1、Designation: D 6538 00 (Reapproved 2005)e1Standard Guide forSampling Wastewater With Automatic Samplers1This standard is issued under the fixed designation D 6538; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEReference (7) was updated in March 2006.1. Scope1.1 This guide covers the selection and use of automaticwastewater samplers includ
3、ing procedures for their use inobtaining representative samples. Automatic wastewater sam-plers are intended for the unattended collection of samples thatare representative of the parameters of interest in the waste-water body. While this guide primarily addresses the samplingof wastewater, the same
4、 automatic samplers may be used tosample process streams and natural water bodies.1.2 The guide does not address general guidelines forplanning waste sampling activities (see Guide D 4687), devel-opment of data quality objectives (see Practice D 5792), thedesign of monitoring systems and determinati
5、on of the numberof samples to collect (see Practice D 6311), operational detailsof any specific type of sampler, in-situ measurement ofparameters of interest, data assessment and statistical interpre-tation of resultant data (see Guide D 6233), or sampling andfield quality assurance (see Guide D 561
6、2). It also does notaddress sampling groundwater.1.3 The values stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
7、esponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 3694 Practices for Preparation of Sample Container
8、s andfor Preservation of Organic ConstituentsD 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD 4687 Guide for General Planning of Waste SamplingD 4840 Guide for Sampling Chain-of-Custody ProceduresD 5088 Practice for Decontamination of Field Equip
9、mentUsed at Nonradioactive Waste SitesD 5283 Practice for Generation of Environmental DataRelated to Waste Management Activities Quality Assur-ance and Quality Control Planning and ImplementationD 5612 Guide for Quality Planning and Field Implementa-tion of a Water Quality Measurement ProgramD 5792
10、Practice for Generation of Environmental DataRelated to Waste Management Activities: Development ofData Quality ObjectivesD 5851 Guide for Planning and Implementing a WaterMonitoring ProgramD 5956 Guide for Sampling Strategies for HeterogeneousWastesD 6233 Guide for Data Assessment for Environmental
11、Waste Management ActivitiesD 6311 Practice for Generation of Environmental DataRelated to Waste Management Activities: OptimizingSampling DesignE 856 Definitions of Terms and Abbreviateions Relating toPhysical and Chemical Characteristics of Refuse DerivedFuel3. Terminology3.1 composite sample, na c
12、ombination of two or moresamples. (D 1129)3.2 representative sample, na sample collected such thatit reflects one or more characteristics of interest (as defined bythe project objectives) of a population from which it wascollected. (D 5956)3.3 sample, na portion of material taken from a largerquanti
13、ty for the purpose of estimating properties or composi-tion of the larger quantity. (E 856)1This guide is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.01.01 onPlanning for Sampling.Current edition approved July 1, 2005. Publishe
14、d August 2005. Originallyapproved in 2000. Last previous edition approved in 2000 as D 6538-00.2For 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 Documen
15、t Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 This guide provides persons responsible for designingand implementing wastewater sampling programs with a sum-mary of the ty
16、pes of automatic wastewater samplers, discussesthe advantages and disadvantages of the different types ofsamplers and addresses recommended procedures for their use.5. Automatic Versus Manual Sampling (1, 2)35.1 The advantages and disadvantages of manual and auto-matic sampling are summarized in Tab
17、le 1. The decision as towhether to use manual or automatic sampling involves manyconsiderations in addition to equipment costs. In general,manual sampling is indicated when infrequent samples arerequired from a site, when biological or sediment samples, orboth, are also required, when investigating
18、special incidents,where sites will not allow the use of automatic devices, formost bacteriological sampling, where concentrations remainrelatively constant, etc. The use of automatic samplers isindicated where frequent sampling is required at a given site,where long-term compositing is desired, wher
19、e simultaneoussampling at many sites is necessary, etc.Automatic sampling isoften the method of choice for storm-generated dischargestudies, for longer outfall monitoring, for treatment plantefficiency studies, where 24-h composite samples are required,etc. The user should review 7.1.22 before selec
20、ting manual orautomatic sampling.6. Types of Samples Collected by Automatic Samplers6.1 Grab SamplesAs defined under the U.S. Environmen-tal Protection Agencys (EPA) National Pollutant DischargeElimination Program, grab samples are individual samplescollected over a period of time not exceeding 15 m
