ISO 24416:2022

Overview

ISO 24416:2022 - Water reuse in urban areas - Guidelines for water reuse safety evaluation - Stability evaluation of reclaimed water - provides a structured framework to assess the water quality stability of reclaimed water from municipal wastewater sources. The standard covers both chemical stability (corrosion, scaling, fouling) and biological stability (microbiologically influenced corrosion, biofouling, bacterial regrowth). It is intended for use across project stages including storage, transportation, application and post‑assessment of reclaimed water systems.

Key topics

• Scope and definitions: Standard terms and definitions aligned with ISO 20670 and related ISO standards for water reuse vocabulary.
• Evaluation principles and system: Concepts and systematic approaches to assessing stability for reclaimed water intended for urban uses.
• Evaluation parameters:
  • Single parameters: routine physical and chemical indicators (e.g., TDS, pH, COD, DO) and biological metrics (e.g., AOC, ATP, BGP).
  • Composite indices: established indices for chemical stability such as Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Calcium Carbonate Precipitation Potential (CCPP), Aggressive Index (AI), Larson Corrosion Index (LR) and Riddick Corrosion Index (RI).
• Selection principles: Guidance on choosing appropriate stability parameters depending on reclaimed water use, infrastructure material and operating conditions.
• Application‑specific parameters: Parameters tailored for pipeline networks and equipment (boilers, heat exchangers, irrigation systems, HVAC, toilet flushing devices).
• Methods and measurement: Evaluation methods and comparison of measurement techniques for biological and chemical stability (informative annexes).
• Informative annexes: Practical resources including corrosion types, country guidelines, boiler water conditioning, industrial reuse standards, and biological stability guideline values.

Note: ISO 24416 provides parameter ranges and methods but does not set critical numerical threshold values; control and management actions (e.g., residual disinfectant strategies) are out of scope.

Applications

ISO 24416 is directly applicable to:

• Design and assessment of urban water reclamation and distribution systems
• Performance evaluation during storage, transport and reuse (e.g., irrigation, recreational water features, toilet flushing, industrial processes)
• Risk assessment for corrosion, scaling, fouling and biofouling in infrastructure and equipment
• Post‑treatment monitoring and asset management to extend equipment life and reduce maintenance/energy costs

Who should use this standard

• Water utilities and operators managing reclaimed water systems
• Environmental and process engineers designing reuse schemes
• Asset managers and facility operators (boilers, heat exchangers, HVAC)
• Consultants, regulators and researchers working on water quality stability and water reuse safety

Related standards

• ISO 20670 (Water reuse - Vocabulary)
• ISO 20761 (Referenced for routine safety parameters)
• ISO 23070 / ISO 8044 (sources for some biological and corrosion terms)

Keywords: ISO 24416:2022, water reuse, reclaimed water stability, chemical stability, biological stability, LSI, RSI, AOC, corrosion, scaling, fouling.