1、Designation: D5975 96 (Reapproved 2010)Standard Test Method forDetermining the Stability of Compost by Measuring OxygenConsumption1This standard is issued under the fixed designation D5975; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 expo
3、sure 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 co
4、mpost 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 con
5、trolled.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,such
6、 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 asstandard. No other uni
7、ts of measurement are included in thisstandard.1.5 There 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 p
8、ractices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D515 Test Methods for Phosphorus in WaterD883 Terminology Relating to PlasticsD1293 Test Methods for pH of WaterD1888 Test Met
9、hods for Particulate and Dissolved Matterin WaterD2908 Practice for Measuring Volatile Organic Matter inWater by Aqueous-Injection Gas ChromatographyD3590 Test Methods for Total Kjeldahl Nitrogen in WaterD4129 Test Method for Total and Organic Carbon in Waterby High Temperature Oxidation and by Coul
10、ometric De-tectionD5338 Test Method for Determining 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
11、 this test method appear inTerminology D883.4. 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
12、.4.1.3 Exposing the compost test samples to the fully stabi-lized compost under controlled composting conditions.4.1.4 Measuring the oxygen consumption rate and deter-mining the cumulative oxygen consumption.1This test method is under the jurisdiction of ASTM Committee D34 on WasteManagement and is
13、the direct responsibility of Subcommittee D34.03 on Treatment,Recovery and Reuse.Current edition approved Jan. 1, 2010. Published January 2010. Originallyapproved in 1996. Last previous edition approved in 2004 as D597596(2004).DOI: 10.1520/D5975-96R10.2For referenced ASTM standards, visit the ASTM
14、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 ASTM website.3“Standard Methods for the Examination of Water and Wastewater,” 17thEdition, 1989, American Public Health A
15、ssociation, 1740 Broadway, NewYork, NY19919.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Obtaining the level of stability from the cumulativeoxygen consumption.5. Significance and Use5.1 A measurement of compost stability is n
16、eeded forseveral reasons. It aids in assessing whether the compostingprocess has proceeded sufficiently far to allow the finishedcompost to be used for its intended application. A differentcompost stability may be required for different applications ofthe compost.5.2 A measurement of compost stabili
17、ty also is needed toverify whether a composting plant is processing the waste topreviously agreed levels of stability. This measurement isuseful in the commissioning of composting plants and theverification of whether plant operators are satisfying permitrequirements.5.3 The level of compost stabili
18、ty 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 susceptible the compost is to renewed bacterial andpossible pathogenic activity. Compost stability is an importantparameter with regard to phytotoxi
19、city and plant tolerance ofthe compost.5.4 The determination of compost stability will allow theselection of well performing composting technologies, as wellas the safe application of compost in its various markets. Themethod indicates a degree of stability, but does not necessarilyindicate that one
20、 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 preparation bin with avolume of 100 to 200 L, with insulation sufficient to maintaincomposting temperatures of 50 to 65C during a period of
21、atleast two weeks when composting similar waste as the wastefrom which the samples were derived, and equipped with airdistribution plate, inlet and outlet, and 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 Thermome
22、ter, 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 composting 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
23、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 temperature control-ling means capable of maintaining the temperature of thecomposting vessels at 58C (6 2C).6.2.3 Pressurized-Air System, providing H2
24、O-saturated airto each of the composting vessels at the appropriate aerationrates.FIG. 1 Optional Set-Up Compost Preparation BinD5975 96 (2010)26.2.4 Suitable devices for measuring oxygen concentrationin the exhaust air of the composting vessels, such as specificsensors or appropriate gas chromatogr
25、aphy.6.3 Miscellaneous:6.3.1 Balance (6 1 mg), to weigh sample and stabilizedcompost.6.3.2 Scales (6 0.1 kg), to weigh composting waste forstabilized compost production.6.3.3 Normal laboratory glassware, equipment, and chemi-cals.6.3.4 Suitable devices and analytical equipment for measur-ing dry sol
26、ids (at 105C), volatile solids (at 550C), volatilefatty acids by aqueous-injection chromatography, and totalKjeldahl nitrogen.7. Reagents and Materials7.1 Analytical-grade cellulose (microcrystalline, as used inthin-layer chromatography) with a particle size of less than 10m, for use as a positive c
27、ontrol.8. Hazards8.1 This test method requires the use of hazardous chemi-cals. Avoid contact with the chemicals and follow manufactur-ers instructions and Materials Safety Data Sheets (MSDS).8.2 The waste materials used for the production of stabilizedcompost, or the compost samples may contain sha
