1、Designation: D 5975 96 (Reapproved 2004)Standard Test Method forDetermining the Stability of Compost by Measuring OxygenConsumption1This standard is issued under the fixed designation D 5975; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the stability of a compostsample by measuring oxygen consumption after e
3、xposure ofthe test compost to a well-stabilized compost under controlled-composting conditions on a laboratory scale involving activeaeration. This test method is designed to yield reproducible andrepeatable results under controlled conditions that resemble theend of the active composting phase. The
4、 compost samples areexposed to a well-stabilized compost inoculum that is preparedfrom municipal solid waste or waste similar to the waste fromwhich the test materials are derived. The aerobic compostingtakes place in an environment where temperature, aeration, andhumidity are monitored closely and
5、controlled.1.2 This test method yields a cumulative amount of oxygenconsumed/g of volatile solids in the samples over a four-dayperiod. The rate of oxygen consumption is monitored as well.1.3 This test method is applicable to different types ofcompost samples including composts derived from wastes,s
6、uch as municipal solid waste, yard waste, source-separatedorganics, biosolids, and other types of organic wastes that donot have toxicity levels that are inhibitory to the microorgan-isms present in aerobic composting systems.1.4 The values stated in SI units are to be regarded as thestandard.1.5 Th
7、ere is no similar or equivalent ISO method.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 health practices and determine the applica-bility of regulato
8、ry limitations prior to use. Specific hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D 515 Test Methods for Phosphorus in WaterD 883 Terminology Relating to PlasticsD 1293 Test Methods for pH of WaterD 1888 Test Methods for Particulate and Dissolved Matterin Water
9、D 2908 Practice for Measuring Volatile Organic Matter inWater by Aqueous-Injection Gas ChromatographyD 3590 Test Methods for Total Kjeldahl Nitrogen in WaterD 4129 Test Method for Total and Organic Carbon in Waterby High-Temperature Oxidation and Coulometric Detec-tionD 5338 Test Method for Determin
10、ing Aerobic Biodegrada-tion of Plastic Materials Under Controlled CompostingConditions2.2 APHA-AWWA-WPCF Standards:2540 D Total Suspended Solids Dried at 103105C32540 E Fixed and Volatile Solids Ignited at 550C33. Terminology3.1 Definitions of terms in this test method appear inTerminology D 883.4.
11、Summary of Test Method4.1 This test method consists of the following:4.1.1 Selecting a compost sample for the determination ofthe stability.4.1.2 Producing a fully stabilized compost from a similarwaste stream under well-controlled laboratory conditions.4.1.3 Exposing the compost test samples to the
12、 fully stabi-lized compost under controlled composting conditions.4.1.4 Measuring the oxygen consumption rate and deter-mining the cumulative oxygen consumption.4.2 Obtaining the level of stability from the cumulativeoxygen consumption.5. Significance and Use5.1 A measurement of compost stability is
13、 needed forseveral reasons. It aids in assessing whether the compostingprocess has proceeded sufficiently far to allow the finished1This test method is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.03.01 onThermal and Biological
14、Treatment.Current edition approved Aug. 10, 1996. Published October 1996.2For 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 standards Document Summary page onthe A
15、STM website.3“Standard Methods for the Examination of Water and Wastewater,” 17thEdition, 1989, American Public Health Association, 1740 Broadway, NewYork, NY19919.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Spost to be used for its int
16、ended application. A differentcompost stability may be required for different applications ofthe compost.5.2 A measurement of compost stability also is needed toverify whether a composting plant is processing the waste topreviously agreed levels of stability. This measurement isuseful in the commiss
17、ioning of composting plants and theverification of whether plant operators are satisfying permitrequirements.5.3 The level of compost stability also will indicate itspotential to cause odors if the compost is stored withoutaeration, as well as the level to which it has been hygienizedand how suscept
18、ible the compost is to renewed bacterial andpossible pathogenic activity. Compost stability is an importantparameter with regard to phytotoxicity and plant tolerance ofthe compost.5.4 The determination of compost stability will allow theselection of well performing composting technologies, as wellas
