1、ICS 13.060.50Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung Schlamm und Sedimen-te (Gruppe S) Teil 22: Bestimmung des Gefriertrockenrckstandes und Herstellung der Gefriertrocken-masse eines Schlammes (S 22)In keeping with current practice in standards published by the Inte
2、rnational Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.ForewordThis standard has been jointly prepared by the Normenausschuss Wasserwesen (Water Practice StandardsCommittee) and Study Group Wasserchemie (Water Chemistry) of the Gesellschaft Deutscher
3、Chemiker(German Chemists Society) (see Explanatory notes).Expert assistance and specialized laboratories will be required to perform the analyses specified in thisstandard. Existing safety instructions shall be observed.Depending on the objective of the analysis, a check shall be made on a case-by-c
4、ase basis as to whetherand to what extent additional conditions will have to be specified.IntroductionThe dry residue and the water content are important factors in the treatment or removal of sludge, sedimentsand other undissolved, water-containing substances. They are also necessary for reference
5、when determin-ing the constituents of the dry matter.The dry matter content is also often used to determine organic and inorganic trace substances (e.g. to checkfor compliance with the requirements of the Klrschlammverordnung (German Regulation on the treatmentof sewage sludge).Freeze-drying of the
6、sample will result in substantially smaller losses of volatile substances than drying at105 C. Reference is made in this context to clause 4 of DIN 38414-2.Ref. No. DIN 38414-22 : 2000-09English price group 06 Sales No. 010605.02DEUTSCHE NORM September 200038414-22Continued on pages 2 to 6. No part
7、of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).German standard methods for the examination of water, waste water and sludge
8、Sludge and sediments (group S)Part 22: Freeze-drying of sludge and determinationof freeze-drying residue (S 22)Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.1 ScopeThe method specified in this standard serves to determi
9、ne the freeze-dying residue of sludge, sediments andother undissolved, water-containing substances.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the t
10、itles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies.Page 2DIN
11、38414-22 : 2000-09DIN 38409-1 German standard methods for the examination of water, waste water and sludge Parameterscharacterizing effects and substances (group H) Determination of total dry residue, filtrate dryresidue and residue on ignition (H 1)DIN 38414-2 German standard methods for the examin
12、ation of water, waste water and sludge Sludge andsediments (group S) Determination of water content, of dry residue and of solids content (S 2)Klrschlammverordnung, as of 15 April 1992, BGBl. (German Federal Law Gazette) I, No. 21, 912934.3 Concepts3.1 Freeze-dried massThe mass of a sample, mTG, obt
13、ained using the drying procedure specified in this standard, and expressed ing or kg.3.2 Freeze-drying residueThe proportion of solids in a sample, wTG, obtained using the drying procedure specified in this standard, andexpressed in g/kg or as a percentage by mass.NOTE 1: The freeze-drying residue s
14、hould not be confused with the total dry residue of a water sampledetermined as a concentration, in mg/l (see DIN 38409-1).3.3 Water contentThe percentage by mass of water in a sample, wTG, determined as a loss in mass using the drying procedurespecified in this standard.3.4 Dry matter concentration
15、The concentration of substances that can be filtered off, TSG, determined by mass using the drying procedurespecified in this standard, and expressed in gram per litre of activated sludge.4 InterferenceDuring storage, sludge samples are likely to undergo changes (e.g. absorption or release of water,
16、 carbondioxide, methane and other substances) that may falsify the results. Substances may be lost as a function oftheir volatilization, with some being deposited in the frozen condensate and others being entrained in the gasextracted by the vacuum pump. There may be some loss of solid particles fro
17、m the surface while the sampleis being dried.Given the relatively large surface area of the constituent particles, freeze-dried samples are extremelyhygroscopic. The water absorption may be minimized by taking suitable measures before and after opening thelyophilizer chamber (e.g. by immediate trans
18、fer to a desiccator containing phosphorus(V) oxide, but withoutapplying vacuum).5 DesignationDesignation of the method of freeze-drying sludge and determining the freeze-drying residue (S 22):Method DIN 38414 S 226 ApparatusThe following equipment shall be used.a) Deep-freezer, explosion-proof, usin
