1、Designation: D7725 12D7725 17Standard Test Method for theContinuous Measurement of Turbidity Above 1 TurbidityUnit (TU)1This standard is issued under the fixed designation D7725; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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 onlineon-line and inlinein-line determination of high-level turbidity in water tha
3、t is greater than1.0 turbidity units (TU) in municipal, industrial and environmental usage.1.2 In principle, there are three basic applications for on-line measurement set ups. This first is the slipstream (bypass) sampletechnique. For the slipstream sample technique a portion of sample is transport
4、ed out of the process and through the measurementapparatus. It is then either transported back to the process or to waste. The second is the in-line measurement where the sensoris brought directly into the process (see Fig. 8). The third basic method is for in-situ monitoring of sample waters. This
5、principleis based on the insertion of a sensor into the sample itself as the sample is being processed. The in-situ use in this test method isintended for the monitoring of water during any step within a processing train, including immediately before or after the processitself.1.3 This test method i
6、s applicable to the measurement of turbidities greater than 1.0 turbidity unit (TU). TU. The absolute rangeis dictated by the technology that is employed.1.4 The upper end of the measurement range is left undefined because different technologies described in this test method cancover very different
7、ranges of turbidity.1.5 Many of the turbidity units and instrument designs covered in this test method are numerically equivalent in calibrationwhen a common calibration standard is applied across those designs listed in Table 1. Measurement of a common calibrationstandard of a defined value will al
8、so produce equivalent results across these technologies. This test method prescribes theassignment of a determined turbidity values to the technology used to determine those values. Numerical equivalence to turbiditystandards is observed between different technologies but is not expected across a co
9、mmon sample. Improved traceability beyondthe scope of this test method may be practiced and would include the listing of the make and model number of the instrument usedto determine the turbidity values.1.5.1 In this test method, calibration standards are often defined in NTU values, but the other a
10、ssigned turbidity units, such asthose in Table 1 are equivalent. For example, a 1 NTU formazin standard is also a 1 FNU, a 1 FAU, a 1 BU, and so forth.1.6 This standard test method does not purport to cover all available technologies for high-level turbidity measurement.1.7 This test method was test
11、ed on different waters, and with standards that will serve as surrogates to samples. It is theusersusers responsibility to ensure the validity of this test method for waters of untested matrices.1.8 Those samples with the highest particle densities typically prove to be the most difficult to measure
12、. In these cases, theprocess monitoring method can be considered with adequate measurement protocols installed.1.9 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.10 This standard does not purport to address all of the safet
13、y concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. Refer to the MSDSs for all chemicals used in this
14、 procedure.1.11 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Ba
15、rriers to Trade (TBT) Committee.1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveill
16、ance of Water.Current edition approved Jan. 1, 2012Dec. 15, 2017. Published June 2012February 2018. Originally approved in 2012. Last previous edition approved in 2012 as D7725 12. DOI: 10.1520/D7725-12.10.1520/D7725-17.This document is not an ASTM standard and is intended only to provide the user o
17、f an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as pu
18、blished by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1TABLE 1 Technologies for Measuring Turbidity Greater Than 1 TU that can be used for In-Line or On-Line ApplicationsDesign and Re
19、portingUnit Prominent Application Key Design Features Typical Instrument Range Suggested ApplicationNephelometric non- ratio(NTU)White light turbidimetersComply with EPA 180.1 for lowlevel turbidity monitoring.Detector centered at 90 degreesrelative to the incident lightbeam. Uses a white light spec