19、 the safe application of compost in its various markets. Themethod indicates a degree of stability, but does not necessarilyindicate that one level is preferable over another level ofstability.6. Apparatus6.1 Stabilized-Compost Inoculum Preparation Bin (see Fig.1):6.1.1 A stabilized-compost inoculum
20、 preparation bin with avolume of 100 to 200 L, with insulation sufficient to maintaincomposting temperatures of 50 to 65C during a period of atleast two weeks when composting similar waste as the wastefrom which the samples were derived, and equipped with airdistribution plate, inlet and outlet, and
21、 airtight lid.6.1.2 Pressurized Air, provided to the composting bin at aprecise and controllable rate up to 200 L/kg waste/day.6.1.3 Thermometer, with temperature measurement up to80C (6 2C).6.1.4 Suitable devices for measuring oxygen and CO2(op-tional) concentrations in the exhaust air of the compo
22、sting bin,such as sensors or appropriate gas chromatography.6.2 Composting Apparatus (see Fig. 2):6.2.1 A series of at least nine composting vessels (one testsubstance, one blank, one positive reference, all in threereplicates) of 2 to 5 L of volume.6.2.2 Incubators, water baths, or other temperatur
23、e control-ling means capable of maintaining the temperature of thecomposting vessels at 58C (6 2C).6.2.3 Pressurized-Air System, providing H2O-saturated airto each of the composting vessels at the appropriate aerationrates.6.2.4 Suitable devices for measuring oxygen concentrationin the exhaust air o
24、f the composting vessels, such as specificsensors or appropriate gas chromatography.6.3 Miscellaneous:6.3.1 Balance (6 1 mg), to weigh sample and stabilizedcompost.FIG. 1 Optional Set-Up Compost Preparation BinD 5975 96 (2004)26.3.2 Scales (6 0.1 kg), to weigh composting waste forstabilized compost
25、production.6.3.3 Normal laboratory glassware, equipment, and chemi-cals.6.3.4 Suitable devices and analytical equipment for measur-ing dry solids (at 105C), volatile solids (at 550C), volatilefatty acids by aqueous-injection chromatography, and totalKjeldahl nitrogen.7. Reagents and Materials7.1 Ana
26、lytical-grade cellulose (microcrystalline, as used inthin-layer chromatography) with a particle size of less than 10m, for use as a positive control.8. Hazards8.1 This test method requires the use of hazardous chemi-cals. Avoid contact with the chemicals and follow manufactur-ers instructions and Ma
27、terials Safety Data Sheets (MSDS).8.2 The waste materials used for the production of stabilizedcompost, or the compost samples may contain sharp objects.Take care when handling.8.3 The composting vessels are not designed to withstandhigh pressures. The system should be operated at close toambient pr
28、essure.9. Stabilized Compost9.1 The stabilized compost, which serves as an inoculumand the test matrix, should be well-aerated compost two to fourmonths old, coming from the organic fraction of municipalsolid waste or source-separated organics, and sieved over ascreen of 10 mm. It is recommended tha
29、t the stabilizedcompost control consumes 15 to 80 mg of oxygen/g of volatilesolids over the four-day test period. The stabilized compostmust have a total solids content between 50 and 60 % on wetweight, an ash content of less than 70 % on total solids, a pHbetween 7 and 8 and be free of volatile fat
30、ty acids (less than100 mg/L as acetic acid). The C/N ratio should be between 10and 20 and the C/P ratio between 30 and 60.9.2 The stabilized compost should be as free as possible oflarger inert materials (for example, glass, stones, metals).These items should be removed manually to produce a homo-ge
31、neous material.10. Test Samples10.1 The test sample must be representative of the compostthat is being assessed for compost quality. Preferably the testsample should be a composite of various grab samples takenthroughout the pile. Otherwise, take samples at various depthsof a compost pile and analyz
32、e these compost samples sepa-rately to assess any variations within the compost pile itself.10.2 When adding the test sample compost to the stabilizedcompost, all basic composting parameters, such as oxygen inthe composting vessel, porosity, and moisture content shouldbe adjusted so as to make a goo
33、d composting process possible.Oxygen levels in the composting vessel should be at least 6 %at all times and no free-standing water nor clumps of materialshould be present.11. Procedure11.1 Preparation of the Samples:11.1.1 Obtain the stabilized compost inoculum from aproperly operating laboratory-sc
34、ale composting bin processinga waste similar to the waste from which the test samples arederived.FIG. 2 Optional Set-Up Using Gas Chromatograph (see also Test Method D 5338)D 5975 96 (2004)311.1.1.1 Screen the stabilized compost to less than 10 mmand manually remove and discard any large inert items
