1.1 本试验方法涵盖了水中浊度的静态测定。静态是指从其来源处移除并在隔离仪器中测试的样品。（参见第节 4. .) 1.2 本试验方法适用于测量浊度大于1.0浊度单位（TU）的浊度。测量范围的上限未定义，因为本测试方法中描述的不同技术可以覆盖非常不同的范围。循环研究涵盖了0-4000个浊度单位的范围，因为该范围内的仪器验证通常可以由可一致复制的标准涵盖。 1.3 当在下列设计中应用通用校准标准时，本试验方法中涵盖的许多浊度单元和仪器设计在校准中在数值上是等效的 表1 . 测量定义值的通用校准标准也将在这些技术中产生同等结果。 表1已知仪器设计、应用、范围和报告单位总结 设计和 报告单位 突出的应用 主要设计特点 典型的 仪表量程 建议 应用范围 浊度非比（NTU） 白光浊度计。符合美国EPA方法180.1，用于低水平浊度监测。 探测器相对于入射光束居中90°。使用白光光谱源。 0.0–40 0.0–40监管 比率白光浊度计（NTRU） 符合ISWTR法规和标准方法2130B。可用于低电平和高电平测量。 使用白光光谱源。主探测器以90°为中心。位于其他角度的其他探测器。仪器算法使用检测器读数的组合来生成浊度读数。 0–10 000 0-40监管 0–10 000其他 浊度法、近红外浊度计、非比例法（FNU） 符合ISO 7027。 波长不太容易受到颜色干扰。适用于有颜色的样品，适用于低水平监测。 探测器相对于入射光束居中90°。使用近红外（780–900 nm）单色光源。 0–1000 0-40监管（非美国） 0-1000其他 比浊近红外浊度计（FNRU） 符合ISO 7027。适用于高色度样品和高浊度监测。 使用近红外单色光源（780–900 nm）。主探测器以90°为中心。位于其他角度的其他探测器。仪器算法使用检测器读数的组合来生成浊度读数。 0–10 000 0-40监管 0–10 000其他 表面散射浊度计（NTU） 浊度是通过样品表面或其附近的光散射来确定的。 探测器相对于入射光束居中90°。使用白光光谱源。 10–10 000 10–10 000 Formazin后向散射（FBU） 不适用于监管目的。最适用于高浊度样品。反向散射是常见的，但不仅仅是探针技术，最好应用于高浊度样品。 使用780–900 nm范围内的近红外单色光源。探测器几何形状相对于入射光束在90°和180°之间。 100–10 000+ 100–10 000 反向散射单元（BU） 不适用于监管目的。最适用于高浊度的样品。 使用白光光谱源（400–680 nm范围）。探测器几何形状相对于入射光束在90°和180°之间。 10–10 000+ 100–10 000+ 甲嗪衰减单元（FAU） 可能适用于某些监管目的。这通常适用于分光光度计。最适用于高浊度的样品。 探测器的几何中心相对于入射光束（衰减）为0°。波长为780–900 nm。 20–1000 20–1000监管 光衰减单元（AU） 不适用于某些监管目的。这通常适用于分光光度计。 探测器的几何中心相对于入射光束（衰减）为0°。波长为400–680 nm。 20–1000 20–1000 浊度多波束单元（NTMU） 适用于EPA监管方法GLI方法2。适用于饮用水和废水监测应用。 探测器的几何中心为0°和90°。仪器算法使用检测器读数的组合，其可能因浊度大小不同而不同。 0.02–4000 0-40监管 0-4000其他 1.3.1 在本试验方法中，校准标准通常以NTU值定义，但其他指定的浊度单位，如 表1 是等效的。例如，1 NTU formazin标准也是1 FNU、1 FAU、1 BU等等。 1.4 本试验方法并不旨在涵盖所有可用于高性能测试的技术- 液位浊度测量。 1.5 该测试方法在不同的天然水和废水中进行了测试，并使用了作为样品替代品的标准。用户有责任确保本试验方法对未经试验基质的水的有效性。 1.6 根据高水平样品中的成分，拟议的样品制备和测量方法可能适用，也可能不适用。颗粒密度最高的样品通常最难测量。在这些情况下，可以考虑替代测量方法，如过程监测方法。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。有关本程序中使用的所有化学品，请参阅MSDS。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 通常监测本试验方法范围内规定水平的浊度，以帮助控制过程，监测水环境的健康和生物，并确定变化对环境事件（天气事件、洪水等）的影响。在饮用水、工厂废水、食品和饮料加工用水以及大量其他依赖水的制造过程中，浊度通常是不可取的。去除通常通过混凝、沉淀和各级过滤来完成。浊度测量提供了污染指标，是监测样品来源或过程中的特性和/或质量的重要测量。 5.2 本试验方法与试验方法不重叠 D6855 对于1–5 TU的范围。如果主要测量值低于1.0 TU，偶尔出现高于该值的峰值，则采用试验方法 D6855 可能更适用。对于始终高于1 TU的测量，本试验方法适用。 5.3 本试验方法适用于浊度，例如测量值高于1 NTU的所有水中的浊度。示例包括环境水（溪流、河流、湖泊、水库、河口）、与水污染控制厂（废水处理厂）相关的过程，以及涉及明显浊度水的各种工业过程。有关清洁水的测量，请参阅测试方法 D6855 . 5.4 应使用的特定技术或仪器类型的适当测量范围等于或低于80 % 各仪器或技术的全面能力。高于该水平的测量可能不可靠。 5.4.1 不建议对水进行稀释，尤其是对于具有快速沉降颗粒（即沉积物）的样品。建议选择涵盖预期范围的适当仪器设计，以避免进行稀释。 5.5 本标准中描述的技术可能无法测量样品的所有方面（吸收和散射）。水、悬浮物或两者的某些特性可能会干扰样品的某些测量特性，例如特定仪器测量的光散射。 5.6 有几种不同的技术可用于测量高浊度。根据应用和测量标准，某些技术可能更适合特定类型的样品。请参阅 表1 和 附录X1 这是一个流程图，有助于为特定应用选择最佳技术。 5.6.1 当测量高浊度时，样品通常会包含显著的干扰，例如来自吸收颗粒、基质中的吸光度和快速沉降颗粒的干扰。这些可能对一种测量技术如何响应浊度变化产生重大影响。通常情况下，谨慎的做法是运行一系列线性稀释，以确定相对于稀释而言，测量的响应是否是预期的。在稀释比响应为线性的情况下，该技术可以充分考虑干扰。如果没有预期的响应，则应考虑使用另一种技术来确定是否可以获得更精确的测量。 5.7 报告测量结果时，还应附上适当的单位。这些单位反映了用于生成测量值的技术。其目的是为用于生成测量结果的技术提供可追溯性，并在必要时与历史数据进行更充分的比较。 部分 7. 描述了每种类型的可跟踪报告单元所基于的技术。 5.7.1 表1 包含可追溯到该技术的技术和相应报告单元的列表。 5.7.1.1 中的方法 表1 根据所用入射光源的类型，可以分为两组不同的设计。这些是宽带白光源或提供400–680 nm范围内光谱输出的光源。这些包括多色光源，如符合监管方法美国EPA方法180.1所需的多色光源，但如果各自的波长在规定范围内，也可以包括单色光源。第二组仪器使用780至900 nm范围内的近红外单色光源。这些设计在报告单元中是可区分的，并且始终以字母F开头。 5.7.1.2 对于不在这些报告范围内的特定设计，应以浊度单位（TU）报告浊度，并使用预定的波长值来表征所使用的光源。 看见 7.4.3 . 5.7.1.3 中列出的那些设计 表1 涵盖ASTM小组委员会目前确定的内容。本文件中未涵盖的未来设计可在方法小组委员会审查后纳入未来版本。 5.7.1.4 参见第节 7. 有关仪器设计的更多详细信息。 5.7.1.5 部分 16 包含合并不同技术分类的精度和偏差数据。精度和偏差部分包括所有实验室的整体数据集和该数据集的较小部分，以提供本试验方法中所示技术所展示的不同技术特征之间的比较。 5.8 本试验方法涵盖从水中采集的样品的测量，并使用典型的实验室或便携式仪器进行分析。

