1、ICS 13.060.50Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung Schlamm und Sedimente(Gruppe S) Teil 19: Bestimmung der wasserdampfflchtigen organischen Suren (S 19)In keeping with current practice in standards published by the International Organization for Standardization(IS
2、O), 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 Chemiker(German Chemists Society) (see Explan
3、atory notes).Expert assistance and specialized laboratories will be required to perform the analyses specified in thisstandard.Depending on the objective of the analysis, a check shall be made on case-by-case basis as to whether andto what extent additional conditions will have to be specified.Ref.
4、No. DIN 38414-19 : 1999-12English price group 06 Sales No. 010612.01DEUTSCHE NORM December 199938414-19Continued on pages 2 to 5. No part 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
5、 the exclusive right of sale for German Standards (DIN-Normen).German standard methods for the examination of water, waste water and sludgeSludge and sediments (group S)Part 19: Determination of steam-volatile organic acids (S 19)Translation by DIN-Sprachendienst.In case of doubt, the German-languag
6、e original should be consulted as the authoritative text.1 ScopeThe intermediates produced by anaerobic degradation of organic substances include volatile organic acids.These acids can be used to monitor industrial digestion processes, especially the digestion of sewagesludge.The method specified in
7、 this standard serves to determine the steam-volatile organic acids in waste waterand liquid sludge in concentrations of 2 mmol to 20 mmol per litre. Higher concentrations may be determinedby diluting the sludge, and even solid sludge can be analysed if it can be made to flow by adding water.2 Norma
8、tive 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 titles of the publications are listedbelow. For dated references, subsequent amendments to or revisions of
9、any of these publications apply tothis standard only when incorporated in it by amendment or revision. For undated references, the latestedition of the publication referred to applies.DIN 12348 Round bottom and flat bottom flasks fitted with 1 : 10 tapered socket for laboratoryuseDIN 12650-3 Piston-
10、operated dispensers for laboratory useDIN 12664-1 One-mark volumetric flasks with flanged rim, conical socket and conical joint, forlaboratory useDIN 12680-1 Graduated cylinders for laboratory useDIN 12691 Class AS fast delivery one-mark bulb pipettes, with a waiting time of 15 seconds, forlaborator
11、y useDIN 12700-3 Burettes fitted with offset burette stopcock with tail, for laboratory useDIN EN ISO 5667-13 Sampling of water Part 13: Guidance on sampling of sludges from sewage and watertreatment works (ISO 5667-13 : 1997)Page 2DIN 38414-19 : 1999-123 ConceptThe organic and steam-volatile acids
12、detected by this method are, when present in municipal waste watersludge, predominantly monocarboxylic acids containing up to six carbon atoms.4 PrincipleThe acids are steam-distilled from a solution acidified with phosphoric acid and, after any acid-forming gaseshave been removed from the distillat
13、e by refluxing, the latter is titrated with sodium hydroxide solution.5 InterferencesSince acid concentrations may change rapidly as a result of biochemical reactions, the samples shall beanalysed immediately after collection. If this is not possible, the determination may be carried out no later th
14、anthe following day, provided the sample is cooled rapidly and stored at 4 C.Vigorous foaming of the sample can be prevented by adding a defoaming agent.6 DesignationDesignation of the method of determining steam-volatile organic acids in sludges (S 19):Method DIN 38414 S 197 ApparatusThe following
15、equipment shall be used.a) Steam-destillation apparatus, as shown in figure 1, or any other suitable equipment.b) Reflux condenser (Allihn condenser), 30 cm long.c) Heating jacket, for flasks of nominal capacity 1000 ml.d) Dispenser, of nominal capacity 3 ml (e.g. DIN 12650-3 dispenser).e) Graduated
16、 cylinder, of nominal capacity 100 ml (e.g. DIN 12680 ME 100 graduated cylinder).f) Burette, of nominal capacity 25 ml (e.g. DIN 12700 SGA 25-005 burette).g) Piston-operated pipettes, of nominal capacities 50 ml, 100 ml and 250 ml.h) Volumetric flask, of nominal capacity 1000 ml (e.g. DIN 12664 MS A
