1、Designation: D6538 10Standard Guide forSampling Wastewater With Automatic Samplers1This standard is issued under the fixed designation D6538; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the selection and use of automaticwastewater samplers including procedures for their use inobtaining representative samples. Auto
3、matic 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 automatic samplers may be used tosample process streams and natural
4、water bodies.1.2 The guide does not address general guidelines forplanning waste sampling activities (see Guide D4687), devel-opment of data quality objectives (see Practice D5792), thedesign of monitoring systems and determination of the numberof samples to collect (see Practice D6311), operational
5、 detailsof any specific type of sampler, in-situ measurement ofparameters of interest, data assessment and statistical interpre-tation of resultant data (see Guide D6233), or sampling andfield quality assurance (see Guide D5612). It also does notaddress sampling groundwater.1.3 The values stated in
6、SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3.1 ExceptionThe inch-pound units given in parenthe-ses are for information only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theres
7、ponsibility 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:2D1129 Terminology Relating to WaterD3694 Practices for Preparation of Sample Containers an
8、dfor Preservation of Organic ConstituentsD3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD4687 Guide for General Planning of Waste SamplingD4840 Guide for Sample Chain-of-Custody ProceduresD5088 Practice for Decontamination of Field EquipmentUsed a
9、t Waste SitesD5283 Practice for Generation of Environmental Data Re-lated to Waste Management Activities: Quality Assuranceand Quality Control Planning and ImplementationD5612 Guide for Quality Planning and Field Implementa-tion of a Water Quality Measurement ProgramD5681 Terminology for Waste and W
10、aste ManagementD5792 Practice for Generation of Environmental Data Re-lated to Waste Management Activities: Development ofData Quality ObjectivesD5851 Guide for Planning and Implementing a WaterMonitoring ProgramD5956 Guide for Sampling Strategies for HeterogeneousWastesD6233 Guide for Data Assessme
11、nt for EnvironmentalWaste Management ActivitiesD6311 Guide for Generation of Environmental Data Re-lated to Waste Management Activities: Selection andOptimization of Sampling DesignE856 Definitions of Terms and Abbreviations Relating toPhysical and Chemical Characteristics of Refuse DerivedFuel3. Te
12、rminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminology D5681.4. Significance and Use4.1 This guide provides persons responsible for designingand implementing wastewater sampling programs with a sum-mary of the types of automatic wastewater samplers, discussesthe adv
13、antages and disadvantages of the different types ofsamplers and addresses recommended procedures for their use.The field settings are primarily, but not limited to, open channel1This guide is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommi
14、ttee D34.01.01 onPlanning for Sampling.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved in 2000. Last previous edition approved in 2005 as D6538 00(2005).DOI: 10.1520/D6538-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Custom
15、er Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.flows in enclosed (e.g., sewer) syste
16、ms or open (e.g., streams oropen ditches, and sampling pressure lines) systems.5. Automatic Versus Manual Sampling (1, 2)35.1 The advantages and disadvantages of manual and auto-matic sampling are summarized in Table 1. The decision as towhether to use manual or automatic sampling involves manyconsi
17、derations 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 special incidents,where sites will not allow the use of automatic devices, formost bac
18、teriological 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, where simultaneoussampling at many sites is necessary, etc.Automatic sampling isoften the
19、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 7.1.23 before selecting manual orautomatic sampling.6. Types of Samples Collected by Automatic Samplers6.