35、 (piecesof glass, stone, wood) that went through the 10 mm screen.Determine on the fraction less than 10 mm the volatile solids,dry solids and carbon, nitrogen and phosphorus contentsaccording to Test Methods D 515, D 1888, D 3590, D 4129,and APHA Test Methods 2540 D and 2540 E. Also determinepH and
36、 volatile fatty acids as described in 11.4.2. Addammonium chloride if the C/N ratio is more than 20 and adjustto a C/N ratio of 15. Add NaH2PO4if the C/P is more than 60and adjust to a C/P ratio of 45.11.1.1.2 Determine the volatile solids and dry solids of allthe test sample composts in accordance
37、with APHA TestMethods 2540 D and 2540 E.11.1.1.3 Weigh out precise amounts of stabilized compostinoculum and test sample compost (roughly 500 g of each percomposting vessel) and mix thoroughly. The relation betweenthe dry weight of the stabilized compost and the dry weight oftest material should be
38、about 1:1. Adjust with water the drysolids content of the mixture to approximately 50 %, and addthe mixture to three composting vessels. Weigh the vesselswith contents.11.1.1.4 The blank consists of the stabilized compost only,containing about 1000 g wet weight/composting vessel foreach of the three
39、 replicates. For the positive control, add 50 gof microcrystalline cellulose to 1000 g of stabilized compostfor each of the three replicates.11.2 Start-Up ProcedureInitiate aeration of the compost-ing vessels with air-flow rates that are sufficiently high toensure that oxygen levels do not drop belo
40、w 6 % in the exhaustair. Oxygen levels should be closely controlled during the first36 h and measured at least four times daily. Adjust air-flowrates as needed for the remainder of the test.11.3 Operating Procedure:11.3.1 Incubate the composting vessels in the dark for aperiod of four days. Keep the
41、 temperature at 58C (6 2C) forthe duration of the test. The incubation time may be extendedif the rate of oxygen consumption during the last 24 h is higherthan during the previous 24 h in the vessels containing thesamples.11.3.2 Check O2concentrations in the outgoing air, fourtimes daily, with a max
42、imum time interval of 5 h.11.3.3 Check air flow daily at the connections before andafter the composting vessels and at the outlets, ensuring that noleaks are present in the complete system. Adjust air flow tomaintain an oxygen concentration of at least 6 % v/v in theexhaust air.11.3.4 Ensure proper
43、composting conditions and shakecomposting vessels after the first day of testing.11.4 End of the Test:11.4.1 At the end of the test weigh the vessels with thecontents and determine the dry solids content remaining in thecompost.11.4.2 Measure the pH in conformance with Test MethodsD 1293. Measure th
44、e pH by diluting the sample to a 5:1 w/wmixture of distilled water to compost, mix by shaking manuallyand measure immediately. If the pH is less than 7, measure thevolatile fatty acids in accordance with Practice D 2908 in theliquid phase after centrifugation of the diluted sample at 3000G forces. T
45、he volatile fatty acids must be below 2000 mg/L asacetic acid.12. Calculation12.1 Determine the volumetric cumulative oxygen con-sumption for each composting vessel over the whole testperiod, using for each reading during the test the followingformula:V15 Oi2 Oe! 3 F 3Dt (1)where:V1= cummulative vol
46、umetric oxygen consumption (L),Oi= oxygen concentration in incoming air (volume %),Oe= oxygen concentration in exhaust air (volume %),F = air flow rate (in L/h), andDt = period of time.12.2 The cumulative volumetric oxygen consumption inlitres, obtained from the previous calculation, is recalculated
47、 tostandard conditions of temperature and pressure, using theformula:V25 V13T2T13p1p2(2)where:V1= cumulative volumetric oxygen consumption (L),V2= cumulative volumetric oxygen consumption understandard conditions (L),T2= standard temperature (273K)T1= ambient temperature (in K),p1= ambient pressure
48、(in atm), andp2= standard pressure (1 atm).Subsequently, the oxygen consumption is recalculated usingthe formula:C 5 V2332 g22.414 L(3)where:C = oxygen consumption in grams,22.414 L = volume of 1 mole of oxygen under standardconditions of temperature and pressure, and32 g = weight of 1 mole of oxyge
49、n.12.3 Determine the net cumulative oxygen consumption ofthe test compost sample by subtracting the oxygen consump-tion of the stabilized compost inoculum in the test vessel fromthe total oxygen consumption of the test vessel, (the oxygenconsumption of the inoculum in the test vessel is the consump-tion per gram of the inoculum in the control vessels multipliedby the weight of inoculum in the test vessel).12.4 Express the oxygen consumption in mg oxygen/gvolatile solids and over four days (mg O2/g VS.4d).13. Interpretation of the Results13.1 Results of oth