17、 1000 volumetric flask).i) One-mark bulb pipette, of nominal capacity 20 ml (e.g. DIN 12691 VPAS 20 one-mark bulb pipette).8 ReagentsOnly analytical grade reagents shall be used and the water used shall be distilled water or water of equivalentpurity.The following reagents shall be used.8.1 0,1 moc1
18、08/c108 sodium hydroxide solution, NaOH.8.2 Phosphoric acid, H3PO4, of density 1,71 g/ml.8.3 1% (V/V) phenolphthalein solution, C20H14O4, in ethanol, C2H5OH.8.4 Standard acid solution, to be prepared by pouring water into a 1000 ml volumetric flask up to about 2 cmbelow the mark, adding 250 ml of ac
19、etic acid, CH3COOH, 100 ml of propionic acid, C2H5COOH, 100 ml of butyricacid, C3H7COOH, and 50 ml of valeric acid, C4H9COOH, below the liquid level using a piston-operated pipettefor each acid, making up to the mark with water and shaking.This solution contains about 7 mmol of organic acids per lit
20、re and will be stable for two weeks if refrigerated at4 C. Determine the acid concentration by titration with sodium hydroxide solution.Page 3DIN 38414-19 : 1999-129 Sampling and sample preparationEnsure that the samples collected are representative of the sludge under test. In the case of digesters
21、, it isrecommended that the samples be collected from the circulation line. To collect samples from containers,settling tanks, sludge thickeners or similar equipment in which strata or zones of different composition may beexpected, use suitable sludge siphons and combine the cores collected to form
22、composite samples. Furtherinformation on sampling is given in DIN EN ISO 5667-13.Wide mouth bottles made of polyolefins (e.g. polyethylene) with a screw cap are suitable as sample containers.Fill them to the brim and shake them immediately before removing the sample, proceeding as described inclause
23、 10.Sample components that settle rapidly (e.g. sand) need not be distributed homogeneously since they do notcontain any volatile organic acids.10 Procedure10.1 GeneralAfter diluting the sample if necessary, take 60 ml of the sludge using a graduated cylinder, transfer it to thedistillation vessel,
24、add 3 ml of phosphoric acid and check that the pH value is less than 3.Add 50 ml of water to the receiver. Fill the boiling flask with about 1 l of water, turn on the heating jacket andpass steam through the distillation vessel for 50 minutes, adjusting the heat input so as to collect a condensatevo
25、lume of 450 ml to 550 ml.*) Keep the stopcock open until boiling begins, then close it and open it again when distillation is complete.1 Sloping splash head2 Feed funnel for water3 Stopcock*)4 DIN 12348 round bottom flask, of nominalcapacity 2000 ml, with NS 60/46 joint, for boiling5 Steam inlet tub
26、e6 Distillation vessel7 500 W heating jacket8 Allihn condenser9 Receiver, DIN 12348 flat bottom flask, ofnominal capacity 1000 mlFigure 1: Antonacopoulos steam distillation apparatus with ground glass jointPage 4DIN 38414-19 : 1999-12Remove the receiver, fit the reflux condenser and boil the distill
27、ate under reflux for ten minutes. Rinsecondensate residues back into the receiver twice using 10 ml of water each time.Add five drops of phenolphthalein solution and titrate the distillate (while still at about 60 C) with sodiumhydroxide solution until the colour changes permanently to pink.10.2 Det
28、ermination of blank value and accuracy of recoveryFor every series of samples, check that the blank value does not exceed 1 mmol/l.When the distillation apparatus is commissioned and whenever specified by the laboratory quality controlprocedures, it will be necessary to determine the accuracy of rec
29、overy, WFR, as a percentage, using water orstandard acid solution, and to calculate it using equation (1):10021=SSVVWFR(1)whereVS1is the volume of distilled standard acid solution used for the titration described in subclause 10.1, in ml;VS2is the volume of sodium hydroxide solution used to titrate
30、the standard acid solution, in ml.The accuracy of recovery shall be 90 % to 100 %.11 Deviations from the procedure described in clause 10The distillation time and condensate volume only apply if the steam-distillation apparatus as shown in figure 1is used. Otherwise, these parameters will have to be