20、tralsource.0.012 to 40 NTU Regulatory reporting ofcleanwaterRatio White Light turbidimeters(NTRU)Complies with ISWTRregulations and Standard Method2130B. Can be used for bothlow and high level measurement.Used a white light spectralsource. Primary detectorcentered at 90. Other detectorslocated at ot
21、her angles. Aninstrument algorithm uses acombination of detector readingsto generate the turbidity reading.0.012 - 10,000 NTRU Regulatory Reporting ofcleanwaterFormazin Nephelometric,near-IR turbidimeters, non-ratiometric (FNU)Complies with ISO 7027. Thewavelengthis less susceptible tocolor interfer
22、ences. Applicablefor samples with color and goodfor low level monitoring.Detector centered at 90 degreesrelative to the incident lightbeam. Uses a near-IR (780-900nm) monochromatic light source.0.012 - 1,000 FNU 0 - 40 FNU ISO 7027Regulatory reportingFormazin Nephelometricnear-IRturbidimeters, ratio
23、metric(FNRU)Complies with ISO 7027.Applicable for samples with highlevels of color and for monitoringto high turbidity levels.Uses a near-IR monochromaticlight source (780-900 nm).Primary detector centered at 90.Other detectors located at otherangles. An instrument algorithmuses a combination of det
24、ectorreadings to generate the turbidityreading.0.012 - 1,000 FNU 0- 40 FNRU ISO 7027Regulatory reportingSurface Scatter Turbidimeters(SSU)Turbidity is determined throughlight scatter from a definedvolume beneath the surface of asample. Applicable for reportingfor USEPA compliancemonitoring.Detector
25、centered at 90 degreesrelative to the incident lightbeam. Uses a “white light”spectral source.0.012-10,000 FNRU 10 - 10,000 SSUFormazin NephelometricTurbidity Multibeam Unit(FNMU)Is applicable to EPA regulatorymethod GLI Method 2.Applicable to drinking water andwastewater monitoringapplications.Dete
26、ctors are geometricallycentered at 0 and 90. Aninstrument algorithm uses acombination of detector readings,which may differ for turbiditiesvarying magnitude.0.012 to 4000 NTMU 0 to 40 NTMU Reporting forEPA and ISO complianeFormazin Attenuation Unit(FAU)Compliance Reporting for ISO7027 for samples th
27、at exceed 40unitsUses a near-IR light source at86030 nm and the detector is 0degrees relative to the centerlineof the incident light beam. Themeasurement is an attenuationmeasurement.10 - 10,000+ FAU 100 - 10,000+ FAUReporting for ISO7027 for levels in excess of40unitsAttenuation Unit (AU) Not appli
28、cable for regulatorypurposes. Best applied forsamples with high levelturbidity.Uses a white light spectralsource (400-680 nm range).Detector geometry is 0 relativeto the incident light beam.10 - 10,000+ AU 100 - 10,000+ AUFormazin Back Scatter(FBU)Not applicable for regulatorypurposes. Best applied
29、to highturbidity samples. Backscatter iscommon probe technology and isbest applied in higher turbiditysamples.Uses a near-IR monochromaticlight source in the 780-900 nmrange. Detector geometry isbetween 90 and 180 relative tothe incident light beam.10,000+ FBU 10,000 FBUForward Scatter RatioUnit(FSR
30、U)The technology encompasses asingle, light source and twodetectors. Light sources can varyfrom single wavelength topolychromatic sources. Thedetection angle for the forwardscatter detector is between 0 and90- degrees relative to thecenterline of the incident lightbeam.The technology is sensitive to
31、turbidities as low as 1 TU. Theratio technology helps tocompensate for color interferenceand fouling.The measurement of ambientwaters such as streams,lakes,and rivers. The range istypicallyfrom about 1 800 FSRU,depending on themanufacturer.Forward Scatter Ratio Unit(FSRU)TABLE 1 Technologies for Mea
32、suring Turbidity Greater Than 1 TU That Can be Used for In-Line or On-Line ApplicationsDesign and ReportingUnit Prominent Application Key Design Features Typical Instrument Range Suggested ApplicationNephelometric Non-Tatio(NTU)White light turbidimeterscomply with EPA 180.1 for low-levelturbidity mo
33、nitoring.Detector centered at 90 degreesrelative to the incident lightbeam. Uses a white light spectralsource.0.012 to 40 NTU Regulatory reporting ofcleanwaterD7725 1722. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to Water2 For referencedASTM standards, visit theASTM website,
34、 www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.Design and ReportingUnit Prominent Application Key Design Features Typical Instrument Range Suggested ApplicationRa
35、tio White LightTurbidimeters(NTRU)Complies with InterimEnhanced Surface Water TreatmentRule (ISWTR) regulations andStandard Method2130B. Can be used for bothlow- and high-level measurement.Used a white light spectralsource. Primary detectorcentered at 90. Other detectorslocated at other angles. Anin
