available volume of air in the respirometer (V) n: volume obtained by the addition of air volumes of the sample chamber, the caustic solution chamber, the transducer chamber for the measure of the air volume or the pressure and all the air contained in the tubing and pump, from which are consecutively subtracted the volume of the aqueous compost suspension and the volume the caustic solution. French: volume d'air disponible dans le respiromètre; V. respirometry n: method of analysis for the determination on the metabolic activity by the oxygen consumption. French: respirométrie. suspension n: system formed of solid matters floating in a fluid. French: suspension. 5 PRINCIPLE When a compost sample is placed in the sample chamber of the respirometer, micro-organisms present in the compost utilize the energy produced by the oxidation of carbon. As a result, oxygen is consumed and carbon dioxide given off. When the generation of carbon dioxide is absorbed by a caustic solution, the volume of oxygen utilized is not counterbalanced by the production of carbon dioxide. As a result, there is a net loss of the available volume of air in the respirometer equal to the volume of oxygen utilized. Oxygen uptake can therefore be determined by measuring the change in volume or pressure drop in the respirometer over a period of time. BNQ, 2004 page 2
6 MATERIAL AND REAGENTS a) Caustic solution: 4,2-mol/l potassium hydroxide solution (KOH), or equivalent. b) Non-biodegradable anti-foaming agent. c) Distilled water. 7 APPARATUS Ordinary laboratory apparatus and: a) respirometer 1 (see Annex A) that shall include the following elements: sample chamber with a minimum capacity of 3 litres equipped with an air diffuser and air lift column; caustic solution chamber; air pump with the appropriate tubing and connections; module for the air intake and the air exhaust in the air circuit (MAIAE); scale available volume of air in the respirometer corresponding to at least 75 % of the volume of the aqueous compost suspension that shall be used for the test; transducers capable of measuring the change in the available volume of air in the respirometer to the nearest 2 ml on a scale of 100 ml or measuring the change with air pressure in the respirometer to the nearest 67 Pa (0,5 mm Hg ) on a scale of 2666 Pa (20 mm Hg ); b) water basin in which the respirometer is placed; c) water heater equipped with a temperature control to maintain the water basin at a test temperature from 24 C to 26 C to the nearest 0,1 C; d) scale capable of weighing to the nearest 1 g; e) thermometer capable of measuring to the nearest 0,5 C; 1. The Arthur Respirometer Model 026-201 from Respirometry Plus LLC company corresponds to these requirements (Respirometry Plus LLC, 574 Prairie Road, Fond du Lac, Wisconsin 54935, USA) This information is provided for the convenience of users of this document and in no way constitutes an endorsement by the BNQ or a recommendation to use said product exclusively. Equivalent products may be used if it can be shown that they achieve the same results. It is the responsibility of users of this document to choose an adequate equivalent product. page 3 BNQ, 2004
f) graduated beaker [based on the volume of the aqueous compost suspension for the test (V s ) specified in Clause 9.4]; g) mechanical stirrer for liquid; h) two sieves with square openings of 6,3 mm and 19 mm in width respectively, complying with the ISO Standard 3310-1; i) blender; j) barometer capable of measuring to the nearest 133 Pa (1 mm Hg ) [optional for respirometers equipped with atmospheric pressure compensator]. 8 SAMPLES 8.1 SAMPLING Sampling and the preparation of samples shall be conducted in accordance with the procedure described in Clauses 8.3, 8.4 and 8.5.1 of Standard CAN/BNQ 0413-200. 8.2 STORAGE OF SAMPLES If the tests cannot be performed within 48 hours after the collection of samples, the samples shall be stored in airtight containers at temperature from 0 C to 5 C until the tests are carried out. 9 PROCEDURE 9.1 SAFETY MEASURES DANGER HANDLE THE CAUSTIC SOLUTION WITH CARE. AVOID ANY CONTACT WITH IT AND WEAR APPROPRIATE INDUSTRIAL EYE AND FACE PROTECTORS, AND RUBBER GLOVES AND CLOTHING. 9.2 CALIBRATION Calibrate all apparatus in accordance with manufacturer instructions. 9.3 TEST PREREQUISITES In order to determine the oxygen uptake of compost, conduct the following analyses: Moisture content shall be determined in accordance with the Method A described in Standard ASTM D 2974. The moisture content shall be the average of two 50-g test portion results and shall be expressed in percentage of mass on a wet weight basis. Total organic matter content shall be determined in accordance with the Method C described in Standard ASTM D 2974. The temperature of the muffle furnace shall BNQ, 2004 page 4