1.1 This test method covers the static determination of turbidity in water. Static refers to a sample that is removed from its source and tested in an isolated instrument. (See Section 4 .) 1.2 This test method is applicable to the measurement of turbidities greater than 1.0 turbidity unit (TU). The upper end of the measurement range was left undefined because different technologies described in this test method can cover very different ranges. The round robin study covered the range of 0–4000 turbidity units because instrument verification in this range can typically be covered by standards that can be consistently reproduced. 1.3 Many of the turbidity units and instrument designs covered in this test method are numerically equivalent in calibration when a common calibration standard is applied across those designs listed in Table 1 . Measurement of a common calibration standard of a defined value will also produce equivalent results across these technologies. TABLE 1 Summary of Known Instrument Designs, Applications, Ranges, and Reporting Units Design and Reporting Unit Prominent Application Key Design Features Typical Instrument Range Suggested Application Ranges Nephelometric non-ratio (NTU) White light turbidimeters. Comply with U.S. EPA Method 180.1 for low level turbidity monitoring. Detector centered at 90° relative to the incident light beam. Uses a white light spectral source. 0.0–40 0.0–40 Regulatory Ratio White Light turbidimeters (NTRU) Complies with ISWTR regulations and Standard Method 2130B. Can be used for both low and high level measurement. Used a white light spectral source. Primary detector centered at 90°. Other detectors located at other angles. An instrument algorithm uses a combination of detector readings to generate the turbidity reading. 0–10 000 0–40 Regulatory 0–10 000 other Nephelometric, near-IR turbidimeters, non-ratiometric (FNU) Complies with ISO 7027. The wavelength is less susceptible to color interferences. Applicable for samples with color and good for low level monitoring. Detector centered at 90° relative to the incident light beam. Uses a near-IR (780–900 nm) monochromatic light source. 0–1000 0–40 Regulatory (non-US) 0–1000 other Nephelometric near-IR turbidimeters, ratio metric (FNRU) Complies with ISO 7027. Applicable for samples with high levels of color and for monitoring to high turbidity levels. Uses a near-IR monochromatic light source (780–900 nm). Primary detector centered at 90°. Other detectors located at other angles. An instrument algorithm uses a combination of detector readings to generate the turbidity reading. 0–10 000 0–40 Regulatory 0–10 000 other Surface Scatter Turbidimeters (NTU) Turbidity is determined through light scatter from or near the surface of a sample. Detector centered at 90° relative to the incident light beam. Uses a white light spectral source. 10–10 000 10–10 000 Formazin Back Scatter (FBU) Not applicable for regulatory purposes. Best applied to high turbidity samples. Backscatter is common with but not all only probe technology and is best applied in higher turbidity samples. Uses a near-IR monochromatic light source in the 780–900 nm range. Detector geometry is between 90° and 180° relative to the incident light beam. 100–10 000+ 100–10 000 Backscatter Unit (BU) Not applicable for regulatory purposes. Best applied for samples with high level turbidity. Uses a white light spectral source (400–680 nm range). Detector geometry is between 90° and 180° relative to the incident light beam. 10–10 000+ 100–10 000+ Formazin attenuation unit (FAU) May be applicable for some regulatory purposes. This is commonly applied with spectrophotometers. Best applied for samples with high level turbidity. Detector is geometrically centered at 0° relative to incident beam (attenuation). Wavelength is 780–900 nm. 20–1000 20–1000 Regulatory Light attenuation unit (AU) Not applicable for some regulatory purposes. This is commonly applied with spectrophotometers. Detector is geometrically centered at 0° relative to incident beam (attenuation). Wavelength is 400–680 nm. 20–1000 20–1000 Nephelometric Turbidity Multibeam Unit (NTMU) Is applicable to EPA regulatory method GLI Method 2. Applicable to drinking water and wastewater monitoring applications. Detectors are geometrically centered at 0° and 90°. An instrument algorithm uses a combination of detector readings, which may differ for turbidities varying magnitude. 