19、g the contact freezing technique where possible, capable of main-taining temperatures down to at least 35 C1).b) Lyophilizer, suitable for accommodating flat bottom dishes, capable of maintaining pressures down to37 Pa, equipped for pressure-controlled drying and fitted with temperature and pressure
20、 sensors.c) Nitrogen gasifier (e.g. drying tower); when using the gasifier, the manufacturers instructions should beobserved.d) Flat bottom dishes, made of aluminium or stainless steel, having a diameter suitable for the lyophilizerracks, having a depth of about 2,5 cm and a base that is not noticea
21、bly uneven. Stainless steel dishes shallnot be used if heavy metals are to be determined in the dry residue.e) Flat sieves, made of stainless steel, having a sealing rim, an aperture size of about 0,2 mm and a diameterto suit the flat bottom dishes.f) Balance, with 0,01 g scale intervals.g) Vessels
22、to receive the dried material (e.g. brown-glass bottles with ground joint).h) Desiccator.1) The sample may also be deep-frozen in a suitably equipped lyophilizer.Page 3DIN 38414-22 : 2000-097 ReagentsThe following reagents shall be used.a) Desiccant, for the gasifier (e.g. silica gel) and, if necess
23、ary, dry inert gas (e.g. nitrogen or argon).b) Phosphorus(V) oxide, P2O5, as desiccant for the desiccator.8 ProcedureAfter weighing the flat bottom dish and sieve, together with any temperature sensor used (attaching a sensorto the base of the dish before freezing will enable the temperature of the
24、sample to be monitored), at ambienttemperature to the nearest 0,1 g, transfer a sufficient quantity of homogenized sample to the dish to give anexpected dry mass of not less than 10 g, ensuring that the layer thickness does not exceed 2 cm (since thefreezing and drying process will be considerably s
25、horter for a thin layer). With the sieve in position, weigh thedish, sieve, any temperature sensor used and the sample. Transfer the dish and sample to the freezer, ensuringit is horizontal.Cool the sample to a temperature of 30 C to 33 C throughout.Cool the trays in the lyophilizer, precool its con
26、denser and allow the vacuum pump to warm up. Place the dishcontaining the frozen sample in the lyophilizer and then evacuate the lyophilizer chamber and condenser.After adjusting the pressure in the lyophilizer to between 37 Pa and 63 Pa to prevent any defrosting of thesample, adjust the rack temper
27、ature so as to maintain the set pressure and prevent defrosting. Values of 37 Paand 63 Pa are equivalent to ice temperatures of about 30 C and about 25 C, respectively (see figure 1).The end of drying, which is when the ice has sublimed, is indicated bya) the final pressure being reached and remaini
28、ng constant, andb) the temperature of the dried product beginning to rise and assuming the ambient temperature or the racktemperature.That drying is complete can be checked by monitoring the pressure. The final pressure and the ice condensertemperature shall be monitored for two hours and shall rema
29、in constant over this period.NOTE: To measure the product temperature correctly, the temperature sensor has to be completely surroundedby the product.It should be ensured that the pressure does not rise when the valve between the lyophilizer chamber and thecondenser is closed. There will be no rise
30、in pressure if all the ice has sublimed.When freeze-drying is complete, switch off the vacuum pump and condenser cooling, then flood the chamberwith a dry gas from the gasifier. Immediately weigh the dish containing the dry matter, with the sieve and anytemperature sensor used. Transfer the dried sa
31、mple to a container for subsequent analysis and store it overphosphorus(V) oxide in a desiccator.Before weighing a sample for further analysis, determine the water content of the sample if necessary. Figure 2shows the water absorption of freeze-dried sewage sludge (in terms of the increase in mass)
32、by way of example.Since the freeze-dried material is not sterile, ensure that hygienic requirements are met while processing thesample, especially in the case of operations that develop dust 1, 2.Figure 1: Temperature/pressure diagram for icePressure, inPaPressure, in mbarTemperature, in CSolidGaseo
33、usPage 4DIN 38414-22 : 2000-099 EvaluationDetermine the freeze-drying residue of the sample, wTG, as a percentage, using equation (1):()fmmmmw -=abacTG(1)and determine the water content of the sample, wWG, as a percentage, using equation (2):()()fmmmmw -=abcbWG(2)wheremcis the mass of the dish conta
34、ining the sample dry matter, including the sieve and any temperature sensorused, in g;mais the mass of the empty dish, including the sieve and any temperature sensor used, in g;mbis the mass of the dish containing the original sludge sample, including the sieve and any temperaturesensor used, in g;f