20、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 min and arerepresentative of conditions at the time of sampling (4). Grabsamples are so
21、metimes 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 appropri-ate when samples are needed to:6.1.1 Characterize an effluent that is not co
22、ntinuous,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 compositing (forexample, pH, temperature, dissolved oxygen, chlorine, purge-able organi
23、cs (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 rapidfluctuations of parameters occur (sequential grabs).6.2 Composite SamplesComposite samples are
24、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 stipulated in a permit, when average pollutantconcentration during the compositing period is
25、 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 container at constanttime intervals. The method is appropriate when the flow of thest
26、ream 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 every 15-min, on average,over a 24-h period.6.2.2 Flow-Proportional Composite SamplesThe
27、re 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 flow monitor (forexample, a 200-mL aliquot is collected for every 5000 L offlow). In th
28、e 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 Composite SamplesA sequential com-posite sample is composed of a series of short-period compos
29、-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 compositing the indi-vidual 1-h composite sample.6.2.4 Continuous Composite SamplesThis meth
30、od 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 list of attributes of the idealautomatic sampler for their use and EPA Region 4 (7) a
31、ndothers (3) have noted other important attributes. These at-tributes and requirements may be specific to EPAs use andwere primarily directed at suction lift type automatic samplers.Not all these sampler characteristics will be important to all3The boldface numbers given in parentheses refer to a li
32、st of references at theend of the standard.TABLE 1 Advantages and Disadvantages of Manual versusAutomatic Sampling of Wastewater (3)Type Advantages DisadvantagesManual Low capital cost Increased variability due tosample handlingPersonnel can compensate forvarious situationsInconsistency in collectio
33、nPersonnel can documentunusual conditionsHigh cost of labor assumingcomposite or multiple grabsamples are collectedNo maintenance Repetitious and monotonoustask for personnelExtra samples can be collectedin a short time if necessaryAutomatic Consistent samples Considerable maintenance forbatteries a
34、nd cleaning;susceptible to plugging bysolidsDecreased variability caused bysample handlingRestricted in size to the generalspecificationsMinimal labor requirement forsamplingGreater potential for samplecontaminationCapable of collecting multiplegrab and multiple aliquotcomposite samplesMay be subjec
35、t to damage byvandalsHigh capital costD6538 102users but their consideration may guide persons selectingautomatic samplers. The desirable features of automatic sam-plers listed below have been summarized and combined fromthe referenced documents.7.1.1 Capable of AC/DC operation with adequate dry bat
36、-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 device if the sampler is placed in a sewer.7.1.3 Total weight, including batteries, less than 18 kg.C
37、ompact 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 (0.13-gal) discrete samples in aminimum of 24 containers. The individual sample aliquot mustbe at l
38、east 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 will prevent accumulation of solids.7.1.8 Intake hose liquid velocity adjustable from 0.6 to 3m/s
39、(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.7.1.12 Exterior case capable of being locked, including lugsfor attaching steel cable to prevent
40、 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 in a temperature range from10 to 40C with the exception of the intake hose.7.1.15 A purge cycle
41、 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. Samplers may be programmed to perform anair purge before and after sampling, and a liquid rinse beforeand after a sample is drawn.
42、7.1.16 Capable of collecting flow-proportional 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
43、when parameters to be analyzed couldbe 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 c
44、orrosion (plastics, fiberglass, stainless 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 Computer Communication:7
45、.1.22.1 Create exportable output files of program settings,sampling program, and history of times, volumes, and otherprogram execution information.7.1.22.2 Ability to calibrate the sample pump volume, andcalibrate any attached parameter modules.7.1.23 Other FactorsOther factors (3) that should becon
46、sidered in selecting an automatic sampler are the:7.1.23.1 Expected variation in water or wastewater compo-sition with time,7.1.23.2 Variation of flow rate with time,7.1.23.3 Specific gravity of the liquid7.1.23.4 Concentration and density of suspended solids ofinterest,7.1.23.5 Presence of floating
47、 materials,7.1.23.6 Characteristics of the site where the sampler will beplaced (e.g., spaced needed for the sampler placement),7.1.23.7 Range of intended use (a permanent site or travel-ing sampler),7.1.23.8 Skill level required for installation and operation ofthe sampler, and7.1.23.9 The level of
48、 accuracy desired.8. Types of Automatic Samplers (1,2,3)8.1 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 orrefrigerate
49、d). While all automatic samplers can collect samplesthrough 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 samplers. 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) ar