0.02–4000 0–40 Regulatory 0–4000 other 1.3.1 In this test method calibration standards are often defined in NTU values, but the other assigned turbidity units, such as those 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. 1.4 This test method does not purport to cover all available technologies for high-level turbidity measurement. 1.5 This test method was tested on different natural waters and wastewater, and with standards that will serve as surrogates to samples. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices. 1.6 Depending on the constituents within a high-level sample, the proposed sample preparation and measurement methods may or may not be applicable. Those samples with the highest particle densities typically prove to be the most difficult to measure. In these cases, and alternative measurement method such as the process monitoring method can be considered. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Refer to the MSDSs for all chemicals used in this procedure. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Turbidity at the levels defined in the scope of this test method are often monitored to help control processes, monitor the health and biology of water environments and determine the impact of changes in response to environmental events (weather events, floods, etc.). Turbidity is often undesirable in drinking water, plant effluent waters, water for food and beverage processing, and for a large number of other water-dependent manufacturing processes. Removal is often accomplished by coagulation, sedimentation, and various levels of filtration. Measurement of turbidity provides an indicator of contamination, and is a vital measurement for monitoring the characteristics and or quality within the sample’s source or process. 5.2 This test method does overlap Test Method D6855 for the range of 1–5 TU. If the predominant measurement falls below 1.0 TU with occasional spikes above this value, Test Method D6855 may be more applicable. For measurements that are consistently above 1 TU, this test method is applicable. 5.3 This test method is suitable to turbidity such as that found in all waters that measure above 1 NTU. Examples include environmental waters (streams, rivers, lakes, reservoirs, estuaries), processes associated with water pollution control plants (wastewater treatment plants), and various industrial processes involving water with noticeable turbidity. For measurement of cleaner waters, refer to Test Method D6855 . 5.4 The appropriate measurement range for a specific technology or instrument type that should be utilized is at or below 80 % of full-scale capability for the respective instrument or technology. Measurements above this level may not be dependable. 5.4.1 Dilutions of waters are not recommended, especially in the case of samples with rapidly settling particles (that is, sediments). It is recommended that an appropriate instrument design that covers the expected range be selected to avoid the need to perform dilutions. 