21、in and arerepresentative of conditions at the time of sampling (4). Grabsamples are sometimes also called individual or discretesamples (5). Sequential grab samples are a series of grabsamples collected at constant increments of either time or flowand provide a history of variation. Grab samples are
22、 appropri-ate when samples are needed to:6.1.1 Characterize an effluent that is not continuous,6.1.2 Provide information about instantaneous concentra-tions of pollutants,6.1.3 Allow collection of samples of varied volume,6.1.4 Corroborate composite samples,6.1.5 Monitor parameters not amenable to c
23、ompositing (forexample, pH, temperature, dissolved oxygen, chlorine, purge-able organics (unless a specialized sampler is used), oil andgrease and others specified by a permit which may includephenols, sulfites and hexavalent chromium).6.1.6 Characterize a waste stream in detail where rapidfluctuati
24、ons of parameters occur (sequential grabs).6.2 Composite SamplesComposite samples are collectedover time, either by continuous sampling or by mixing discretesamples, and represent the average characteristics of the wastestream during the compositing period. Composite samples arecollected when stipul
25、ated in a permit, when average pollutantconcentration during the compositing period is to be deter-mined, and when wastewater characteristics are highly vari-able. There are four types of composite samples.6.2.1 Time Composite SamplesThis method requires dis-crete sample aliquots be collected in one
26、 container at constanttime intervals. The method is appropriate when the flow of thestream is constant (flow rate does not vary more than 610 % ofthe average flow rate (4) or when flow monitoring equipmentis not available. The EPA allows time-proportional samplingand requires samples be collected ev
27、ery 15-min, on average,over a 24-h period.6.2.2 Flow-Proportional Composite SamplesThere aretwo methods used for this type of sample (4). The mostcommonly used method with automatic samplers collects aconstant sample volume at varying time intervals proportionalto stream flow based on input from a f
28、low monitor (forexample, a 200-mL aliquot is collected for every 5000 L offlow). In the other flow-proportional compositing method, thesample is collected by varying the volume of each aliquot asthe flow varies, while maintaining a constant time intervalbetween the aliquots.6.2.3 Sequential Composit
29、e SamplesA sequential com-posite sample is composed of a series of short-period compos-ites, each of which is held in an individual container, forexample, four sample aliquots are composited (one every 15min) to form hourly composites (4). The 24-h sequentialcomposite is then manually made by compos
30、iting the indi-vidual 1-h composite sample.6.2.4 Continuous Composite SamplesThis method re-quires that the sample be collected continuously at a constantrate or proportional to flow (4). This method is seldom usedwith automatic samplers.7. Attributes of Automatic Samplers7.1 The EPA (6) developed a
31、 list of attributes of the idealautomatic sampler for their use and EPA Region 4 (7) and3The boldface numbers given in parentheses refer to a list of references at theend of the standard.TABLE 1 Advantages and Disadvantages of Manual versusAutomatic Sampling of Wastewater (3)Type Advantages Disadvan
32、tagesManual Low capital cost Increased variability due tosample handlingPersonnel can compensate forvarious situationsInconsistency in collectionPersonnel can documentunusual conditionsHigh cost of labor assumingcomposite or multiple grabsamples are collectedNo maintenance Repetitious and monotonous
33、task for personnelExtra samples can be collectedin a short time if necessaryAutomatic Consistent samples Considerable maintenance forbatteries and cleaning;susceptible to plugging bysolidsDecreased variability caused bysample handlingRestricted in size to the generalspecificationsMinimal labor requi
34、rement forsamplingGreater potential for samplecontaminationCapable of collecting multiplegrab and multiple aliquotcomposite samplesMay be subject to damage byvandalsHigh capital costD 6538 00 (2005)e12others (3) have noted other important attributes. These at-tributes and requirements may be specifi
35、c to EPAs use andwere primarily directed at suction lift type automatic samplers.Not all these sampler characteristics will be important to allusers but their consideration may guide persons selectingautomatic samplers. The desirable features of automatic sam-plers listed below have been summarized
36、and combined fromthe referenced documents.7.1.1 Capable of AC/DC operation with adequate dry bat-tery energy storage for 120-h operation at 1-h samplingintervals.7.1.2 Suitable for suspension in a standard manhole yet stillaccessible for inspection and sample removal.Asecure harnessor mounting devic
37、e if the sampler is placed in a sewer.7.1.3 Total weight, including batteries, less than 18 kg.Compact and portable enough for one-person installation.7.1.4 Sample collection interval adjustable from 10 min to 4h.7.1.5 Capable of collecting a single 9.5-L (2.5-gal) sampleand/or collecting 500-mL (0.