28、rp objects.Take care when handling.8.3 The composting vessels are not designed to withstandhigh pressures. The system should be operated at close toambient pressure.9. Stabilized Compost9.1 The stabilized compost, which serves as an inoculumand the test matrix, should be well-aerated compost two to
29、fourmonths old, coming from the organic fraction of municipalsolid waste or source-separated organics, and sieved over ascreen of 10 mm. It is recommended that the stabilizedcompost control consumes 15 to 80 mg of oxygen/g of volatilesolids over the four-day test period. The stabilized compostmust h
30、ave 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 fatty 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 c
31、ompost should be as free as possible oflarger inert materials (for example, glass, stones, metals).These items should be removed manually to produce a homo-geneous material.10. Test Samples10.1 The test sample must be representative of the compostthat is being assessed for compost quality. Preferabl
32、y the testsample should be a composite of various grab samples takenthroughout the pile. Otherwise, take samples at various depthsof a compost pile and analyze these compost samples sepa-rately to assess any variations within the compost pile itself.10.2 When adding the test sample compost to the st
33、abilizedcompost, all basic composting parameters, such as oxygen inthe composting vessel, porosity, and moisture content shouldbe adjusted so as to make a good composting process possible.FIG. 2 Optional Set-Up Using Gas Chromatograph (see also Test Method D5338)D5975 96 (2010)3Oxygen levels in the
34、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-scale composting bin processinga waste similar to the
35、 waste from which the test samples arederived.11.1.1.1 Screen the stabilized compost to less than 10 mmand manually remove and discard any large inert items (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 c
36、arbon, nitrogen and phosphorus contentsaccording to Test Methods D515, D1888, D3590, D4129, andAPHA Test Methods 2540 D and 2540 E. Also determine pHand volatile fatty acids as described in 11.4.2. Add ammoniumchloride if the C/N ratio is more than 20 and adjust to a C/Nratio of 15.Add NaH2PO4if the
37、 C/P is more than 60 and adjustto a C/P ratio of 45.11.1.1.2 Determine the volatile solids and dry solids of allthe test sample composts in accordance 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 ea
38、ch percomposting vessel) and mix thoroughly. The relation betweenthe dry weight of the stabilized compost and the dry weight oftest material should be about 1:1. Adjust with water the drysolids content of the mixture to approximately 50 %, and addthe mixture to three composting vessels. Weigh the ve
39、sselswith 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 replicates. For the positive control, add 50 gof microcrystalline cellulose to 1000 g of stabilized compostfor each of the three replicates.11.2 Sta
40、rt-Up ProcedureInitiate aeration of the compost-ing vessels with air-flow rates that are sufficiently high toensure that oxygen levels do not drop below 6 % in the exhaustair. Oxygen levels should be closely controlled during the first36 h and measured at least four times daily. Adjust air-flowrates
41、 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 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
42、higherthan during the previous 24 h in the vessels containing thesamples.11.3.2 Check O2concentrations in the outgoing air, fourtimes daily, with a maximum 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 nol
43、eaks 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 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
44、 with thecontents and determine the dry solids content remaining in thecompost.11.4.2 Measure the pH in conformance with Test MethodsD1293. Measure the 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
45、7, measure thevolatile fatty acids in accordance with Practice D2908 in theliquid phase after centrifugation of the diluted sample at 3000G forces. The volatile fatty acids must be below 2000 mg/L asacetic acid.12. Calculation12.1 Determine the volumetric cumulative oxygen con-sumption for each comp
46、osting vessel over the whole testperiod, using for each reading during the test the followingformula:V15 Oi2 Oe! 3 F 3Dt (1)where:V1= cummulative volumetric oxygen consumption (L),Oi= oxygen concentration in incoming air (volume %),Oe= oxygen concentration in exhaust air (volume %),F = air flow rate
47、 (in L/h), andDt = period of time.12.2 The cumulative volumetric oxygen consumption inlitres, obtained from the previous calculation, is recalculated tostandard conditions of temperature and pressure, using theformula:V25 V13T2T13p1p2(2)where:V1= cumulative volumetric oxygen consumption (L),V2= cumu
48、lative volumetric oxygen consumption understandard conditions (L),T2= standard temperature (273K)T1= ambient temperature (in K),p1= ambient pressure (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
49、 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 oxygen.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 Expres