5.5 Technologies described in this standard may not measure all aspects (absorption and scatter) of a sample. Some of the properties of the water, the suspended material, or both may interfere with the certain measured property of the sample, such as the scattering of light that the particular instrument is measuring. 5.6 Several different technologies are available for use in the measurement of high-level turbidity. Some technologies may be better suited for specific types of samples, depending on the application and measurement criteria. Please refer to Table 1 and Appendix X1 which is a flow chart to help assist in selecting the best technology for the specific application. 5.6.1 When measuring high levels of turbidity the samples will often contain significant interferences such as that from absorbing particles, absorbance in the matrix, and rapidly settling particles. These may have a significant impact on how one measurement technology responds to changes in turbidity. Often times it will be prudent to run a series of linear dilutions to determine if the measured response was expected relative to the dilution. In cases where the response to dilution ratio is linear, the technology may be adequately accounting for the interferences. If the response is not expected, another technology should be considered to determine if a more accurate measurement could be obtained. 5.7 When reporting the measured result, appropriate units should also be attached. The units are reflective of the technology used to generate the measurements. The intention is to provide traceability for the technology used to generate the measured result, and if necessary, provide more adequate comparison to historical data. Section 7 describes technology that each type of traceable reporting units is based. 5.7.1 Table 1 contains the list of technologies and respective reporting units that will be traceable to that technology. 5.7.1.1 The methods in Table 1 can be broken down into two distinct groups of designs which are based on the type of incident light source used. These are broad-band white light source or light sources that provide a spectral output in the 400–680 nm range. These include polychromatic light sources, such as those that are necessary to comply with regulatory method U.S. EPA Method 180.1, but also can include mono-chromatic light sources if the respective wavelength falls within the specified range. The second group of instruments uses a near IR monochromatic light source that is in the range of 780 to 900 nm. These designs are distinguishable in the reporting units and will always begin with the letter F. 5.7.1.2 For a specific design that falls outside of these reporting ranges, the turbidity should be reported in turbidity units (TU) with a subscripted wavelength value to characterize the light source that was used. See 7.4.3 . 5.7.1.3 Those designs listed in Table 1 cover those that were currently identified by the ASTM subcommittee. Future designs that are not covered in this document may be incorporated into a future revision after review by the method subcommittee. 5.7.1.4 See Section 7 for more details regarding instrument designs. 5.7.1.5 Section 16 contains precision and bias data that incorporates the different classifications of technologies. The precision and bias section includes the overall data set of all laboratories and smaller segments of this data set to provide comparisons across distinguishing technological features that are exhibited by those technologies that are represented in this test method. 5.8 This test method covers the measurement of samples collected from waters and analyzed using typical laboratory based or portable-based instruments.