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D1889-00 – Standard Test Method Technical Guide
📐 Scope and Significance of the Method
The ASTM D1889-00 standard defines the test method for determining the turbidity of water and wastewater. It is specifically applicable to the measurement of turbidity in the range of 1.0 to 40 Nephelometric Turbidity Units (NTU). For samples with higher turbidity, the standard permits measurement through serial dilution to bring them within the applicable range.
Turbidity is an expression of the optical properties of a sample that cause light to be scattered and absorbed rather than transmitted in straight lines. This is caused by suspended and dissolved matter such as clay, silt, finely divided organic matter, plankton, and organic acids. The presence of turbidity is undesirable in drinking water, plant effluent waters, and water used for food and beverage preparation.
⚡ Safety Note: It is the responsibility of the user to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. All relevant Material Safety Data Sheets (MSDS) must be reviewed before preparing or using standards and before calibrating or performing instrument maintenance per Section 1.5.
⚙️ Instrumentation and Test Procedure
The test method relies on nephelometric techniques, which involve comparing the intensity of light scattered by the water sample to the intensity of light scattered by a reference standard under defined conditions. The higher the intensity of scattered light, the higher the turbidity of the sample.
Two primary types of instruments are detailed in this standard:
- Photoelectric Nephelometer: Operates based on an instrumental comparison of light scattered by the static sample versus a reference standard.
- Calibrated Slit Turbidimeter: Uses a visual comparison of the intensity of light scattered by the static sample versus a reference sample in the same container.
Instrument calibration relies on specific standards detailed in Section 12 and 8.2.2-8.2.4. The standard specifies the use of Styrene-divinylbenzene (SDVB) polymer standards, used as received, and Formazin polymer preparations and dilution methods.
💡 Key Procedure Tip: The Formazin polymer preparation and dilution methods, detailed in Sections 8.2.2 through 8.2.4 of the standard, provide the primary turbidity reference. Always prepare these standards immediately before calibration for the most accurate results.
| 🟦 Parameter | 📏 Specification / Value | 📐 Details |
|---|---|---|
| Test Method | Nephelometric (Light Scatter) | Comparison of scattered light by sample vs. a standard. |
| Measurement Range | 1.0 – 40 NTU | Higher turbidity levels allowed via serial dilution. |
| Primary Standard | Formazin Polymer | Prep and dilution methods provided in 8.2.2-8.2.4. |
| Secondary Standard | SDVB Polymer | Styrene-divinylbenzene, used as received from the manufacturer. |
📊 Terminology and Referenced Standards
The standard specifically defines key optical and operational terms to ensure uniform application. The definitions for “turbidity” and “nephelometric turbidity” are formally established in ASTM Terminology D 1129. Furthermore, the standard incorporates several critical ASTM practices and EPA methods to ensure comprehensive and standardized testing procedures.
| 🟦 Standard / Practice | 🎯 Title / Purpose | ⚡ Application in D1889 |
|---|---|---|
| D 1129 | Terminology Relating to Water | Defines core terminology (turbidity, etc.). |
| D 1193 | Specification for Reagent Water | Defines quality of water for preparing reagents and standards. |
| D 2777 | Practice for Precision and Bias | Provides statistical framework for method validation. |
| EPA 180.1 | Determination of Turbidity by Nephelometry | EPA regulatory counterpart for cross-reference. |
❓ Frequently Asked Questions
🔍 What is the specific turbidity range covered by this standard?
The test method is directly applicable to measuring turbidities in the range from 1.0 to 40 Nephelometric Turbidity Units (NTU). Higher turbidities can be measured by applying serial dilution to bring the sample within the applicable range.
💡 What types of waters were tested for this method?
The test method was specifically tested on municipal drinking water and final effluent discharges. It is the user’s responsibility to ensure the validity of this test method for waters of untested matrices.
⚡ What are the two main types of nephelometric instruments described?
The standard describes two primary instrument types: the Photoelectric Nephelometer, which uses an instrumental comparison; and the Calibrated Slit Turbidimeter, which relies on a visual comparison of light scattered by the sample against a reference standard.
📌 What reference standards are used for calibration in D1889?
Calibration relies on Styrene-divinylbenzene (SDVB) polymer standards (used as received from manufacturer or distributor) and Formazin polymer preparations and dilution methods, which must be prepared according to the specific guidelines in Section 8 of the standard.