be 550 C. Results shall be expressed as a percentage of mass on a dry weight basis. 9.4 PREPARATION OF THE TEST PORTION Prepare the aqueous compost suspension for respirometry analysis as follows: a) Take and weigh, to the nearest 1 g, a representative test portion of compost from which matter greater than 19 mm has been removed. The mass of the test portion (mc) shall be approximately the mass calculated using the following equation: mrs = 20 V (1 te 100) s 9.5 TEST where mrs: mass of the test portion to be taken, in grams; V s : volume of aqueous compost suspension for the test, in litres; te : moisture content of compost, expressed as a percentage of mass on a wet weight basis (see Clause 9.3). b) Measure a volume of distilled water equivalent to the volume of the aqueous compost suspension for the test (V s ) which shall be at least 2 litres. Set aside 1 litre for items d) and f). NOTE Larger volumes may be used provided that requirements for the minimum available volume of air in the respirometer (V) specified in item a) of Chapter 7 are met. c) Mix small quantities of the test portion with distilled water in a blender for 15 s to 30 s, filter the mixture through a 6,3-mm sieve and collect the aqueous compost suspension. d) When sieving is completed, collect the compost retained by the 6,3-mm sieve and mix with 500 ml of distilled water in the blender for 15 s to 30 s. e) Filter the mixture through the 6,3-mm sieve, collect the aqueous compost suspension and discard the compost retained by the 6,3-mm sieve. f) Dilute the aqueous compost suspension to the volume of the aqueous compost suspension for the test (V s ) determined in item a). Perform the respirometry analysis as follows: a) Prepare the respirometer for the test. Ensure that the water of the water basin is at the temperature of 25 C ± 1 C. page 5 BNQ, 2004
b) Record the temperature (T) of the water in the water basin to the nearest 0,5 C and the atmospheric pressure (P) in kilopascals. c) Heat the aqueous compost suspension until the suspension has reached the test temperature (T) of the water in the water basin, to the nearest 0,2 C. d) Place the aqueous compost suspension in the sample chamber of the respirometer. e) Start the respirometer and check for foaming. If foam forms and may enter the respirometer air circuit, add 3 ml of a non-biodegradable anti-foaming agent to the aqueous compost suspension. f) Vent the air circuit for a minimum of 3 minutes. g) Start the test and record the decrease in volume or pressure in the air circuit over a period of 18 h to 24 h. The atmospheric pressure (P) shall be recorded each time the air circuit is vented or at the end of a test if no reading was taken earlier. When measuring pressure on a continuous basis, the mean between the pressure at the beginning of the test and the pressure at the end of the test shall be used in calculations. If the respirometer is equipped with an atmospheric pressure compensator, the pressure used for the calculations shall be 101,325 kpa. h) If, during the test, the change in volume of air reaches about 3 % of the available volume of air in the respirometer, vent the air circuit for a period of 3 minutes with fresh air and continue the test. NOTE Venting the air circuit prevents oxygen depletion in the air of the circuit to a level that might affect biological activity. 10 CALCULATION AND PRESENTATION OF RESULTS The oxygen uptake rate of compost shall be calculated, according to the case, using the following equations of items a) and b): a) if the respirometer is equipped with a volumetric transducer: Q = V V O 2 32 1000 msv t where Q : oxygen uptake, in milligrams of oxygen per kilogram of volatile solids per hour BNQ, 2004 page 6