35、 is a conversion factor (here, f = 100 %).10 Expression of resultsAll results are subject to a degree of uncertainty, this often being greatest for lower concentrations.In this standard, the concentration range from 3,4 % to 6,4 % has been chosen for the determination of theuncertainty of measuremen
36、t (expressed as reproducibility coefficient of variation). As can be seen from thevalues in table 1, the uncertainty is between 1,3 % and 2,9 %.For a different concentration range, the uncertainty can be estimated from laboratory quality assurance data(e.g. range control cards for duplicate determin
37、ations), another method being interlaboratory testing. Theuncertainty of measurement may vary considerably with the type of sample.Report freeze-drying residues or water contents of up to 10 % to the nearest 0,01 %, and those over 10 % tothe nearest 0,1 %.Figure 2: Increase in mass of a freeze-dried
38、 sample that was storedin the open after gasification with a dry gasIncrease in mass, in gTime, in minPage 5DIN 38414-22 : 2000-09EXAMPLE:Dry matter content, as freeze-drying residue, wTG: 6,49 %Water content, wWG: 93,5 %11 Test reportThe test report shall refer to this method and include the follow
39、ing details:a) identification of sample;b) expression of results as specified in clause 10;c) details of any sample pretreatment;d) any deviation from this standard and an indication of any circumstances that may have affected the result.12 Results of interlaboratory testingAn interlaboratory test c
40、arried out in the autumn of 1993 yielded the results shown in table 1.Table 1: Determination of freeze-drying residueSample Type of sample LNNAP wTGSR VR SI VI% % %A Sewage sludge 17 64 3,0 3,390 0,094 2,9 0,044 1,3B Sewage sludge 16 59 1,7 6,350 0,085 1,3 0,042 0,7Key to symbols used:L number of la
41、boratoriesN number of measurementsNAP percentage of outlierswTGfreeze-drying residueSR reproducibility standard deviationVR reproducibility coefficient of variationSI repeatability standard deviationVI repeatability coefficient of variationExplanatory notesThis standard incorporates the German stand
42、ard method Freeze-drying of sludge and determination of thefreeze-drying residue (S 22), jointly prepared by the Normenausschuss Wasserwesen (Water Practice Stand-ards Committee) of DIN and Study Group Wasserchemie of the Gesellschaft Deutscher Chemiker.Standard methods published as DIN Standards ar
43、e obtainable from Beuth Verlag GmbH, either individually orgrouped in volumes. The standard methods included in the loose-leaf publication entitled DeutscheEinheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung will continue to be published by Wiley-VCH Verlag and Beuth Verlag GmbH.Standar
44、d methods or draft standards bearing the group title German standard methods for the examinationof water, waste water and sludge are classified under the following categories (main titles):General information (group A) (DIN 38402)Sensory analysis (group B) (DIN 38403)Physical and physicochemical par
45、ameters (group C) (DIN 38404)Anions (group D) (DIN 38405)Cations (group E) (DIN 38406)Substance group analysis (group F) (DIN 38407)Gaseous constituents (group G) (DIN 38408)Parameters characterizing effects and substances (group H) (DIN 38409)Biological-ecological methods of analysis (group M) (DIN
46、 38410)Microbiological methods (group K) (DIN 38411)Bio-assays (group L) (DIN 38412)Individual constituents (group P) (DIN 38413)Sludge and sediments (group S) (DIN 38414)Bio-assays with microorganisms (group T) (DIN 38415)In addition to the methods described in the DIN 38402 to DIN 38415 series of
47、standards, there are a numberof European Standards available, which also form part of the collection of German standard methods.Information on Parts of these series of standards that have already been published can be obtained from theoffices of the Normenausschuss Wasserwesen, telephone (+ 49 30 26
48、01-2549), or from Beuth Verlag GmbH,Burggrafenstrae 6, 10787 Berlin, Germany.Page 6DIN 38414-22 : 2000-09Bibliography1 Laboratoriumssicherheit. Vorlufige Empfehlungen fr den Umgang mit pathogenen Mikroorganismen undfr die Klassifikation von Mikroorganismen und Krankheitserregern nach den im Umgang m
49、it ihnen auftre-tenden Gefahren (Laboratory safety. Preliminary recommendations for the handling of pathogenic microor-ganisms and for the classification of microorganisms and pathogens according to the risks associated withtheir handling). Bundesgesundheitsblatt (German Federal Health Gazette) 24, as of 30 October 1981: 22,pp. 347359.2 Unfallverhtungsvorschrift Biotechnologie (German Accident Prevention Regulation on biotechnology).3 Bortlisz, J. and Velten, L. Herstellung und Bestimmung der Trockenmasse von Klrschlmmen, Sedimente