36、strument algorithm uses acombination of detector readingsto generate the turbidity reading.0.01210 000 NTRU Regulatory reporting ofcleanwaterFormazin Nephelometric,Near-IRTurbidimeters, Non-Ratiometric(FNU)Complies with ISO 7027. Thewavelengthis less susceptible tocolor interferences. Applicablefor
37、samples with color and goodfor low-level monitoring.Detector centered at 90 degreesrelative to the incident lightbeam. Uses a near-IR (780900nm) monochromatic light source.0.0121 000 FNU 040 FNU ISO 7027regulatory reportingFormazin NephelometricNear-IRTurbidimeters, RatioMetric (FNRU)Complies with I
38、SO 7027.Applicable for samples with highlevels of color and for monitoringto high turbidity levels.Uses a near-IR monochromaticlight source (780900 nm).Primary detector centered at 90.Other detectors located at otherangles. An instrument algorithmuses a combination of detectorreadings to generate th
39、e turbidityreading.0.0121 000 FNU 040 FNRU ISO 7027regulatory reportingSurface ScatterTurbidimeters(SSU)Turbidity is determined throughlight scatter from a definedvolume beneath the surface of asample. Applicable for reportingfor EPA compliancemonitoring.Detector centered at 90 degreesrelative to th
40、e incident lightbeam. Uses a “white light”spectral source.0.01210 000 FNRU 1010 000 SSUFormazin NephelometricTurbidity Multibeam unit(FNMU)Is applicable to EPA regulatorymethod GLI Method 2.Applicable to drinking water andwastewater monitoringapplications.Detectors are geometricallycentered at 0 and
41、 90. Aninstrument algorithm uses acombination of detector readings,which may differ for turbiditiesvarying magnitude.0.012 to 4000 NTMU 0 to 40 NTMU Reporting forEPA and ISO complianeFormazin Attenuation Unit(FAU)Compliance Reporting for ISO7027 for samples that exceed 40units.Uses a near-IR light s
42、ource at860 30 nm and the detector is 0degrees relative to the centerlineof the incident light beam. Themeasurement is an attenuationmeasurement.1010 000+ FAU 10010 000+ FAUReporting for ISO7027 for levels in excess of40unitsAttenuation Unit (AU) Not applicable for regulatorypurposes. Best applied f
43、orsamples with high-levelturbidity.Uses a white light spectralsource (400680 nm range).Detector geometry is 0 relativeto the incident light beam.1010 000+ AU 10010 000+ AUFormazin Back Scatter(FBU)Not applicable for regulatorypurposes. Best applied to highturbidity samples. Backscatter iscommon prob
44、e technology and isbest applied in higher turbiditysamples.Uses a near-IR monochromaticlight source in the 780900 nmrange. Detector geometry isbetween 90 and 180 relative tothe incident light beam.10 000+ FBU 10 000 FBUForward Scatter RatioUnit(FSRU)The technology encompasses asingle, light source a
45、nd twodetectors. Light sources can varyfrom single wavelength topolychromatic sources. Thedetection angle for the forwardscatter detector is between 0 and90degrees relative to thecenterline of the incident lightbeam.The technology is sensitive toturbidities as low as 1 TU. Theratio technology helps
46、tocompensate for color interferenceand fouling.The measurement of ambientwaters such as streams,lakes,and rivers. The range istypicallyfrom about 1800 FSRU,depending on themanufacturer.Forward Scatter Ratio Unit(FSRU)D7725 173D2777 Practice for Determination of Precision and Bias of Applicable Test
47、Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3864 Guide for On-Line Monitoring Systems for Water AnalysisD6698 Test Method for On-Line Measurement of Turbidity Below 5 NTU in WaterD7315 Test Method for Determination of Turbidity Above 1 Turbidity Unit (TU)
48、 in Static Mode2.2 Other Publications:EPA 180.1 Methods for Chemical Analysis of Water and Wastes, Turbidity3GLI Method 2 Great Lakes Instruments (GLI) Turbidity4ISO 7027 Water Quality Determination of Turbidity5Standard Method 2130B Standard Methods for the Examination of Water and Wastewater63. Te
49、rminology3.1 DefinitionsDefinitions: For definitions of terms used in this method refer to Terminology D1129.3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 attenuation-detection angle, nthe angle that is formed between the incident light source and the primary detector, andthat is at exactly 0-degrees.3.2.1.1 DiscussionThis is typically a transmission measurement.backscatter-detection angle, nthe angle that is formed between the incident lightsour