38、13-gal) discrete samples in aminimum of 24 containers. The individual sample aliquot mustbe at least 100 mL.7.1.6 Capable of multiplexing repeated aliquots into dis-crete bottles.7.1.7 One intake hose with a minimum inner diameter of0.64 cm (0.25 in) and a weighted, streamlined intake screenwhich wi
39、ll prevent accumulation of solids.7.1.8 Intake hose liquid velocity adjustable from 0.6 to 3m/s (2.0 to 10 ft/s) with dial setting.7.1.9 Minimum lift capacity of 6.1 m (20 ft).7.1.10 Explosion proof construction.7.1.11 Watertight exterior case to protect components in theevent of rain or submersion.
40、7.1.12 Exterior case capable of being locked, including lugsfor attaching steel cable to prevent tampering and to providesecurity.7.1.13 An integral sample container compartment capableof maintaining samples at 4 to 6C for a period of 24 h atambient temperatures up to 38C.7.1.14 Capable of operating
41、 in a temperature range from10 to 40C with the exception of the intake hose.7.1.15 A purge cycle to flush the sample intake tubingbefore and after each collection interval, and a mechanism tosense and clear a plugged sample line and then collect thecomplete sample.7.1.16 Capable of collecting flow-p
42、roportional and time-composite samples.7.1.17 Materials of construction that contact the samplemust not compromise the integrity of the sample for theintended use.NOTE 1Some references prohibited sample contact with metal (6) andcontact with plastic or metal parts when parameters to be analyzed coul
43、dbe impacted by these materials (7).7.1.18 Water velocity in intake hose (greater than 0.6 m/s2.0 ft/s) and aliquot volume are independent of lift heightsexperienced during the sampling event.7.1.19 Overall construction, including casing, of materialsresistant to corrosion (plastics, fiberglass, sta
44、inless steel).7.1.20 Exterior surface a light color to reflect sunlight.7.1.21 Low cost, availability of spare parts, warranty, easeof maintenance, reliability and ruggedness of construction, andcapable of being repaired in the field.7.1.22 Other FactorsOther factors (3) that should beconsidered in
45、selecting an automatic sampler are the:7.1.22.1 Expected variation in water or wastewater compo-sition with time,7.1.22.2 Variation of flow rate with time,7.1.22.3 Specific gravity of the liquid7.1.22.4 Concentration and density of suspended solids ofinterest,7.1.22.5 Presence of floating materials,
46、7.1.22.6 Characteristics of the site where the sampler will beplaced,7.1.22.7 Range of intended use (a permanent site or travel-ing sampler),7.1.22.8 Skill level required for installation and operation ofthe sampler, and7.1.22.9 The level of accuracy desired.8. Types of Automatic Samplers (1,2,3)8.1
47、 There are three main types of automatic samplers,suction lift, pressure or forced flow, and mechanical. Each hasits advantages and limitations and all types are available inmodels designed to preserve samples via cooling (iced orrefrigerated). While all automatic samplers can collect samplesthrough
48、 time, some samplers are designed to be triggered byinputs from online devices measuring flow, pH, temperature,conductance, etc., and collect samples under specific condi-tions (for example, pH 9.0).8.2 Suction LiftSuction lift devices can be further subdi-vided into peristaltic and vacuum type samp
49、lers. Peristalticpump devices are the most commonly used type in the UnitedStates and use a rotating head to pinch a flexible hose creatinga vacuum to transport the sample to the container. Vacuumdevices (8) are more popular in Europe and use a vacuumpump to transport the sample to the sample container. Suctionlift samplers are portable, versatile due to their light weight andcan purge the transport line between samples. Their mainlimitation is that their lift capacity which is claimed to range upto 9 m but may be significantly less. Also, since suction liftdevice
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