31、 modified so that the requirements relating to the blank valueand the accuracy of recovery are met.The titration may also be carried out potentiometrically using a suitable glass electrode to measure the pH valueinstead of using phenolphthalein as an indicator.The end point will then be the point of
32、 inflection in the titration curve.12 EvaluationCalculate the concentration of steam-volatile organic acids, c(S), in mmol/l, using equation (2):30110NaOHS -=P)()()(VVVcc(2)wherec(NaOH) is the concentration of the sodium hydroxide solution, in mol/l;V1is the volume of sodium hydroxide solution used
33、to titrate the sample, in ml;V0is the volume of sodium hydroxide solution used to titrate the blank, in ml;VPis the sample volume taken, in ml.If the concentration is to be reported in milligrams of acetic acid per litre, multiply the value of c(S) by 60,05.13 Expression of resultAll results are sub
34、ject to a certain degree of uncertainty, this often being greatest for lower concentrations. Inthis standard, the concentration range from 3,27 to 16,97 mmol/l has been chosen for the determination of theuncertainty of measurement (expressed as reproducibility coefficient of variation). As can be se
35、en from thevalues in table 1, the uncertainty is between 5,5 % and 18,5 %. For a different concentration range, theuncertainty can be estimated from laboratory quality assurance data (e.g. range control cards for duplicatedeterminations), another method being interlaboratory testing. The uncertainty
36、 of measurement may varyconsiderably with the type of sample.Report the values to not more than three significant places after rounding to the nearest 0,1 mmol/l or thenearest 1 mg/l.EXAMPLES:Steam-volatile organic acids: 4,2 mmol/lAcetic acid equivalent: 252 mg/l14 Test reportThe report shall refer
37、 to this method and include the following details:a) identification of sample (origin, date and time of day of sampling);b) expression of result as specified in clause 13;c) any pretreatment of sample;d) any deviation from this standard and an indication of any circumstances that may have affected t
38、he result.Page 5DIN 38414-19 : 1999-1215 Results of interlaboratory testingAn interlaboratory test carried out in 1996 yielded the results given in table 1.Table 1: Results of interlaboratory testingType of sample L N NAP X Soll X WFR SR VR SI VI% mmol/l mmol/l % mmol/l % mmol/l %Untreated sewage sl
39、udge 12 47 2,1 3,27 0,606 18,5 0,237 7,02Spiked sewage sludge No. 1 12 47 2,1 6,32 6,17 97,7 0,667 10,8 0,198 3,2Spiked sewage sludge No. 2 12 48 0,0 11,72 11,52 98,3 0,834 7,2 0,243 2,1Spiked sewage sludge No. 3 12 48 0,0 16,72 16,97 101,5 0,939 5,5 0,266 1,6Key to symbols used:L number of laborato
40、ries WFR accuracy of recoveryN number of measurements SR reproducibility standard deviationNAP percentage of outliers VR reproducibility coefficient of variationX Soll conventional true value SI repeatability standard deviationX overall mean VI repeatability coefficient of variationExplanatory notes
41、This standard incorporates the German standard method Determination of steam-volatile organic acids (S 19)jointly prepared by the Normenausschuss Wasserwesen (Water Practice Standards Committee) of DIN andStudy Group Wasserchemie of the Gesellschaft Deutscher Chemiker.Standard methods published as D
42、IN Standards are 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 Verl
43、ag GmbH.Standard methods or draft standards bearing the group title German standard methods for the examination ofwater, 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 phys
44、icochemical parameters (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 andsubstances (group H) (DIN 38409)Biological-ecological methods of analysis
45、(group M) (DIN 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 38
46、415 series of standards, there are a number ofEuropean Standards available, which also form part of the collection of German standard methods.Information on these standards can be obtained from the offices of the Normenausschuss Wasserwesen,telephone (+ 49 30 2601-2459), or from Beuth Verlag GmbH, Burggrafenstrae 6, 10787 Berlin, Germany.