V : change in the available volume of air in the respirometer over the entire period of testing, in millilitres [if the air circuit was vented during the test as per item h) of Clause 9.5, V is the sum of measured changes in volume over the entire period of testing] 32 : mass of one mole of oxygen, in grams VO 2 : volume of one mole of oxygen at the test temperature and pressure (P), in litres, calculated using the following equation: VO 2 = ( 273 + ) n R T P msv : mass of the volatile solids contained in the test portion, in grams, calculated using the following equation: ( 1 te 100) 100 msv = mc mog t n R T P : time taken for the test, in hours [if the air circuit was vented during the test as per item h) of Clause 9.5, t is the time taken for the test minus the time the air circuit was vented and no data was recorded] : number of moles of oxygen : gas constant [8,314 34 J/(mol K)] : temperature of the test, in degrees Celsius [temperature of the water of the water basin (see item b) of Clause 9.5)] : atmospheric pressure of test, in kilopascals [see items b) and g) of Clause 9.5] mc : mass measured in item a) of Clause 9.4, in grams te : moisture content, expressed as a percentage of mass on a wet weight basis (see Clause 9.3) mog : organic matter content, expressed as a percentage of mass on a dry weight basis (see Clause 9.3); b) if the respirometer is equipped with a pressure transducer: Q = V V O 2 32 1000 msv t where Q : oxygen uptake, in milligrams of oxygen per kilogram of volatile solids per hour page 7 BNQ, 2004
V : change in the available volume of air in the respirometer over the entire period of testing, in milliliters, calculated using the following equation: V = V P 1000 P 32 : mass of one mole of oxygen, in grams VO 2 : volume of one mole of oxygen at the test temperature and pressure (P), in litres, calculated using the following equation: VO 2 = ( 273 + ) n R T P msv : mass of the volatile solids contained in the test portion, in grams, calculated using the following equation: ( 1 te 100) 100 msv = mc mog t V : time taken for the test, in hours [if the air circuit was vented during the test as per item h) of Clause 9.5, t shall be the time taken for the test minus the time the air circuit was vented and no data was recorded] : available volume of air in the respirometer, in litres P : atmospheric pressure drop in the air circuit over the entire period of testing, in kilopascals [if the air circuit was vented during the test as per item h) of Clause 9.5, P is the sum of measured pressure drops over the entire period of testing] P n R T : atmospheric pressure of the test, in kilopascals : number of moles of oxygen : gas constant [8,314 34 J/(mol K)] : temperature of the test, in degrees Celsius [temperature of the water of the water basin (see item b) of Clause 9.5)] mc : mass measured in item a) of Clause 9.4, in grams te : moisture content, expressed as a percentage of mass on a wet weight basis (see Clause 9.3) mog : organic matter content, expressed as a percentage of mass on a dry weight basis (see Clause 9.3) BNQ, 2004 page 8
11 TEST REPORT The test report shall include the following information: a) this standard number; b) all information necessary for the identification of the sample, the name of the testing laboratory and dates (in all-numerical format by order of year [with four digits]-month-day) of the sampling and performance of the test; c) temperature, in degrees Celsius, at which the sample was maintained during the period between sampling and the performance of the test; d) all recorded measurements; e) calculation of results; f) details of any deviation from the procedure specified in this standard. -0-0-0-0-0-0-0-0-0-0-0-0-0-0- page 9 BNQ, 2004
ANNEX A (informative) RESPIROMETER-PRINCIPLE OF OPERATION The sample chamber, caustic solution chamber, air pump, module for the air intake and the air exhaust in the air circuit and volumetric or pressure transducer are connected to form a closed air circuit. The elements are submerged in a water basin in which the water is temperature controlled to maintain the temperature of the test portion and air at a constant, known temperature. The air pump circulates air continuously in the closed air circuit. Air circulation ensures continuous oxygen (O 2 ) uptake for micro-organisms present in the aqueous compost suspension. Oxygen is consumed by the metabolic activity of micro-organisms in the test portion in sample chamber and carbon dioxide (CO 2 ) is generated and then collected in the caustic solution. The volume of CO 2 collected decreases the available volume of air in the respirometer equivalent to the volume of O 2 consumed. The diminution of volume is measured by the volumetric or pressure transducer of the respirometer. To ensure sufficient concentration of O 2 in the air during the experimentation, a module for the air intake and the air exhaust in the air circuit, which may be automated, allows the exchange of air in the closed air circuit. FIGURE A.1 DIAGRAM OF A RESPIROMETER page 10 BNQ, 2004