ASTM D6855-17(2023)

Overview

ASTM D6855-17(2023) is a standard test method developed by ASTM International for the static determination of turbidity levels below 5 Nephelometric Turbidity Units (NTU) in water samples. Turbidity, an optical property caused by suspended and dissolved matter in water, is a key indicator of water quality. This standard is essential for applications involving drinking water, process water, and high-purity industrial water where low turbidity levels are desired. By specifying reliable methods for measurement and calibration, ASTM D6855-17(2023) ensures rapid and accurate turbidity assessment, enabling effective process control and compliance with regulatory standards.

Key Topics

• Applicability and Scope

  • Suitable for measuring turbidity below 5.0 NTU in static water samples.
  • Applies to municipal drinking water, ultra-pure water, and low turbidity samples.
  • Calibration is based on NTU values, with equivalency for other accepted turbidity units.

• Measurement Principles

  • Turbidity is determined using nephelometric methods, measuring the intensity of light scattered at a 90° angle from the incident light path.
  • The test method outlines requirements for instrumentation, including nephelometers and ratio nephelometers.

• Calibration and Reporting

  • Calibration uses traceable standards, such as formazin.
  • Results must be reported with appropriate units, reflective of the measurement technology (e.g., NTU, FNU, FNRU).
  • Provides guidance for using alternative designs, requiring transparent reporting of wavelength and units for comparability.

• Quality Assurance

  • Recommends rigorous calibration, verification, and quality control procedures.
  • Emphasizes proper sample handling, cell cleanliness, and avoidance of interferences (such as bubbles, color, and large particles) for data reliability.

Applications

• Drinking Water Quality Monitoring

  • Ensures water meets regulatory turbidity limits, contributing to public health and safety.
  • Facilitates compliance with EPA Method 180.1 and ISO 7027, both referenced for regulatory purposes.

• Process Control in Industry

  • Used in water treatment facilities to adjust operations (coagulation, settling, filtration) based on real-time turbidity feedback.
  • Vital for food and beverage manufacturing where product quality depends on low-turbidity water.

• High-Purity and Ultra-Pure Water Systems

  • Supports water-dependent processes in electronics, pharmaceuticals, and laboratories where even low levels of turbidity can impact product outcome.

• Environmental Compliance

  • Provides a rapid assessment tool for regulatory and internal audits of effluent and surface waters, supporting sustainability practices and environmental stewardship.

Related Standards

• ASTM D1129 - Terminology Relating to Water
• ASTM D1193 - Specification for Reagent Water
• ASTM D3370 - Practices for Sampling Water from Flowing Process Streams
• ASTM D5847 - Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
• ASTM D7315 - Test Method for Determination of Turbidity Above 1 Turbidity Unit in Static Mode
• EPA Method 180.1 - Chemical Analysis of Water and Wastes: Turbidity
• ISO 7027 - Water Quality - Determination of Turbidity

Practical Value

Implementing ASTM D6855-17(2023) helps organizations standardize low-level turbidity measurements, improving water quality management and compliance. Its procedures support the use of current and emerging technologies, ensuring traceable, reliable results. Adherence to this standard helps industries maintain quality control, regulatory adherence, and operational efficiency while protecting water resources.

Keywords: ASTM D6855-17(2023), turbidity measurement, low turbidity water, nephelometric method, drinking water quality, process water, water analysis standard, formazin standard, EPA Method 180.1, ISO 7027, water treatment compliance, industrial water quality.